Dissertations / Theses on the topic 'Woodchips'
To see the other types of publications on this topic, follow the link: Woodchips.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 25 dissertations / theses for your research on the topic 'Woodchips.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Ajmani, Manu. "Sorption of veterinary antibiotics to woodchips." Kansas State University, 2011. http://hdl.handle.net/2097/13169.
Full textAbstract:
Master of ScienceDepartment of Civil Engineering
Alok Bhandari
In the upper Midwest, subsurface tile drainage water is a major contributor of nitrate (NO[subscript]3–N) coming from fertilizers and animal manure. Movement of NO[subscript]3-N through tile drainage into streams is a major concern as it can cause eutrophication and hypoxia conditions, as in the Gulf of Mexico. Denitrifying bioreactors is one of the pollution control strategies to treat contaminated tile drainage water. These bioreactors require four conditions which are: 1) organic carbon source, 2) anaerobic conditions, 3) denitrifying bacteria and 4) influent NO[subscript]3-N. This research focuses on investigating fate of veterinary antibiotics in woodchips commonly used in in-situ reactors. Tylosin (TYL) and sulfamethazine (SMZ) are two veterinary antibiotics which are most commonly used in the United States and can be found in tile water after manure is land applied. Partition coefficients of TYL and SMZ on wood were determined by sorption experiments using fresh woodchips and woodchips from an in situ reactor. It was concluded that the woodchips were an effective means to sorb the veterinary antibiotics leached into the tile water after application of animal manure. Linear partition coefficients were calculated and phase distribution relationships were established for both the chemicals. The fresh woodchips gave inconclusive data but predictions could be made by the information determined in the experiments using woodchips from a ten year old woodchip bioreactor. Desorption was also studied and the likelihood of desorption was predicted using the Apparent Hysteresis Index. Overall, it was found that the old woodchips allowed for quick sorption of both antibiotics. It was also found that SMZ had reversible sorption on old woodchips. Thus, it was concluded that the woodchip bioreactor would not be effective for removal of veterinary antibiotics from tile drainage. More research is required for the fate of TYL and to confirm the conclusion.
2
Mohamed, M. "Fluidised bed gasification and pyrolysis of woodchips." Thesis, University of Leeds, 1989. http://etheses.whiterose.ac.uk/21074/.
Full textAbstract:
The work presented in this thesis includes experimental investigation using a basic fluidised bed to gasify woodchips and cold modelling studies to improve the fluid bed reactor dynamics incorporating bed internals, such as draft tubes and jets. Low grade fuel gas was produced from woodchips as feedstock, in a 154 mm i/d fluidised bed as the main experimental part of the project using air as the gasifying medium. The influence of a number of process variables on the gasification process were studied including fuel feedrates, temperatures and bed heights, with respect to their effects on quality and quantity of the fuel gas produced. It was found that fuel gas of about 6 MJ/Nm3 can be obtained with temperatures in excess of 700 °c and with fuel feedrates in excess of 3.5 times stoichiometric. The process also benefitted from increasing the static bed heights of the fluidised bed, which was due to the better separation of the combustion and gasification zones. The cold modelling studies coducted using a 2-D glass model employing a draft tube a nd jet system, and using a novel photographic technique produced more realistic data. This showed that both the systems in question produced induced recirculation rates which can be controlled by the process variables such as bed height, bed and jet velocities. Further studies employing these systems for biomass conversion should prove that a better fuel gas quality and quantity can be achieved. In addition a variety of feedstocks can be utilised using the same reactor configuration.
3
Wade, James Patrick. "Biotic and Abiotic Remediation of Acetaminophen with Woodchip and Biochar-amended Woodchip Adsorbents." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/64157.
Full textAbstract:
Pharmaceuticals and personal care products found in the environment pose a significant hazard to human and ecosystem health. While there has been significant work on the fate and remediation of pharmaceuticals and personal care products in wastewater treatment, relatively little work has explored the fate, transport and remediation of these compounds in non-point source input. This is concerning given the increasing use of pharmaceuticals in livestock production and wastewater treatment derived biosolids frequently applied to land. These experiments aimed to quantify the abiotic adsorption and biotic transformation and uptake potential of woodchips and biochar-amended woodchips as a potential sorbent strategy for diffuse acetaminophen (ACT) pollution.
Batch reactions were created in triplicate, supplied with 5 mM ACT, and analyzed over an eight hr period using ultraviolet spectrophotometry (298 nm). Ultraviolet absorbance readings for each time step then were compared to standard curves and solution ACT concentration was determined. Decreases in ACT from initial concentrations were the result of either abiotic and/or biotic. Overall, the woodchips and biochar-amended woodchips showed similar removal efficiency (16-21% of initial concentration). Whole model ANOVA analysis showed biologic activity having no significant effect on ACT solution concentration. However, within group ANOVA comparison showed significant differences between abiotic and biotic WC and abiotic and biotic WC treatments (controlling for media). Thus, the media effect could have masked the effect of biology on ACT removal. Species capable of degrading ACT exist and further study into their ability to grow and survive on these sorbents requires further work.Master of Science
4
Neupane, Binod. "Incorporating Biodiversity Impact into Environmental Life Cycle Assessment of Woodchips for Bioethanol Production." Fogler Library, University of Maine, 2011. http://www.library.umaine.edu/theses/pdf/NeupaneB2011.pdf.
Full text
5
Pan, Ji-ning. "The modelling and validation of one dimensional storage drying of woodchips for fuel." Thesis, University of Aberdeen, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294142.
Full textAbstract:
Since wood fuel when used sustainably provides an energy source that does not contribute to greenhouse warming, its use in future is likely to increase. Contractors prefer to chip trees and residues green to minimise power required and machinery wear. For non-specialised combustion systems the green woodchips should then be dried to increase their calorific value and to allow buffer storage without significant dry matter loss or the development of hazardous fungal spores. As the drying of wood chips has never been rigorously defined, a study was undertaken to determine the drying characteristics of green woodchips. A drying bin was built to simulate storage drying in one dimension. Data from three drying runs using spruce and birch whole tree provided data to validate a one-dimensional heat and mass transfer drying model converted from an existing grain drying routine. The specific energy consumption varied from 2.0 MJ/kg of moisture removed using unheated air during summer drying to 5.0 MH/kg during winter when dried with air warmed by 28°C. Dry matter loss in birch during drying and a period of two months cool storage was approximately 2%. Mean evaporation rate ranged from 1.9 kg/h in winter to 2.9 kg/h in summer. This gave a drying rate of 1% and 2.2% per day, inwinter and summer respectively. Hardwoodbirch released its moisture more readily than softwood Sitkaspruce. Airflow rates used ranged from 0.26-0.63 m3/s pertonne of dry matter. The dust levels on the woodchips ranged from 3.0 mg/m3 ofair before drying up to 55 mg/m3 of air after drying. The concentrations of colony forming units on woodchips ranged from2.0 X 104 cfu/m3 of air before drying up to 8.0 X 105cfu/m3 of air after drying.
6
Ettema, William Dirk. "Alternative tile intake design for intensively managed agro-ecosystems." Thesis, University of Iowa, 2014. https://ir.uiowa.edu/etd/1451.
Full textAbstract:
The overarching objective of this study is to assess the effectiveness and performance of ATIs. In doing so, this research provides a fundamental understanding of the flow and sediment propagation through a different combination of porous media (pea gravel and woodchips). The research hypothesizes that the theory of advection and diffusion describes the migration of flow and identifies a myriad of depositional networks of sediment. A key hypothesis of the study is that global and local pressure differentiation affects the flow pathways and distribution with intimate effects of sediment trapping efficiency and distribution within the permeameter. A significant goal of this study is to decompose the key mechanisms that affect this migration of sediment under a fixed value for the head and incoming concentration. The nature of the study is experimental and is supported by limited numerical and field analysis. Although the experimental setup is site specific to the conditions encountered in the study location, it offers a generic way of examining flow and sediment intrusion within a permeable bed. The study in that sense hypothesizes that the intrusion by Einstein is valid and it shows the change in the hydraulic gradient that occurs during an event and during a sequence of events. A secondary goal of this research is to understand the cyclicity in the migration of sediment in a sequence of different events, where the initial conditions of each run constitutes the outcome of the final result of the previous runs. The nature of those experiments is to mimic the occurrence of sequential events in nature, although the continuous examined in the laboratory as reflective of conditions representing extreme runs. This research also treats the hydraulic conductivity as a dynamic entity to reflect the effect of localized clogging on the propagation of flow. The experimental design of this research considers a series of experimental runs to address the aforementioned objectives of this research and test the posed hypothesis.
7
Moberg, Mikhal. "THE EFFECTIVENESS OF SPECIFICALLY DESIGNED FILTER MEDIA TO REDUCE NITRATE AND ORTHOPHOSPHATE IN STORMWATER RUNOFF." Master's thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3677.
Full textAbstract:
Throughout Central Florida surface water and ground water are decreasing in quantity and quality in part because of excess Nitrate and Phosphorus nutrients. Stormwater runoff serves as a medium for transport of Nitrate and Phosphorus to surface water and ground water. The goal of this experiment is assess the Nitrate and Phosphorus removal in stormwater using select media. The results of a literature search, batch test experimentation and column test experimentation are used to determine an optimal media blend that may be implemented in detention ponds to reduce Nitrate and Phosphorus. The extensive literature search revealed 32 different media that may be used to remove Nitrate and Phosphorus. Each potential media was qualitatively and quantitatively evaluated based on 5 criteria: 1) relevance, 2) permeability, 3) cost, 4) availability in Florida, and 5) additional environmental benefit. The top 7 performing media: Florida peat, sandy loam, woodchips, crushed oyster shell; crushed limestone, tire crumb and sawdust were selected for batch test experimentation. The aerobic conditions in batch test experimentation prohibited the growth of denitrifying bacteria, therefore media mixes were selected for column test experimentation based on Ammonia and Orthophosphate concentrations. Batch test experimentation showed the most effective media to be 50% sand, 30% tire crumb, 20% sawdust by weight (media mix 1) and 50% sand, 25% sawdust, 15% tire crumb, 10% limestone by weight (media mix 2). Media mix 1, media mix 2 and a control are tested in column test experimentation, where the control is site soil from Hunters Trace development in Ocala, Florida. Column test experimentation models a dry detention pond where water passes through a 48 inch unsaturated zone then a 48 inch saturated zone. To test Nitrate and Orthophosphate removal potential, pond water augmented with Nitrate (0.38, 1.26, 2.5 mg/L NO3-N) and Orthophosphate (0.125, 0.361, 0.785 mg/L PO4-P) was pumped into the columns. Media mix 1 and media mix 2 outperformed the control in both Nitrate and Orthophosphate removal. Media mix 1 and media mix 2 had Nitrate removal efficiencies ranging from 60% to 99% and the control had Nitrate removal efficiencies ranging from 38%-80%. Media mix 1 and media mix 2 averaged Orthophosphate removal efficiencies ranging from approximately 42% to 67%. For every run in every influent Orthophosphate concentration the saturated control added Orthophosphate to the water. The Nitrate and Orthophosphate removal performances for media mix 1 and media mix 2 could not be directly compared because of different influent saturated nutrient concentrations.M.S.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Environmental Engr MSEnvE
8
Hlaváč, David. "Roštový kotel na spalování biomasy o parametrech páry 88 t / h, 9,6 MPa, 520°C." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-232165.
Full textAbstract:
The thesis deals with steam boiler design of 88 tons per hour capacity and with the outlet steam parameters of 9,6 MPa and 520 °C. Fuel for boiler is wood chips. The main focus of the thesis is on heat calculation, design of dimensions and layout of heat surfaces. The thesis also include drawing of steam boiler.
9
Kopeček, Marián. "Roštový kotel na spalování biomasy." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-241224.
Full text
10
Hrnčířová, Michaela. "Návrh sušky na biomasu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229754.
Full textAbstract:
This thesis deals with reducing the moisture content of biomass drying and its subsequent use as biofuel. The work is a belt drying and its integration into the system with a grate boiler. It proposes a variety of drying options for use of different drying media. In the end, an economic evaluation of the combustion system uses a belt dryer, and a system without any possibility of drying the fuel before it enters the boiler.
11
D'Ugo, Lucia. "Characterization of hydrothermal carbonization products from woodchip." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/9366/.
Full textAbstract:
L’idrotermocarbonizzazione è un processo che permette di convertire un’elevata quantità di materie prime solide in carbone. Ciò viene realizzato inserendo come sostanza in input, oltre alla materia prima iniziale, acqua liquida e, successivamente, riscaldando fino a 180°C, temperatura alla quale inizia la reazione esotermica ed il processo diventa di tipo stand-alone. Tale reazione presenta un tempo di reazione variabile nel range di 4÷12 h. I prodotti in uscita sono costituiti da una sostanza solida che ha le caratteristiche del carbone marrone naturale e un’acqua di processo, la quale è altamente inquinata da composti organici.
In questo elaborato viene illustrata una caratterizzazione dei prodotti in uscita da un impianto di idrotermo carbonizzazione da laboratorio, il quale utilizza in input pezzi di legno tagliati grossolanamente.
Inizialmente tale impianto da laboratorio viene descritto nel dettaglio, dopodiché la caratterizzazione viene effettuata attraverso DTA-TGA dei materiali in ingresso ed uscita; inoltre altre sostanze vengono così analizzate, al fine di confrontarle col char ed i pezzi di legno. Quindi si riporta anche un’analisi calorimetrica, avente l’obiettivo di determinare il calore di combustione del char ottenuto; attraverso questo valore e il calore di combustione dei pezzi di legno è stato possibile calcolare l’efficienza di ritenzione energetica del processo considerato, così come la densificazione energetica riscontrata nel materiale in uscita.
In aggiunta, è stata eseguita un’analisi delle specie chimiche elementari sul char ed il legno in modo da determinare i seguenti parametri: fattori di ritenzione e fattori di ritenzione pesati sulla massa in termini di concentrazione di C, H, N e S. I risultati ottenuti da tale analisi hanno permesso di effettuare una caratterizzazione del char.
Un tentativo di attivazione del char viene riportato, descrivendo la procedura di attivazione seguita e la metodologia utilizzata per valutare il buon esito o meno di tale tentativo di attivazione. La metodologia consiste di uno studio isotermo dell’adsorbimento di acido acetico sul char “attivato” attraverso una titolazione. I risultati sperimentali sono stati fittati usando le isoterme di Langmuir e Freundlich e confrontati con le capacità di adsorbimento del semplice char e di un campione di carbone attivo preso da un’azienda esterna.
Infine si è considerata l’acqua di processo, infatti un’analisi fotometrica ne ha evidenziato le concentrazioni di TOC, COD, ioni nitrato e ioni fosfato. Questi valori sono stati conseguentemente confrontati con i limiti italiani e tedeschi massimi ammissibili per acque potabili, dando quindi un’idea quantitativa della contaminazione di tale acqua di processo.
12
Paul, Robert Myers. "Use of woodchip for agricultural livestock bedding." Thesis, Bangor University, 2013. https://research.bangor.ac.uk/portal/en/theses/use-of-woodchip-for-agricultural-livestock-bedding(d26f7f1e-7f99-40fc-80f1-8faf8a39da19).html.
Full textAbstract:
Straw price increases due to biofuel demand have created a perceived need within the agricultural industry to investigate and develop alternative bedding materials for housing ruminant livestock. This thesis addresses the suitability of woodchip, as such an alternative, indoor bedding material for livestock, focusing particularly on management of the soiled bedding, its nutrient composition, its use as an agronomic resource and its economic viability within the Welsh farming sector. In all studies, straw was used as the benchmark to which the woodchip treatments were compared. Many studies have investigated the use of woodchip in out-winter pads (OWP), but the material’s indoor performance and in particular, its potential for re-use, is not well documented. Two independent housing trials, both including sheep and cattle, were conducted. The first trial (ADAS) assessed the effect of different initial woodchip moisture contents on the performance of the bedding material and its subsequent composting. The second trial (IGER) evaluated the effects of hay and silage diets on woodchip’s bedding and composting performance. The ADAS trial showed that woodchip’s absorbency capacity and physical shape were critical in determining its bedding and composting success. In comparison to differences determined by bedding materials and livestock characteristics, the IGER trial suggested that dietary inputs had little influence on the woodchip’s bedding and composting performance. Overall, the results indicate that composting of spent woodchip bedding was less effective than that of straw bedding, due to the lack of available N which limited microbial activity. The limited breakdown of the woodchips during composting, however, does potentially allow the re-use of the bedding materials for further housing cycles. Barley sown growth trials, amended with composted bedding materials showed that woodchip composts yielded reduced biomass in comparison to conventional NPK based fertilisers and straw bedding compost. When the coarse woody fraction of the compost was removed (>8 mm in diameter), leaving just the fine (< 8mm) nutrient-enriched fraction, plant growth performance was slightly enhanced at application rates equivalent to 100 t ha-1. Estimates of N loss from woodchip treatments were high during housing, but limited during composting due to a generic lack of available nutrients, compared to straw. Using economic modelling, a cost/benefit analysis of woodchip bedding versus straw showed that woodchip is more cost efficient than straw on the condition it is re-used. In summary, the thesis concludes that woodchip is a potentially viable alternative to straw bedding for Welsh farmers, on condition of specific management practices. Future work is required to identify and mitigate N losses during the woodchip bedding phase.
13
Erikson, Erica. "Comparison of Different Wood Types for Use as a Porous Substrate in Denitrifying Woodchip Bioreactors." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-450541.
Full textAbstract:
Explosives used in the mining industry release nitrate into the environment, causing concerns for the water quality in local river-systems. One way of reducing the nitrate loading into the environment is through a woodchip bioreactor. Water is passed through the bioreactor, where denitrifying microbial communities use the organic carbon from the substrate for energy, together with the nitrate. The efficiency of the denitrification process depends on various factors, including the type of carbon source selected and the temperature. To determine a suitable organic substrate to use in colder environments, column experiments were conducted, comparing different woodchip types. Three columns contained woodchips from pine, spruce and birch. In the fourth column, barley wheat was mixed with pine woodchips. An influent solution was pumped into the columns contained 50 mg/L nitrate-nitrogen. The effluent water was sampled and analysed twice per week for nitrate, nitrite and ammonium concentrations. The pH and alkalinity were analysed weekly to determine that denitrification was taking place. Three column conditions were tested. During the initial period, the columns were kept in 21 °C with a hydraulic residence time (HRT) of 6.3 days. In the following period, the columns were refrigerated at a temperature of 5°C. During the final period, the HRT was lowered to 3.2 days. After a 106-day runtime, it could be concluded that pine woodchips were the most effective substrate for denitrification in 5 °C temperature. The column with pine woodchips removed nitrate efficiently and produced the least amount of by-products and released DOC with a short HRT. The pine woodchips and barley straw column had high nitrite accumulation, and the nitrate removal rate in the birch and spruce woodchip columns was low in 5 °C conditions.Sprängmedel som används inom gruvindustrin släpper ut nitrat i miljön, vilket kan leda till problem med vattenkvaliteten i lokala vattensystem. Ett sätt att reducera mängden nitrat som släpps ut är genom en bioreaktor med träflis. Vatten passeras genom bioreaktorn, där denitrifierande microbakteriella grupper använder det organiska kolet från substratet för energi, tillsammans med nitratet. Effektiviteten av den denitrifierande processen beror på flertalet faktorer, däribland vilken sorts kolkälla som valts ut och vilken temperatur bioreaktorn håller. För att identifiera ett bra organiskt substrat att använda i kallt klimat genomfördes ett kolumnexperiment som jämförde olika sorters träflis. Tre kolonner innehöll träflis från tall, gran och björk. I en fjärde kolonn blandades kornhalm med träflis från tall. En lösning med koncentrationen 50 mg/L kväve i form av nitrat pumpades in i kolonnerna. Utloppsvattnet från de fyra kolonnerna analyserades två gånger per vecka för koncentration av nitrat, nitrit och ammonium. pH och alkalinitet analyserades varje vecka för att se att denitrifikation skedde. Tre olika förutsättningar testades i kolonnerna. I den första perioden hölls kolonnerna i 21 °C med en hydraulisk uppehållstid på 6,3 dagar. I den följande perioden kyldes kolonnerna till 5 °C. I den sista perioden sänktes uppehållstiden till 3,2 dagar. Efter 106 dagar gick det att fastställa att tall-träflisen var det mest effektiva substratet för denitrifikation i 5 °C. Kolonnen med träflis från tall sänkte nitrathalten i vattnet och producerade minst biprodukter, samt frigjorde organiskt kol även vid kort uppehållstid. Kolonnen med tallflis och kornhalm ackumulerade mycket nitrit, och kolonnerna med träflis från björk och gran hade låga nivåer av nitrat-rening när temperaturen sänktes till 5 °C.
14
Clemente, Andres. "Design and modelling of a photovoltaic driven fan solar air heater for drying woodchip in Scotland." Thesis, Edinburgh Napier University, 2011. http://researchrepository.napier.ac.uk/Output/4417.
Full textAbstract:
In the wood fuel supply chain, the water contained in the product determines one aspect of the quality of the wood. It is necessary to reduce the moisture content (MC) of the wood in order to reduce transport and storing costs and also to increase the heating value of the wood. In this thesis a solar thermal application has been developed to dry woodchips using exclusively solar energy. The novel solar woodchip dryer comprises a small woodchip dryer and a solar air thermal system (SATS) to increase the temperature of the drying air. The particularity of this woodchip dryer is that the input air flow is governed by a photovoltaic driven fan. Based on the experimental results obtained, the woodchip dryer and the SATS thermal performance were modelled and a simulation tool for predicting the dried woodchip production during a period of time has been developed. Two small capacity dryers, a thin and a thick layer dryer, have been designed and built to dry woodchip based on the flow capacity of the SATS. The drying performances are studied for both configurations comparing the drying times, drying rates and efficiencies at different test conditions. The drying curves obtained from each test are modelled as a function of key parameters, temperature and velocity employing the Page model equation. Based on the experimental results, a drying model has been successfully developed to predict the MC when the woodchip dryer operates within a range of drying conditions. A quantitative and qualitative analysis of the SATS thermal performance has been conducted employing various solar air collector configurations under Scottish weather conditions. The pneumatic characteristics of the solar dryer including the dryer are determining for the analysis of the system performance. Because of the PV driven fan electrical characteristics, the SATS presents a unique operation regime in which air flow depends exclusively on solar radiation. Thus the SATS thermal performance has been successfully modelled as a function of irradiance. The study necessarily includes the effect of environmental factors such as wind and cloudiness in the transient regime. The potential of using a solar woodchip dryer has been assessed based on the results obtained from modelling the dryer and the SATS together. The feasibility and employability of using the solar dryer for drying woodchips is discussed considering the productivity, the energy savings, costs and integration.
15
Wallnäs, Felicia. "Spatial and temporal changes in microbial community composition in a full-scale woodchip bioreactor for treating mine water." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-413949.
Full textAbstract:
Incomplete detonation of nitrogen-based explosives can lead to abundant levels of nitrate in mine groundwater. The possibility of reducing nitrogen levels from the wastewater through denitrification, anammox and DNRA has been investigated using a full-scale bioreactor. The bioreactor is situated subsurface and is filled with pine woodchips. Groundwater is pumped to the bioreactor and subsequently discharged to a drainage ditch. In this thesis the distribution of the microbial community was determined using quantification of functional genes representing a specific functional community. The 16S rRNA gene was used as proxy for the total bacterial community, nirS and nirK for nitrite reduction, nosZI and nosZII genes for nitrous oxide reduction, nrfA for DNRA, and hdh for anammox reaction. Denitrification appeared as the main nitrogen-reducing process in the bioreactor due to more abundant levels of functional genes. The abundance of nitrous oxide reductase was higher than nitrite oxide, indicating good nitrouse oxide reduction. Anammox could not be detected and DNRA was suggested in the end of the bioreactor due to a decrease in nitrate concentration. The distribution of abundances was not affected by the depth or the time which samples were collected. However, abundances collected at different lengths of the bioreactor showed significant differences for 16S rRNA and the functional genes nirS, nosZI and nrfA. This suggests changing environmental conditions along the bioreactor length. Creating an assay for quantification of sulphate reducing bacteria was also investigated. This was not achieved and the size and distribution of the sulphate reducing community remains to investigate. The bioreactor in the present study can reduce nitrogen from mining water but further analysis are needed in order to understand long-term temporal changes.
16
Nordström, Albin. "Denitrification in a Low Temperature Bioreactor System : Laboratory column studies." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-226585.
Full textAbstract:
Denitrification is a microbially-catalyzed reaction which reduces nitrate to N2 through a series of intermediate nitrogen compounds. Nitrate is a nutrient and its release into the environment may lead to eutrophication, depending on the amount that is released and the state of the recipient. The release of nitrate from the mining industry in Kiruna (Sweden) has been identified as an eutrophication risk, and a denitrifying bioreactor is to be constructed at the site to reduce the nitrate release.Since the denitrification rate decreases with temperature and the temperature in Kiruna during large parts of the year drops below 0˚C, the denitrifying bioreactor therefore has to be designed for the site-specific environment in terms of flow rate and hydraulic residence time. Laboratory column studies are used to study and determine the nitrate removal rate in a low temperature environment (5˚C) with pine wood chips as reactive matrix/ electron donor; the input solution had an average concentration of 35 mg NO3-N/L and a high sulfate concentration. Nitrate removal was studied as a function of hydraulic residence time and temperature. Parameters that were monitored include pH, alkalinity and concentrations of ammonium, nitrite and sulfate in the effluent from the columns. On three occasions, samples were gathered along the flow path in the columns (concentration profiles) such that changes in nitrate, nitrite, and occasionally ammonium concentration could be studied in relation to each other. The study concluded that a denitrifying bioreactor utilizing pine wood chips as the reactive matrix is a suitable option for nitrate treatment in a low temperature (5˚C) environment. Under the conditions of the study, effluent nitrate, nitrite, and ammonium concentrations are below limits established in legislation. Nitrate removal rates are given for zero-order nitrate reduction and overall first-order nitrate reduction, as the concentration profiles revealed a decrease in nitrate removal rate as nitrate concentration dropped below 3 mg NO3-N/L.Nitrat är ett näringsämne som kan orsaka övergödning vid utsläpp, beroende på halterna och recipienten. Växterna som tar upp kväve kommer så småningom att dö och sjunka mot botten där de förmultnar. Förmultningen kräver syre, och vid ökad växtlighet så ökar även konsumtionen av syre då det finns mer organiskt material att bryta ned. Detta leder i slutändan till syrefria områden, där djurliv och växtlighet är mer begränsade. Nitratutsläpp från gruvindustrin i Kiruna har blivit identifierad som en potentiell övergödningsrisk och en denitrifierande bioreaktor ska därmed installeras för att minska utsläppen. Denitrifikation är en mikrobiell reaktion som reducerar nitrat till kvävgas genom en serie av intermediära kväveföreningar. En denitrifierande bioreaktor använder sig utav denitrifikation för att minska nitratkoncentrationer i vatten som passerar genom bioreaktorn som består av huvudsakligen; (1) bakterierna som sköter denitrifikationen, och (2) en kolkälla som fungerar som ”mat” till de denitrifierande bakterierna, Hastigheten varvid nitrat omvandlas till kvävgas genom denitrifikation, minskar med temperatur och den denitrifierande bioreaktorn måste därmed anpassas till omgivningen där den ska placeras med avseende på uppehållstid i reaktorn. Uppehållstiden måste vara tillräcklig för att minska nitratkoncentrationen till önskad nivå, men samtidigt så får uppehållstiden inte vara för lång då andra ämnen kan reagera och bilda ofördelaktiga produkter vid låga nitratkoncentrationer. Kolonnstudier i en låg-tempererad miljö (5˚C) är ett första steg för att studera hastigheten av nitratförbrukning i en sådan omgivning, och används i detta arbete med träflis av tall som kolkälla. Parametrar som påverkar, och varierar som ett resultat av, denitrifikation (exempelvis pH och sekundära föroreningar) övervakas. Hastigheten av nitratförbrukning som fås från kolonnstudierna kan sedan används som riktlinjer för konstruktionen av en denitrifierande bioreaktor i fältskala i Kiruna. Studiens slutsats är att en denitrifierande bioreaktor med träflis av tall som reaktivt medium är ett fungerande alternativ för nitrat reducering i en lågtempererad miljö (5˚C) då nitrat effektivt reduceras till under gränsvärden fastslagna i lag. Även andra potentiella biprodukter (exempelvis nitrit och ammonium) som kan resultera från den miljö som den denitrifierande bioreaktorn ger upphov till är under de gränsvärden som finns fastslagna i lag.
17
Rossouw, Johanna Martina. "The use of different ecosystem components as indicators of ecosystem development during platinum mine tailings rehabilitation / Johanna Martina (Juanita) Rossouw." Thesis, North-West University, 2005. http://hdl.handle.net/10394/1405.
Full text
18
Miller, Elisa Madeleine. "Fire mitigation and exotic species invasions in the Front Range: Responses of soil and vegetation to woodchip amendments in thinned forest, across a gradient of experimentally-manipulated nutrient availability." Connect to online resource, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3315813.
Full text
19
Baláži, Martin. "Roštový kotel na spalování uhlí a dřevní biomasy." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-241700.
Full textAbstract:
This thesis solves a design of a grate boiler burning wood chips or brown coal with a heat output of 160 MW. Stoichiometry flue gas is calculated according to the specified composition of each fuel. The dimensions of the individual heating surfaces are primarily calculated for burning wood chips and subsequently checked for the combustion of brown coal. Design of the boiler is completed by checking the overall heat output. Boiler design is accompanied by drawing documentation.
20
Yeralan, Serdar. "Drying of woodchips in a packed bed." 1991. http://catalog.hathitrust.org/api/volumes/oclc/24159928.html.
Full textAbstract:
Thesis (M.S.)--University of Wisconsin--Madison, 1991.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 48-49).
21
Sullivan, Matthew E. "Characterization of ash in the pressurized downdraft combustion of woodchips." 1993. http://catalog.hathitrust.org/api/volumes/oclc/32691580.html.
Full textAbstract:
Thesis (M.S.)--University of Wisconsin--Madison, 1993.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 76-77).
22
DiGregorio, Gayle. "The effects of woodchips and buried food on behavior patterns and psychological well-being of captive rhesus monkeys." 1989. http://catalog.hathitrust.org/api/volumes/oclc/21617220.html.
Full textAbstract:
Thesis (Ph. D.)--University of Wisconsin--Madison, 1989.Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 106-130).
23
Ima, Chukwunonyerem Samuel. "Prediction of woodchip-induced lateral pressures on biofilter walls." 2008. http://hdl.handle.net/1993/21134.
Full text
24
Bai, Shih-Ting, and 白士庭. "Characterization of PCDD/Fs and dl-PCBs Emitted from Woodchip Boilers." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/68990617957898043589.
Full textAbstract:
碩士國立中央大學
環境工程研究所
105
This study characterizes the formation and emission of PCDD/Fs and dl-PCBs in two woodchips boilers during different operating periods. Two woodchips boilers (referred to as Plant A and B) investigated in this study are located in northern Taiwan. The sampling program of Plant A was conducted during different operating stages, including start-up, normal operation and shut-down periods. The results indicate that PCDD/F and dl-PCB concentrations (588.2 ng/Nm3) at APCDs inlet during the start-up period are much higher than those measured during normal operation and shut-down periods due to unstable combustion conditions. Concentrations of PCDD/F and dl-PCB (41.05 ng/Nm3) measured at APCDs inlet during the shut-down period were even lower than that measured during the normal operating period. It is due to the lack of carbon and chlorine sources since woodchip was not fed into the boiler during the shut-down period. The Plant B was investigated under three operating conditions, including full feed loading with injection of activated carbon, full feed loading without injection of activated carbon and half feed loading with injection of activated carbon. PCDD/Fs and dl-PCBs concentrations (113.6 ng/Nm3) measured at APCDs inlet during the half feed loading are lower than those measured during the full feed loading (139.4 ng/Nm3) due to the reduction of input woodchips. The removal efficiences of gas-phase PCDD/Fs and dl-PCBs achieved with ACI+BF are 95.60% and 92.05%, respectively, which are higher compared to the case without injection of activated carbon (85.74% and 79.76%, respectively). It demonstrates that gas-phase PCDD/Fs and dl-PCBs emissions can be effectively reduced by activated carbon injection. Durig full feed loading with the injection of activated carbon, PCDD/F and dl-PCB concentrations at APCDs inlet of the Plant A are significantly higher than those measured in the Plant B, due to the lower combustion temperature (500-850 oC) compared with Plant B (850-925 oC). Combustion condition remarkably affects PCDD/F and dl-PCB formation within the woodchip combustion process. The TEQ concentration of PCDD/Fs measured at the stack of the Plant A during different operating stages are significantly higher than the emission limit, while those of Plant B are lower than the regulation limit (0.5 ng I-TEQ/Nm3). For both Plants A and B, solid-phase PCDD/Fs dominate at APCDs inlet during different operating conditions because combustion of woodchips generates high concentration particulate matter. Different operating stages of woodchips combustion do not affect distributions of PCDD/F congeners significantly. Major PCDD/F congeners at APCDs inlet of Plants A and B during different periods include 1,2,3,4,6,7,8-HpCDF, 1,2,3,4,6,7,8-HpCDD and OCDD. The composition of feeding materials and different operating conditions affect the distributions of dl-PCB congeners. Concentrations of dioxin (PCDD/Fs+dl-PCBs) in the BF ash of Plants A and B during full feed loading with injection of activated carbon are measured 979.2 and 406.2 ng/g. Removal efficiencies of PCDD/Fs and dl-PCBs of the Plant A are 95.56% and 88.63%, respectively, while those of the Plant B are 99.29% and 94.94%. PCDD/Fs and PCBs emission factors of Plant A are 17.24 and 1.120 μg WHO-TEQ/ton, respectively. For the Plant B, the emission factors of PCDD/Fs and PCBs are 1.520 and 0.1400 μg WHO-TEQ/ton, respectively.
25
Hart, Jeffrey L. (Jeffrey Le). "Evaluating the rates of nitrate removal for a nitrate containing, low organic carbon wastewater interacting with carbon-containing solid substrates." Thesis, 2012. http://hdl.handle.net/1957/28584.
Full textAbstract:
The primary objective of this study was to evaluate the rates of nitrate removal for a nitrate containing, low organic carbon wastewater interacting with four different carbon-containing solid substrates (alder woodchips, corn silage, manure and woodchip biochar). Batch systems were tested for nitrate removal, and systems with a combination of three carbon substrates (75% woodchips, 12.5% silage, and 12.5% manure or woodchip biochar by mass) produced average nitrate removal rates of 571 and 275 mg-N L⁻¹ D⁻¹, and systems containing the carbon substrates individually produced rates between 11.4 - 3.3 mg-N L⁻¹ D⁻¹. Silage proved to be the dominant carbon substrate providing high quantities of organic carbon to fuel denitrification. With the introduction of semi-continuous flow, all systems had nitrate removal rates that converged to 13.3 – 6.4 mg-N L⁻¹ D⁻¹, which is approximately two orders of magnitude smaller than the rates of the mixture systems in the batch experiment. Silage appeared to be removed from of the systems with liquid exchange potentially causing the rate decreases. Columns filled with various volume fractions of woodchips (100%, 25%, 12.5%, and 0%) produced nitrate removal rates between 30.8 – 2.4 mg-N L⁻¹ D⁻¹ at a 24 hour and 12 hour hydraulic residence time (HRT). Greater nitrate removal was achieved with higher HRTs and larger fractions of woodchips (the 100% woodchip system at a 24 hour HRT produced the fastest nitrate removal rate of 30.8 mg-N L⁻¹ D⁻¹). When rates were normalized to the amount of woodchips in each column, higher efficiency was found in lower woodchip fraction systems (the 12.5% woodchip column produced the highest normalized nitrate removal rate of 56 mg-N L⁻¹ D⁻¹ L[subscript woodchips]⁻¹). Woodchips proved to be best suited as a long term carbon substrate for nitrate removal in a system containing a nitrate concentrated, low organic carbon wastewater. However, large amounts of woodchips were necessary to achieve nitrate removal greater than 50%. A 41 acre hypothetical wetland with a 3.3 day HRT and a nitrate influent concentration of 45 mg-N L⁻¹ would require 30,000 yd³ of woodchips to achieve 68% nitrate removal based on the values obtained in the bench scale column experiment.Graduation date: 2012