Дисертації з теми "Digested sludges"
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1
Erkan, Muge. "Reactivation Potential Of Indicator Bacteria In Anerobically Digested Sludges After Dewatering Processes." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613656/index.pdf.
Анотація:
Anaerobic digestion process which has long been known to successfully reduce the
organic content of sludge is one of the most common alternatives to meet
pathogen reduction requirements for particular classes of biosolids. However, it has
recently been reported that, significantly higher densities of indicator bacteria have
been measured in dewatered cake samples compared to samples collected right
after anaerobic digestion. In addition, this increase in bacterial population has been
commonly observed after centrifugation but not after belt filter dewatering. Even
though several theories have emerged to explain this occurrence, with the use of
molecular tools such as Quantitative Polymerase Chain Reaction (Q
2
Oliveira, Ivo Miguel Delgado Bandeira. "Evaluation of sewage digested sludge conditioning and dewatering through qualitative and quantitative laboratory methodologies towards process monitoring." Thesis, University of South Wales, 2017. https://pure.southwales.ac.uk/en/studentthesis/evaluation-of-sewage-digested-sludge-conditioning-and-dewatering-through-qualitative-and-quantitative-laboratory-methodologies-towards-process-monitoring(5a847c8f-77dc-47c8-86cf-20a64900fb42).html.
Анотація:
This thesis reports on investigations that have contributed to an advancement in the applied and fundamental understanding on how the nature, related storage and processing of digested sewage sludge can influence polymer conditioning and dewatering. The work concentrated more specifically on evaluating the impact of thermal hydrolysis as a pre-treatment to anaerobic digestion (AD) of mainly secondary sewage sludges (Advanced AD, AAD plants) in comparison with conventional mesophilic AD (CMAD) on conditioning and dewatering of the digestate, as this knowledge seemed to be lacking for an AAD technology that is increasingly being implemented. An additional contribution to knowledge from this study relates to the evaluation of how polymer conditioning and dewatering of digested sludges could be monitored using rheometric measurements. It was concluded that digested sludge biofloc characteristics (size, shear viscosity and organic matter composition) affected the most the conditioning and dewatering results but these varied depending on the process conditions i.e. AAD versus CMAD and digestate handling conditions. The reduction in particle size and shear viscosity (η[0.1 s-1]) per g Total Solids as well as the increased solubilization of protein, organically bound nitrogen and chemical oxygen demand of the digestates which contributed to the increased conditioning requirements affected also the dewatering rate and the strength of the flocs produced after conditioning. The changes in the digested sludge biofloc characteristics were detected by rheometric measurements which were well correlated with changes in organic matter composition and polymer conditioning requirements (r of 0.9 and 0.8). It was proposed that the variations in η[0.1 s-1] and organic matter content such as soluble protein could be used to predict polymer dose requirements to achieve good filterability (R2 of 0.7; significance F and p < 0.05). Future work is however required in order to consolidate these findings by monitoring conditioning, dewatering and η[0.1 s-1] of the digestate at full scale.
3
Charles, Antoine Henri Etienne. "Étude thermo-rhéologique de boues digérées : application à l’écoulement en conduite dans les procédés de méthanisation." Electronic Thesis or Diss., Ecole nationale supérieure Mines-Télécom Lille Douai, 2023. http://www.theses.fr/2023MTLD0008.
Анотація:
Le besoin en traitement des eaux usées par la société est assurée en usine d’épuration par des traitements menant à la production de boues. Afin d’anticiper l’augmentation de ce besoin à l’avenir, les filières de traitement de ces boues doivent atteindre une certaine efficacité, en termes de traitement et de valorisation des boues. Parmi ces filières, le procédé de méthanisation permet de réduire significativement le volume des boues générées et permet par la suite une valorisation agronomique et énergétique, sous forme de digestat, de biogaz, d’électricité ou de chaleur. Il est néanmoins limité par un contrôle inefficace du transport des boues digérées en son sein, du fait de la méconnaissance de la thermo-rhéologie, en termes de connaissances et de méthodes de caractérisation et en termes d’hydrodynamique en conduite de ces boues très diverses. Cela se manifeste opérationnellement, en aval de la phase de dimensionnement et de conception, lors de l’opération par des pompages inefficaces, des hétérogénéités de la matrice ou des colmatages de composants.C’est dans cette optique d’apport des éléments scientifiques, de la caractérisation thermo-rhéologique des boues digérées d’une part et de la mise en évidence de l’hydrodynamique en conduite de ces fluides d’autre part, que le travail de recherche mené dans le cadre de cette thèse s’inscrit.Premièrement, des protocoles dédiés à caractériser spécifiquement chaque comportement non-newtonien sont établis pour cela. L’application de ces protocoles, au centre de recherche Energie Environnement de l’IMT Nord Europe et sur la plateforme Caractérisation du partenaire industriel, montre que les caractéristiques thermo-rhéologiques des boues digérées sont fidèlement modélisées par un modèle d’Herschel-Bulkley non modifié. En effet, la contrainte seuil et la rhéofluidification sont significativement pré-pondérantes devant les autres caractéristiques thermo-rhéologiques de thixotropie, de visco-élasticité et de thermo-dépendance. Le phénomène physique non anticipé de glissement aux parois est observé sur ces boues digérées, menant à une hydrodynamique hétérogène de l’écoulement en conduite de faible inertie et de faible rugosité des parois.Deuxièmement, un dispositif expérimental dédié à l’étude de l’écoulement en conduite de tels fluides est mis en place en vue de déterminer leurs comportements hydrodynamiques. Il permet de démontrer, à l’aide de fluides de travail (solution s de Carbopol), que ces fluides suivent une transition rhéo-inertielles (RIT) vers la turbulence. Cette transition se distingue par l’existence d’un régime de pré-transition, inexistant pour un fluide newtonien, au sein duquel l’écoulement présente une asymétrie, qui est observée par visualisation directe. Ces visualisations, couplées à la mesure des pertes de charges, permettent de quantifier l’intermittence de la RIT à partir des structures turbulents visualisées. Cela permet de contrôler le mouvement de tels fluides par la connaissance de la stabilisation de leurs écoulements et de l’augmentation du temps de séjour des structures turbulentes, du fait des caractéristiques non-newtoniennes (sans visco-élasticité).Ainsi, ce manuscrit synthétise les éléments scientifiques développés dans le cadre de cette thèse pour répondre aux problématiques opérationnelles rencontrées. Les verrous découlant du mande de connaissances fondamentales de la thermo-rhéologie et de l’hydrodynamique des boues qui y circule, l’étude axe sa recherche sur ces deux domaines pour apporter les fondamentaux qui pourront permettre l’amélioration de la maîtrise du transport des boues au sein du procédé de méthanisation en usine d’épurationThe society’s wastewater treatment needs are met by waste water treatment plants that produce sludges. In order to anticipate the increase in this requirement in the future, the sludge treatment processes must achieve a certain level of efficiency in terms of sludge treatment and recovery. The anaerobic digestion process significantly reduces the volume of sludge generated and can the be used for agricultural and energy purposes, in the form of digestate, biogas, electricity or heat. It is nevertheless limited by ineffective control of the transport of digested sludge within it, due to a lack of knowledge of thermo-rheology, in terms of understanding and characterisation methods, and of the hydrodynamics involved in handling these very diverse sludges. This manifests itself operationally, downstream of the sizing and design phase, in inefficient pumping, matrix heterogeneity or component clogging.It is in this context of providing scientific elements, on the one hand of the therm-rheological characerisation of digested sludge and on the other hand of the demonstration of the hydrodynamics of these fluids in operation, that the research work carried out within the framework of this thesis falls within the scope of.Firstly, protocols dedicated to the specific characterisation of each non-Newtonian behaviour have been established. The application of these protocols, at the ITM Nord Europe – Energy Environment research centre and on the industrial partner’s Characterisation plateform, shows that the thermo-rheological characteristics of digested sludge are accurately modelled by a non-modified Herschel-Bulkley model. Yield stress and shear-thinning are significantly more important than the other thermo-rheological characteristics of thixotropy, viscoelasticity and thermo-dependence. The unanticipated physical phenomon of wall slip is observed in these digested sludges, leading to heterogeneous flow hydrodynamics under conditions of low inertia and loaw wall roughness.Secondly, an experimental set-up dedicated to studying the flow of such fluids in pipe is being set up, with a visualisation to determining their hydrodynamic behaviour. Using working fluids (Carbopol solutions), it was demonstrated that these fluids undergo a rheo-inertial transition (RIT) towards turbulence. This transition is characterised by the existence of a pre-transition regime, non-existent for a Newtonian fluid, within which the flow exibits an asymmetry, which is observed by direct visualisation. These visualisations, coupled with the measurement of pressure drops, also make it possible to quantify the intermittency of the RIT on the basis of the turbulent structures visualised. This makes it possible to control the movement of such fluids through knowledge of the stabilisation of their flows and the increase in the residence time of turbulent structures, due to the non-Newtonian characteristics without viscoelasticity.Thus, this thesis manuscipt summarises the scientific elements developed within the framework of this thesis to respond to the problems of the operational obstacles encountered. As these problems stem from a lack of fundamental knowledge of the thermo-rheology and hydrodynamics of the sludge that flows through it, the study focuses its research on these two areas in order to provide the fundamentals that will make it possible to improve the control of sludge transport within the anaerobic digestion process in wastewater treatment plants
4
Kidby, David W. "Biogas hydrogen as an indicator of digester instability in anaerobic sewage sludge digesters." Thesis, University of Essex, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280473.
5
Geminiani, Andrea. "Sustainable valorization of digested sewage sludge into added-value products." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
Анотація:
Before being discharged in a water body, municipal wastewater undergoes filtration, sedimentation, biological oxidation, and nutrient abatement in a wastewater treatment plant (WWTP); typically, the resulting sewage sludge is anaerobically digested for biomethane production. The sludge management practices currently involve landfill disposal and energy-intensive treatments, such as incineration or co-incineration, while agricultural soil applications and composting account for a minor amount. From a sustainability point of view, landfill disposal and incineration of sludge are not efficient in terms of energy consumption or waste material recovery. Thus, scientific research led to the development of innovative technologies aiming to decrease the sewage sludge volume and odour issues and to promote the valorization of the feedstock. In particular, the process described in this thesis, devised by HBI Srl., combines hydrothermal carbonization (HTC) of sewage sludge with hydrochar gasification. The HTC products are hydrochar and HTC liquor; the former can be used for energy production and carbon capture and storage, while the latter can increase the methanogenic sludge potential. Hydrochar then undergoes gasification in an upstream (counter-current) fixed-bed reactor, resulting in syngas and ash production. Once purified from fly ash by a cyclone, the produced syngas is nowadays burned in a torch. Future applications might involve heat and power cogeneration and the production of useful platform chemicals. Since the water excess is recirculated back to the WWTP, the only process by-product is the gasification ash, which can be potentially valorized as a fertilizer additive thanks to its significantly high content of phosphorous and relatively low content of heavy metals. Lastly, CHNS, SEM-EDX, TGA were performed on digested sewage sludge and hydrochar samples, confirming the potential of this promising sludge valorization technology.
6
Campbell, Alison June. "The behaviour of pharmaceuticals in anaerobic digester sludge." Thesis, University of Portsmouth, 2013. https://researchportal.port.ac.uk/portal/en/theses/the-behaviour-of-pharmaceuticals-in-anaerobic-digester-sludge(995bec06-33fd-4c74-96a3-db4aba5a1c30).html.
Анотація:
Pharmaceuticals are biologically active compounds that may be consumed in hundreds of tonnes per year, and which are excreted into municipal sewerage systems. Many pharmaceuticals persist during sewage treatment, and significant environmental risk has been linked to incomplete removal of pharmaceuticals. Evaluation of this risk is important and should be as representative as possible, taking into consideration all significant exposure routes and removal processes. Sludge treatment processes are of particular interest because they offer a final opportunity for the removal of persistent compounds before the disposal of treated biosolids. During environmental risk assessment, it is currently assumed that anaerobic sludge treatment results in insignificant removal of persistent and adsorptive compounds from sewage sludge. This project was undertaken to address whether this assumption is valid. This thesis describes research into the behaviour and fate of pharmaceuticals in anaerobic digester sludge, and examines how redox conditions influence removal efficiency. Nine commonly used pharmaceuticals (caffeine, cimetidine, fluoxetine, ibuprofen, metformin, naproxen, paroxetine, propranolol and salicylic acid) were selected for use based upon detection levels within sewage sludge and predicted anaerobic biodegradability. Initial experiments were conducted to identify toxicity to anaerobic microorganisms and anaerobic biodegradability. No toxicity to the microorganisms in anaerobic sludge was identified at ≤ 50 mg C L-1for any of the selected pharmaceuticals. The extent of removal in anaerobic sludge and the principal removal mechanism was found to vary between the selected pharmaceuticals. Metformin and salicylic acid were removed by 82 and 93% through mineralisation, respectively; naproxen was completely removed through primary biodegradation; fluoxetine, paroxetine and propranolol were removed by 92 and 96 and 55% due to adsorption, respectively. It was hypothesised that the removal of pharmaceuticals in anaerobic sludge through biodegradation and adsorption would be observed at varying rates under differing redox conditions. Test systems using headspace gas flushing and chemical amendment were evaluated for the control of redox conditions, with Eh measurements and DOC removal being used to indicate the stability of the system and its capacity for biodegradation. The addition of nitrate, sulfate and carbonate resulted in poised Eh values in the region of +200, -200 and -200 mV, respectively and 81, 78 and 74% removal of DOC, respectively. This methodology was subsequently used to evaluate the removal of naproxen, propranolol and fluoxetine under carbonate-, nitrate- and sulfate-amended conditions. Significant differences (p = 0.001) in the removal of naproxen through primary biodegradation were found to exist between different redox conditions. Naproxen was completely removed under control conditions, while 26, 98 and 61% removal was observed under nitrate- sulfate- and carbonate amended conditions, respectively. Some differences were observed in Kd values, however, redox amendment was found to have little influence upon the elimination of propranolol and fluoxetine through adsorption. It was identified from this work that pharmaceuticals within the aqueous phase degraded under anaerobic conditions as predicted, while pharmaceuticals associated with the biosolids were removed through adsorption and present a potential threat to the environment on the disposal of treated biosolids. This work supports the current industry assumption that anaerobic treatment of biosolids offers limited opportunity for the removal of adsorptive pharmaceuticals, and also found no evidence for their enhanced removal under redox-controlled conditions. While research described within this thesis increases knowledge of the behaviour of pharmaceuticals in sewage sludge under anaerobic conditions, data is presented for a limited range of test substances only, and further investigation into the behaviour of additional compound classes is recommended.
7
Ishaq, Farryad. "Trace metal supplementation in wastewater sludge digesters." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3896/.
Анотація:
Multiple studies have shown the importance of transition metals for the microorganisms involved in anaerobic digestion. Deficiencies in metals can translate into suboptimal digester performances and therefore where present an opportunity to stimulate anaerobic digestion exists. Previous supplementation studies that have used EDTA complexed metals have shown conflicting results. Assays supplemented with cobalt-EDTA on its own consistently responded to a level equal to or higher than that from assays supplemented with a combination of metals. The results seemingly indicate that cobalt was the most commonly deficient metal in the sludge digesters. However this study has raised questions about the bioavailability of other metals as EDTA chelates, particularly nickel-EDTA. Differing levels of bioavailability for different EDTA complex metals explain how conflicting results for EDTA complexed metals can exist. Metal deficiencies were present 69% of the time in the wastewater sludge digesters samples. Given the questions raised about the bioavailability of metal-EDTA chelates the prevalence of deficiencies was likely to have been higher. At a site specific level it was found that a lower than expected Vmax for a given sites acetoclastic methanogen population corresponded with a positive response from supplementation and therefore it can act as an indicator of metal requirement.
8
Qi, Yinan. "Effect of centrifugal dewatering on the regrowth of fecal coliforms and Salmonella in anaerobically digested biosolids." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 192 p, 2008. http://proquest.umi.com/pqdweb?did=1601522491&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Анотація:
Thesis (Ph.D.)--University of Delaware, 2008.Principal faculty advisors: Steven K. Dentel, Dept. of Civil & Environmental Engineering; and Diane S. Herson, Dept. of Biological Sciences. Includes bibliographical references.
9
Lau, Shiew Wei. "Conditioning and dewatering of anaerobically digested sludge from municipal wastewater treatment processes." Thesis, Curtin University, 2015. http://hdl.handle.net/20.500.11937/1594.
Анотація:
This thesis presented the dewatering performance improvement of anaerobically digested sludge with novel application and assessment of conditioning aids. The effectiveness of sludge conditioning was evaluated by batch experiments using a series of 250-mL jar test beakers. The optimal dosage was found at 15–20 g/kg chitosan with enhanced dewaterability and rheological behaviour. The dual-chemical conditioning results indicate a higher rate of water removal at the expense of dry solids content compared to single conditioning.
10
Chiarella, Renato. "Laboratory study of H¦2S reduction in anaerobic digester sludge." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0001/MQ34346.pdf.
11
Murambadoro, Daniel K. "The structural performance of egg-shaped sludge digesters." Master's thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/5019.
12
Turkmen, Muserref. "Sulfur-containing odorants and the effects of high salinity in anaerobically digested biosolids." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 224 p, 2007. http://proquest.umi.com/pqdweb?did=1257807571&sid=6&Fmt=2&clientId=8331&RQT=309&VName=PQD.
13
Nash, Jeffrey William. "Characteristics and conditioning of anaerobically digested sludge from a biological phosphorus removal plant." Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/44128.
Анотація:
A study of the anaerobically digested sludge form a
full-scale biological phosphorus removal (BPR) plant (York
River Wastewater Treatment Plant, York River, Va.) was
conducted to determine the effects of BPR on sludge
characteristics and conditioning requirements. Data
collected from the plant indicated that both the total and
soluble phosphorus (P) concentrations in the anaerobically
digested sludge increased dramatically with the initiation
of BPR. Accompanying this increase in total P was an
increase in the total concentrations of magnesium and
potassium content of the sludge, supporting the observations
that these ions are coâ transported with P during the
accumulation and release of P by P accumulating organisms.
The majority of the phosphate present in the pre- and post-
BPR anaerobically digested sludges was bound by calcium,
magnesium, and iron phosphorus precipitates including
hydroxyapatite, struvite, and vivianite. Calcium phosphorus
precipitates were the most prevalent in both sludges, but
the percentage of magnesium phosphorus precipitates
increased with the onset of BPR.
Cationic organic polymer conditioning dosages needed to
achieve acceptable sludge dewatering rates for the post-BPR
sludge were similar to those required by the pre-BPR sludge.
The cationic organic polymer used to condition these sludges
was ineffective in removing excess phosphate; therefore, the
addition of either one or both of the inorganic chemicals
ferric chloride and calcium hydroxide was required to remove
soluble phosphorus. Conditioning with either ferric
chloride or calcium hydroxide alone was not effective in
achieving acceptable dewatering rates; however, when used
together the chemicals produced acceptable dewatering rates
and soluble P removal from the post-BPR sludge.Master of Science
14
Williams, Tyson. "Competitive exclusion as a means to reduce Escherichia coli regrowth in digested sludge." Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/9221.
Анотація:
In recent years, it has been reported that numbers of Escherichia coli increase significantly following centrifugation of sludge during the treatment process. E. coli is used as an indicator of the microbiological quality of sludge-derived products destined for agricultural recycling and of the efficacy of the sludge treatment processes. The re-growth phenomenon is of concern because of the potential for additional treatment requirement / higher disposal costs and loss of consumer confidence associated with a compliance failure. It is hypothesised that a competitive exclusion treatment could be the solution wherein the digestate be exposed to a ‘probiotic’ or defined mixture of micro-organisms, to effectively out compete or eliminate any resident E. coli remaining following treatment. The competitive exclusion principle as a treatment method has already seen application in various industrial sectors, the most well-known being the poultry industry. In experiments it was determined that an antimicrobial producing organism would be most likely to succeed. From the candidates screened, Lactobacillus reuteri proved the most promising. L. reuteri is a known producer of reuterin in the presence of glycerol and organic acids as a part of its normal metabolic activity. In sludge derived nutrient broth in the presence of glycerol and low pH, L. reuteri addition resulted in a reduction of E. coli to undetectable levels. In sludge cake under the same conditions, L. reuteri was less successful. However the addition of glycerol and L. reuteri to sludge cake restricted E. coli growth to a 2 log increase from the initial concentration of E. coli recorded following pasteurisation (an average of around 1x102 cfu/gDs), in comparison in the positive control a 4 log increase was recorded. From this result the sludge cake could be defined as conventionally treated. It can be concluded that competitive exclusion and L. reuteri show promise as a treatment for reducing E. coli re-growth in sludge cake
15
CRISTINA, GIULIO. "The hidden potential of digested sewage sludge: a recycling approach to combat desertification." Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2903484.
16
Holloway, Ryan W. "Forward osmosis for concentration of anaerobic digester centrate." abstract and full text PDF (free order & download UNR users only), 2006. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1436020.
17
Wong, Tak Ian. "Numerical flow simulations of an egg-shaped anaerobic sludge digester in wastewater treatment /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?EVNG%202005%20WONG.
18
Olsson, Jesper. "Enhanced biogas production from municipal WWTPs : Co-digestion of microalgae with sewage sludge and thermophilic secondary digestion of mesophilic digested sludge." Licentiate thesis, Mälardalens högskola, Framtidens energi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-27911.
Анотація:
Biogas is produced when organic material is broken down in oxygen-free (anaerobic) conditions. This process is called anaerobic digestion and is used in most large and medium-sized municipal wastewater treatment plants in Sweden. In the wastewater treatment sewage sludge is obtained, from the mecanical-, biological and chemical treatment step, which contains decomposable organic material. The sludge is pumped into a digester, which is an airtight container. In the digester raw biogas, consisting of methane and carbon dioxide, is produced. The material that comes out of the digester is a nutrient rich residue (digestate) which can be used as a fertilizer or soil conditioner. The purpose of this study was to explore ways to increase the biogas production that takes place at the municipal wastewater treatment plants by either co-digestion of sewage sludge with microalgae from a possible future biological purification steps or to use two digestion stages in series with different operating temperatures, mesophilic (37ºC) followed by a thermophilic digestion (55ºC). The challenges with these methods, which are also taken into consideration in the studies, were changes in the dewaterability of the digestate, system efficiency regarding electricity and heat consumption, the ability to recycle nutrients, changes in the carbon footprint from the treatment plant, change of the pollution level in the digestate and the ability to create a sanitization method for the digestate. The results from the first part showed in both batch digestability tests and continuous anaerobic digestion experiment that microalgae cultivated on wastewater can be a feasible feedstock for anaerobic co-digestion with sewage sludge. Microalgae improved the biogas production in mesophilic conditions but not in thermophilic digestion. In the semi-continous experiment, with the addition of a natural mix of microalgae grown from wastewater to sewage sludge, the specific methane production was enhanced with 39 % for every gram organic matter reduced. The specific methane production for every gram added organic matter to the reactors were 9% lower in the digester where microalgae had been added. When microalgae were added the total digestibility was reduced compared to the reference digestion with only sewage sludge. Filterability tests indicated that the addition of microalgae enhanced the dewaterability of the digested sludge. Heavy metal levels in the microalgae substrate were much higher than in the sludge which could restrict the utilization of the digestate on arable land in a possible future full scale application. The results in the second part showed that the process solution could be a self-sufficient sanitation method. The highest organic loading rates tested in this study were in the range causing an unstable process due to high ammonia levels The thermophilic digestion gave the sludge worse dewaterability. However, a subsequent aeration step could improve the properties again.
19
Malhotra, Saimon. "Molecular biological characterisation of the functional microbial communities in anaerobic digesters." Thesis, University of Liverpool, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272792.
20
Galvagno, Giampiero. "Sidestream control of dissolved nutrients in anaerobically digested sludge centrate using anammox and chemical precipitation." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/59775.
Анотація:
The objective of this research was to assess specific side-stream processes for biodegradation and precipitation of dissolved nutrients in dewatering centrate and support the seamless integration of an anaerobic digester (AD) into a biological nutrient removal wastewater treatment plant (WWTP). Anaerobic digestion processes release reactive and non-reactive dissolved nutrients which are returned to the mainstream treatment process in the dewatering centrate. Conventional side-stream treatment processes are typically designed for removal of reactive nutrients (ie, nitrate/nitrite, ammonia and orthophosphate). However, many WWTPs with low total nitrogen and total phosphorus criteria will also be impacted by the non-reactive, difficult-to-degrade nutrient forms such as polyphosphates (poly-P), dissolved organic phosphorus (DOP) and dissolved organic nitrogen (DON). In this study, characterization was made of a conventional suspended growth deammonification treatment (Anammox) process for transforming poly-P, DOP and DON in two types of dewatering centrate. The first centrate feed studied was from the full-scale Annacis Island WWTP (AIWWTP), Canada. The second centrate feed was from a lab-scale AD fed waste sludge from the existing City of Kelowna Wastewater Treatment Facility (KWTF), Canada. The Anammox process showed similar treatment characteristics for both the KWTF and AIWWTP centrates with excellent DON removal and poor non-reactive dissolved phosphorus (NRDP) removal. A statistical comparison of the DOP and poly-P through the Anammox process suggests that DOP has a higher biodegradation potential. Utilization of a post-Anammox, poly aluminum chloride chemical dosing, optimized based on zeta potential, was able to achieve the objective of precipitating residual DON and NRDP and producing an effluent with lower dissolved nutrients than the pre-digestion KWTF dewatering centrate scenario.
Additional testing was conducted on final effluent to characterize the dissolved phosphorus and determine an optimal coagulant dose. The testing suggests that the dissolved phosphorus in effluent could be associated with colloidal dissolved organic matter (DOM). Furthermore, coagulant batch dosing experiments using poly aluminium chloride (PACL) and poly epichlorohydrin amine (polyepiamine) provides strong support for the use of zeta potential measurements as a way to optimize coagulant dose.Applied Science, Faculty of
Engineering, School of (Okanagan)
Graduate
21
Carliell-Marquet, Cynthia. "The effect of phosphorus enrichment on fractionation of metals and phosphorus in anaerobically digested sludge." Thesis, Loughborough University, 2000. https://dspace.lboro.ac.uk/2134/17074.
Анотація:
In designated nutrient-sensitive areas, phosphorus must be removed from sewage before it is discharged to the receiving water body. Phosphorus-rich sludge is generated, which is usually digested anaerobically prior to disposal. This research investigated the effect of phosphorus enrichment on metal and phosphorus fractionation in anaerobically digested sludge. The use of two complementary sequential chemical extraction procedures to measure phosphorus and metal fractionation, was a key focus of the research. The fractionation procedures were tested by sequentially extracting inorganic compounds (phosphates, sulphides and carbonates) which showed that the operationally defined metal and phosphorus fractions were not always representative of precise metal phases. Species were tentatively assigned to metal and phosphorus fractions using model compound results. Laboratory-scale batch anaerobic digestion experiments were performed, in which model compounds were used to simulate conditions of soluble and insoluble phosphorus enrichment. Soluble phosphorus at concentrations of 500 mg/l or greater was found to retard volatile solids removal and methane production in the laboratory digesters. Soluble phosphorus enrichment facilitated precipitation of calcium, magnesium and manganese but increased trace metal solubility, particularly that of chromium. Enrichment of digesters with Na2HP04 and MgCb caused struvite to precipitate in digesters containing 1000 mg/l of additional phosphorus. FeP04 enrichment of digested sludge showed that ferric iron was reduced to ferrous iron, releasing soluble phosphorus into the digester. Most of the phosphorus was reprecipitated as ferrous phosphate, causing co-precipitation of magnesium, manganese and cobalt. By contrast, A1P04 added to the digesters was stable in the sludge. Full-scale CPR sludge digestion (Fe2(S04)3 dosing) caused soluble phosphorus in the digester to decrease below 0.05 mg/l. Phosphorus remained associated with iron in the sludge fraction but soluble calcium and magnesium concentrations in the full-scale digester increased as a result of CPR sludge digestion. Comparison of laboratory and full-scale results showed that the fate of iron-precipitated phosphorus in digested sludge was primarily dependent pn the molar ratio of Fe:P in the sludge. Full-scale BPR sludge digestion showed high concentrations of soluble phosphorus in the digester and some struvite precipitation, although phosphorus was precipitated primarily as calcium phosphate, as was found to occur in the laboratory digesters simulating BPR sludge digestion.
22
Gu, Xiangyang. "Improving heavy metal bioleaching efficiency through microbiological control of inhibitory substances in anaerobically digested sludge." HKBU Institutional Repository, 2003. http://repository.hkbu.edu.hk/etd_ra/504.
23
Balaguer-Barbosa, Maraida. "Recovery of Nutrients from Anaerobically Digested Enhanced Biological Phosphorus Removal (EBPR) Sludge through Struvite Precipitation." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7471.
Анотація:
Water resources in Florida have been severely degraded by eutrophic conditions, resulting toxic algae blooms, which negatively affect health and tourism. Eutrophication, or excessive amount of phosphorus (P) and nitrogen (N) in water, overstimulates the production of aquatic plants, depletes dissolved oxygen, and deteriorates the aquatic environment. However, phosphorus is a non-renewable resource essential for all living organisms. In fact, more than half of the total demand for P globally is to supply the food industry, which has concerningly accelerated the depletion rates of phosphate reserves.
In many wastewater treatment plants (WWTPs), the enhanced biological phosphorus removal (EBPR) approach has been employed to achieve high phosphorus removals from wastewater through phosphate-accumulating organisms (PAOs). However, during either anaerobic or aerobic digestion of EBPR sludge, stored polyphosphates are released and carried into the sidestream, which is typically returned to the headworks of the main treatment facility, thereby recycling phosphorus back into the system. This treatment train is highly inefficient because nutrients rather are recirculated rather than recovered.
Struvite (MgNH4PO4•6H2O) is precipitated in oversaturated aqueous solutions with equal molar concentrations of magnesium, ammonium, and phosphate. The controlled crystallization of struvite may be applied to remove phosphorus and some ammonium from sidestreams, which is the liquid portion of the digester effluent. Struvite can be employed as a sustainable slow-release fertilizer due to its low solubility in water. This offers the opportunity of marketing the struvite produced under controlled conditions and creating a revenue for the utility.
The specific research objectives of this thesis are (1) to investigate different possible operating conditions under which anaerobically digested sludge from EBPR facilities might be treated through struvite precipitation; (2) to quantify the removal of N and P from sidestreams from anaerobically digested EBPR sludge via struvite precipitation and assess the composition of the precipitate obtained; and (3) to generate a cost analysis to assess the trade-offs between the capital and operation and maintenance (O&M) costs of struvite production and the benefits such as reduced chemical use and production of a slow-release fertilizer.
The main parameters affecting struvite precipitation are the Mg2+ to PO43- molar ratio, pH, temperature, mixing speed, hydraulic retention time (HRT), and the seed quantity added to promote nucleation. Different operating conditions within these parameters were batch-tested as part of this study using sidestream from the pilot-scale anaerobic digester (AD) fed from Falkenburg Advanced Wastewater Treatment Plant (FAWWTP) EBPR sludge. Additionally, the effect of temperature and pH were investigated using Visual MINTEQ simulations. Analysis of Variance (ANOVA) was employed to investigate the variance within the removals from the centrate obtained for phosphate, ammonium, magnesium, and calcium. The chemical composition of the solids collected after employing the selected operating conditions was analyzed by powder X-ray diffraction (PXRD).
The results for the batch tests performed as part of this thesis were quantified in terms of the removals of phosphate, ammonium, magnesium, and calcium from the centrate. The greatest amount of phosphate removal was achieved by operating the struvite reactor at 4.0 mmol of Mg2+ per mmole of PO43-. The other molar ratios tested were 1.0, 2.0, and 3.0. Visual inspection of the data showed significant variability in removals of ammonium, calcium, and magnesium, which are likely to be correlated with the highly variable influent concentrations into the struvite reactor. In this case, ANOVA will require larger data sets to accurately analyze variance in the results. The statistical results given by ANOVA for the pH suggests that the main species to contribute with struvite being precipitated are statistically stable within the tested pH values of 8.5, 9.0, and 9.5. The results obtained by the simulation using Visual MINTEQ indicated that maximum saturation as function of pH takes place at a pH between 9.5 and 10.0. The ANOVA for the mixing speed showed that significant amounts of ammonium were removed at higher mixing speeds. This is likely due ammonium being volatilized, which is enhanced by turbulence. Magnesium and phosphate showed lower removals at higher mixing speeds, suggesting that too high mixing speeds will promote struvite seed dissolution. ANOVA identified NH4+ and Ca2+ as the species significantly impacted by modifying the HRT from 8 to 20 minutes. This suggests that prolonged HRT promotes inorganic nitrogen species to volatilize. It is likely that at higher HRT, tricalcium phosphates (TCP) or other favored calcium species coprecipitated together with struvite. Regarding the added struvite seed for nucleation, the greatest removals of ammonium, magnesium, and, phosphate were observed when 1g/L of struvite seed was added. The results also indicated that adding 5 and 10 g/L was an excessive amount of seed, which ended up contributing significantly to more nutrients into the centrate rather than precipitating them. The results also suggested that the struvite crystals formed in the sidestream by secondary nucleation, since removals close to zero were reached after adding no seed. The optimum temperature identified by the simulation in Visual MINTEQ was 21°C.
Operating the struvite reactor under the optimal conditions identified in the batch tests, resulted in an average of 99% total P (TP) and 17% total N (TN) removals. The precipitate molar composition for [Mg2+:NH4+:PO43-] was equal to [2:2:1] based on the concentrations that disappeared from the aqueous solution, suggesting that other minerals coprecipitated with struvite. Visual MINTEQ predicted that together with struvite, CaHPO4 and CaHPO4•2H2O will also precipitate under the tested conditions. However, given the obtained ratio it is likely that other unpredicted species by Visual MINTEQ, such as magnesium carbonates or magnesium hydroxide coprecipitated with struvite. PXRD analysis also revealed that the sample was likely contaminated struvite, although the specific contaminants were not identified.
A cost analysis was performed to distinguish the economic feasibility of incorporating a struvite harvesting system to treat the anaerobically digested sidestream from the Biosolids Management Facility (BMF) within the Northwest Regional Water Reclamation Facility (NWRWRF). Three different scenarios were evaluated; in Scenario (1) Ostara® Nutrient Recovery Technologies Inc. (Ostara®) evaluated the production of struvite from anaerobically digested EBPR sidestream using a fluidized reactor. In Scenario (2), Ostara® evaluated the production of struvite in a fluidized bed reactor by employing Waste Activated Sludge Stripping to Remove Internal Phosphorus (WASSTRIP™) in a mixture of post-anaerobic digestion centrate and pre-digester thickener liquor. Scenario (3) was addressed by Schwing Bioset Inc. (SBI) for a continuously-stirred reactor followed by a struvite harvesting system.
Scenario (2) offers the highest TP and TN recoveries through WASSTRIP™ release due to the additional mass of phosphorus that is sent to the phosphorus recovery process. Therefore, although Scenario (2) has the highest total capital costs ($5M) it also has the shortest payback period (18 years). Scenarios (1) and Scenario (3) have similar payback periods (22-23 years) but very different total capital costs. The annual savings by producing struvite in Scenario (3) is $40K, which is about 30% less than producing struvite in Scenario (1). This is probably because the only savings considered under Scenario (3) were the lower alum usage and the fertilizer revenue; however, the savings by producing class A biosolids, were not accounted for. Consequently, the reduced total capital cost of $960K and the annual payment amount per interest period close to $80K, positioned Scenario (3) as the more feasible one, considering 20 years as the expected life of the asset at a 5% interest rate.
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Ozkan, Yucel Umay G. "Co-treatment Of Hazardous Compounds In Anaerobic Sewage Sludge Digesters." Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609952/index.pdf.
Анотація:
Xenobiotic compounds, which are exclusively man made, are produced in large quantities every year and released to the environment. Besides, anaerobic sludge digestion offers advantage in co-treatment of hazardous substances produced by the industry. The performance of the digesters can be monitored by modeling efforts. In this study, Anaerobic Digestion Model No.1 (ADM1) was calibrated, and validated for full-scale digester, lab-scale digester, and lab-scale digester seeded with totally different anaerobic biomass than that of full-scale digester. The model xenobiotic compound, a mono azo dye RO107, was co-treated with sewage sludge in an anaerobic digester. High removal efficiencies as 98% was found for azo dye at standard operating conditions of anaerobic digesters. The digester performance was not effected from azo dye or its reduction products. The dye reduction mechanism was modeled by biochemical mechanism due to unspecific enzymes and by chemical mechanism due to sulfide reduction. Some of the dye metabolites were suggested to be degraded by aerobic biotreatment. The anaerobic reduction metabolites of RO107 were identified as 2-(4-aminophenylsulfonyl) ethanol and 2,5-diamino-4-formamidobenzenesulfonic acid, and sulfanilic acid.
25
Roussel, Jimmy. "Metal behaviour in anaerobic sludge digesters supplemented with trace nutrients." Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4369/.
Анотація:
Trace nutrients (metals) supplementation has been demonstrated to have a beneficial effect on the welfare of anaerobic digesters but there was a lack of information on the chemistry controlling their fate. The aim of this research was to determine the reactions governing the chemical behaviour of metals in anaerobically digested sludge and predict the fate of those metals when supplemented as MeEDTA. After the assessment of a wide range of analytical techniques, a suite of suitable analytical techniques1 were used to determine the metals behaviour in two case studies of metals supplementation: iron dosing and MeEDTA supplementation. The behaviour of the metals was controlled by the solid phase throughout a primary reaction (sulphide precipitation) and secondary reactions (phosphate precipitation, adsorption and organic complexation). The competition between the strength of metal's binding and EDTA complexation controlled the fate of the supplemented metals in anaerobic digesters. Transfer of CoEDTA in the solid phase was found to be divided into two reactions, where the second has a slow kinetic depending on the availability of the counter-ion reacting with EDTA. A key conclusion was that the presence of weaker metal-bound compounds mixed with strong sulphide precipitates changed the understanding of metals speciation, especially concerning their potential availability and consequently their behaviour as trace nutrients.
26
Huezo, Sanchez Luis. "Technical, economic, and carbon dioxide emission analyses of managing anaerobically digested sewage sludge through hydrothermal carbonization." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587121997256614.
27
Koksoy, Gozde Tugba. "Investigation Of Digester F/m Ratio As A Parameter To Affect Sludge Minimization And Gas Production Of Ultrasonically Treated Sludge." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610699/index.pdf.
Анотація:
Ultrasonic sludge disintegration &ndashthe most commonly used mechanical pretreatment method- enables the occurrence of cavitation bubbles to extract intracellular material from the cell into aqueous phase. However, there is a lack of information on the volatile solids loading on the anaerobic digestion process performance of ultrasonically treated sludge. In this thesis work, the effect of sonication on disintegration of waste activated sludge (WAS) and an important parameter digester F/M (food to microorganism) ratio on ultrasonically treated WAS were investigated. First, preliminary studies were conducted. It was obtained that when the sonication power and time increased, soluble COD in the supernatant increased as well. Then, batch anaerobic digestion tests were conducted. Effect of F/M ratio in the digesters by using sonicated sludges at different powers was analyzed. For the sludge sonicated at high power, the methane content increased up to 55.1 % at F/M ratio of 10 compared to untreated sludge. On the other hand, methane generation rate slowed down with the increase in F/M ratio. Moreover, 10 % and 15 % increase in the destruction of MLVSS and total COD content was observed for sonicated sludges compared to the untreated sludges, respectively. In summary, both the sonication as a pretreatment method and the increase in digester F/M ratio increased the biogas production and the solids reduction during anaerobic digestion prosess. These results may have important implications for the operation of full scale systems in terms of system efficiency and operation.
28
Smith, Robert C. "Ecological Factors in Design of a Two-Sludge Nitrifying Activated Sludge System Incorporating Side-Stream Treatment of Anaerobic Digester Supernatant." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1291307830.
29
Dogan, Ilgin. "Combination Of Alkaline Solubilization With Microwave Digestion As A Sludge Disintegration Method: Effect On Gas Production And Quantity And Dewaterability Of Anaerobically Digested Sludge." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609685/index.pdf.
Анотація:
The significant increase in the sewage sludge production in treatment plants makes anaerobic digestion more important as a stabilization process. However hydrolysis is the rate-limiting step of anaerobic digestion because of the semirigid structure of the microbial cells. Pretreatment of waste activated sludge
(WAS) leads to disruption of cell walls and release of extracellular and intracellular materials. Therefore biodegradability of sludge will be improved in terms of more biogas production and sludge minimization. Among the pretreatment methods, alkaline, thermal and thermochemical pretreatments are effectual ones. Considering the effect of thermal pretreatment, microwave technology in which the sample reaches to elevated temperatures very rapidly is a very new pretreatment method. However no previous research has been conducted to test the effectiveness of microwave (MW) irradiation combined with alkaline pretreatment. Since both of these techniques seem to be highly effective, their combination can act synergistically and even more efficient method can be obtained. Therefore the main objective of this study was to investigate the effect of combination of a chemical method (alkaline pretreatment) and a physical method (microwave irradiation) in improving anaerobic digestion of WAS.
In the first part of the study, alkaline and MW pretreatment methods were examined separately, then their combinations were investigated for the first time in the literature in terms of COD solubilization, turbidity and CST. Highest SCOD was achieved with the combined method of MW+pH-12. In the second part, based on the results obtained in the first part, alkaline pretreatments of pH-10 and pH-12MW pretreatment alone and combined pretreatments of MW+pH-10 and MW+pH-12 pretreated WAS samples were anaerobically digested in small scale batch anaerobic reactors. In correlation with the highest protein and carbohydrate releases with MW+pH-12, highest total gas and methane productions were achieved with MW+pH-12 pretreatment reactor with 16.3% and 18.9% improvements over control reactor, respectively. Finally the performance of MW+pH-12 pretreatment was examined with 2L anaerobic semi-continuous reactors. 43.5% and 53.2% improvements were obtained in daily total gas and methane productions. TS, VS and TCOD reductions were improved by 24.9%, 35.4% and 30.3%, respectively. Pretreated digested sludge had 22% improved dewaterability than non-pretreated digested sludge. Higher SCOD and NH3-N concentrations were measured in the effluent of pretreated digested sludge
however, PO4-P concentration did not vary so much. Heavy metal concentrations of all digested sludges met Soil Pollution Control Regulation Standards. Finally a simple cost calculation was done for a MW+pH-12 pretreatment of WAS for a fictitious WWTP. Results showed that, WWTP can move into profit in 5.5 years.
30
Chan, Lau Chi. "Bioleaching of heavy metals from anaerobically digested sewage sludge using isolated indigenous iron- and sulphur-oxidizing bacteria." HKBU Institutional Repository, 2001. http://repository.hkbu.edu.hk/etd_ra/279.
31
Širůček, Vojtěch. "Experimentální sušárna čistírenských kalů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-231024.
Анотація:
The master’s thesis is focused on the issue of solar drying of sewage sludge. The sludge management of wastewater treatment plants is described in the first part of this thesis. This theoretical part also deals with description of drying and dryers used for sludge treatment. The second part of the thesis is focused on the experimental solar drying of sewage sludge and the evaluation of the results.
32
Demitry, Morris Elya. "Anaerobic Digestion Process Stability and the Extension of the ADM1 for Municipal Sludge Co-Digested with Bakery Waste." DigitalCommons@USU, 2016. https://digitalcommons.usu.edu/etd/4945.
Анотація:
Uncertainty about anaerobic digestion process stability is the main issue preventing more widespread use of the process as a source of energy recovery in wastewater treatment facilities. The overall objective of this research was to study the feasibility of enhancing biogas production inside wastewater facilities using co-digestion of municipal sludge with bakery waste. Another objective was to improve the stability index and a mathematical model that can be useful tools to predict the process stability of municipal sludge digestion alone, and when it is mixed with bakery waste, as a substrate for microorganisms.
Experiments were conducted in three phases. In phase 1, a full-scale anaerobic digester at Central Weber Sewer Improvement District, Ogden, UT, receiving a mixture of primary and secondary sludge, was monitored for one hundred days. Chemical oxygen demand (COD), and volatile solids (VS) mass balances were conducted to evaluate the stability of the digester and its capability of producing methane gas. The COD mass balance accounted for nearly 90% of the methane gas produced while the VS mass balance showed that 91% of the organic matter removed resulted in biogas formation. Other parameters monitored included: pH, alkalinity, VFA, and propionic acid. The values of these parameters showed that the digester was running under stable steady state conditions. At mesophilic temperature, the stability index was determined and equal to 0.40 L (CH4)/ g(ΔVS)
In phase 2, the feasibility of adding BW to MS was tested in batch reactors scale. The biogas production was enhanced and the digester was stable until the range of 37- 40% of BW to 63-60% of MS. The ADM1 coefficients were modified to accurately predict the digester performance. The modified model outputs (pH, VFA, and methane) were within acceptable ranges when compared with the observed data from the batch reactors.
In phase 3, the feasibility of MS and BW were tested using an Induced Bed Reactor (IBR) with a 50:50% ratio of MS:BW (COD basis). The process was stable during different hydraulic retention times and the ADM1 was modified to predict the stability of the process in the IBR.
33
Jiang, Junli. "Use of Manganese Compounds and Microbial Fuel Cells in Wastewater Treatment." Thesis, KTH, VA-teknik, Vatten, Avlopp och Avfall, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-96295.
Анотація:
Manganese compounds have a high potential for treating wastewater, both for utilizing its oxidation, flocculation ability and catalyst ability in anaerobic nitrification. The promising use of manganese compounds (such as permanganate and manganese dioxide) is regarded as an effective method of treating organic compounds in wastewater from municipal and industrial wastewater. Now it is newly realized possibilities to combine manganese compounds with Microbial Fuel Cell technology. Aiming at reusing the biomass in anaerobic digested sludge for degrading organic pollutants and simultaneously recovering electric energy, Single-chamber Microbial Fuel Cell (SMFC) system was developed and investigated during the main experimental part. Considering the electricity generation rate and characteristics of cathode, MnO2 was used as the reactant on the cathode electrode; meanwhile, the substrate types in anode compartment also were investigated and then extra sodium acetate was added to investigate the power generation performance. Two parts of the research were carried out during the whole project. The chemical treatment part was mainly designed to find out the best dosage of KMnO4 in flocculation when concurrent reacted with magnesium and calcium compounds when treating reject wastewater from digester at Hammarby Sjöstadsverk. The other part was studied to see whether it is possible to improve electricity generation by degrading organic pollutants when MnO2 was used as a cathodic reactant in sediment microbial fuel cell which consisted of anaerobic digested sludge from UASB.
34
Ek, Anders. "Ultrasonic treatment of sewage sludge in order to increase biogas yields." Thesis, Linköping University, Department of Water and Environmental Studies, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-4581.
Анотація:
Biogas, a mixture of methane and carbon dioxide, is produced in the anaerobic digestion of sewage sludge. After anaerobic digestion, the digested sludge is often allowed to degas for one or two days. This gas is seldom utilised, but if the degassing could be accelerated, utilisation would be easier. Ultrasound can be used as a pretreatment method for waste activated sludge. It has a disintegrating effect on the sludge and causes lysis of bacteria in the sludge. It also speeds up the hydrolysis; the limiting step of anaerobic digestion of waste activated sludge. Ultrasound can be used to degas waterbased liquids. Ultrasonic degassing of sewage sludge has not been examined previously. The present study aims to investigate the effect of ultrasound on waste activated sludge as well as the potential of ultrasound to speed up the degassing of digested sludge. A semi-continuous, lab-scale digestion experiment was performed with four reactors: two receiving untreated sludge and two receiving treated sludge. The effect of the sonicator was 420 W and the treatment time was 6 min, which corresponds to an energy input of 8.4 kWh/m3. Total solids (TS) of the waste activated sludge was ~3.5 %. The ultrasonic treatment caused an increase in gas production of 13 %. There was no difference in methane content. The concentration of filterable chemical oxygen demand (fCOD) increased 375 %, or from 2.8 % to 11 % of total COD. In terms of energy loss/gain the increase in gas production resulted in a loss of 2.7 kWh/m3, i.e. more energy is needed to treat the sludge than the potential energy of the increased gas production. However, if the sludge is thickened to a TS >5 %, a net energy gain should be reached. The effect of ultrasound on the degassing of digested sludge was examined in three barrels. The degassing was measured with and without circulation as well as with ultrasonic treatment. The digested sludge had a gas emission rate of 115 L/(m3 day). No direct burst of gas occurred due to ultrasonic treatment. Over two days more gas was emitted from the barrel equipped with ultrasound, probably due to an induced post-digestion. Thus, ultrasonic pretreatment of waste activated sludge increases the biogas yield. It is inconclusive, whether ultrasonic treatment of digested sludge effects the degassing or not.
35
Madikizela, Phindile. "The applicability of anaerobically digested pasteurized pit latrine faecal sludge as a fertilizer to grow Radish and Garden cress." Thesis, Rhodes University, 2017. http://hdl.handle.net/10962/59235.
36
Wennman, Pär. "Decomposition and nitrogen transformations in digested sewage sludge applied to mine tailings-effects of temperature, soil moisture, pH and plants /." Uppsala : Dept. of Soil Sciences, Swedish Univ. of Agricultural Sciences, 2004. http://epsilon.slu.se/9157666288.pdf.
37
Naidoo, Pranava. "Stresses in egg-shaped sludge digesters in the form of ellipsoidal shells of revolution." Master's thesis, Faculty of Engineering and the Built Environment, 2019. http://hdl.handle.net/11427/30871.
Анотація:
Anaerobic sludge digesters of the squat cylindrical shape have inherent flaws which drive up maintenance costs, limits its ability to maintain optimum environmental conditions and is not shaped for efficient mixing. The egg-shaped sludge digester is an effective solution to these flaws. However, the analysis of these structures are complex and design guides are not readily available to designers of anaerobic sludge digesters. In previous studies, various shells of revolution were considered as egg-shaped sludge digester geometries. In terms of stress behaviour, these studies found the geometries to be suitable to act as egg-shaped sludge digesters. This thesis extends the list of geometries explored and considers the stress behaviour in an ellipsoid of revolution. First, only the membrane stress distributions were considered by varying a parameter e (the major axis radius over the minor axis radius) of the ellipsoidal shell. To conduct the study, closed form solutions for the meridional and hoop stresses were derived. The stress distributions of the varying ellipsoidal geometries were then compared and analysed. Additionally, the parametric study considered structural efficiency of the shell. Following this, in order to judge the effectiveness of the geometry, it was compared to findings of previous studies on different geometries. The study compared the geometries on the bases of volume, smoothness and maximum hoop stresses. It was found that the ellipsoidal geometry faired extremely well against the other geometries in the volume and maximum hoop stress criteria. Due to the limitations of the membrane theory of shells to predict bending stresses at supports and other discontinuities, a finite element study was conducted to achieve a complete shell stress distribution. Special attention was paid to bending at the support region where large meridional stress peaks occur as well as bending stresses seen at the apexes. Following this, various support conditions were tested to gather a full understanding of how this affects the total stress distribution in the shell. Finally based on findings of the study a design guide for egg-shaped digesters of ellipsoidal geometry was given.
38
Sen, Dipankar. "Kinetics of the release and precipitation of phosphorus in anaerobic digesters sequencing biological phosphorus removal systems." Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/91075.
Анотація:
The extent of release and precipitation of phosphorus stored in the poly-phosphate granules of microorganisms present in anaerobic digesters sequencing a biological phosphorus removal (BPR) activated sludge system was examined. The research was conducted at the York River Wastewaster Treatment plant which was converted from a conventional system to a A/O process for biological phosphorus removal. The primary and secondary anaerobic digesters each had a solids retention time of approximately 120 days.
The results indicated that at least 60 percent of the phosphorus in the poly-phosphate granules would be solubilized during endogenous decay and digestion under anaerobic conditions. This is accompanied by the release of potassium, magnesium and limited amounts of calcium.
The release of magnesium and phosphorus in the high ammonium containing environment of the primary digester results in the precipitation of about 1000 mg/L of struvite (MgNH₄PQ₄H₂O), a relatively adhesive and kinetically fast precipitate. Struvite can form on floes of biomass inside the primary digester, on walls, inside pipes, and in areas affected by lower temperatures and higher pH. The phosphorus level in the secondary digester effluent is controlled by the kinetics of formation of competitive precipitates like struvite, calcium-phosphorus compounds and vivianite (Fe₃(PO₄)₂). The formation of vivianite is limited by the competitive precipitation of siderite (FeCO₃ ). The extent to which the compounds are precipitated depends on the solids retention times, ionic strengths, size and amorphous nature of the precipitates and the substitution of foreign ions in the crystal lattice. The effective solubility products of these precipitates, as applicable to anaerobic digesters, were determined.M.S.
39
Williams, Yasheemah. "Treatment of poultry slaughterhouse wastewater using an expanded granular sludge bed anaerobic digester coupled with anoxic/aerobic hybrid side stream ultrafiltration membrane bioreactor." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2758.
Анотація:
Thesis (Master of Engineering in Chemical Engineering)--Cape Peninsula University of Technology, 2017.For more than a decade, poultry product consumption increased in developed and developing countries, with more than 470 new slaughterhouses being constructed in South Africa (SA). Customer demand for poultry products resulted in a rapidly growing poultry industry, with consequential increases in the quantity of organic solid and liquid waste being produced from the poultry slaughterhouses. Annually, the productivity and profitability within the livestock production sector has increased, an evaluation based on the number of slaughtered and sold animals. Potable water is required for these animals, resulting in the generation of high strength wastewaters. Instantaneous disposal of such wastewaters into the environment is concerning as it results in odour and the spreading of diseases in local rivers and freshwater sources. The generated poultry slaughterhouse wastewater (PSW) contains a high quantity of biodegradable organic, suspended and colloidal matter in the form of proteins, fats, oil and grease (FOG), protein from meat, blood, skin, and feathers, resulting in high Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD), which can contribute to environmental deterioration if not treated adequately before discharge. On average, PSW contains a high concentration of BOD, COD, nitrogen, pathogenic and non-pathogenic viruses, bacteria and parasites, including their eggs. These characteristics make PSW highly polluted with a large quantity of bird carcass debris including FOG. Due to the high concentration of organic matter and suspended solids in the wastewater, it is necessary to pre-treat the PSW prior to sequential anaerobic treatment. Most of the contaminants present in the PSW can be reduced by means of numerous treatment steps, i.e. physical, chemical and biological treatment. For this study, biological treatment methods, physical separation methods, and a membrane bioreactor system, were used to treat PSW. The biological treatment methods used were an anaerobic digester (AD) followed by a single stage nitrification/denitrification reactor and then a third stage in which an ultrafiltration (UF) and Microfiltration (MF) membrane bioreactor (MBR) was used. The AD used was an Expanded Granular sludge Bed Reactor (EGSB) as anaerobic digestion is one of the most effective biological wastewater treatment methods used, as it reduces the organic matter to even produce biogas as a renewable energy source. The basis of anaerobic treatment method relies on suitable bacteria cultivated in the absence of dissolved oxygen, facilitating decomposition of organic matter into a renewable source such as biogas. Similarly, biological nitrification/denitrification processes for the removal of total nitrogen (TN) in wastewater has become one of the most commonly used processes within the wastewater treatment sector. Nitrification and denitrification processes can be performed by some microorganisms within the wastewater in Wastewater Treatment Plants (WWTPs) The PSW used was collected at different times from a local poultry slaughterhouse in the Western Cape (South Africa) and stored in a refrigerator at 4°C until it was fed to the first stage of the treatment which was the EGSB. Before being fed to the EGSB, the PSW was filtered with a sieve to remove feathers and agglomerated FOG to avoid clogging of the tubing. The EGSB was inoculated with 0.747 L anaerobic granular sludge, had a working volume of 2.7 L, an inner diameter of 0.065 m and a height of 0.872 m respectively. Ceramic marbles with an average diameter of 0.0157m were placed at the bottom of the bioreactor as packing for the underdrain and to maintain the granular sludge within the heated section of the bioreactor. The EGSB was fed with three types of PSW: 50% (v/v), 70% (v/v), which was diluted with distilled water. Thereafter once the system stabilised the reactor was fed with undiluted PSW (100%). Each dilution was operated at different Hydraulic Retention Times (HRTs) and Organic Loading Rates (OLRs), with average HRTs used being 62.5, 57.5 and 49.65 h. Furthermore, the average OLRs were 1, 2 and 3 g tCOD/L.day respectively. The performance of the EGSB was determined using tCOD, Total Suspended Solids (TSS) and FOG, with overall averaged removal rates for these constituents being 69%, 98% and 92% respectively. The highest tCOD removal of 93 % (optimal efficiency) was obtained at an average HRT of 57.5 h with a corresponding average OLR of 2 g tCOD/L.day.
40
Isik, Ferit. "Applicability of ultrasound conditioning of waste activated sludge to reduce foaming potential in the anaerobic digesters." [Ames, Iowa : Iowa State University], 2006.
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Wang, Han. "Ammonium Removal and Electricity Generation by Using Microbial Desalination Cells." Thesis, KTH, VA-teknik, Vatten, Avlopp och Avfall, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-96298.
Анотація:
Microbial fuel cell (MFC) has become one of the energy-sustainable technologies for wastewater treatment purpose in the recent years. It combines wastewater treatment and electricity generation together so as to achieve energy balance. By inoculating microorganism in the anode chamber and filling catholyte in the cathode chamber, and also with the help of a proton exchange membrane (PEM) between them, the MFC can transfer protons and produce power. Microbial desalination cells (MDC) are based on MFC’s structure and can fulfill desalination function by the addition of a middle chamber and anion exchange membrane (AEM). This study focuses on ammonium removal and electricity generation in MDC system. Mainly two types of liquid were tested, a solution of Hjorthorn Salt and filtrated supernatant. The experiments were performed at Hammarby Sjöstad research station and laboratory of Land and Water Resources department, Stockholm. It consists of a preparation stage, a MFC stage and a MDC stage. Until the end of MFC stage, biofilm in the anode chamber had been formed and matured. After that, solutions of different initial concentrations (1.5, 2.5, 5, 15 g/L) of Hjorthorn Salt and also filtrated supernatant have been tested. Ammonium removal degree can be obtained by measuring the initial concentration and cycle end concentration, while electricity generation ability can be calculated by voltage data which was continuously recorded by a multimeter. Results showed that this MDC system is suitable for ammonium removal in both of Hjorthorn Salt solutions and supernatant. The removal degrees in Hjorthorn Salt solution at desalination chamber were 53.1%, 52.7%, 60.34%, and 27.25% corresponding to initial NH4+ concentration of 340.7, 376, 376 and 2220 mg/L. The ammonium removal degrees in the supernatant were up to 53.4% and 43.7% under 21 and 71 hours operation, respectively. In power production aspect, MDC produced maximum voltage when potassium permanganate was used in the cathode chamber (217 mV). The power density in solutions of Hjorthorn Salt was relative low (46.73 - 86.61 mW/m3), but in the supernatant it showed a good performance, up to 227.7 and 190.8 mW/m3.
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Lamprecht, Corne. "UASB granulation enhancement by microbial inoculum selection and process induction." Thesis, Stellenbosch: University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/1477.
Анотація:
Thesis (PhD (Food Science))--University of Stellenbosch, 2009.In the absence of anaerobic granules, anaerobically digested sewage sludge is frequently used to seed industrial upflow anaerobic sludge blanket (UASB) reactors. Because of its flocculent nature, start-up with digested sludge instead of granular sludge proceeds much slower and presents various operational problems. Any manner in which the granulation of digested sludge can be enhanced would benefit UASB reactor start-up and application in developing countries such as South Africa. The main objective of this dissertation was to improve granulation and reduce UASB reactor start-up by using pre-treated digested sludge as seed. The sludge was pre-treated based on the batch granulation-enhancement model of Britz et al. (2002). The main aim of the model was to improve extracellular polymer (ECP) production of lactate-utilising populations by applying short-term controlled organic overloading in a mechanically agitated environment. The batch granulation-enhancement (pre-treatment) process was applied to an ECP-producing digester strain, Propionibacterium jensenii S1. Non-methanogenic aggregates were formed when batch units were incubated on a roller-table instead of a linear-shake platform. Larger, more stable aggregates were obtained in the presence of apricot effluent medium. Preliminary batch granulation-enhancement studies confirmed that using the roller-table as mixing system had a positive influence on batch granulation-enhancement. The roller-table showed the most potential for handling larger volumes in comparison to a linear-shake waterbath and linear-shake platform. The addition of 450 mg.L-1 Fe2+ at the start of the study also influenced aggregate numbers positively. These studies revealed that pre-treatment results varied depending on the seed sludge source. A denaturing gradient gel electrophoresis (DGGE) method was applied for the detection of Archaea in digested sludges and UASB granules. In addition, a methanogenic marker containing methanogens important to the granulation process was constructed to aid identification. The positive influence of DMSO and “touchdown” PCR on the elimination of artifactual double bands in DGGE fingerprints were also demonstrated. Results revealed that only one of the four digested sludges tested contained Methanosaeta concilii (critical to granular nuclei formation) while it was present in all the UASB granules regardless of substrate type. Four digested sludges were obtained from stable secondary digesters. DGGE indicated the presence of M. concilii in all sludges. The Athlone 4Sb-sludge was the only sludge which exhibited measurable methanogenic activity during substrate dependent activity testing. The ST-sludge showed the highest increase in volatile suspended solids (VSS) particles ≥0.25 mm2. Laboratory-scale UASB reactor start-up was done with both sludges and start-up proceeded better in the Athlone 4Sb-reactor. Athlone 4Sb-sludge batches were pre-treated in a rolling-batch reactor in the presence of either lactate or sucrose and used to seed lab-scale UASB reactors B (sucrose seed) and C (lactate seed). Start-up efficiencies were compared to a control (Reactor A). Overall Reactor B was more efficient that the control. At the end of the study the Reactor B sludge had a higher methanogenic activity than the control reactor. It also had the highest increase in VSS ≥1.0 mm2. Pre-treatment of digested sludge in the presence of sucrose, therefore, aided granulation and reduced UASB reactor start-up time.
43
Pathak, Ankit Bidhan. "Anaerobic Co-Digestion of High Strength Food Waste with Municipal Sewage Sludge: An assessment of Digester Performance and gas production." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/48596.
Анотація:
Anaerobic digestion is perhaps the simplest and most widely accepted method for solids and residuals management in the field of wastewater treatment. An emerging trend with regard to anaerobic digestion is the addition of additional organic or industrial wastes rich in degradable material (COD) that can lead to increased methane production and reduce the energy demand of the facility.
The objective of this research was to evaluate the effect of adding significant quantities (>20% of feed volume) of High Strength Food Wastes (HSW) to digesters treating conventional municipal sludge by monitoring key parameters such as pH, influent and effluent solids, ammonia, Volatile Fatty Acids (VFAs) and alkalinity. Daily gas production was also closely monitored. Four digesters were set up and exposed to different food waste loading rates. A comparison was drawn between the performance of these reactors, one of which was fed only with sewage sludge and served as the control. If the bacteria in the system are able to metabolize this additional COD, it should show up as an increase in gas production with little or no increase in effluent COD.
Ammonia is another crucial parameter that needs to be closely watched as it can have an inhibitory effect on methane production. As part of this study, the impact of addition of free ammonium (simulating high ammonium concentration in the feed sludge or food waste) on digester performance was assessed. The digesters were closely monitored for signs of poor performance or failure.Master of Science
44
Dornack, Christina. "Biogas production from organic waste and biomass - fundamentals and current situation." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-99414.
Анотація:
The use of renewable waste for bioenergy production is in discussion because of the concurrence to the food or animal feed. The treatment of organic waste is necessary in order to keep clean the environment. The combination of those proposals, the waste utilization and the production of renewable energy can be combined with several techniques. In Vietnam the energy demand will increase rapidly in the next years, because a lot of people do not have access to electricity. The development of power sources is limited mainly to large central power plants using hydropower and traditional fossil fuels. So in the country there exists a considerable potential for sustainable energy sources like biomass and residues. The biogas potential is large due to the high livestock population. There are more than 30 million animals in farms, mostly pigs, cattle, and water buffalo. There is a high potential for biogas utilization. Biogas production is economic in small and in big plants, so household biogas digesters are one opportunity for production of renewable energy in small villages or cities with a high livestock population. The advantage of anaerobic treatment of organic waste is the work in closed loops. The treatment of organic waste and the utilization of digested sludge from wastewater treatment plants are samples for the circulation of materials after use. The remaining materials can be used in the natural circulation process, because the nutrients such as nitrogen, phosphorous and carbon, and also trace elements remain in the digested matter. In biogas plants a huge variety of substrates can be used. The adaption of biogas technology to the special conditions of the substrates, the increase of the prices for energy, the aim to replace fossil energies with renewable energies will be forced in the next yearsViệc sử dụng chất thải có thể tái tạo được để sản xuất năng lượng sinh học là vấn đề còn đang được thảo luận vì sự cạnh tranh với thức ăn hoặc thức ăn cho động vật. Việc xử lý các chất thải hữu cơ là cần thiết để giữ sạch môi trường. Sự kết hợp của các đề xuất đó, tận dụng các chất thải và sản xuất năng lượng tái tạo có thể có thể được kết hợp với một số kỹ thuật. Ở Việt Nam, nhu cầu năng lượng sẽ tăng lên nhanh chóng trong những năm tiếp theo, bởi vì rất nhiều người vẫn chưa có điện sử dụng. Sự phát triển của các nguồn năng lượng chỉ giới hạn chủ yếu là các nhà máy điện lớn trung tâm sử dụng thủy điện và các nhiên liệu hóa thạch truyền thống. Vì vậy, trong nước tồn tại tiềm năng đáng kể cho các nguồn năng lượng bền vững như sinh khối và những nguồn khác. Tiềm năng khí sinh học lớn do quần thể động vật nuôi rất lớn. Có hơn 30 triệu động vật trong trang trại, chủ yếu là lợn, bò, trâu nước. Tiềm năng sử dụng khí sinh học rất cao. Sản xuất khí sinh học rất có hiệu quả kinh tế trong các nhà máy nhỏ và lớn, do đó, các thiết bị phản ứng tạo khí sinh học ở các hộ gia đình là một cơ hội để sản xuất năng lượng tái tạo trong các thành phố hay làng mạc nhỏ với số lượng lớn các gia súc được chăn nuôi. Ưu điểm của việc xử lý kỵ khí các chất thải hữu cơ là làm việc trong vòng khép kín. Việc xử lý các chất thải hữu cơ và sử dụng bùn phân hủy từ các nhà máy xử lý nước thải là các ví dụ cho việc tuần hoàn các vật chất sau khi sử dụng. Các vật chất còn lại có thể được sử dụng trong quá trình tuần hoàn tự nhiên, vì các chất dinh dưỡng như phốt pho, nitơ và carbon, và cả các nguyên tố vi lượng vẫn tồn tại trong nguyên liệu đã phân hủy. Trong các nhà máy khí sinh học, rất nhiều loại chất nền có thể được sử dụng. Sự cải tiến công nghệ sản xuất khí sinh học theo các điều kiện đặc biệt của các chất nền, sự gia tăng của giá năng lượng, mục đích thay thế nguồn năng lượng hóa thạch bằng năng lượng tái tạo sẽ là bắt buộc trong những năm tới
45
Connan, Romain. "Feasibility of anammox for the treatment of sewage sludge digester supernatant : from inoculum enrichment and cultivation to process configurations and emissions." Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1S103/document.
Анотація:
Ces travaux de thèse porte sur l'étude d'un procédé de traitement des eaux usées intitulé "anammox". C'est un procédé biologique reposant sur le métabolisme d'un groupe de bactéries du même nom permettant l'épuration de l'azote. Ces travaux développent une méthodologie pour leur identification et leur culture et aboutissent à la mise en application de bio-réacteur de traitement à l'échelle du laboratoireThis work focuses on the study of a wastewater treatment process entitled "anammox". It is a biological process based on the metabolism of a group of bacteria of the same name allowing the purification of nitrogen. This work develops a methodology for their identification, their culture and for the implementation of bioreactor treatment at the laboratory scale
46
Mažrimas, Jonas. "Technologinių rodiklių įtaka Kauno nuotekų valyklos metantanko veikimo efektyvumui." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20120530_124508-96080.
Анотація:
Darbo tikslas – nustatyti technologinių rodiklių įtaką Kauno nuotekų valyklos metantanko efektyvumui.
Darbo uždaviniai:
nustatyti išsiskyrusių biodujų debito priklausomybę nuo temperatūros, organinės medžiagos suirimo laipsnio, palyginti teorinį ir faktinį pagaminamų biodujų kiekį.
Tyrimo objektai: Kauno miesto nuotekų valykloje dumblo pūdymui periodiškai naudojami du metantankai.
Tyrimo metodika: buvo stebimi pagrindiniai rodikliai, įtakojantys biodujų išeigą metantanke: pirminio dumblo debitas, perteklinio dumblo debitas, temperatūra ir organinės medžiagos suskilimo laipsnis. Apskaičiuotas organinės medžiagos kiekis dumble, nustatytas teorinis biodujų kiekis. Apdoroti 75 dienų tyrimų duomenys.
Tyrimo rezultatai: biodujų debitas tiesiogiai proporcingas organinės medžiagos kiekiui, esančiam pirminio ir perteklinio dumblo mišinyje. Dumblas pastoviai susidaro pirminiuose ir antriniuose sėsdintuvuose, todėl negalima reguliuoti tiekiamo dumblo debito į metantanką, nes tai gali sutrikdyti nuotekų valymo proceso eigą. Vidutiniškai per dieną į Kauno miesto nuotekų valyklos metantanką tiekiama 432,5 m3 dumblo. Organinės medžiagos kiekis dumble priklauso nuo nuotekų, atitekančių į valyklą, sudėties.
Kauno miesto nuotekų valyklos metantankas dirba mezofiliniu režimu. Pagal tyrimų duomenis metantanko darbo temperatūra svyruoja tarp 32,7 – 35,4 °C. Dėl šio temperatūrinio intervalo išsiskiriančių biodujų debitas yra netolygus. Išsiskyrusių biodujų debitas kinta nuo 4600 m3/d iki 9400 m3/d... [toliau žr. visą tekstą]The object of the research: the two anaerobic digesters that are used for the sludge digestion in Kaunas wastewater treatment plant. The aim of the research: to determine the influence of the technological indicators on the performance efficiency of the anaerobic digester in Kaunas wastewater treatment plant. The objectives of the research: to estimate the dependence of the amount of biogas on the temperature and the degree of biolysis; to compare theoretical and actual amount of the biogas produced. Research methods: the main indicators, influencing biogas emission from the anaerobic digester, such as: primary sludge discharge, surplus sludge discharge, temperature, and the degree of biolysis, were observed. The amount of the organic material in the sludge was evaluated, theoretical amount of biogas was determined from the chart. Research data acquired in 75 days was processed. The results of the research: biogas discharge is directly proportional to the amount of organic material in the compound of primary and surplus sludge. Sludge is constantly forming in the primary and secondary sludge separators, therefore the sludge discharge added to the anaerobic digester cannot be controlled, as this could disorganize the process of wastewater treatment. On the average, 432,5 m3 of sludge are added to the anaerobic digester in Kaunas wastewater treatment plant. The amount of the organic material in the sludge depends on the composition of the sewage that the treatment plant is... [to full text]
47
Pinto, Nuno Filipe Pereira. "Contributo para a minimização do consumo energético numa ETAR: estudo do efeito de diferentes proporções de lamas primárias e ativadas no processo de digestão anaeróbia - o estudo de caso da ETAR do Seixal." Master's thesis, ISA/UL, 2015. http://hdl.handle.net/10400.5/9240.
Анотація:
Mestrado em Engenharia do Ambiente - Instituto Superior de AgronomiaHuman population exponential growth and the pressures associated with human activities have caused drastic changes in the biosphere, leading to irreversible transformation in the life quality of our planet. Over the years, concerns about the quality and quantity of potable water and water and wastewater treatment methodologies have increased, making it the main focus of research. The main goal of this thesis is to study the minimization of the WWTP energy consumption, using different ratios of primary sludge and waste activated sludge (PS:WAS) as input in anaerobic digestion (AD). The impact of each proportion - T0 = 100:00; T1 = 80:20; T2 = 60:40; T3 = 40:60 , v:v – was analyzed in terms of biogas production and correspondent energy potential generated, as well as the main physicochemical characteristics and operational parameters of the anaerobic digestion process. Results show that increasing the PS proportion in the feeding mixtures, leads to an increase in the potential energy produced (55% for T0; 42% for T1; 32% for T2). Considering that most WWTP work on T3, this study provides a tool to optimize the sludge streams management as AD feeding, increasing the production of energy and decreasing the energetic costs associated to the WWTP
48
Gomez, Eddie F. "Effects of Organic Loading Rate on Reactor Performance and Archaeal Community Structure in Mesophilic Anaerobic Digesters Treating Municipal Sewage Sludge." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1268065746.
49
Straub, Timothy Mark 1963. "Inactivation of bacteriophages MS-2 and PRD1 and poliovirus type 1 in Pima Clay Loam and Brazito Sandy Loam soils amended with anaerobically digested sewage sludge." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/277884.
Анотація:
Inactivation of bacteriophages MS-2 and PRD1, and poliovirus type 1 were measured in Pima Clay Loam and Brazito Sandy Loam soils amended with anaerobically digested sewage sludge. Inactivation was determined at 15°C, 27°C, and 40°C with soils maintained at 30% moisture, and amended soils exposed to evaporation. No inactivation of PRD1 was observed within 30 days and 16 days at 15°C and 27°C respectively with little inactivation after 7 days at 40°C. Inactivation of MS-2 and poliovirus was approximately 2 fold greater at 27°C compared to 16°C. At 40°C neither virus was recovered 24 hours after sludge amendment. Evaporation to less than 5% soil moisture resulted in rapid loss of titer for all three viruses regardless of temperature. Survival of MS-2 and poliovirus 1 in sludge amended fields (15°C) was longer than comparable laboratory studies. None of the viruses were recovered in fields amended during the summer (33°C) after 7 days. A method was also developed to remove cell culture toxic components from these soils.
50
Starman, David. "Opportunities for nutrient recovery in post digestion sludge handling : analysis and feasibility study using municipal scale aerobic and anaerobic digesters." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003127.