Dissertations / Theses on the topic 'Resource recovery'

Vancouver’s expanding population is putting pressure on the city’s water and wastewater infrastructure; more efficient uses of this resource need to be explored as the cost of upgrading the city’s water and sewer network is daunting. Wastewater presents a significant source of water and heat and, if properly exploited, can reduce pressure on existing infrastructure while reducing stress on the receiving environment. This thesis presents a model with three scenarios that seek to quantify and optimize the amount of water that can be cascaded within the Vancouver Sewerage Area, as well as evaluates each reuse scheme for the economic, environmental, and social benefits associated with each. The first scenario shows a number of potential sources and sinks for direct cascading of wastewater between industries, however water quality represents a significant barrier to this form of water reuse. With the implementation of a satellite water reclamation facility (WRF) in scenario 2, water quality is no longer a barrier and water recycling potential is significantly increased. However, proximity becomes a problem as many of the industries are too far away from the WRF and the cost of pumping and infrastructure far outweighs the benefits of water reuse. When the model is modified in scenario 3 to include the rest of the industrial, commercial, and institutional (ICI) sector and multifamily housing, the potential for water reuse is much greater than the first two scenarios due to the proximity of reclaimed water sinks. The scenario with the greatest water reuse potential, a satellite WRF supplying ICI and multifamily water users, was calculated to recycle upwards of 1,000,000m³/year. Implementation of this scenario would require up to 50 years to allow for public acceptance, policy implementation, and buy in from government and industry. The required infrastructure is extensive but with proper planning over an appropriate time period, the added benefit of energy recovery from wastewater, and participation from industry and government, water reuse can be a viable option for Vancouver.

Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1990.
Includes bibliographical references (leaves 46-47).
A potential threat to the earth's ecosystem and the people and animals living here is improper disposal of trash. The average American throws away 3.5 pounds of trash daily. While we have focused our concerns on the arms race and other looming and important issues, the day to day levels of trash coming from our homes and industries continues to grow. In many areas of the country landfills are closing and communities are struggling for solutions. : The information uncovered while researching this topic reveals that this situation can be addressed and handled responsibly. In order to achieve such success people must be willing to change their habits, work together, and take the time to retrieve and recover valuable resources from the "waste" stream. By doing so a significant amount of money, energy, and resources will be conserved. This thesis is an exploration into the ways a suburban community might proceed to do this in a useful and a meaningful way. A site in Belmont, Massachusetts was chosen to illustrate this proposal.
by David Gayley Milliken.
M.Arch.

Municipalities are increasingly facing solid waste disposal problems due to lack of sanitary landfill sites, high costs of landfill management and increasingly stringent environmental standards. Consequently, they are turning toward innovative disposal practices to alleviate these problems. However, very little comprehensive information is available to decision makers on the range of options available in resource recovery development and the factors that can influence choices. This thesis tests the hypothesis that there are a definable set of factors or circumstances that have led resource recovery developers to make specific decisions regarding ownership, operation, financing, system technology, and air pollution control technology. The thesis is divided into three stages: development of case studies on 9 resource recovery facilities in the state of Virginia; development and analysis of a nationwide survey to test the patterns illustrated in these case studies; and finally, the development of a guide for resource recovery developers that will serve as preliminary guidance in their choice of development options.
M. Arch.

Reliable sensor values are important for resource-efficient control and operations of wastewater treatment processes. Automatic fault detection methods are necessary to monitor the increasing amount of data produced in any modern water resource recovery facility (WRRF). Most on-line measurements exhibit large variations under normal conditions, due to considerable variations in the influent flow. The work reported in this licentiate thesis deals with fault detection in WRRFs. In the first paper, we studied how Gaussian process regression (GPR), a probabilistic machine learning method, could be applied for fault detection in WRRFs. The results showed that the standard parameter estimation method for GPR suffered from local optima which could be solved by instead estimating the distribution of the parameters with a sequential Monte Carlo algorithm (GPR-SMC). The GPR-SMC allowed for automatic estimation of missing data in a simulated influent flow signal with high noise, which is a representative signal for on-line sensors in WRRFs. In addition, the GPR-SMC provided uncertainty predictions for the estimated data and accurate sensor noise estimates. Care should be taken in selecting a suitable kernel for GPR, since the results were in contrast to the general assumption that prior knowledge can easily be encoded by means of selecting a proper kernel. Here, the autocorrelation graph was found useful as diagnostic tool for selecting a proper kernel. In the second paper, we studied how active fault detection (AFD) could be used to reveal information about the sensor status. The AFD was implemented by evaluating the change in a dissolved oxygen (DO)-signal caused by the sensor's automatic cleaning system. Fault signatures were obtained for fouling and several other sensor faults such as a worn out or mechanically damaged membrane. This demonstrates the potential of AFD, not only for fault detection, but also for fault diagnosis. Interestingly, the progression of the sensor bias due to organic biofilm fouling differed depending on the measurement technique used within the DO-sensor. This is new knowledge that is valuable for process control and should be further studied. The AFD was implemented on a full scale system to demonstrate its applicability, which is rarely done in research papers in the field of WRRFs.

El rabdomiosarcoma (RMS) és el sarcoma de parts toves més comú en la infància i el seu origen rau en les cèl·lules embrionàries precursores del múscul esquelètic. Histològicament se subdivideix en dos tipus: l'embrionari (RMSe) i l'alveolar (RMSa), diferint en presentació clínica, pronòstic i resposta a la teràpia, i és el RMSa el que presenta pitjor pronòstic. El neuroblastoma (NBL) és el tumor sòlid extracranial més habitual en la infància i el tercer càncer pediàtric més recurrent. Representa un 15% de les morts pediàtriques per càncer. Hi ha diversos factors que determinen l'afectació del tumor: l'edat al moment del diagnòstic, l'estadi, alteracions cromosòmiques, la histologia i l'estat de l'oncogèn N-MYC. La supervivència tant del RMS com del NBL se situa al 70%, però aquesta es redueix fins al 30% en els casos de RMS amb malaltia metastàtica i recidiva, i fins al 20% en els casos de NBL d'alt risc. Aquests casos s'associen a la disseminació del tumor a causa de la metàstasi, quan els tractaments regulars no són efectius. És en aquest context on existeix la necessitat d'estudi dels factors que regulen el procés metastàtic per tal d'identificar noves dianes terapèutiques i així millorar la supervivència d'aquest grup de pacients. Les integrines són receptors transmembrana cel·lulars amb capacitat de transmetre senyal de l'exterior a l'interior de la cèl·lula i viceversa, que en modifiquen la plasticitat, adhesió i invasió cel·lular i estan implicades en processos patològics com la metàstasi. Anteriorment a aquesta tesi doctoral, el nostre grup d'investigació va suggerir per primera vegada la integrina α9β1 com una proteïna clau en la invasió de les cèl·lules de RMS. En aquesta tesi doctoral es demostra el paper de la integrina α9β1 en la invasió del RMS tant in vitro com in vivo mitjançant la seva inhibició genètica. Es mostra per primera vegada el paper del miR-7 i el miR-324 com a reguladors de la integrina α9β1. També es descriu com l'expressió de la integrina α9β1 en els tumors de RMS resulta en una tendència a una menor supervivència dels pacients, i posicionen la integrina α9β1 com a un marcador de mal pronòstic en el RMS. El caràcter invasiu de la integrina α9β1 es demostra també en el NBL, on l'expressió de la proteïna en les seves línies cel·lulars és molt elevada i contundent. S'ha dissenyat molècules blocadores contra la integrina α9β1 a partir d'un dels seus múltiples lligands, tot dirigint el treball cap a una recerca translacional per intentar cobrir les necessitats de la clínica en el tractament del RMS i el NBL. Els inhibidors seleccionats presenten efectes antiinvasius en les línies cel·lulars de RMS i NBL positives per la integrina α9β1. S'ha dut a terme un model murí de metàstasi de RMS amb l'administració dels dos inhibidors més prometedors. Un d'ells ha demostrat ser efectiu in vivo, en el qual s'ha observat un retard en l'aparició de metàstasi i una menor incidència de metàstasi comparat amb el grup control. En resum, en aquesta tesi doctoral es descriu el paper de la integrina α9β1 en el RMS i el NBL i es demostra el rol d'aquesta en la metàstasi. A més, es desenvolupa un nou inhibidor contra la integrina α9β1, que presenta un fort efecte antiinvasiu tant in vitro com in vivo. Així doncs, es proposa la integrina α9β1 com una nova diana terapèutica contra el procés metastàtic en el càncer pediàtric.
Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in childhood and it is derived from primitive mesenchyme that retained its capacity for skeletal muscle differentiation. Histologically, it can be divided into two main subtypes: embryonal rhabdomyosarcoma (RMSe) and alveolar rhabdomyosarcoma (RMSa), with differing in clinical presentation, prognosis and responses to therapy, with RMSa having the worst prognosis. Neuroblastoma (NBL) is the most common extracranial solid tumor in childhood and the third most recurrent pediatric cancer. It accounts for around 15% of all pediatric oncology deaths. Several factors determine tumor involvement: the age at the time of diagnosis, the stage, chromosomal disorders, histology and the state of the N-MYC oncogene. Survival rates for RMS and NBL are 70%, but fall to 30% in cases of metastatic RMS and recurrence, and to 20% in cases of high risk NBL. These cases are associated with the dissemination of the tumor due to metastasis, when regular treatments are not effective. It is in this context where there is a need to study the factors that regulate the metastatic process in order to identify new therapeutic targets and thus improve the survival of this group of patients. Integrins are cellular transmembrane receptors capable of transmitting signal from the outside to the inside of the cell and viceversa. They can modify plasticity, adhesion and cell invasion and are involved in pathological processes such as metastasis. Prior to this doctoral thesis, our research group suggested α9β1 integrin as a key protein in the invasion of RMS cells for the first time. In this work, we demonstrate the role of α9β1 integrin in invasion both in vitro and in vivo through its genetic inhibition. The role of miR-7 and miR-324 as regulators of the α9β1 integrin is shown for the first time. How the expression of α9β1 integrin in RMS tumors results in a tendency for poorer survival for patients is also described, and α9β1 integrin is positioned as a poor prognostic marker in the RMS. The invasiveness of α9β1 integrin is also demonstrated in the NBL, where there is high protein expression in its cell lines. Blocking molecules have been designed against α9β1 integrin from one of its multiple ligands, and work directed towards translational research in order to cover the clinical needs of the treatment of RMS and NBL. Selected inhibitors have antiinvasive effects on α9β1 integrin RMS and NBL cell lines. A murine metastases model of RMS has been performed with the administration of the two most promising inhibitors. One of these has been shown to be effective in vivo, with a delay in the appearance of metastasis and a lower incidence of metastasis compared to the control group. To sum up, this thesis describes the role of α9β1 integrin in the RMS and NBL and demonstrates its role in metastasis. In addition, a new inhibitor is developed against α9β1 integrin, which has a strong antiinvasive effect both in vitro and in vivo. Accordingly, α9β1 integrin is proposed as a new therapeutic target against the metastatic process in pediatric cancer.

Forest industries produce large amounts of carbon rich sludges as by-products in their processes. Presently sludge is treated as a poor quality biofuel for co-incineration, some mills treat it solely as a disposal problem. This thesis provides an introduction to production, composition and disposal issues of sludge. It also includes a presentation of strategies for sludge handling.

The main concern with energy recovery from sludge is connected to high content of water (50-80%). Mechanical dewatering is an energy efficient method of decreasing the water content. However, there are limitations to how far sludge can be dewatered mechanically. Thermal dewatering is sometimes required to dewater the sludge beyond these limits, in order to obtain a high quality biofuel for incineration and/or thermal gasification. It is often inefficient, from an energy point of view, to incorporate thermal dewatering in the sludge handling strategy.

An interesting alternative to thermal processes is anaerobic digestion, which is a biological process used for energy recovery. Advantages with anaerobic digestion include biogas production, efficient treatment of sludge with high content of water and potential for nutrients recovery. The process and the kinetics of anaerobic digestion are presented.

The aim of this thesis is to present a method for evaluating different sludge handling strategies from an energy perspective, and to further develop anaerobic digestion as a process for energy recovery from sludge. The thesis is based on two papers. Paper I presents an inclusive approach with focus on energy use and energy recovery in wastewater management, including wastewater treatment and sludge handling. Paper II explores the possibility to enhance biogas production by anaerobic co-digestion of pulp mill sludge with municipal sewage sludge.

Thesis: S.M. in Technology and Policy, Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 100-102).
Resource allocation decisions in post-disaster operations are challenging because of situational dynamics, insufficient information, organizational culture, political context, and urgency. We propose a methodology to create a data-driven decision process for post-disaster resource allocation that enables timely, transparent and consistent decision-making during crisis. Our methodology defines the decisions that must be made, identifies relevant historical, initial, and trending data sources, and develops numerical thresholds, quantitative relationships, and optimization models to support decision making. The general process also offers flexibility to consider non-quantitative factors and spans multiple review periods. We apply this methodology to the Federal Emergency Management Agency's (FEMA) program for establishing and managing Disaster Recovery Centers (DRCs) after a disaster. A detailed case study of one disaster response and relevant historical data provide the basis for DRC decision making thresholds, relationships, and optimization models. We then apply the newly developed process to several recent disaster response scenarios and find that FEMA could have reduced cost by 60-80% while providing sufficient capacity for survivors. Finally, we discuss the generalizability of the methodology to other post-disaster programs along with limitations and potential future work.
by Julia N. Moline.
S.M. in Technology and Policy

Recovering valuable resources from wastewater will transform wastewater management from a treatment focused to sustainability focused strategy, and creates the need for new technology development. An innovative treatment concept - osmotic bioelectrochemical system (OsBES), which is based on cooperation between bioelectrochemical systems (BES) and forward osmosis (FO), has been introduced and studied in the past few years. An OsBES can accomplish simultaneous treatment of wastewater and recovery of resources such as nutrient, energy, and water (NEW). The cooperation can be accomplished in either an internal (osmotic microbial fuel cells, OsMFC) or external (microbial electrolysis cell-forward osmosis system, MEC-FO) configuration. In OsMFC, higher current generation than regular microbial fuel cell (MFC) was observed, resulting from the lower resistance of FO membrane. The electricity generation in OsMFC could greatly inhibit the reverse salt flux. Besides, ammonium removal was successfully demonstrated in OsMFC, making OsMFCs a promising technology for "NEW recovery" (NEW: nutrient, energy and water). For the external configuration of OsBES, an MEC-FO system was developed. The MEC produced an ammonium bicarbonate draw solute via recovering ammonia from synthetic organic solution, which was then applied in the FO for extracting water from the MEC anode effluent. The system has been advanced with treating landfill leachate. A mathematical model developed for ammonia removal/recovery in BES quantitatively confirmed that the NH4+ ions serve as effective proton shuttles across cation exchange membrane (CEM).
Ph. D.

Landfill leachate contains valuable, recoverable organics, water, and nutrients. This project investigated leachate treatment and resource recovery from landfill leachates by innovative methods such as forward osmosis (FO), bioelectrochemical systems (BES), and advanced oxidation. In this study, a microbial fuel cell (MFC) removed 50-75% of the ammonia from a leachate through the electricity driven movement of ammonium to the cathode chamber followed by air stripping at high pH (> 9). During this process, the MFC system removed 53-64% of the COD, producing a net energy of 0.123 kWh m-3. Similarly, an integrated microbial desalination cell (MDC) in an FO system recovered 11-64% of the ammonia from a leachate; this was affected by current generation and hydraulic retention time in the desalination chamber. The MDC-FO system recovered 51.5% of the water from a raw leachate. This increased to 83.5% when the FO concentrate was desalinated in the MDC and then recirculated through the FO unit. In addition, the project investigated humic acid (HA) recovery from leachate during the synergistic incorporation of FO, HA recovery, and Fenton's oxidation to enhance leachate treatment and to reduce Fenton's reagent requirements. This led to the investigation of harmful disinfection byproducts (DBPs) formation during Fenton's oxidation of landfill leachate. The removal of leachate UV-quenching substances (humic, fulvic, and hydrophilic acids) using an MFC and a chemical oxidant (i.e., sodium percarbonate) with a focus on energy production and cost efficiency were also studied. BES treatment can reduce leachate organics concentrations; lower UV absorbance; recover ammonia; and, in combination with FO, recover water. Although BES is promising, significant work is needed before its use in landfill leachate becomes practical. FO application to leachate treatment must consider the choice of an appropriate draw solute, which should require minimal effort for regeneration. Resources like HA in leachate deserve more attention. Further efforts can focus on purification and application of the recovered products. The emerging issue of DBP formation in leachate treatment also requires attention due to the potential environmental and human health effects. The broader impact of this study is the societal benefit from more sustainable and cost-efficient leachate treatment.
Doctor of Philosophy
On average, each of us produces 3 – 4 pounds of solid waste every day. In the U.S., the yearly generation of solid waste is 250 million tons, while the global generation is 1.1 billion tons. The global management cost of solid waste is around 200 billion dollars. About half of U.S. municipal solid waste ends up in landfills, in China, this number is 80%. Among the different municipal solid waste (MSW) management approaches, landfilling is the most common because of its low cost and relatively low maintenance requirements. In a landfill, the combination of precipitation and solid waste degradation produce leachate, a complex wastewater. A ton of municipal solid waste can generate 0.05–0.2 tons of leachate in its lifetime during the process of landfilling. Leachate contains a vast array of pollutants, which can result in major environmental impact and adverse human health risk if not contained and treated appropriately. At present, leachate is mostly treated biologically, without any resource recovery. Among the myriad recoverable resources in landfill leachates, water and ammonia are the most abundant. We applied innovative approaches such as, bioelectrochemical systems, forward osmosis, advanced oxidation to recover resources and remove contaminants from leachate simultaneously. We also incorporated these novel technologies to help each other. For instance, we recovered humic fertilizer from leachate prior to advanced oxidation (i.e., Fenton’s oxidation) that helped the reduction of Fenton’s reagent requirements. The next step of our study could be the pilot scale application of the proposed techniques so that it can be applied in field. The broader impacts of this study include improvements in sustainability and cost efficiency of leachate treatment that can benefit the society.

La presente tesis doctoral se enfoca en evaluar un sistema de eliminación biológica de fósforo (enhanced biological phosphorus removal, EBPR) orientado a un escenario de recuperación de recursos. Los resultados obtenidos se dividieron en cuatro capítulos, los cuales aparecen en los capítulos 4, 5, 6 y 7. Los temas estudiados en cada capítulo se resumen a continuación: Capítulo 4. Se estudió a largo plazo un sistema SBR-EBPR cuya configuración fue modificada con la finalidad de obtener un líquido altamente enriquecido con P. La configuración del sistema SBR-EBPR consistió en incluir una etapa de extracción de sobrenadante al final de la etapa anaeróbica (después de un periodo de sedimentación). El líquido extraído tiene la mayor concentración de P en el ciclo SBR, lo cual implica que la disponibilidad de este nutriente estaría limitada para los requerimientos metabólicos de los microrganismos responsables de este proceso, comprometiendo la eficiencia del proceso EBPR. Por ello se evaluaron diferentes volúmenes de extracción. Capítulo 5. Se estudió el comportamiento de la actividad EBPR usando tiempos de retención celular (TRC) cortos, esto con la finalidad de evaluar su posible integración en sistemas energéticamente eficientes, como el proceso A/B. Con este fin, se operaron tres diferentes reactores secuenciales (por lotes) con una configuración convencional a 25 ºC y a TRC de entre 3-14 días. Capítulo 6. La influencia de la temperatura y el SRT sobre el proceso EBPR fueron evaluadas, a corto y largo plazo. En este capítulo se usaron tres sistemas EBPR, los cuales se operaron a temperaturas de entre 10-20 ºC y a TRC de entre 3.5-15 días. Capítulo 7. La biomasa obtenida de los diferentes sistemas (SBR-EBPR), usados en el capítulo 6 se metió a pruebas de digestión anaerobia, esto con la finalidad de evaluar su potencial de producción de metano. Debido a que cada biomasa contenía diferentes concentraciones de PHA, la influencia del contenido de PHA sobre la de producción de metano también fue evaluada.
This doctoral thesis focuses on evaluating an EBPR (enhanced biological phosphorus removal process) system oriented to the scenario of resource recovery. The results obtained are divided into four chapters, which are presented in chapters 4, 5, 6 and 7. The topics studied in each chapter are summarized below: Chapter 4. A SBR-EBPR system was studied in the long term by modifying its configuration in order to obtain an anaerobic supernatant enriched in phosphorus. The configuration of system SBR-EBPR included one stage for the extraction of supernatant at the end of anaerobic stage (after a period of sedimentation). The extracted liquid has the largest concentration of P in the SBR cycle, which implies that the availability of this nutrient would be limited for the metabolic requirements of the PAO, compromising the efficiency of the process EBPR. For this reason, different extraction volumes were assessed. Chapter 5. The behavior of the EBPR activity using short cell retention times (SRT) was studied in order to assess the possibility of its integration to energetically efficient systems, such as the A/B process. With this purpose, different SBR were operated with a conventional configuration. These SBR were operated at 25 °C and at 3-14 days SRT. Chapter 6. the influence of temperature and SRT on the EBPR process was assessed (in both the short and long terms) using three EBRP systems. These systems were operated at t temperatures between 10-20 ºC and at TRC between 3.5-15 days. Chapter 7. The biomass obtained in the different operational periods of the SBR-EBPR systems used in chapter 6 was subjected to an anaerobic digestion test to evaluate its methane production. Because each biomass contained different concentrations of PHA, the influence of PHA content on methane production was also evaluated.

End-of-life car passenger tyres represent a major waste management problem, with more than 450,000 tonnes of used tyres being generated each year in the UK alone (approximately 55,000,000 tyres). Recent legislation has made 100% material or value recovery from waste tyres an imperative. There are many different waste tyre management options available. The most commonly used processes include: retreading, use as fuel in incinerators and cement kilns and reprocessing to produce rubber crumb which has further applications in asphalt mixtures, carpet underlay and playgrounds. The theme of the research presented is a fundamental study and development of tyre pyrolysis. Pyrolysis is an attractive method to sustainably recover valuable components of the tyre rubber through the generated carbonaceous solid, oil and gas. Both conventional and microwave-induced pyrolysis have been investigated. Microwave pyrolysis offers an exciting alternative to traditional pyrolysis because of the potentially significant energy efficiency advantage offered. In the first instance an investigation of the optimisation of the pyrolysis conditions by statistical design using conventional means to produce a carbonaceous solid char has been undertaken. This was followed by the investigation of microwave-induced pyrolysis using modified commercially available microwave equipment as well as a bespoke and novel 2450 MHz, 2 kW rotary microwave furnace developed for the purposes of this project by Cobham Microwave Ltd. Carbonaceous solids produced by varying different experimental parameters, such as power levels and pyrolysis duration are reported and analysed. In addition, the main constituents of the oils generated have been identified and comparisons made with traditional thermal pyrolysis oil. Reuse of the solid residue is an important activity which has been researched. This char is often described as carbon black, but given that it contains all the solid, inorganic components present in the tyre, as well as carbon black, it is better described as “char filler”. The suitability of this waste tyre-derived char for reuse in the rubber industry as a filler substitute has been evaluated and is presented. The results show that the char has similar properties to a semi-reinforcing filler with potential for improvement.

As populations grow and urban centres expand, meeting water demand and wastewater management requirements will become increasingly difficult. Goal 6 of the Sustainable Development Goals is to: 'Ensure availability and sustainable management of water and sanitation for all'. Part of the approach to achieving this will be reusing wastewater and will require a greater understanding of the institutional arrangements that support or obstruct reuse. This research was designed to achieve this and aimed to develop a set of factors that investors could use to assess the institutional feasibility of reuse in a given setting. The methodology combined a case study approach, focusing on wastewater systems in Bangalore, India and Hanoi, Vietnam, with triangle analysis to assess: the content of policies and laws; the structures (formal and informal) to implement laws and reuse projects; and the culture around acceptance and engagement in reuse. The reuse practices observed in Bangalore were treatment and use within apartments, centralized treatment and sale to industries, use in agriculture after natural attenuation, groundwater recharge and lake regeneration. In Hanoi the only reuse was indirect use from rivers feeding fish ponds and fields, although formal treatment and use is planned. Critically, both cities have environmental and water resources policies and laws that advocate reuse, as well as related local legislation. However, support for reuse is not reciprocated in industrial, agricultural or fisheries law, the result being that reuse does not always take place as planned. Legislation is required along the whole sanitation chain to the point of wastewater use. Structures to implement reuse are also vital. In Bangalore the water board has initiated reuse projects and established the New Initiatives Division but resources are a limiting factor. Effective institutions include expertise, manpower and financing mechanisms, which are lacking in both cities. The environment agency is also engaged in reuse though legislation on recycling in residential and commercial complexes but guidance for users is inadequate, expectations are perceived to be excessive and monitoring is almost impossible. The driver for reuse is increasingly the benefits observed by users. In the case of apartments this is a reliable water source and reduced costs of water supply. As a result, a private sector in wastewater treatment is becoming established. The active civil society and strong, independent media are instrumental in providing information to potential users and holding authorities to account in Bangalore. Their absence in Hanoi is notable. In summary, institutional elements to be considered are: supportive legislation across all sectors; details of acceptable reuse, deterrents and inducements; budget allocation; structures to enable reuse; strong civil society, NGOs, courts, media and universities providing evidence of suitability and safety; donors and finance mechanisms; and stakeholders willing to use the products. Encumbrances are inconsistent or uncoordinated legislation, lack of cooperation and insufficient benefit sharing or perceptions of benefits along the reuse chain.

Water shortage, water contamination, and the emerging challenges in sustainable water resources management (e.g., the likely impacts of climate change and population growth) necessitate adopting a reverse logistics approach, which is the process of moving wastewater from its typical final destination back to the water supply chain for reuse purposes. This practice not only reduces the negative impacts of wastewater on the environment, but also provides an alternative to withdrawal from natural water resources, forming a closed-loop water supply chain. However, the design of such a supply chain requires an appropriate sustainability assessment, which simultaneously accounts for economic, environmental, and social dimensions. The overall aim of this work was therefore to contribute to the literature by evaluating the impacts of water reclamation and reuse according to the triple-bottom-line sustainability indicators (i.e., economic, environmental, and social) and to develop frameworks and mathematical models to help decision-makers, stakeholders, and officials with the design of sustainable water reclamation and reuse systems. The applicability of the developed frameworks and models was examined using real case studies and hypothetical scenario analyses. This enactment also revealed the tradeoffs and thresholds associated with the design of sustainable water reclamation and reuse systems. To conquer the mentioned goal, the research was conducted in three major sections. The first part of the research was outlined to design possible scenarios for water reuse based on water reuse guidelines and evaluate the different types of end-use based on the three major dimensions of sustainability (i.e., economic, environmental and social aspects), simultaneously. The different reuse types considered include unrestricted urban reuse, agricultural reuse, indirect potable reuse (IPR), direct potable reuse (DPR), distributed unrestricted urban reuse, as well as some degree of decentralization of treatment plants for distributed unrestricted urban reuse. The tradeoff investigation and decision-making framework were demonstrated in a case study and a regret-based model was adopted as the support tool for multi-criteria decision-making. This study revealed that although increasing the degree of treatment for water reuse required implementation of advanced treatment options and it increased the implementation, operation, and maintenance (O&M) costs of the design, it increased the value of resource recovery significantly, such that it can offset the capital and O&M costs associated with the treatment and distribution for DPR. Improving the reclaimed water quality also reduced the environmental footprint (eutrophication) to almost 50% for DPR compared to the other reuse scenarios. This study revealed that the distance between the water reclamation facility and the end use plays a significant role in economic and environmental (carbon footprint) indicators. In the second part of this research, a multi-objective optimization model was developed to minimize the costs and environmental footprint (greenhouse gas emissions), and maximize social benefits (value of resource recovery) of the water reclamation systems by locating the treatment facility, allocating treatment capacity, selecting treatment technology, and allocating customers (final reclaimed water users). The expansion of the water reclamation system in Hillsborough County, Florida was evaluated to illustrate the use of the model. The impacts of population density and topography (elevation variation) of the water service area on the model outputs were also investigated. Although the centralization of treatment facilities takes advantage of the economies of scale, the results revealed that simultaneous consideration of economic and environmental indicators favored decentralization of treatment facilities in the study area. This was mainly due to the significant decrease in water transfer requirements, especially in less populous areas. Moreover, the results revealed that contribution of population density to the optimal degree of decentralization of treatment facilities was significant. In the last part of this work, hypothetical scenarios for a water service area were generated to evaluate the impacts of external variables on the design of water reclamation and reuse systems. Although the conducted sensitivity analyses in the previous sections revealed the tradeoffs and thresholds associated with the design of water reclamation systems, the concept of a hypothetical study helped with the elimination of case-specific factors and local conditions that could possibly influenced the outcomes. These factors, which were specific to the case studies (e.g., the location of candidate sites for implementation of water reclamation facilities and special population distribution patters) made barriers to the conclusions and hurdled the interpretation of findings. Two major factors, which were found to be significant among the factors influencing the design of water systems (i.e., elevation variation and population density), were selected for the evaluation. Accordingly, three different topographies (i.e., flat region, medium elevation variation, and hilly) and three types of population density (i.e., low, medium, and high) were considered for the design of hypothetical cases and the previous model developed in the second section was modified and used to evaluate the impacts. The results revealed that although decentralization of water reclamation facilities decreases the costs and environmental impacts associated with water transfer phase (i.e., wastewater collection and reclaimed water distribution), there were tradeoffs between the impacts of decentralization of treatment plants and the benefits from economies of scale for treatment. The results showed that when the population density is high and there is moderate to high elevation variations in the water service area, decentralization of treatment facilities is the beneficiary option. However, if the population density is low, economies of scale for treatment becomes more influential and lower degrees of decentralization of treatment facilities is preferred.

2015 - 2016
The ever-expanding population, the increasing consumption of resources and the shortage of primary raw materials have addressed the transition of waste management strategies from the linear model based on the “wear and tear” on a circular approach aiming at preventing waste and recycling materials. In this view, the attention has been focused on the use of anthropogenic stock resources in place of virgin materials as promoted by the concept of “urban mining”. Waste electrical and electronic equipment (WEEE) is regarded as the backbone stream in urban mining. It represents the waste stream characterized by the highest grow rate per year (3-5%) and by the most wide-ranging source of materials, since WEEE can contain more than 1000 different substances, including base, precious and critical metals. The recovery of metals defined critical raw materials as rare earth elements from electronic waste appears, thus, an important opportunity both in economic and environmental terms. However, the recycling of WEEE is challenged by the complex nature of such waste stream which, beside valuable materials, includes hazardous substances as well. The presence of these toxic components has raised great concern especially in developing countries where the informal recycling sector is still widespread, handling WEEE with unsafe and inadequate practices as a result of a lack of legislation. In high-income countries, separate collection is the first step of a system pursuing the WEEE sustainable management; mechanical processes are then applied to separate the different materials, including metals which are destined to further recycling by means of metallurgical processes. The metallurgical treatments currently used for metal recovery from WEEE are, however, claimed to have severe impacts on the environment due to the generation of secondary pollutants. Moreover, the industry of WEEE recycling is still in its early stage, especially if referred to the recovery of rare earth elements. All these reasons have contributed to increase the interest of both scientific and industrial research in addressing a cost-effective and environmental friendly treatment of end-of-life electrical and electronic products. In this background the present research work aimed to:  the characterization of WEEE in terms of base and critical metal contents, in order to identify and quantify the valuable materials and the hazardous substances for addressing a sustainable recycling strategy;  the assessment of critical metal fate during the conventional mechanical treatments of WEEE with reference to the sorting effectiveness and the recycling potential;  the evaluation of the feasible application of innovative treatments in the field of hydro- and bio-metallurgy for the recovery of valuable and critical metals from WEEE. To this end, the experimental activity was developed in three main steps, matching the specific objectives of the research project:  the first phase was focused on the characterization of WEEE in terms of base and critical metals. Representative samples were collected over the treatment chain of a full scale mechanical treatment plant operating in South Italy and analysed by their metal content;  the data obtained from the metal characterization were, thus, used in the second phase to carry out a mass flow analysis in order to investigate the fate of metals, particularly the critical ones, during the conventional mechanical treatments;  the third phase focused on hydro- and bio-metallurgical tests for the recovery of valuable and critical metals from WEEE. As the results from the previous phase pointed out that after the conventional mechanical treatments significant concentrations of precious metals and rare earth elements were gathered in dust stream originating from process air cleaning, dust was used as secondary source of critical metals and tested for the treatments proposed. Both chemical agents, including a non-conventional one as thiourea, and biological species were used to perform leaching processes. The use of dust, actually destined to landfill disposal, as well as the treatments investigated for the recovery of critical metals marked the novelty of the research. The first two phases were carried out at the Sanitary Environmental Engineering Division (SEED) of Salerno University. The hydrometallurgical tests included in the third phase were performed at SEED laboratory as well, whereas the biometallurgical tests were conducted at the laboratory facility of the Institute for water education Unesco-IHE in Delft (Netherlands). Results of the experimental activity showed that rare earth elements contained in WEEE at trace concentrations do not enter the recovery chain as around 80% in mass were lost in dust streams during the conventional mechanical treatments. Similarly, 24% of precious metals entering the mechanical treatments were conveyed in the dust fraction. Therefore, this matrix appears a potential secondary source of valuable and critical metals to be further processed for metal recovery. Chemical and biological leaching processes proved their great potential in extracting up to 99% of the critical metals contained in the dust. These promising outcomes suggested that both hydro- and biometallurgical processes can be regarded as a suitable option for the management of the dust fractions, which currently represents a cost for the treatment plant. The treatment of dust through these processes provides, indeed, a way to reintroduce this matrix, actually sent to landfill, in the “loop” of product lifecycle, thus limiting the losses of resources in accordance with the new circular economy approach. Moreover, the results of this study are of relevant interest as they highlighted the potential of recovering valuable and critical metals from waste streams using low-cost and environmentally friendly processes in the filed of biometallurgy as an effective alternative to both pyrometallurgical and conventional chemical processes, especially for treating low grade materials as WEEE. [edited by author]
La popolazione in continua espansione, il crescente sfruttamento delle risorse e la conseguente carenza di materie prime hanno orientato negli ultimi anni le strategie di gestione dei rifiuti da un approccio lineare basato sul modello del “estrai-produci-usa-getta” verso una visione circolare in cui i rifiuti di un’attività diventano materie prime per un’altra. L’attenzione è stata, pertanto, sempre più incentrata sulla possibilità di utilizzare i residui delle attività antropiche come scorte di materie secondarie in sostituzione di materiali vergini, così come promosso dal noto concetto dell’ “urban mining” o “miniere urbane”. In tale contesto, i rifiuti di apparecchiature elettriche ed elettroniche (RAEE) costituiscono ad oggi delle vere e proprie miniere urbane. Tale flusso di rifiuti è caratterizzato dai maggiori tassi di crescita per anno (35%) e dalla più varia composizione di materiali dal momento che i RAEE possono contenere più di 1000 differenti sostanze, tra cui metalli di base, metalli preziosi e metalli critici. La possibilità di recuperare dunque “materie prime critiche”, quali le terre rare presenti all’interno dei rifiuti elettronici, si configura come una importante opportunità sia in termini economici che ambientali. Tuttavia, il riciclaggio dei RAEE è ostacolato dalla loro complessa natura che, accanto a materiali di valore, prevede anche sostanze pericolose. La presenza, difatti, di componenti tossiche è motivo di grande preoccupazione specialmente in riferimento ai paesi in via di sviluppo dove il “canale informale” è ancora ampiamente diffuso ed i RAEE vengono gestiti in maniera inadeguata in conseguenza di una mancanza di riferimenti normativi. Nei paesi sviluppati, la raccolta differenziata è il primo step di un sistema che mira a perseguire una gestione sostenibile dei RAEE; processi di trattamento meccanico sono poi implementati per separare i metalli dai restanti materiali per il loro successivo recupero mediante processi metallurgici. I trattamenti metallurgici attualmente utilizzati per il recupero dei metalli dai RAEE hanno tuttavia gravi impatti sull’ambiente a causa della produzione di rifiuti secondari. Inoltre, l’industria del riciclo dei RAEE è ad oggi ancora nella sua fase iniziale soprattutto in riferimento al recupero delle terre rare. Tutte queste ragioni hanno contribuito ad accrescere l’interesse sia del mondo scientifico che di quello industriale verso lo sviluppo di tecnologie a basso costo e minor impatto per il trattamento dei RAEE. In tale contesto, il presente progetto di ricerca è stato mirato a:  caratterizzare i RAEE in termini di metalli di base e metalli critici, in modo tale da identificare e quantificare il contenuto di materiali di valore e sostanze pericolose per sviluppare una valida e sostenibile strategia di trattamento;  valutare il destino dei metalli critici nel corso dei convenzionali trattamenti meccanici dei RAEE con particolare riferimento all’efficienza di selezione e al potenziale di recupero;  investigare la fattibilità dell’applicazione di trattamenti innovativi nel campo dell’idro- e della bio-metallurgia per il recupero dei metalli critici e di valore dai RAEE. A tale scopo, l’attività sperimentale è stata sviluppata secondo tre fasi principali, funzionali al raggiungimento degli obiettivi specifici del progetto di ricerca:  la prima fase è stata incentrata sulla caratterizzazione dei RAEE in termini di metalli di base e metalli critici. Campioni rappresentativi di RAEE sono stati prelevati presso un impianto di trattamento a scala reale localizzato nel Sud Italia e analizzati nel loro contenuto di metalli;  i dati ottenuti dalla caratterizzazione sono stati quindi utilizzati nella seconda fase dell’attività, al fine di condurre un bilancio di massa per investigare il destino dei metalli, in particolare di quelli critici, durante i convenzionali trattamenti meccanici;  la terza e ultima fase è stata focalizzata sull’applicazione dei processi idro- e bio-metallurgici per il recupero dei metalli critici e di valore dai RAEE. Dal momento che i risultati della fase precedente hanno evidenziato che a seguito dei convenzionali trattamenti meccanici significative concentrazioni di metalli preziosi e terre rare vengono raccolte nelle polveri originate dal processo di trattamento dell’aria, tale matrice è stata utilizzata come fonte secondaria di metalli critici per testare i trattamenti proposti. Sia agenti chimici, tra cui un agente non convenzionale come la tiourea, che agenti biologici sono stati utilizzati per eseguire le prove di lisciviazione. L’uso della polvere, al momento destinate a smaltimento a discarica, ed i trattamenti proposti per il recupero dei metalli critici hanno segnato l’innovazione della ricerca. Le prime due fasi sono state svolte presso la Divisione di Ingegneria Sanitaria Ambientale (SEED) dell’Università degli studi di Salerno. Le prove idrometallurgiche incluse nella terza fase dell’attività sperimentale sono state anch’esse condotte presso il laboratorio SEED mentre le prove biometallurgiche sono state svolte presso il laboratiorio dell’Istituto Unesco-IHE di Delf (Paesi Bassi). I risultati dell’attività sperimentale condotta hanno mostrato che le terre rare presenti in tracce all’interno dei RAEE non entrano nella catena di recupero, dal momento che circa l’80% in massa risulta concentrato in flussi, quali le polveri, non destinati al successivo recupero. In maniera analoga, il 24% dei metalli preziosi contenuti nei RAEE in ingresso al trattamento meccanico sono raccolti all’interno di tale frazione. Le polveri si configurano, pertanto, come una potenziale fonte secondaria di materiali critici e di valore da essere sottoposta a successivo recupero. I processi idro- e biometallurgici applicati hanno mostrato il loro grande potenziale nel recupare fino al 99% dei metalli critici concentrati nelle polveri. Tali promettenti risultati hanno evidenziato che i processi idro-e biometallurgici possono essere considerati come una valida opzione di gestione delle polveri derivanti dal trattamento meccanico dei RAEE che attualmente rappresentano un costo di smaltimento per l’impianto. Il trattamento delle polveri mediante tali processi fornisce una strategia per reintrodurre tale matrice, al momento smaltita in discarica, nella spirale del ciclo di vita dei prodotti, limitando la perdita delle risorse in essa contenute in accordo con l’approccio promosso dall’economia circolare. Inoltre, i risultati del presente studio sono di rilevante interesse dal momento che hanno mostrato, in particolare, il potenziale di recupero di metalli critici e di valore dai RAEE mediante processi a basso costo e basso impatto nel campo della biometallurgia, come valida alternativa ai convenzionali trattamenti piromentallurgici ed idrometallurgici. [a cura dell'autore]
XV n.s

An analysis of solid waste management was performed in Gaborone, Botswana to identify the quantity of different types of solid waste that are generated annually and the possible strategies for improved waste management. In order to achieve the objective of the project, present waste management practice in Gaborone was analysed and waste composition study was carried out in Gamodubu landfill, Gaborone. Waste from household, commercial, industrial and others (defence and institutional) stratums were selected for sampling. Different samples were taken and forwarded to sorting analysis. The waste was categorized into 10 categories and one of the categories (plastic) is further divided into 5 Subcategories. The output of the study results the quantity of solid waste generated in Gaborone, composition of solid waste categories from different stratums and its flow to the landfill and the quality of waste, annually. These findings helped in serving the importance and the need of better waste management system in order to improvise the potential for resource recovery under social considerations.

To-date, sanitation has mainly been approached from a public and environmental health perspective and this implies that excreta and other organic waste streams are seen not only as a hazard to quickly get rid of but also as a very costly menace to manage. However, looking at sanitation management from a resource recovery perspective provides an avenue for solutions with multiple co-benefits. Revenues from sanitation end-use products can act as an incentive for improving sanitation infrastructure while also covering part or all of the investment and operation costs for the same. Until now, estimating the potential for resource recovery from sanitation systems and technologies has largely been done on a case by case basis according to project or geography with no standardized universal tools or methodologies being used across the world. This study is aimed at developing a generic model for the rapid estimation of the quantities of various resources that can be recovered from sanitary waste streams in urban areas. Key waste streams from sanitation systems in low and middle income countries were identified and their major characterization parameters identified. The mathematical relationships between key waste stream characterization parameters and the potential amounts of resource products derived from treatment were determined and then used to develop the model in MS Excel. The model was then tested with waste stream flow rates and characterization data (for faecal sludge, sewage sludge and organic municipal solid waste) from the city of Kampala with two scenarios; the current collection amounts (390 m3 of faecal sludge, 66 tonnes of sewage sludge and 700 tonnes of organic solid waste) and the potential amounts with increased collection efficiency and coverage (900 m3 of faecal sludge, 282 tonnes of sewage sludge and 2199 tonnes of organic solid waste). The results were shared with Kampala city authorities to obtain feedback. The results showed that there is significant potential in utilizing the daily amounts of the three waste streams collected in Kampala. With increased collection coverage and efficiency, they could altogether yield; up to 361,200 Nm3 of biogas per day which could meet the daily energy needs of 824,000 people that are currently met by firewood. Alternatively, the three sources could produce, 752 tonnes of solid combustion fuel per day which could meet the daily energy needs of 1,108,700 people that are currently met by firewood. As a third alternative, the three sources could produce 198 tonnes of Black Soldier Fly prepupae per day which could substitute for 134 tonnes of dry fish per day currently used as animal feed ingredient and up to 909 tonnes of compost fertilizer per day which is enough to substitute two tonnes of urea that is currently used by farmers. The model thus proved to be a simple way to provide decision support by making rapid estimations of the potential for resource recovery in urban areas, without the burden of having to do full scale feasibility studies. It is expected that this model could be a useful complement to the excreta flow diagrams (SFDs) developed within the Sustainable Sanitation Alliance (SuSanA) and hence give a holistic picture of the potential of a closed loop approach to excreta and waste management in cities.

Le méthanol est un composé organique volatil (COV) important, présent dans les effluents gazeux et liquides des industries de transformation telles que les pâtes à papier et papiers, la fabrication de peinture et les raffineries de pétrole. Aux États-Unis seulement, environ 55 377 tonnes de méthanol ont été émises dans l'atmosphère en 2017 et au moins 65% du total des émissions provenaient des usines Kraft des industries de la pâte à papier et du papier. Le traitement biologique anaérobie des effluents gazeux et liquides riches en méthanol a été testé dans des configurations de bioréacteurs, telles que des filtres à biotrickling (BTF) et des réacteurs à lit de boues anaérobie à flux ascendant (UASB). Les acides gras volatils (AGV) produits dans ces bioréacteurs ont été quantifiés et une analyse de bilan massique a été réalisée. Une élimination du méthanol en phase gazeuse ainsi qu'une réduction du thiosulfate (~ 1000 mg/L) ont été effectuées pendant 123 jours dans un BTF anoxique. Une capacité d'élimination maximale (ECmax) de 21 g/m3.h pour le méthanol et l'élimination complète du thiosulfate ont été atteintes. Pour examiner l'élimination du méthanol en phase gazeuse ainsi que la réduction du sélénate, un autre BTF anoxique a été mis en œuvre pendant 89 jours sous une alimentation par étapes et continue en sélénate. L'efficacité d'élimination du sélénate était respectivement > 90% et ~ 68% au cours d'une alimentation par étapes et continue en sélénate et une ECmax de méthanol de 46,4 g/m3.h. La bioréduction anaérobie du sélénate couplée à l'oxydation du méthane a été étudiée dans des réacteurs discontinus et un BTF inoculé avec un sédiment marin et opéré pendant 348 jours et une réduction complète pouvant atteindre 143 mg/L de sélénate alimenté par étapes a été obtenue. En outre, les effets de différentes concentrations de sélénate, de sulfate et de thiosulfate, individuellement, sur l'utilisation du méthanol pour la production d'AGV ont été examinés dans des systèmes de traitement par lots. Pour l'étude sur le méthanol en phase liquide, l'acétogénèse du condensat encrassé (FC) obtenu dans une industrie de réduction en pâte chimique a été testée dans trois réacteurs UASB fonctionnant à 22, 37 et 55 °C pendant 51 jours. Une efficacité d'élimination maximale du méthanol de 45% dans le réacteur à 55 °C et une élimination presque complète de l'éthanol et de l'acétone ont été obtenues dans tous les réacteurs UASB. Avant l’acétogénèse du FC, les réacteurs UASB ont été mis en fonctionnement pendant 113 jours dans des conditions rapportées induir une acétogenèse des eaux usées synthétiques riches en méthanol. La récupération d’AGV a été explorée au moyen d’études d’adsorption utilisant des résines échangeuses d’anions dans des systèmes de traitement par lots. La capacité d'adsorption de différents AGV sur Amberlite IRA-67 et Dowex optipore L-493 a été examinée en ajustant les données expérimentales à des modèles isothermes et cinétiques d'adsorption. Ensuite, un processus séquentiel par lots a été testé pour obtenir une séparation sélective de l'acétate du mélange d'AGV
Methanol is an important volatile organic compound (VOC) present in the gaseous and liquid effluents of process industries such as pulp and paper, paint manufacturing and petroleum refineries. An estimated 55,377 tonnes of methanol was emitted to the atmosphere in the year 2017 in the United States alone and at least 65% of the total emission was from the Kraft mills of the pulp and paper industries. The anaerobic biological treatment of methanol-rich gaseous and liquid effluents was tested in two bioreactor configurations, namely a biotrickling filter (BTF) and an upflow anaerobic sludge blanket (UASB) reactor. The volatile fatty acids (VFA) produced in these bioreactors were quantified and a mass balance analysis was carried out. Gas-phase methanol removal along with thiosulfate (~ 1000 mg/L) reduction was carried out for 123 d in an anoxic BTF. A maximum elimination capacity (ECmax) of 21 g/m3.h for methanol and complete removal of thiosulfate was achieved. To examine the gas-phase methanol removal along with selenate reduction, another anoxic BTF was operated for 89 d under step and continuous selenate feeding, wherein the selenate removal efficiency was > 90% and ~ 68%, respectively, during step and continuous selenate feed and a methanol ECmax of 46.4 g/m3.h was achieved. The anaerobic bioreduction of selenate coupled to methane oxidation was investigated in batch reactors and a BTF inoculated with marine sediment and operated for a period of 348 d. Complete reduction of up to 143 mg/L of step fed selenate was achieved in the BTF. Furthermore, the effect of selenate, sulfate and thiosulfate on methanol utilization for VFA production was individually examined in batch systems. For the study on liquid-phase methanol, acetogenesis of foul condensate (FC) obtained from a chemical pulping industry was tested in three UASB reactors operated at 22, 37 and 55 ºC for 51 d. A maximum methanol removal efficiency of 45% in the 55 ºC reactor and nearly complete removal of ethanol and acetone in all UASB reactors was achieved. Prior to acetogenesis of the FC, the UASB reactors were operated for a period of 113 d under conditions reported to induce acetogenesis of methanol-rich synthetic wastewater. The recovery of VFA was explored through adsorption studies using anion exchange resins in batch systems. The trends and capacity of adsorption of individual VFA on Amberlite IRA-67 and Dowex optipore L-493 were examined by fitting the experimental data to adsorption isotherm and kinetic models. Subsequently, a sequential batch process was tested to achieve selective separation of acetate from the VFA mixture

For intensive production systems like the Blue Ridge Aquaculture (BRA), based in Martinsville, VA, there are significant economic incentives to reuse the waste by diverting it into a cropping system that would increase the total productivity and total resource-reuse efficiency, and decrease the environmental, ecological, and financial costs of aquacultural waste disposal. In order to facilitate the reuse of effluent from the tilapia production at the BRA, a green house was developed. On this site, sludge waste from recirculating aquaculture was separated and composted using a vermicomposting technique and the resulting compost was utilized as an amendment to conventional greenhouse potting mixes. These aquacultural waste products were compared to conventional greenhouse culture of a common ornamental annual plant.

It was hypothesized that (1) vermicomposted aquaculture sludge would increase the growth of plants over conventional greenhouse potting mixes, and (2) recycled aquacultural wastewater can serve as a quality source of irrigation water, and plant response would differ with irrigation method. Plant growth and 11 out of 12 plant tissue nutrients were greater when compost was increased in the substrate. Plant root growth and 3 out of 12 tissue nutrients were increased when irrigated with wastewater. Plant shoot mass and total mass was greater when irrigated by ebb and flow irrigation compared to overhead mist irrigation, and 4 out of 12 tissue nutrients were greater when irrigated with mist irrigation. Overall plant performance was greatest with 15% vermicomposted sludge in the substrate and watered with wastewater by ebb and flow irrigation.

Master of Science

Background Phosphorous levels around the world are decreasing rapidly, as urbanization increases. This is significant as phosphorus is a resource that is required by all living organisms and is a key ingredient in many fertilizers. Similar to the peak oil phenomenon, phosphorus will soon experience a peak in its production, and it is predicted that within the next century, naturally occurring phosphorous will be completely depleted. Moreover, methods of nitrogen production such as the Haber‐Bosch process contribute largely towards global energy expenditure and greenhouse gas emissions. Considering this, researchers have aimed to investigate methods of recovering phosphorus and nitrogen to help cope with the increasing global demand and promote environmental sustainability. Urine has been identified as a potential source of recoverable phosphorus and nitrogen. Urine accounts for approximately 1% of the total volume of domestic wastewater. Conversely, urine accounts for 80%, 60% and 63% of the nitrogen, phosphorus and potassium in domestic wastewater, respectively. Moreover, wastewater treatment plants specifically target the removal of nitrogen and phosphorus. This is because these substances can cause a toxic environment in surface water, which can have a negative effect on aquatic organisms. This research aimed to evaluate a novel mode of resource recovery, through the assessment of a decentralized approach to urine treatment. Methodology Two methodological approaches were adopted to evaluate this system. In the first, a thorough review of literature was conducted to assess current innovations pertaining to urine treatment technologies. Public perceptions regarding the collection and recycling of urine were also researched. This culminated in the creation of design charts depicting treatment sequences for fresh and hydrolyzed urine, aimed at maximum resource recovery. These charts were entirely based on values from published literature and basic calculations. Secondly, geographic information systems (GIS) were used to assess the transportation and logistics of a decentralized urine treatment system, using the City of Cape Town as an illustrative case study. In this model, existing urinals at frequently visited shopping centres are theoretically replaced with waterless nutrient recovery urinals. Within these urinals, urea hydrolysis is prevented from occurring in an attached urine collection container. This minimizes nitrogen losses and allows for a solid, phosphorous based fertilizer to form. The collected urine is retrieved from individual buildings and transported to a resource recovery facility (RRF) by truck. The collected urine is filtered to remove the solid fertilizer, while the remaining liquid is concentrated to produce a liquid fertilizer. Finally, the recovered material is then sold as fertilizers to wholesalers. The implication of transportation and logistics was also assessed through four scenarios of decentralization. In scenario one, one RRF was used. In scenarios two, three and four; two, four and eight RRFs were used, respectively. The economic and environmental implications of each scenario were then evaluated through standard engineering economics and potential greenhouse gas (GHG) emissions. Ideal treatment sequence It was deduced that the most promising treatment sequence for maximum resource recovery, based on nutrient recovery rates and operating conditions, incorporated a combination of alkaline stabilization and volume reduction. Calcium hydroxide and reverse osmosis (RO) were the chosen mediums for stabilization and volume reduction. If this sequence is used, almost all urine constituents can be recovered. Moreover, a liquid fertilizer with a 3.3 - 0 ‐ 0.8 NPK rating, and 11 grams of calcium phosphate, per litre of urine treated, can theoretically be produced. This was the chosen treatment sequence for the decentralized urine transportation system. Decentralized urine transportation treatment It was found that the main contributor to GHG emissions in the decentralized system was the truck. Driving distance decreased as the number of RRFs increased, which led to a decrease in the GHG emissions because of fuel consumption. However, warehouse rental costs were a large contributor to operating expenditure (OPEX) and increased proportionately as the degree of decentralization increased. Therefore, a globally optimal solution incorporating the minimum cost, minimum GHG emissions and shortest travel distance was not possible. From a financial perspective, increased decentralization was not appealing, meaning the use of one RRF was the most favourable scenario. Weight limitations of the truck were found to influence the travel route designations within the model road network. However, transportation had a small effect on the systems monetary cost, as it only accounted for 2% to 6% of the total OPEX across all design scenarios. This is likely due to the geographical configuration of Cape Town. Similar studies in larger areas with more dispersed collection locations may yield different results. It was found that a positive net present value was achieved if the recovered fertilizer was capable of being sold at prices in line with commercially available liquid fertilizers, with similar nitrogen content. However, it is likely overly optimistic to believe the recovered liquid fertilizer could break into the South African fertilizer market and immediately compete with established products. Although, it was shown that the liquid fertilizer produced would only need to be sold at R22.75/L to equate the total system expenditure to the total income, over a five‐year period. Conclusion and Outlook It was determined that the decentralized approach to urine treatment, investigated in this research, exhibited several advantages over biological nutrient removal at conventional wastewater treatment plants. These advantages included lower GHG emissions and energy expenditure for a similar operating cost. This study ultimately shows that the collection of source‐separated urine for the purposes of resource recovery holds significant potential from a monetary and an environmental perspective. Furthermore, the combination of transportation planning and waste management could play an important role in future studies aiming to improve decentralized sanitation systems.

The water sector is entering a period of uncertainty, as stressors such as climate change pose unknown risks to its infrastructure. Utilities need to build resilience to handle unpredictable changes, but the field of resilience in water management is still at its infancy. This thesis will first examine the state of the art of resilience implementation in water resource recovery facilities (WRRF) and identify challenges to its implementation. Secondly, a framework to measure resilience using modelling techniques is proposed. Thirdly, a WRRF model is calibrated and validated at full scale using state of the art dynamic aeration modelling, to be used to validate the framework with two stressors: stormwater and power outage
El sector de l'aigua està entrant en un període d'incertesa, ja que estressors com el canvi climàtic suposen un perill desconegut per a la seva infraestructura. Les companyies han d'incorporar resiliència per tal de gestionar els canvis impredictibles, però aquest camp de la ciència a l'àmbit de la gestió de l'aigua està a la seva infància. Aquesta tesi examinarà primer l'estat de l'art de la implementació de resiliència en plantes de tractament d'aigua, i identificarà reptes per a la seva implementació. A continuació, una guia per a mesurar resiliència amb l'ajuda de tècniques de modelacio es proposada

La transizione dal concetto di ‘’impianto di trattamento delle acque reflue’’ a quello di ‘’impianto di recupero di risorse dalle acque reflue a bassa impronta di carbonio’’ è stata indirizzata affrontando i seguenti temi: il riutilizzo dell'acqua depurata, il recupero di risorse e la valutazione dell'impronta di carbonio. In particolare, per quanto riguarda il riutilizzo dell'acqua depurata sono stati analizzati e confrontati trattamenti convenzionali di affinamento del refluo e soluzioni innovative che prevedono trattamenti anaerobici a membrana. In questo contesto, è stata operata per circa due anni una filiera di trattamento a scala pilota, composta da un reattore anaerobico UASB combinato con una membrana di ultrafiltrazione (AnMBR). Operando con un carico organico (OLR) di 1 kg COD/m3/giorno, la produzione di biogas era di circa 0.39 ± 0.2 L/giorno. L'aumento dell'OLR a 2 kg COD/m3/giorno ha determinato un aumento della produzione di biogas fino a 4.11 ± 3.1 L/giorno. Le condizioni di elevata salinità (1500 mgCl/L) hanno influito negativamente sulla produzione di biogas senza creare fenomeni di sporcamento aggiuntivi alla membrana. L'effluente finale trattato soddisfa gli standard di qualità della CLASSE A del nuovo regolamento UE 741/2020 per il riutilizzo dell'acqua ed è adatto per scopi di fertirrigazione in agricoltura. Un'unità aggiuntiva è stata combinata al trattamento AnMBR per la rimozione dei contaminanti emergenti (CECs), utilizzando polimeri a impronta molecolare (MIPs). È stata avviata una colonna di adsorbimento e il diclofenac è stato utilizzato come composto target. L'efficienza di rimozione è risultata pari al 50%. Sono state inoltre indagate la presenza di microplastiche (MPs) nelle acque reflue. Dai risultati sperimentali lo schema a fanghi attivi convenzionali, in scala reale, ha rimosso l'86% di MPs, mentre la filiera anaerobica su scala pilota ha ottenuto una rimozione del 94%. In questo scenario è stato anche progettato e realizzato un prototipo per il campionamento di volumi di refluo significativi al fine di rilevare concentrazioni rappresentative di MPs. Sono stati affrontati, inoltre, l’aspetto dell’inquinamento dovuto ai sovraflussi di piena della fognatura mista e i problemi relativi alla balneazione delle acque validando in campo filiere di trattamento modulari composte da filtro rotativo dinamico, adsorbimento su carbone attivo granulare e disinfezione UV. I risultati del pilota hanno mostrato rimozioni di TSS, COD ed E.Coli rispettivamente pari al 90%, 69% e 99%. Inoltre, sono stati condotti studi di fattibilità su impianti in piena scala che prevedono l’integrazione di soluzioni di recupero delle risorse quali fosforo, acidi grassi volatili e biopolimeri. In particolare, sono state valutate, utilizzando metodi quali CBA, S-LCA ed SRL, soluzioni eco-innovative, sviluppate nell'ambito del progetto H2020 Smart-Plant da integrare agli impianti esistenti ai fini di chiudere il ciclo dell’acqua. Complessivamente, gli impianti di depurazione integrati con le SMARTechs mostrano benefici ambientali e sociali, con un valore economico totale (TEV) massimo superiore di un 23% rispetto allo scenario di base, mentre i valori di SRL sono risultati nel range 6-7, dimostrando una buona accettazione sociale e un buon potenziale di adattamento delle SMARTechs. Infine, è stato approfondito il tema del Carbon Footprint per il servizio di depurazione, proponendo un nuovo approccio metodologico. La maggior parte dei fattori di emissione considerati è stata validata da campagne di misura in 12 impianti. I valori specifici dell’impronta di carbonio sono pari a 0.04-0.20 tonCO2eq/AE/anno, variabili in base alle dimensioni dell'impianto. Le categorie più impattanti sono state individuate nelle emissioni indirette associate ai GHG disciolti, scaricati nel corpo idrico superficiale e al consumo energetico, che contribuiscono rispettivamente per il 13-70% e il 10-40%.
Technical solutions for the transition from ‘wastewater treatment plant’ (WWTP) to the concept of ‘low-carbon water resource recovery facility’ (WRRF) were assessed, addressing i) water reuse, ii) resource recovery and iii) carbon footprint assessment. Specifically, in terms of water reuse, conventional ‘’fit-for-purpose’’ treatments and innovative solutions as anaerobic treatments were analysed and compared. A pilot scale system, placed in a hotspot of seawater intrusion, composed of an upflow granular anaerobic sludge blanket (UASB) reactor coupled with AnMBR (Anaerobic Membrane Bioreactor) was set-up and operated for more than 2 years. At an organic loading rate (OLR) of 1 kg COD/m3/d, biogas production was around 0.39 ± 0.2 L/d. The increase of the OLR to 2 kg COD/m3/d resulted in increase of biogas production to 4.11 ± 3.1 L/d with fermented cellulosic sludge addition. High saline conditions of 1500 mgCl/L adversely affected the biogas production without deteriorating the membrane operation. The final effluent met quality standards of CLASS A of the new EU regulation741/2020 for water reuse and resulted suitable for fertigation purposes in agriculture. An additional unit was coupled with the AnMBR treatment for removing contaminants of emerging concern (CECs), using Molecurarly Imprinted Polymers (MIPs) as adsorbent filler. An adsorption column was started-up and diclofenac was used as target compound. Removal efficiency was up to 50%. Additionally, microplastics (MPs) occurrence and removals in wastewater treatments were investigated. The full-scale conventional activated sludge scheme removed 86% of MPs, while the pilot-scale UASB+AnMBR configuration achieved 94% MPs removal. The results highlighted an accumulation phenomenon of MPs in the sludge and this affected negatively the methanogenic activity of anaerobic biomass. In this scenario also a prototype system for collecting significant wastewater sampling volumes to detect more representative MPs concentrations was designed and realized. On the other hand, water pollution in stormwater and related water bathing issues were addressed assessing combined sewer overflows (CSOs) management strategies and validating advanced compact treatments, composed of dynamic rotating belt filter, adsorption on granular activated carbon and UV disinfection, to minimize their impacts. The results of pilot treatment showed great potential for TSS, COD and E. coli removal efficiencies with more than 90%, 69% and 99%, respectively. Moreover, feasibility studies in full-scale WWTPs, addressing resource recovery solutions, including phosphorous salts, volatile fatty acids and biopolymers recovery were carried out. In particular, real environment eco-innovative solutions, developed within the H2020 Smart-Plant project to renovate existing WWTPs and close the circular value chain, were assessed using Cost-Benefit Analysis (CBA), Social Life Cycle Assessment (S-LCA) and Social Readiness Level (SRL) methods. Overall, the SMARTechs created benefits both from an environmental and social point of view, with a maximum total economic value (TEV) up to +23% compared to baseline scenario. In terms of social assessment SMARTechs fell in SRL range of 6-7, which implies a good societal acceptance and adaptation potential. Finally, Carbon Footprint Assessment for the wastewater treatment service was deeply investigated, proposing a new methodological evidence-based approach. Most of the considered emissions factors for carbon footprint assessment were validated by site-specific measurements campaigns in 12 WWTPs. Specific carbon footprints resulted in the emissions of 0.04-0.20 tonCO2eq/PE/y, varying according to the size of the plant. The most impactful categories were identified for indirect emissions associated with dissolved GHGs discharged in the surface water body and due to energy consumption, which accounted for 13–70% and 10–40%, respectively.

Wastewater treatment has developed as a mature technology over time. However, conventional wastewater treatment is a very energy-intensive process. Bioelectrochemical system (BES) is an emerging technology that can treat wastewater and also recover resources such as energy in the form of electricity/hydrogen gas and nutrients such as nitrogen and phosphorus compounds. Microbial electrolysis cell (MEC) is a type of BES that, in the presence of an additional voltage, can treat wastewater and generate hydrogen gas. This is a promising approach for wastewater treatment and value-added product generation, though it may not be sustainable in the long run, as it relies on fossil fuels to provide that additional energy. Thus, it is important to explore alternative renewable resources that can provide energy to power MEC. Waste heat is one such resource that has not been researched extensively, particularly at the low-temperature spectrum. This was utilized as a renewable resource by converting waste heat to electricity using a device called thermoelectric generator (TEG). TEG converted simulated waste heat from an anaerobic digester to power an MEC. The feasibility of TEG to act as a power source for an MEC was investigated and its performance compared to the external power source. Various cold sources were analyzed to characterize TEG performance. To explore this integrated TEG-MEC system further, a hydraulic connection was added between the two systems. Wastewater was used as a cold source for TEG and it was recirculated to the anode of the MEC. This system showed improved performance with both systems mutually benefitting each other. The operational parameters were analyzed for the optimization of the system. The integrated system could generate hydrogen at a rate of 0.36 ± 0.05 m3 m-3 d-1 for synthetic domestic wastewater treatment. For the practical application, it is necessary to estimate the cost and narrow the focus on the functions of the system. Techno-economic analysis was performed for MEC with cost estimation and net present value model to understand the economic viability of the technology. The application niche of the BES was described and directions for addressing the challenges towards a full-scale operation were discussed. The present system provides a sustainable method for wastewater treatment and resource recovery which can play an important role in human health, social and economic development and a strong ecosystem.
Doctor of Philosophy
An average person produces about 50-75 gallons of wastewater every day. In addition to the households, wastewater is generated from industries and agricultural practices. As the population increases, the quantity of wastewater production will inevitably increase. To keep our rivers and oceans clean and safe, it is essential to treat the wastewater before it is discharged to the water bodies. However, the conventional wastewater treatment is a very energy (and thus cost) intensive process. For low-income and developing parts of the world, it is difficult to adapt the technology everywhere in its present form. Furthermore, as the energy is provided mostly by fossil fuels, their limited reserves and harmful environmental effects make it critical to find alternative methods that can treat the wastewater at a much lower energy input. For a circular and sustainable economy, it is important to realize wastewater as a resource which can provide us energy, nutrients, and water, rather than discard it as a waste. Bioelectrochemical systems (BES) is an emerging technology that can simultaneously treat wastewater and recover resources in the form of electricity/hydrogen gas, and nitrogen and phosphorus compounds. Microbial electrolysis cell (MEC) is a type of BES that is used to treat wastewater and generate hydrogen gas. An additional voltage is supplied to the MEC for producing hydrogen. In the long run, this may not be sustainable as it relies on fossil fuels to provide that additional energy. Thus, it is important to explore alternative renewable resources that can provide energy to power MEC. Waste heat is a byproduct of many industrial processes and widely available. This was utilized as a renewable resource by converting waste heat to electricity using a device called thermoelectric generator (TEG). TEG converted simulated waste heat from an anaerobic digester to power an MEC. The mutual benefit for MEC and TEG was also explored by connecting the system electrically and hydraulically. Cost-estimation of the system was performed to understand the economic viability and functions of the system were developed. The present system provides a sustainable method for wastewater treatment and resource recovery which can play an important role in human health, social and economic development and a strong ecosystem.

More than 80 per cent of wastewater from human activities is discharged into the rivers or sea without any pollution removal, and the Sustainable Development Goals (SDGs) aim to halve this proportion and increase recycling and reuse globally by 2030. Treatment plants in Sub-Saharan Africa often fail due to lack of operating funds, poor regulation and poor design that does not take into account human factors. The failure of treatment plants can also be put down partly to the funding structures for management, which are often dependent on the disposal tariffs charged. Without sufficient regulation and enforcement, which is often lacking in Sub-Saharan Africa, this often leads to illegal disposal of faecal sludge. Due to the nutrient content and energy potential of wastewater, there is increasing focus on reuse of faecal sludge in ways that can contribute funds for maintenance and incentivise good management of treatment facilities. This research investigates potential designs for the re-use of faecal sludge in small cities in Sub-Saharan Africa to ensure proper treatment. Conducting two case studies using qualitative and quantitative methods, the research looks at the potential for re-use to be scaled up in Sunyani, Ghana and Mzuzu, Malawi, and whether different designs can ensure good management. Building upon the research investigation into how previous designs have failed in case studies, the research also investigates the use of agent-based modelling (ABM) as a modelling approach to explore social and technical aspects of sanitation systems to predict how different designs and management approaches can work. In Sunyani, biogas was the most acceptable option to customers whilst also providing a good business model to fund faecal sludge treatment, either as a decentralised system at public toilets where the fresh sludge is better for biogas production, or centrally at the existing disposal site. The success of biogas as a model that can fund maintenance and ensure good management would depend on the faecal sludge quality of public toilet sludge in the city and the investment level required and how any operating approach would work between the government and private sector. In Mzuzu, two main approaches to faecal sludge re-use exist currently: the implementation of Skyloos as above ground household toilets which provide compost, and a central disposal site from which compost is illegally harvested. At disposal, farmers remove sludge from the ponds and apply it untreated directly onto agricultural land. At times, private sector emptying services do not use the ponds, but also apply untreated sludge to agricultural land. Skyloos were found to have varying levels of success from different Non- Governmental Organisation (NGO) projects, with key sustainability issues being the availability of financing mechanisms, management between landlords and tenants and the trust of and engagement with implementing organisations. Existing approaches to waste management and re-use were found to be inaccessible and not working when implemented for the poorest and people with disabilities. Adopting re-use of faecal sludge in agriculture in Malawi would require improved marketing of sanitation options, financing options for households to incentivize adopting the technology, not targeting to poorest households and people with disabilities, and an improved management model for the treatment site to ensure safe disposal and production of compost. Looking at ABM as a way of modelling faecal sludge treatment systems in Sub- Saharan Africa, two models of different approaches in Mzuzu were developed to look at scaling up Skyloo toilets and managing the treatment plant. Both models demonstrate the potential of ABM to incorporate social and technical aspects into predicting the performance of different designs and approaches. The success and use of modelling depends on the quality of data that can be collected before implementing system approaches. Overall the thesis presents different models of treatment and re-use that can work and contribute to operating and maintenance of systems. It is unlikely that any design system will be so profitable that the treatment and re-use of sludge will be able to ensure good management without regulation, so the success of designs depends on relationships between the government and private sector and households in small cities.

Organic matter and nutrients present in urban and industrial wastewater should be removed or valorised to reduce its impact on the environment. Conventional wastewater treatments are focused on the removal of these pollution sources at the minimum cost. The idea of resource recovery from wastewater is changing the concept of the conventional wastewater treatment plants that tend to incorporate little by little processes as anaerobic digestion, MBR, biofilm, granulation, etc. However, their application to obtain reusable by-products from wastes should be cost effective. Winery wastewater is an effluent with a highly biodegradable organic load, worth considering for biogas production, and low nutrient content. A sidestream anaerobic membrane bioreactor (AnMBR) was started up and operated under organic load oscillations. The stable operation was assured by keeping a ratio between intermediate alkalinity and total alkalinity (IA/TA) below 0.3 achieving a 96.7±2.7% COD removal efficiency. The biogas production varied according with the OLR that was on average 0.50±0.17 m(3)(biogas)/m(-3)(digester)/d(-1) with an 87.1±3.0% of methane. The external membrane module reached a flux of 20.2 ± 8.5 LMH at a crossflow velocity of 0.64 m s-1. The crossflow velocity helped to remove the cake layer attached on the membrane that was the main contribution (>80%) to flux decline. The energy demand of the AnMBR was calculated considering the net energy production of a combined heat and power (CHP) unit. It was concluded that only when influent COD was over 3.25 gCOD 1:1- the energy balance was positive. Considering the upscaling of the AnMBR of the present study, the submerged membrane configuration would be a more feasible option due to its lower operational costs, especially in winter season. Simulating the conditions of winter season, winery wastewater was treated in the AnMBR at low temperatures of 25°C and 15°C. Since the organic load of winery wastewater in winter is much lower than in summer (vintage season), the average OLR applied was 0.32 and 0.29 kgCOD m(-3)(digester)/d(-1) the average COD removal reached was 80% and 71% at 25°C and 15°C., respectively. Moreover, higher degree of fouling was observed despite the amount of suspended solids was lower, so frequent cleanings were necessary. The effluent of anaerobic digestion often requires a post-treatment to remove nutrients, especially nitrogen. Compared with conventional biological nitrogen removal, nitritation/denitritation (N/DN) via nitrite represent a 25% less aeration and 40% less external carbon source. In order to reach higher flexibility and reducing space requirements, N/DN can be carried out in a sequencing batch reactor (SBR). Under feast and famine conditions applied in the SBR, storage compounds can be served as internal carbon sources for post-anoxic denitrification. A novel scheme was developed for the treatment of municipal wastewater; consisting in an UASB reactor followed by a short cut sequencing batch reactor (scSBR) in the main water line. Nitritation/denitritation was integrated with the selection of polyhydroxyalkanoate (PHA) storing biomass. Biowaste fermented liquid was applied as carbon source in the feast regime. The average nitrogen removal was 83%. After achieving an acceptable ammonia removal of 93%, there was enough available PHA for the subsequent denitritation, reaching a maximum nitrite removal of 98%. The maximum PHA content was 10.6% (gPHA gTSS-1) after 10 h of accumulation when biowaste fermented liquid (C/N/P= 100/4.5/0.42) was applied. Nitrogen removal limits could be successfully met while PHA-storing biomass was selected. Although higher PHA yields can be achieved under complete aerobic conditions, this novel scheme presents an added value due to the integration of the PHA production in the nitritation/denitritation process.
Un dels reptes de les estacions depuradores d'aigües residuals (EDAR) és aconseguir una elevada eficiència d'eliminació de contaminants amb menys demanda energètica, atenent als requeriments legals, cada dia més restrictius. A més a més, l'afany de recuperació de recursos a partir dels residus promou el desenvolupament de noves tecnologies pel tractament d'aigües residuals valoritzant-ne la matèria orgànica i els nutrients que conté. La digestió anaeròbia és un procés pel qual la matèria orgànica es transforma en una font d'energia, com és el biogàs. Actualment, la digestió anaeròbia s'aplica a residus com els fangs de depuradora, purins, etc. En aquesta tesi, s'ha estudiat la digestió anaeròbia per al tractament d'aigües residuals amb poca càrrega orgànica, utilitzant bioreactors de membrana anaeròbics (BRM-An) per tal de retenir la biomassa en el digestor. S'ha tractat aigua residual procedent de la indústria vitivinícola, caracteritzada per un alt contingut en matèria orgànica i pobre en nutrients, avaluant la flexibilitat del BRM-An a oscil•lacions de càrrega orgànica, així com la seva viabilitat en termes energètics. Pel que fa a l'aigua residual municipal, la digestió anaeròbia requereix de post-tractaments d'eliminació de nutrients. En aquesta tesi, s'han estudiat dos processos d'eliminació de nitrogen: nitrificació/desnitrificació (N/DN) via nitrit i nitrificació parcial — Anammox (de l'anglès anaerobic ammonium oxidation). Ambdós possibilitats presenten un estalvi considerable en comparació amb la N/DN convencional. És ben sabut que la N/DN via nitrit suposa una reducció de les necessitats d'aireig i matèria orgànica. En el present treball s'ha estudiat la integració de l'eliminació de nitrogen via nitrit amb la producció de polihidroxialcanoats (PHA), bioplàstics d'alt interès comercial que s'acumulen a l'interior de les cèl•lules donades les condicions adients (sacietat — fam). Tots els estudis s'han portat a terme a escala de laboratori i s'han obtingut conclusions satisfactòries en al majoria de casos, arribant a la conclusió que valoritzant la matèria orgànica present en les aigües residuals com una font de recursos i reduint el cost dels sistemes d'eliminació de nutrients, les EDAR esdevindran processos molt més sostenibles.

Current treatment of wastewater can effectively remove the contaminants; however, the effluent is still not widely reused because of some undesired substances like pathogens and trace organic chemicals. To promote water reuse, membrane-based technologies have emerged as a robust and more efficient alternative to current treatment practice. Among these membrane processes, forward osmosis (FO) utilizes an osmotic pressure gradient across a semi-permeable membrane to reclaim high-quality water. Still, several key challenges remain to be addressed towards broader FO application, including energy-intensive draw regeneration to yield product water and salinity buildup in the feed solution. To bypass energy-intensive draw regeneration, commercial solid fertilizers was utilized as a regeneration-free draw solute (DS), harvesting fresh water towards direct agricultural irrigation. However, using nutrient-rich fertilizers as DS resulted in an elevated reverse solute flux (RSF). This RSF, known as the cross-membrane diffusion of DS to the feed solution, led to deteriorated solute buildup on the feed side, reduced osmotic driving force, increased fouling propensity, and higher operation cost. To effectively mitigate solute buildup while achieving energy-efficient water reclamation, a parallel electrodialysis (ED) device was integrated to FO for DS recovery in the feed solution. The salinity in the feed solution was consistently controlled below 1 mS cm-1 via the hybrid FO-ED system. Considering solute buildup is merely a consequence of RSF, direct control of RSF was further investigated via operational strategy (i.e., an electrolysis-assisted FO) and membrane modification (i.e., surface coating of zwitterion-functionalized carbon nanotubes). Significantly reduced RSF (> 50% reduction) was obtained in both approaches with minor energy/material investment. With two major bottlenecks being properly addressed for energy-efficient water reclamation, FO was further integrated with a microbial electrolysis cell (MEC) to achieve integrated nutrient-energy-water recovery from high-strength wastewater (i.e., the digestor centrate). The abovementioned research projects are among the earliest efforts to address multiple key challenges of FO during practical application, serving as a cornerstone to facilitate the transformation of current water/wastewater treatment plant to resource recovery hub in order to ensure global food-energy-water security.
Doctor of Philosophy
Exploring alternative water supply, for instance via reusing wastewater, will be essential to deal with the global water crisis. Current wastewater treatment can effectively remove the contaminants; however, the treated wastewater is still not widely reused due to the possible presence of residual contaminants. In recent years, membrane-based technologies have emerged as a promising treatment process to produce clean water. Among all available membrane technologies, forward osmosis (FO) takes advantage of the osmotic pressure difference across a special membrane to extract fresh water from a low-salinity FEED solution (for example, wastewater) to a high-salinity DRAW solution. The reclaimed fresh water can be reused for other applications. Still, the FO process is facing several critical challenges for broader applications. The first challenge is that additional energy is required to separate clean water from the diluted DRAW solution, leading to notably increased energy consumption for the FO process. To bypass this energy-intensive separation, commercial solid fertilizers was utilized as a separation-free DRAW solution for FO process. Once the clean water is extracted to the DRAW solution (fertilizer), the diluted fertilizer solution together with the fresh water can be directly used for agricultural irrigation. The second challenge is that, when fertilizer is applied as the DRAW solution, nutrient rich fertilizers can penetrate the FO membrane and escape to the FEED solution (wastewater). This phenomenon is known as the reverse solute flux (RSF). RSF can result in many adverse effects, such as wastewater contamination and increased operational cost. To prevent this, we used an additional device named electrodialysis to effectively recapture the “escaped” fertilizers in the FEED solution. Besides this indirect approach to recover escaped fertilizers, we also investigated direct approaches to control RSF, including operational strategy and membrane modification. With two major challenges being properly addressed for energy-efficient water reclamation, FO was further combined with a microbial electrolysis cell (MEC) to achieve multiple resource recovery from wastewater, including water, nutrient, and energy components. The above mentioned research projects are among the earliest efforts to address multiple key challenges of FO during water and resource recovery from wastewater to ensure global food-energy-water security.

碩士
大葉大學
環境工程學系碩士班
98
A technology development for the recycling of tin sludge waste into a product of tin (II) chloride was implemented in this study. The main tasks of this study include: study on HNO3 leaching, study on HCl leaching, study on the pH adjustment method, study on the crystallization method and purity analysis of tin (II) chloride. The results of this study reveal that 100% Pb and 93.88% Zn contained in the tin sludge waste can be removed by using HNO3 leaching method to obtain a high purity of SnO2. 94.76% of this obtained SnO2 can be dissolved by using HCl leaching method with the addition of H3PO2. 100% Sn contained in this dissolving solution can be recovered into a metallic Sn by using Zn replacement method. The recovered metallic Sn is then subject to HCl leaching process to form a tin (II) chloride solution. The final target product of tin (II) chloride can then be obtained by crystallizing this solution. The determined purity of this obtained tin (II) chloride product is about98.69%.

碩士
大葉大學
環境工程學系碩士班
95
The copper sludge may serious pollute the environment, if it is not properly disposed of. In order to recover the copper from copper sludge, a series of tests of leaching, crystallization and replacement are conducted in this study. The results of this study reveal that the copper sludge can be 100% dissolved into a leaching solution by adding 36N sulfuric acid and deionized water. After first crystallization, a high purity of CuSO4 crystal can be obtained from this leaching solution. The remaining crystallization solution which contains 6.28％ of copper is sent back to the leaching and crystallization process to enhance the copper recovery. After second crystallization, the remaining crystallization solution which contains 4.32％ of copper is subjected to a replacement process by adding iron powder to recover the copper of this solution. A maximum of 99.57％ of copper can be recovered by this process. The remaining replacement solution (FeSO4) which contains 6.24％ of ferrous ion can be used as a flocculant reagent for waste water treatment. This study can achieve a 100% recovery of copper and zero waste discharge for copper sludge recycling.

Single cell protein (SCP) defines the dried cells of microorganisms that can be used as a protein supplement both in animal feed or human food. SCP could represent an effective alterna-tive to meet the high and growing demand of feed products. This work aimed to develop a simple and economically feasible process to obtain SCP by adding value to an industrial waste stream. Spent sulfite liquor (SSL), pure glycerol and crude glycerol and two different types of wood oils were selected. However, the wood oils were early discharged (after characterization) as possible substrates due to their low chemical oxygen de-mand (COD) content and an unpleasant and undesirable smell. Thus, only SSL and pure and crude glycerol were tested. Crude glycerol proved to be the most viable choice given the high COD content – - g O2/L – and the low price per ton of COD – 200 €/ton COD. In continuous mode it was possible to achieve biomass concentrations of - g CDW/L (- g CDW/g COD) while efficiently removing - % of the COD of the influent stream. When tested in batch mode, biomass concentration reached a maximum of - g CDW/L (- g CDW/g COD) after - days of operation. After - days of operation, CDW per liter started to decrease which could indicate some sort of inhibition by fermentation by-products or other toxic compounds. Considering a batch operation mode, it was possible to produce SCP (- %w/w of protein content) with a commercial price of - €/ton protein. Thus, SCP production was considered feasible since it was possible to obtain a product that can highly compete with other feed products, for example, fishmeal (market price: 1.940 €/ton protein).

碩士
大葉大學
環境工程學系碩士班
102
The purpose of this study was to recover Indium and Gallium metals from Gallium containing dust, collected during the process of manufacturing light-emitting diodes. This research was conducted and major processes involved: collection of Gallium-containing dust, composition analysis, immersion corrosion, pH adjustment, precipitation, crystallization and replacement methods. Results from this study show that the flue dust contained 4.04wt% Gallium and 60.61wt% Indium. XRD analysis of the flue dust showed that Gallium was in the form of Gallium Nitride (GaN) and Indium as metal. Impregnating agents such as sulfuric acid, hydrochloric acid, nitric acid and sodium hydroxide were used in this study for determining the optimal reagent for impregnation and dissolution of the Gallium-containing dust. For the optimum Gallium leaching solution, Iron and Zinc sheets were used for the replacement of Gallium from solution. The replacement efficiencies were 68.10% and 8.05% for Zinc and Iron sheets respectively. The optimum impregnation solution was further used for the recovery of Gallium by crystallization recovery. The white crystals obtained after crystallization were analyzed by Scanning Electron Microscopy-Election Dispersion Spectroscopy (SEM-EDS), and showed that the major crystalline material by weight contained 27.91% Gallium, 27.67% Sodium and 44.42% Oxygen and other elements. The optimum leaching solution for Gallium was hydrochloric acid. For the precipitation of Gallium from this optimum leaching solution, sodium chloride and sodium sulfide were used as precipitation agents to precipitate and recover Gallium. Gallium precipitation in sodium chloride yielded 56.59% recovery of Gallium as Gallium chloride and Gallium precipitation in sodium sulfide yielded 47.20% recovery of Gallium as Gallium sulfide. In this study hydrochloric acid effectively leached 100% Gallium from optimum gallium-impregnated solution.

碩士
大葉大學
環境工程學系碩士班
91
As the gallium arsenide (GaAs) production continues to increase, the amount of scrap GaAs generated each year is also noticeable. Due to the hazardous material of As and valuable resource of Ga contained in the scrap GaAs, the discarded GaAs will present hazardous effects to the environments if they are not treated properly. The main objective of this study is to adopt hydrometallurgial methods to recover the valuable metal of Ga from GaAs and to disposal its hazardous material of arsenic properly. In this study, several methods of leaching, solvent extraction, cementation, ion-exchange, crystallization, electric winning are adopted to investigate the recovery of Ga and treatment of As. This study shows that Ga and As can be leached by 0.5 N NaOH with 0.5 vol% H2O2 (solid/liquid: 4g/100ml; leaching time: 1 hours) to obtain a 100% recovery of Ga and As. This optimal leaching solution is then subjected to a series recycling process of a pH adjustment (to 1.8 with H2SO4), a solvent extraction (by using 5 vol% D2EHPA), a back-extraction (by using 6N H2SO4) and Crystallization to obtain a product of gallium sulfuric (H4Ga2(SO4)5．12H2O). The total recovery of Ga by using aforementioned processes is about 70.7% . For the solution containing As, it is first treated by a pH adjustment to 11 with NaOH Then, Fe2(SO4)3 is added at a Fe/As ratio of 6 to precipitate the As as FeAsO4. The remaining As contained in the solution can be further removed by ion-exchange method by using Amberjet 4400 OH. The aforementioned processes can achieve a 99.999% removal of As.

碩士
大葉大學
環境工程研究所
90
Scrap lithium batteries contains various metals of lithium (Li), cobalt (Co), aluminum (Al) and nickel (Ni). These metals may seriously pollute the environment, if they are not properly disposal. In order to minimize the pollution problems and to conserve the limited natural resources, a hydrometallurgical procedure is developed in this study to recover these valuable metals (i.e., Li and Co) contained in the scrap lithium batteries. In this study, several methods of electricity discharge, leaching, solvent extraction, cementation, precipitation and electrolytic winning are adopted to investigate the recovery efficiency of lithium and cobalt of scrap lithium battery. The result of this study reveals that the positive electrode of lithium battery mainly contains Li (65400ppm), Co (529000ppm), Ni (11400ppm ) and Al (110300ppm). These metals can be leached with 4.0 N HCl at 70℃ (solid/liquid: 3g/100ml; leaching time: 2 hours) to obtain a optimal leaching recovery of 96.4% for Li and 99.7% for Co. After pH adjustment of the optimal leaching solution to 8 with NaOH, the Li can remain in the solution whereas the Co, Ni and Al precipitate as a jelly mixture. After filtration, the Li can be recovered as lithium carbonate precipitate by the addition of saturated sodium carbonate solution at 95℃. The precipitated jelly mixture was dissolved in the sulfuric acid with ammonia water at pH 4.3 to precipitate Al. Then, the Co and Ni contained in the solution can be recovered as a Co-Ni mixture by electrolytic refining.

碩士
大葉大學
環境工程學系碩士班
101
This study focuses on the recycling of neodymium metal from waste neodymium containing magnet. Methods adopted include: grinding and screening, component analysis, surface coating, leaching, pH adjustment, electrolysis and replacement method to determine the optimal recovery technology. Analysis revealed neodymium content of 192,649 mg/kg, 0.06% water content, 86.00% ash content, 14.06% combustible material and specific gravity 5.25. Optimum leaching conditions were determined to be 3N sulfuric acid with a solid-liquid of 3g/50ml at 70°C for 5 minutes which leached 100% of neodymium. Neodymium hydroxide with a purity of 98.83% can be recovered at pH 1 as a precipitate by pH adjustment using sodium hydroxide. Scanning Electron Microscopy determined the purity of the crystalline neodymium to be 99% with empirical formula Nd(OH)3.

碩士
大葉大學
環境工程學系碩士班
102
The purpose of this study was to recover Gallium (Ga) metal from scrap sapphire wafer, collected during the manufacturing process of light-emitting diodes. The major processes involved in this research are collection of scrap sapphire wafer, composition analysis, grinding and screening, leaching, precipitation, replacement, electrolysis and crystallization. The result of this study reveals that the Ga, water, ash, combustible content and specific gravity of the collected scrap sapphire wafer was 6426.67 mg/kg, 0.22%, 99.98%, 0% and 4.1549 respectively. An optimum Ga containing leaching solution was obtained after a series of leaching tests of the scrap sapphire wafer. The Ga leaching solution was precipitated using NaCl and Na2S to reach a Ga recovery of 48.74% and 54.15% respectively. The Ga leaching solution was also subjected to replacement using Zn, Fe and Al to reach a Ga recovery of 36.30%, 31.31% and 52.64% respectively. Further, the recovery of Ga from optimal leaching solution was also done by electrolysis method for 8 hours to obtain Ga recovery 52.17%. The Ga contained in the optimal leaching solution was also recovered by crystallization process and the obtained Ga product's enrichment was 14 times greater.

碩士
大葉大學
環境工程學系碩士班
101
The main purpose of this study is to recycle platinum from platinum containing waste. The methods adopted in this study include: collection of platinum containing waste and composition analysis, grinding and screening, impregnated dissolution, reduction, precipitation, replacement, product component analysis and determination of the optimum platinum recovery solution. The collected platinum containing waste comprised 0.979% platinum and has a density of 7.67. In this study an investigation was conducted to determine the optimum conditions for the best impregnated platinum dissolution. Sieving of the platinum-containing waste was conducted before treatment with hydrochloric acid. The addition of an oxidant impregnating agent at a specified solid-liquid ratio under agitation at a constant heating temperature resulted in 100% platinum impregnation recovery. The use of a precipitating agent at room temperature induced the precipitation of platinum. The precipitation of platinum from the platinum impregnation solution can be achieved at 99.84%. Moreover, high purity platinum products were obtained after high temperature heating of precipitated platinum product. After heating, a platinum black of 100% purity was obtained.

碩士
大葉大學
環境工程學系碩士班
104
The purpose of this study was to recover gallium metal resources for the recycling of gallium-containing wastes obtained from the light-emitting diode manufacturing process. The methods investigated for gallium recovery were: pH adjustment, replacement, electrolysis, crystallization and ion exchange. Research results indicated the gallium metal content in the waste was 10403 mg/kg, while the moisture, ash and combustible contents were 0.66%, 99.5%, 0.05% respectively, and the specific gravity was 2.37. The optimum leaching conditions for gallium recovery from the gallium-containing wastes were: 1N sodium hydroxide leaching solution at a solid-liquid ratio of 3g / 50ml for 1 hour, at 70℃; under these operating conditions, gallium recovery of up to 100% can be achieved. After pH adjustment to 7 using HCl solution, 98.9% gallium was precipitated. For all replacement experiments, 0% gallium was obtained with iron, aluminum and zinc replacement separately. After 7.5 hours of electrolysis, gallium electrolytic recovery of up to 77.88% was achieved. Crystallization of gallium was achieved after heating for 3 hours at 90 ℃; this was confirmed by the production of a white product. Upon addition of AMBERJET 1500H ion exchange resin to the leaching solution, 98.25% gallium recovery was obtained after three hours. Keywords: gallium-containing waste, recycling, resources, waste

碩士
大葉大學
環境工程學系碩士班
93
The main purpose of this research is to recover the Polycarbonate (PC) plastic and silver from scrap digital video disk (DVD). The upper and lower PC plastics which composed of the DVD are manually separated. The removal efficiencies of surface coating layers (i.e., acrylic glue, protecting glue, silver, memory dye and advertisement ink) of these separated PC plastics by various leaching solution are investigated in this research. The recovery of silver which contained in the final leaching solution by replacement, electrical wining and precipitation methods is also studied in this research. The results of this study reveal that all the surface coating layers of the separated PC plastics can be 100% removed by using 6.0N Nitric acid as the leaching solution with a solid/liquid ratio of 3g/25ml, leaching time of 90 minutes and leaching temperature of 50℃ This leaching test is performed in an ultrasonic cleaning device. The silver coating which 100% leached into this leaching solution can be totally recovered by adding sodium chloride solution (10 ml leaching solution mixed with 0.05ml of 1M sodium chloride solution ) to form a AgCl precipitate. The PC plastic and AgCl precipitate recovered from aforementioned recycling processes can then be sold to the recyclers for further recycling treatments. This research also conducts a LCA (Life Cycle Assessment) study for DVD product by SimaPro 5.0. The results of this LCA study show that environment impact values for DVD’s manufacture stage, transportation stage, and usage stage are 0.864 mPt, 0.00261 mPt and 0.36 mPt , respectively. For DVD’s disposal stage, three solutions of incineration, landfill and recycling are investigated. The LCA study for the recycling solution of DVD is according to the best recycling processes obtained in this research. The environment impact values of incineration, landfill and recycling solutions obtained in this LCA study are 0.247 mPt, 0.223 mPt, and 1.56mPt, respectively. The larger environment impact value means a greater impact to the environment.

碩士
國立雲林科技大學
環境與安全工程系碩士班
93
This research aims to the recovery of silver from the fixing waste liquid with electrolysis .To find out the best efficiency of recovering silver condition by changing the electric current, and estimate the economic benefits the recovery of silver in high electric current and low electric current, To determine the treatmet of the high COD waste liquid after retrieving the silver. The experimental result shows that 98.21% silver are recovery when high electric current is 3A electrolytic 3.5 hours, and the purity of silver is 98.62% and it only 80.55% silver retrieve. When low electric current is 0.5A while being electrolytic for 8 hour. The purity of silver is 99.16%. The recovery efficiency and the electric consumption are considered to assess the economic benefits during the electrolyis. The recovery amount of the silver is 2228.95mg/L in 0.5A for 8 hours electrolysis, and 0.00752 kWh electric consumption；the recovery amount of the silver is 3067.26mg/L in 3A for 3.5 hours electrolysis, and 0.04378kWh electric consumption. From the recovery efficiency, electrolytic time and electric consumption, we know that the electric current 3A, is the best condition for silver retrieve from waste fixer liquid. Original fixing waste liquid with 99,616 mg/L COD. After electrolyzing for 8 hours in 3A electric current ,COD ture to 81,504 mg/L. And 18,112 mg/L COD are removed, therefore using high electric current to electrolyze and oxidizing the fixing waste liquid can retrieve the silver effectivly, and remove COD concentration indirectly as well.

碩士
大葉大學
環境工程學系碩士班
93
ABSTRACT The main purpose of this study is to recover the valuable metals of Indium and Tin as well as the clean glass substrate from scrap liquid crystal display (LCD). After manually dismantling, the liquid crystal and polarizing filter which attached to the surface of glass substrate can be removed by immersing this glass into the ethyl alcohol and liquid nitrogen baths, respectively. The indium tin oxide (ITO) which coated on the remaining glass surface can be 100% leached either by hydrochloric acid or by sodium hydroxide. The optimum hydrochloric acid leaching procedure is (1) Use 6 N hydrochloric acid as the leaching solution under 70℃ with the solid/liquid ratio of 10 grams/50 milliliters. (2) After two hours leaching, the indium and tin can be 100% leached into the leaching solution from glass substrate. (3) The pH of this leaching solution is adjusted to 13 by NaOH to precipitate indium from solution. 90% recovery of indium can be achieved by this process. (4) The remaining leaching solution which containing tin is then adjusted by HCl to reach a pH of 7 to precipitate tin. The recovery of tin by this process is 100%. Whereas, the optimum sodium hydroxide leaching procedure is：(1) Use 3 N hydrochloric acid as the leaching solution under 70℃ with the solid/liquid ratio of 10 grams/50 milliliters. (2) After two hours leaching, the indium and tin can be 100% leached into the leaching solution from glass substrate. (3) After filtration, the valuable indium can be recovered as a precipitate, and the recovery of indium by this process is 100%. (4) The remaining leaching solution which containing tin may be used for further resource recovery or for final disposal.

碩士
大葉大學
環境工程學系碩士班
92
A series of tests of roasting, leaching, solvent extraction, precipitation and crystallization were conducted in this study to recover the valuable metals of tungsten and vanadium from scrap De-NOX Catalysis. The leaching result of this study reveals that 95.6 % of vanadium and 93.6 % of tungsten can be leached from scrap De-NOX Catalysis under the leaching conditions of solid/water=20g/200ml, temperature=70℃, and leaching time=1 hour. After the leaching solution treated by solvent extraction method, 92.2% of total tungsten can be extracted into organic phase under the conditions of 5 vol.% TOA(Tri-octylamine), O/A=1/1, pH=0.5, reducing agent=sodium sulfite (one vanadium equivalent weight) and extraction time=20 minutes. Whereas, 93.5% of total vanadium will remain in the aqueous solution after solvent extraction process. 91.5% of the total tungsten contained in the organic phase can be back-extracted into aqueous solution by using 0.25N NH4OH. This aqueous solution can be further processed by precipitation method with HCl to obtain a product of NH4WO4．3H2O. A final recovery 83.3 % of total tungsten is achieved by using aforementioned processes. For the vanadium contained in the aqueous solution after solvent extraction, it can be recovered by using crystallization process with NH4Cl to obtain a product of NH4VO3. The final recovery of total vanadium by using aforementioned processes is about 93.5 %.

碩士
大葉大學
環境工程學系碩士班
105
The purpose of this research is to study the recovery of samarium and cobalt metals from scrap Sm-Co magnet. The main tasks of this research are the sample collection, screening, composition analysis, leaching and purification. The results of this research shows that 90.68% of this collected scrap Sm-Co magnet sample has a size less than 100 mesh (0.149 mm) with a specific gravity, moisture content, ash content and combustible content of 6.11, 41.51%, 66.98% and -8.49%, respectively. This samarium and cobalt contents of this collected sample are 201,422mg/kg and 293,111mg/kg. The optimum leaching conditions for this sample were as follows：1N nitric acid, 3 hours, 70℃,and a solid-liquid ratio of 1g/50ml. Under these conditions, 100% samarium and cobalt can be leached. When this obtained optimum leaching solution is adjusted to pH 11 by ammonia, 100% samarium and 44.63% cobalt can be precipitated. The cobalt remained in the pH adjusted filtrate solution can be 100% recovered by electrolysis for 5 hours at a current density of 0.3 (A/cm2).

碩士
大葉大學
環境工程學系碩士班
100
The internal components of modern touch panel products contain Silver and other valuable resources, with their composition being mainly plastic and silver. Plastic recovery from touch panel is achieved via Thermal Cracking Technology (pyrolysis at 550°C for 2 hours). This pyrolysis slag contains valuable silver metal which can be recovered after further recycling processes. This study focuses on the recovery of silver from pyrolysis slag of touch panel. The processes of grinding, screening, leaching, replacement, electrolysis, and precipitation among other processes are employed here to recover and restore silver to its valuable state. 100% Silver recovery of pyrolysis slag was achieved under the following optimum conditions: grinding and screening to particle size less than 50 mesh (0.297 mm) and leaching in 4N nitric acid (5g/50ml) at room temperature for 1 hour. With the addition of reaction agent into the obtained optimum silver leaching solution at room temperature for 24 hours, silver sponge-like structures were produced. This sponge-like structure of silver was refined into ingot in a high-temperature. Alternatively, 100% silver contained in the obtained optimum leaching solution can be recovered by adding 12N hydrochloric acid to form the silver chloride precipitate with purity greater than 96%.

碩士
大葉大學
環境工程學系碩士班
102
ABSTRACT The purpose of this study was to recover Gallium(Ga) metal from waste liquid, collected during the process of manufacturing light-emitting diodes. The major processes of this study involved: collection of Ga waste liquid, composition analysis, precipitation, crystallization, adsorption and replacement methods. Results show that the waste liquid contained 0.4655wt% Ga with pH 13.45 and was subjected to replacement by Fe, Zn and Al to reach a Garecovery of 25.82%, 29.20% and 69.13% respectively.The waste liquid was precipitated using HCl, NaCl and Na2S to reach a Ga recovery of 71.53%, 83.19% and 82.65% respectively. Clam, shrimp, oyster, egg shell, crab shell, coffee ground, tea leave and chitosan were used as adsorbents and the Ga adsorption efficiencies were 32.78%, 52.41%, 36.21%, 35.55%, 36.91%, 60.74%, 65.40% and 34.62% respectively. Thiswaste liquid was also subjected to the crystallization method. The obtained crystal was analyzed by SEM-EDS and showed Ga, Sodium, Silicon and Oxygen percentages to be 30.84%, 14.00%, 8.91% and 46.98% respectively. And its Ga concentration is 22.23% analyzed by ICP. The enrichment of Ga of this crystal is 49 times of the the original waste liquid. Key Words: gallium, recycling, resources, waste liquid

碩士
大葉大學
環境工程學系研究所
107
The purpose of this study is to recover palladium (Pd) metal resource from "palladium-containing wastes" for the domestic and foreign markets. The main processes adopted in this study involving collection of Pd-containing waste, composition analysis, leaching, pH adjustment, purification and recovery. The result of this study shows that the moisture, ash and combustible content of the collected palladium-containing wastes are 2.33%, 92.32% and 5.35%, respectively. The metal content of Pd and aluminum (Al) in this sample are 506 mg/kg and 199,667 mg/kg, and the density analysis shows a value of 3.16 g/cm3. After grinding for 34 minutes, about 92.45% of the sample’s particles are smaller than 100 mesh (0.149 mm). The ground sample with a size of -100 mesh is used for following leaching tests in order to optimize the leaching recovery condition. The optimal leaching recovery rate of Pd and Al are 95.07% and 56.41%, by using a leaching condition of 10N hydrochloric acid (HCl) with solid-liquid ratio of 1g/50ml and addition 20ml of H2O2 at 70°C for 3 hours. 99.35% of Al and 6.87% of Pd contained in the optimal leaching solution can be precipitated by adjusting the solution’s pH to 8 with ammonia water. After filtration, the Pd-containing filtrate is crystallized at 70°C for 3 hours to obtain a Pd product. It contains 2169.37 mg/kg of Pd which can achieve a Pd enrichment rate of 4.29 times.