Готові списки джерел за темами / Anaerobic hydrolysis

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Добірка наукової літератури з теми "Anaerobic hydrolysis"

Автор: Grafiati

Опубліковано: 10 січня 2023

Оновлено: 28 січня 2023

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Статті в журналах з теми "Anaerobic hydrolysis"

Johansen, J. E., and R. Bakke. "Enhancing hydrolysis with microaeration." Water Science and Technology 53, no. 8 (April 1, 2006): 43–50. http://dx.doi.org/10.2166/wst.2006.234.

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Effects of microaeration on hydrolysis of primary sludge are investigated in 500 ml batch reactors at 377 °C. Two experiments, one with a microaerobic inoculum and one with a combination of a microaerobic and an anaerobic inoculum, are carried out to also investigate the role of the inoculum. Assuming an acidogenic, methanogenic and aerobic biomass yield of 0.1, 0.05 and 0.45 mgC/mgC, respectively, a 50–60% hydrolysis increase, during the 4 day experiment, is observed with a ratio between aerobic and anaerobic metabolism in the range 0.5–0.7. The extra hydrolysed products are oxidized to carbon dioxide and incorporated into new biomass. The oxygen utilization to carbon dioxide production ratio was ∼1:1 on a mol basis. Effects of the oxygen supplied on the hydrolysis of carbohydrates, proteins and lipids are analyzed based on measurements and balances of dissolved carbon, nitrogen and COD. The total observed hydrolysis increase can be accounted for by increased hydrolysis of carbohydrates and proteins. Lipids are only hydrolysed when anaerobic inoculum is added, but no effect of oxygen availability is detected.

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Cassini, S. T., M. C. E. Andrade, T. A. Abreu, R. Keller, and R. F. Gonçalves. "Alkaline and acid hydrolytic processes in aerobic and anaerobic sludges: effect on total EPS and fractions." Water Science and Technology 53, no. 8 (April 1, 2006): 51–58. http://dx.doi.org/10.2166/wst.2006.235.

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Sludge samples from an upflow anaerobic sludge blanket (UASB) reactor and four submerged aerated biofilters (BFs) of a wastewater treatment plant (1,000 inhab.) were processed at bench scale by alkaline and acid hydrolysis with the objective to evaluate the organic matter solubilization, volatile solids (VS) destruction and the effect of hydrolytic processes on the extracellular polymeric substances (EPS) fraction of the sludge samples. The results showed that alkaline hydrolysis of sludge samples treatment with 1.0% total solids (TS) using NaOH 20 meq L−1 was more efficient on organic matter solubilization and VS destruction than acid hydrolysis. The EPS sludge content was also affected by the alkaline treatment of anaerobic sludge samples. The EPS concentrations (mg EPS/gVSS) on the anaerobic sludge after the alkaline treatment were significantly lowered according to sample height in the UASB reactor. Data indicated that the EPS sludge fraction is the main component affected by the alkaline hydrolytic process of anaerobic sludge samples.

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Goel, Rajeev, Takashi Mino, Hiroyasu Satoh, and Tomonori Matsuo. "Comparison of hydrolytic enzyme systems in pure culture and activated sludge under different electron acceptor conditions." Water Science and Technology 37, no. 4-5 (February 1, 1998): 335–43. http://dx.doi.org/10.2166/wst.1998.0659.

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Enzymatic hydrolysis under different electron acceptor conditions in nutrient removal activated sludge treatment processes is a weak link in the Activated Sludge Model no. 2 (Henze et al., 1995). An experimental study was undertaken to gain insight into the hydrolysis process with specific focus on hydrolysis kinetics and rates under different electron acceptor conditions. Two pure cultures, Bacillus amyloliquefaciens (Gram positive) and Pseudomonas saccharophila (Gram negative) were chosen for the study. In addition, activated sludge grown in an anaerobic-aerobic system was tested for enzymatic activity using starch as the model substrate. The hydrolytic enzymes were found to be released into the bulk in pure cultures whereas the enzyme activity was found to be mainly associated with the cell surfaces in activated sludge. Further, it was observed that the development of the hydrolytic enzyme system in Bacillus amyloliquefaciens and P. saccharophila is strongly suppressed under anoxic and anaerobic conditions. However, the effect of anaerobic and aerobic incubation on hydrolytic enzyme activity in activated sludge was found to be small. Starch hydrolysis kinetic data from batch experiments with activated sludge followed substrate saturation kinetics that were linear with biomass concentration. Finally, the similar hydrolytic enzyme activities observed under anaerobic and aerobic phases of a sequencing batch reactor are explained by considering the aspects of enzyme location and enzyme system development under aerobic and anaerobic phases. It is proposed that the floc bound enzymes are recycled in a single sludge system so that an equilibrium exists between enzyme loss and synthesis at steady state.

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Rajagopal, Rajinikanth, and Fabrice Béline. "Anaerobic hydrolysis and acidification of organic substrates: Determination of anaerobic hydrolytic potential." Bioresource Technology 102, no. 10 (May 2011): 5653–58. http://dx.doi.org/10.1016/j.biortech.2011.02.068.

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Bochmann, G., T. Herfellner, F. Susanto, F. Kreuter, and G. Pesta. "Application of enzymes in anaerobic digestion." Water Science and Technology 56, no. 10 (November 1, 2007): 29–35. http://dx.doi.org/10.2166/wst.2007.727.

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Owing to the very low economic value of brewer's spent grains, its utilisation for biogas production is very promising. The hydrolysis of ligno-cellulose is the rate limiting step in anaerobic digestion. Enzymatic pre-treatment promotes the hydrolysis of ligno-cellulose, breaking it down to lower molecular weight substances which are ready to be utilised by the bacteria. A cheap raw multi-enzyme produced by a solid state fermentation (SSF) process is a good substitute for expensive conventional enzyme. The SSF enzyme application to spent grain has been investigated by carrying out enzymatic solubility tests, hydrolytic experiments and two-step anaerobic fermentation of spent grain. Gas chromatograph analysis was conducted to quantify fatty acids concentrations, while CH4, CO2, O2, H2 and H2S were measured to determine biogas quality by means of a gas analyser. DS, oDS, pH were also measured to analyse the anaerobic digestion. The result shows that enzyme application promotes the hydrolysis of ligno-cellulose, indicated by higher enzymatic solubility and fatty acid concentration in a hydrolytic bioreactor. Moreover, biogas production is also increased. The quality of the gases produced is also enhanced. Since the anaerobic digestion can be operated in a stable performance, it can also be concluded that SSF enzyme is compatible with anaerobic digestion.

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Lü, F., P. J. He, L. P. Hao, and L. M. Shao. "Impact of recycled effluent on the hydrolysis during anaerobic digestion of vegetable and flower waste." Water Science and Technology 58, no. 8 (October 1, 2008): 1637–43. http://dx.doi.org/10.2166/wst.2008.511.

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Two trials were established to investigate the effect of recycled effluent on hydrolysis during anaerobic co-digestion of vegetable and flower waste. Trial I evaluated the effect by regulating the flow rate of recycled effluent, while Trial II regulated the ratio of hydrolytic effluent to methanogenic effluent, which were recycled to hydrolysis reactor. Results showed that the recirculation of methanogenic effluent could enhance the buffer capability and operation stability of hydrolysis reactor. Higher recycled flow rate was favourable for microbial anabolism and further promoted hydrolysis. After 9 days of hydrolysis, the cumulative SCOD in the hydrolytic effluent reached 334, 407, 413, 581 mg/g at recycled flow rates of 0.1, 0.5, 1.0, 2.0 m3/(m3·d), respectively. It was feasible to recycling a mixture of hydrolytic and methanogenic effluent to the hydrolysis reactor. This research showed that partially introducing hydrolytic effluent into the recycled liquid could enhance hydrolysis, while excessive recirculation of hydrolytic effluent will inhibit the hydrolysis. The flow ratio 1:3 of hydrolytic to methanogenic effluent was found to provide the highest hydrolysis efficiency and degradation rate of lignocelluloses-type biomass, among four ratios of 0:1, 1:3, 1:1 and 3:1. Under this regime, after 9 days of hydrolysis, the cumulative TOC and TN in the hydrolytic effluent reached 162 mg/g and 15 mg/g, the removal efficiency of TS, VS, C and cellulose in the solid phase were 60.66%, 62.88%, 58.35% and 49.12%, respectively. The flow ratio affected fermentation pathways, i.e. lower ratio favoured propionic acid fermentation and the generation of lactic acid while higher ratio promoted butyric acid fermentation.

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Ferreiro, N., and M. Soto. "Anaerobic hydrolysis of primary sludge: influence of sludge concentration and temperature." Water Science and Technology 47, no. 12 (June 1, 2003): 239–46. http://dx.doi.org/10.2166/wst.2003.0652.

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Anaerobic hydrolysis of primary sludge from urban wastewater treatment was first studied as part of anaerobic sludge stabilisation and later as a process for readily biodegradable matter (volatile fatty acids) production in order to improve biological nutrient removal. Furthermore, hydrolysis was found to be the rate limiting step in both single- or two-step anaerobic treatment of domestic wastewater. However, the influence on the process of several factors such as sludge concentration and temperature is still barely understood, as are kinetic aspects. The aim of this work was to study the influence of sludge concentration and temperature on the hydrolytic and acidogenic conversion of primary sludge and to determine the hydrolysis kinetic coefficients at different temperatures. Specific VFA production varied from 0.17 to 0.34 gVFACOD/gVSS of raw primary sludge, depending mainly on the assay sludge concentration and, to a lesser extent, on the process temperature. The first-order hydrolysis constants were 0.038, 0.095 and 0.169 d−1 for 10, 20 and 35°C, respectively.

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Selling, Robert, Torbjörn Håkansson, and Lovisa Björnsson. "Two-stage anaerobic digestion enables heavy metal removal." Water Science and Technology 57, no. 4 (March 1, 2008): 553–58. http://dx.doi.org/10.2166/wst.2008.054.

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To fully exploit the environmental benefits of the biogas process, the digestate should be recycled as biofertiliser to agriculture. This practice can however be jeopardized by the presence of unwanted compounds such as heavy metals in the digestate. By using two-stage digestion, where the first stage includes hydrolysis/acidification and liquefaction of the substrate, heavy metals can be transferred to the leachate. From the leachate, metals can then be removed by adsorption. In this study, up to 70% of the Ni, 40% of the Zn and 25% of the Cd present in maize was removed when the leachate from hydrolysis was circulated over a macroporous polyacrylamide column for 6 days. For Cu and Pb, the mobilization in the hydrolytic stage was lower which resulted in a low removal. A more efficient two-stage process with improved substrate hydrolysis would give lower pH and/or longer periods with low pH in the hydrolytic stage. This is likely to increase metal mobilisation, and would open up for an excellent opportunity of heavy metal removal.

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Menzel, Theresa, Peter Neubauer, and Stefan Junne. "Role of Microbial Hydrolysis in Anaerobic Digestion." Energies 13, no. 21 (October 23, 2020): 5555. http://dx.doi.org/10.3390/en13215555.

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There is a growing need of substrate flexibility for biobased production of energy and value-added products that allows the application of variable biodegradable residues within a circular economy. It can be used to balance fluctuating energy provision of other renewable sources. Hydrolysis presents one of the biggest limitations during anaerobic digestion. Methods to improve it will result in broader process applicability and improved integration into regional material cycles. Recently, one focus of anaerobic digestion research has been directed to systems with a separate hydrolysis–acidogenesis stage as it might be promised to improve process performance. Conditions can be adjusted to each class of microorganisms individually without harming methanogenic microorganisms. Extensive research of separate biomass pretreatment via biological, chemical, physical or mixed methods has been conducted. Nevertheless, several methods lack economic efficiency, have a high environmental impact or focus on specific substrates. Pretreatment via a separate hydrolysis stage as cell-driven biotransformation in a suspension might be an alternative that enables high yields, flexible feeding and production, and a better process control. In this review, we summarize existing technologies for microbial hydrolytic biotransformation in a separate reactor stage and the impacts of substrate, operational parameters, combined methods and process design as well as remaining challenges.

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Higuchi, Y., A. Ohashi, H. Imachi, and H. Harada. "Hydrolytic activity of alpha-amylase in anaerobic digested sludge." Water Science and Technology 52, no. 1-2 (July 1, 2005): 259–66. http://dx.doi.org/10.2166/wst.2005.0526.

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Hydrolysis is usually considered to be a rate-limiting step in anaerobic digestion. For improving anaerobic solid waste treatments, it is essential to elucidate the mechanism of hydrolysis. In this study, alpha-amylase, one of the hydrolytic enzymes, was investigated for the elucidation of more precise mechanism of hydrolysis. Alpha-amylase activity of solid starch-degrading bacteria (SDB) was estimated through batch experiments with several different substrates and with distinction between cell-bound and cell-free alpha-amylase. Monitoring of newly isolated strains of SDB was done by fluorescence in situ hybridization. Results indicated that cell-bound alpha-amylase is chiefly responsible for the hydrolysis in the digested sludge, providing very useful information that the contact between microbial cells and solids is significantly important. The activity of alpha-amylase of the digested sludge remained quite low when not required, but increased as they recognized appropriate substrates. Several-fold higher activity was obtained for starch or maltose as compared to glucose only.

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Дисертації з теми "Anaerobic hydrolysis"

Fraser, Kino Dwayne. "Increased Anaerobic Digestion Efficiency via the Use of Thermal Hydrolysis." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/33979.

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Waste sludge is frequently treated by anaerobic digestion to kill pathogens, generate methane gas and reduce odors so the sludge can be safely land applied. In an attempt to reduce sludge volumes and improve sludge dewatering properties, the use of thermal hydrolysis (TH), a sludge pretreatment method, has been adopted by numerous wastewater treatment plants, among them being the District of Columbia Water and Sewage Authority (DC WASA). The use of anaerobic digestion in collaboration with thermal hydrolysis has been shown to increase VS removal, COD removal and biogas production. The sludge generated also dewaters to a higher cake solids than from conventional anaerobic digestion. Unfortunately, DC WASA has found that the use of thermal hydrolysis had brought about two major issues. These are: (a) does thermal hydrolysis increase destruction of fats, oils and greases compared to conventional digestion? and (b) is the mixing method used at Virginia Tech (recirculating gas mixing) capable of stripping ammonia from the digester? Therefore the main purpose of this study is to evaluate these issues which occur with the use of the thermal hydrolysis process.

Experiments were conducted in two phases. The first phase was to assess the performance of anaerobic digesters via their biogas production with and without long chain fatty acid addition and with or without thermal hydrolysis. This research was further carried out in two stages. First a mixture of unsaturated long chain fatty acids (hydrolyzed and unhydrolyzed) was used. The fatty acid mixture included oleic, linoleic and linolenic acids, which contain one, two and three double bonds, respectively.

In the second stage, the effect of a single unsaturated fatty acid (hydrolyzed and unhydrolyzed) was analyzed. If extra gas is generated, grease addition to the digesters will be implemented. If thermal hydrolysis produces more gas, the greases will be added through the thermal hydrolysis unit rather than being added directly to the digester. The results showed that addition of long chain fatty acids greatly increased gas production and the long chain fatty acids that were thermally hydrolyzed generated more gas than the untreated long chain fatty acids, although the gain was not large.

The second phase of the study was carried out by alternating the type of recirculating gas mixing (partial and continuous) in the anaerobic bioreactor. To achieve this goal, short-term anaerobic bioreactor studies were conducted by varying the frequency of the gas. The result showed that continuous gas recirculation at the bottom of the digester was responsible for stripping ammonia from the system. It appeared that up to 500 mg/L of ammonia was being stripped from the digester operating at 20 day solids retention time. This suggests that ammonia can be stripped if a reduction of ammonia in the digester was desired.
Master of Science

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Bishnoi, Pallavi. "Effects of Thermal Hydrolysis Pre-Treatment on Anaerobic Digestion of Sludge." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/34539.

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The increased demand for advanced techniques in anaerobic digestion over the last few years has led to the employment of various pre-treatment methods prior to anaerobic digestion to increase gas production. These pre-treatment methods alter the physical and chemical properties of sludge in order to make it more readily degradable by anaerobic digestion. The thermal hydrolysis process has been used in several treatment plants around the world, but none currently operate in the US. Thermal hydrolysis causes cell walls to rupture under the effect of high temperature and high pressure and results in highly solubilized product which is readily biodegradable. The performance of the process was evaluated for a treatment plant located in Dallas, TX. The performance assessment was based on various characteristics including pH, solids removal, COD removal and gas production. The study was conducted in two phases to investigate the effect of change in mesophilic temperature (37oC and 42oC) and the effect of solids retention time (SRT) (15 days and 20 days). Thermally hydrolyzed combined (1:1) primary and waste activated sludge was fed to a Thermal Hydrolysis (TH) anaerobic digester and its performance was compared to a conventional mesophilic anaerobic digester receiving non pre-treated sludge. The thermal hydrolysis pre-treatment was found to be more effective as compared to the conventional anaerobic digester. The efficiency of the process varied slightly with increase in temperature but the change in SRT was seen to have a greater impact on the digesterâ s performance. The pre-treatment technique was observed to deliver the best results at a 20 day SRT.
Master of Science

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Moreira, Cesar M. "Steam hydrolysis and anaerobic digestion of biodegradable (polylactic acid) packaging waste." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0025168.

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Zhou, Yingjun. "Pilot-scale anaerobic digestion of municipal biowaste with thermal hydrolysis pre-treatment." 京都大学 (Kyoto University), 2013. http://hdl.handle.net/2433/174908.

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Oyekola, Oluwaseun Oyekanmi. "The enzymology of sludge solubilisation under biosulphidogenic conditions : isolation, characterisation and partial purification of endoglucanases." Thesis, Rhodes University, 2004. http://hdl.handle.net/10962/d1003980.

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Endoglucanases play an important function in cellulose hydrolysis and catalyse the initial attack on the polymer by randomly hydrolysing the β-1,4 glucosidic bonds within the amorphous regions of cellulose chains. Cellulolytic bacteria have been isolated and characterised from the sewage sludge and the activation of several hydrolytic enzymes under biosulphidogenic conditions of sewage hydrolysis has been reported. The aims of this study were to: identify, induce production, locate and isolate, characterise (physicochemical and kinetic) and purify endoglucanases from anaerobic biosulphidogenic sludge. The endoglucanase activities were shown to be associated with the pellet particulate matter and exhibited a pH optimum of 6 and temperature optimum of 50 °C. The enzymes were thermally more stable when immobilised to the floc matrix of the sludge than when they were released into the aqueous solution via sonication. For both immobilised and released enzymes, sulphate was slightly inhibitory; activity was reduced to 84 % and 77.5 % of the initial activity at sulphate concentrations between 200 and 1000 mg/l, respectively. Sulphite was stimulatory to the immobilised enzymes between 200 and 1000 mg/l. Sulphide stimulated the activities of the immobilised endoglucanases, but inhibited activities of the soluble enzymes above 200 mg/l. The enzyme fraction did not hydrolyse avicel (a crystalline substrate), indicating the absence of any exocellulase activity. For CMC (carboxymethylcellulose) and HEC (hydroxylethylcellulose) the enzyme had K_m,app_ values of 4 and 5.1 mg/ml respectively and V_max,app_ values of 0.297 and 0.185 μmol/min/ml respectively. Divalent ions (Cu²⁺, Ni²⁺ and Zn²⁺) proved to be inhibitory while Fe²⁺, Mg²⁺ and Ca²⁺ stimulated the enzyme at concentrations between 200 and 1000 mg/l. All the volatile fatty acids studied (acetic acid, butyric acid, propionic acid and valeric acid) inhibited the enzymes, with acetic acid eliciting the highest degree of inhibition. Sonication released ~74.9 % of the total enzyme activities into solution and this was partially purified by PEG 20 000 concentration followed by DEAE-Cellulose ion exchange chromatography, which resulted in an appreciable purity as measured by the purification factor, 25.4 fold.

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Masse, Lucie. "Anaerobic degradation of fat particles in slaughterhouse wastewater with and without hydrolysis pretreatment." Thesis, University of Ottawa (Canada), 2001. http://hdl.handle.net/10393/9039.

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Lipids represent an important fraction of the particulate organic charge in slaughterhouse wastewater. Anaerobic treatment of slaughterhouse wastewater has been reported to be slowed down or impaired because of high concentrations of suspended solids, particularly fats. However, the fate of lipids during anaerobic digestion has been poorly defined, especially for wastewaters from the meat processing industry. The objectives of this thesis were thus (1) to evaluate the effect of hydrolysis pretreatment on the anaerobic digestion of fat particles in slaughterhouse wastewater; (2) to characterise and quantify neutral fat hydrolysis and long-chain fatty acid (LCFA) oxidation during anaerobic degradation of slaughterhouse wastewater with and without hydrolysis pretreatment; and (3) to determine the effect of particle size on fat hydrolysis. The efficiency of four pretreatments to hydrolyse and reduce the size of pork and beef fat particles during mixing at room temperature was tested: NaOH and three commercial lipases of plant, bacterial and animal origins. The most promising pretreatment was the pancreatic lipase PL-250 that could significantly reduce the initial average particle size (Din) of pork fat by a maximum of 40% after 4 h of mixing at room temperature. Approximately 35% of the neutral fat was hydrolysed after 5.5-h of pretreatment with 250 mg/l of PL-250 in a substrate containing approximately 2000 mg/l of pork fat particles. Most of the free LCFAs released during the hydrolytic pretreatment remained adsorbed on the fat particle surface. The effect of pretreatment with PL-250 on subsequent anaerobic digestion of the substrate was evaluated by feeding control and enzyme pretreated slaughterhouse wastewater containing pork fat particles to anaerobic sequencing batch reactors (ASBRs) operated at 25°C. The main conclusions from the experiment were: (1) Pretreatment with PL-250 only had a small effect on pork fat particle digestion at 25°C, marked by a decrease of about 5% in digestion time to achieve 80% reduction in initial neutral fat and free LCFA concentrations. (2) Anaerobic degradation of pork fat particles is mainly controlled by free LCFA oxidation and, in ASBRs operated at 25°C, near maximum oxidation rate is reached at low free LCFA concentration. Consequently, increasing the initial free LCFA concentration by prehydrolysing the substrate will have limited effect on fat degradation rate. (3) At Din ranging from 60 to 450 mum, pork fat hydrolysis rate in anaerobic reactors is not a function of particle size. The fat particles became more filamentous and plate-like as their size was increased. Bacteria could probably colonise the inside as well as the outside of the particles. Consequently, specific surface area (m2/m3) available for hydrolysis was not significantly increased by decreasing the pork fat particle size. (4) Neutral fat hydrolysis and free LCFA oxidation rates can be adequately modelled using first-order and Monod-type kinetics, respectively. The first-order hydrolysis rate constant averaged 0.63 +/- 0.07 d-1, while the maximum oxidation rate (kmax) and half-saturation concentration (Ks) were estimated at 164 +/- 37 mg free LCFA /l/d and 35 +/- 31 mg free LCFA/1, respectively. (5) Fat hydrolysis rate will be underestimated if based on the increase in soluble compounds with respect to particulate organics. An analytical method that removes bound LCFAs from solids surface must be used to measure lipid hydrolysis.

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Lu, Hung-Wei. "Evaluation of Solubilization with Thermal Hydrolysis Process of Municipal Biosolids." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/64914.

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The increased demand for advanced sludge stabilization in wastewater treatment facilities over the past decade has led to the implementation of various pretreatment techniques prior to anaerobic digestion. In an attempt to reduce sludge volumes and improve sludge conditioning properties, the use of thermal hydrolysis process before anaerobic digestion has been adopted with an increase in solids destruction, COD removal, and methane gas. In this study, the evaluation of thermal hydrolysis process as a viable pretreatment strategy to anaerobic digestion has been conducted in order to assess its capacity for solids solubilization. Solubilization experiments were conducted at temperatures ranging from 130 to 170℃ and reaction times between 10 and 60 min. Anaerobic biogas production by thermally pre-treated sludge was carried out through a mesophilic anaerobic digester. The results showed that solids solubilization increased with increases in temperature and time, while temperatures above 160℃ for 30 min strongly affected the sludge characteristics. Ammonia production via deamination by thermal hydrolysis was less significant than protein solubilization at a temperature of 170℃. Both protein and carbohydrate solubilization were more dependent on temperature than reaction time. The enhancement of the biogas production was achieved with increases in temperature as pretreatment of 170℃ yielded 20% more biogas than at 130℃. However, it seems the enhancement was linked to the initial biodegradability of the sludge.
Master of Science

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Wilson, Christopher Allen. "Mechanisms of Methanogenic Inhibition in Advanced Anaerobic Digestion." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/40432.

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A series of lab-scaled digestion studies including conventional mesophilic anaerobic digestion(MAD), thermophilic anaerobic digestion (TAD) at a range of treatment temperatures, and mesophilic high solids digestion of thermally pretreated wastewater sludge (THD) were carried out. Enhanced digestion performance in terms of solids destruction and methane generation by THD relative to MAD was achieved, and was largely attributable to the solubilization and subsequent biodegradation of energy-rich substrates within blended primary and secondary sludge. TAD was observed to underperform MAD, especially at elevated temperatures as methanogenic inhibition resulted in the accumulation of headspace hydrogen, thus resulting in poor removal of volatile fatty acids. The thermodynamics of fatty acid metabolism was favorable at each digestion temperature, thus it was concluded that microbial inhibition was the controlling factor in poor thermophilic performance. Inhibition by free unionized ammonia (NH₃) was characterized for THD and MAD biomass. Acetic acid degradation was equally affected over a range of NH₃ concentrations; however, methane generation by THD was less sensitive to ammonia inhibition, thus suggesting that methanogenesis by THD was less dependent on the NH₃-sensitive process of aceticlastic methanogenesis. Total ammonia nitrogen (TAN) and bicarbonate alkalinity were stoichiometrically produced from proteinaceous material during thermal hydrolytic pretreatment and subsequent high solids anaerobic digestion. Combined effects of TAN and high pH resulted in NH₃-inhibition during THD. Kinetic evaluations suggested that a growth rate reduction of approximately 65% was associated with in-situ NH₃ concentrations of the THD reactor. NH₃-inhibition was apparently responsible for a shift in dominant methanogenic community of the aceticlastic Methanosarcina barkeri in MAD to the hydrogenotrophic Methanoculleus bourgensis in THD. A similar shift in methanogenic community was observed between low temperature thermophilic digestion at 47°C, where the dominant order was Methanosarcinales, to high temperature thermophilic digestion at 59°C where the dominant order was Methanobacteriales. These findings support a process-driven pathway shift from aceticlastic to non-aceticlastic methanogenesis between 180 and 290 mg/L NH₃-N. Such a threshold is supported by previous literature related to ammonia tolerance of pure cultures of methanogens and has significant implications for the kinetic design of advanced anaerobic digestion processes.
Ph. D.

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Siegert, Irene. "Anaerobic digestion of solid wastes : fundamental studies on the factors governing microbial hydrolysis reactions." Thesis, University of Southampton, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417406.

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Hamid, Hanna. "Effect of microwave hydrolysis on transformation of steroidal hormones during anaerobic digestion of municipal sludge cake." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/43963.

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Книги з теми "Anaerobic hydrolysis"

Rollón, Analiza Palenzuela. Anaerobic digestion of fish processing wastewater with special emphasis on hydrolysis of suspended solids. Rotterdam: Balkema, 1999.

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Rollon, Analiza. ANAEROBIC DIGESTION FISH PROCESS (IHE Thesis). Routledge, 1999.

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Kirchman, David L. Processes in anoxic environments. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198789406.003.0011.

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During organic material degradation in oxic environments, electrons from organic material, the electron donor, are transferred to oxygen, the electron acceptor, during aerobic respiration. Other compounds, such as nitrate, iron, sulfate, and carbon dioxide, take the place of oxygen during anaerobic respiration in anoxic environments. The order in which these compounds are used by bacteria and archaea (only a few eukaryotes are capable of anaerobic respiration) is set by thermodynamics. However, concentrations and chemical state also determine the relative importance of electron acceptors in organic carbon oxidation. Oxygen is most important in the biosphere, while sulfate dominates in marine systems, and carbon dioxide in environments with low sulfate concentrations. Nitrate respiration is important in the nitrogen cycle but not in organic material degradation because of low nitrate concentrations. Organic material is degraded and oxidized by a complex consortium of organisms, the anaerobic food chain, in which the by-products from physiological types of organisms becomes the starting material of another. The consortium consists of biopolymer hydrolysis, fermentation, hydrogen gas production, and the reduction of either sulfate or carbon dioxide. The by-product of sulfate reduction, sulfide and other reduced sulfur compounds, is oxidized back eventually to sulfate by either non-phototrophic, chemolithotrophic organisms or by phototrophic microbes. The by-product of another main form of anaerobic respiration, carbon dioxide reduction, is methane, which is produced only by specific archaea. Methane is degraded aerobically by bacteria and anaerobically by some archaea, sometimes in a consortium with sulfate-reducing bacteria. Cultivation-independent approaches focusing on 16S rRNA genes and a methane-related gene (mcrA) have been instrumental in understanding these consortia because the microbes remain uncultivated to date. The chapter ends with some discussion about the few eukaryotes able to reproduce without oxygen. In addition to their ecological roles, anaerobic protists provide clues about the evolution of primitive eukaryotes.

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Частини книг з теми "Anaerobic hydrolysis"

Sudalyandi, Kaliappan, and Rajeshbanu Jeyakumar. "Enhancement of Hydrolysis." In Biofuel Production Using Anaerobic Digestion, 37–51. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-3743-9_3.

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Sudalyandi, Kaliappan, and Rajeshbanu Jeyakumar. "Hydrolysis and Assessment." In Biofuel Production Using Anaerobic Digestion, 53–84. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-3743-9_4.

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Sudalyandi, Kaliappan, and Rajeshbanu Jeyakumar. "Kinetics and Modelling of Hydrolysis." In Biofuel Production Using Anaerobic Digestion, 85–97. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-3743-9_5.

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Henze, Mogens. "Hydrolysis/fermentation and Anaerobic Wastewater Treatment." In Wastewater Treatment, 299–326. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-662-04806-1_9.

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Hurst, G., M. Peeters, and S. Tedesco. "Integration of Catalytic Biofuel Production and Anaerobic Digestion for Biogas Production." In Springer Proceedings in Energy, 125–31. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-63916-7_16.

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AbstractThe drive towards a low carbon economy will lead to an increase in new lignocellulosic biorefinery activities. Integration of biorefinery waste products into established bioenergy technologies could lead to synergies for increased bioenergy production. In this study, we show that solid residue from the acid hydrolysis production of levulinic acid, has hydrochar properties and can be utilised as an Anaerobic Digestion (AD) supplement. The addition of 6 g/L solid residue to the AD of ammonia inhibited chicken manure improved methane yields by +14.1%. The co-digestion of biorefinery waste solids and manures could be a promising solution for improving biogas production from animal manures, sustainable waste management method and possible form of carbon sequestration.

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Edirisinghe, D. I. U., S. M. W. T. P. K. Ariyarathna, and C. S. Kalpage. "Mathematical Modeling of the Hydrolysis Phase in Anaerobic Digestion of Solid Waste." In Lecture Notes in Civil Engineering, 559–66. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-9749-3_49.

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Vavilin, Vasily A., Sergei V. Rytov, and Ljudmila Ya Lokshina. "Two-Phase Model of Hydrolysis Kinetics and Its Applications to Anaerobic Degradation of Particulate Organic Matter." In Biotechnology for Fuels and Chemicals, 45–57. Totowa, NJ: Humana Press, 1997. http://dx.doi.org/10.1007/978-1-4612-2312-2_5.

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Kovalev, Andrey, Dmitriy Kovalev, Vladimir Panchenko, Valeriy Kharchenko, and Pandian Vasant. "Way for Intensifying the Process of Anaerobic Bioconversion by Preliminary Hydrolysis and Increasing Solid Retention Time." In Advances in Intelligent Systems and Computing, 1195–203. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-68154-8_101.

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Li, Xin-Liang, Lars G. Ljungdahl, Eduardo A. Ximenes, Huizhong Chen, Carlos R. Felix, Michael A. Cotta, and Bruce S. Dien. "Properties of a Recombinant β-Glucosidase from Polycentric Anaerobic Fungus Orpinomyces PC-2 and Its Application for Cellulose Hydrolysis." In Proceedings of the Twenty-Fifth Symposium on Biotechnology for Fuels and Chemicals Held May 4–7, 2003, in Breckenridge, CO, 233–50. Totowa, NJ: Humana Press, 2004. http://dx.doi.org/10.1007/978-1-59259-837-3_20.

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Quiñones, Teresa Suárez, Matthias Plöchl, Katrin Päzolt, Jörn Budde, Robert Kausmann, Edith Nettmann, and Monika Heiermann. "Hydrolytic Enzymes Enhancing Anaerobic Digestion." In Biogas Production, 157–98. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118404089.ch6.

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Тези доповідей конференцій з теми "Anaerobic hydrolysis"

Zheng Zhen, Liu Bin, and Yu Xu. "Enhancement of sewage sludge anaerobic digestibility by Alkaline-Thermal hydrolysis pretreatment." In 2011 International Conference on Remote Sensing, Environment and Transportation Engineering (RSETE). IEEE, 2011. http://dx.doi.org/10.1109/rsete.2011.5964492.

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Qiao, W., W. Wang, R. Xun, Kazuyuki Tohji, Noriyoshi Tsuchiya, and Balachandran Jeyadevan. "Microwave Thermal Hydrolysis Of Sewage Sludge As A Pretreatment Stage For Anaerobic Digestion." In 2007. AIP, 2008. http://dx.doi.org/10.1063/1.2896967.

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Flatabø, Gudny Øyre, and Wenche Hennie Bergland. "Anaerobic Co-Digestion of Products from Biosolids Pyrolysis – Implementation in ADM1." In 63rd International Conference of Scandinavian Simulation Society, SIMS 2022, Trondheim, Norway, September 20-21, 2022. Linköping University Electronic Press, 2022. http://dx.doi.org/10.3384/ecp192059.

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Pyrolyzing biosolids can decrease volume and increase value of solids while anaerobic digestion of gas and liquids from the process could increase overall methane production. Prediction of process behavior and biogas yield through simulation is valuable when considering new substrates for anaerobic digestion. In this study, gas and liquids from biosolids pyrolysis were implemented in Anaerobic Digestion Model No 1 (ADM1) together with a stream of thermally hydrolyzed sludge/food waste used in an industrial biogas plant. Average operational data from the industrial plant was used to calibrate the base scenario in ADM1, achieving a good fit. Simulation scenarios evaluating two hydrolysis constants for the pyrolysis liquid showed minor differences at the load simulated and simulated variations in composition of the liquid showed minor differences. Simulation of adding a relevant stream of pyrolysis liquid and gas together increased methane production by 7 % but decreased overall methane yield from 63 % to 61 % compared to the base scenario.

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Wang, Zhongjiang, and Wenzhe Li. "Study on Interaction of Influencing Factors on Propionic Acid Content in the Process of Anaerobic Hydrolysis and Acidogenesis." In 2012 Second International Conference on Intelligent System Design and Engineering Application (ISDEA). IEEE, 2012. http://dx.doi.org/10.1109/isdea.2012.685.

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Binder, James J., and Stephen A. Torres. "Implementation of the Taunton, Massachusetts Regional Solid Waste Management Facility." In 17th Annual North American Waste-to-Energy Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/nawtec17-2310.

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Taunton, Massachusetts (City) is a city of 55,000 people located in Southeast Massachusetts, approximately 35 miles from Boston. Currently it hosts a regional landfill that will reach capacity in 2013. Beginning in 2005, the City began the process of searching for a solid waste management technology to replace the landfill. The focus for the search has been on conversion technologies capable of recovering materials and producing electricity or fuels, and maximizing diversion of waste from landfilling. Technologies being considered include both traditional and emerging technologies; e.g., composting, co-composting, thermal gasification, aerobic and anaerobic digestion, hydrolysis and mechanical means of waste separation into useful products. Landfilling and traditional waste-to-energy technology are not being considered.

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Tharifa, Firyal, Khansa Luqyana Hapsari, Cindy Rianti Priadi, and Heri Hermansyah. "Effect of magnesium addition to volatile fatty acids and particulate chemical oxygen demand in hydrolysis phase of anaerobic waste treatment." In INTERNATIONAL CONFERENCE ON EMERGING APPLICATIONS IN MATERIAL SCIENCE AND TECHNOLOGY: ICEAMST 2020. AIP Publishing, 2020. http://dx.doi.org/10.1063/5.0006309.

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Samarasiri, B. K. T., P. G. Rathnasiri, and Dave Fernando. "Development of an Enzymatic Hydrolysis Pretreatment Strategy to Improve Batch Anaerobic Digestion of Wastewater Generated in Desiccated Coconut Processing Plants." In 2019 Moratuwa Engineering Research Conference (MERCon). IEEE, 2019. http://dx.doi.org/10.1109/mercon.2019.8818847.

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Ugwu, Samson N., and Christopher C. Enweremadu. "Comparative Studies on the Effect of Selected Iron-Based Additives on Anaerobic Digestion of Okra Waste." In ASME 2019 13th International Conference on Energy Sustainability collocated with the ASME 2019 Heat Transfer Summer Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/es2019-3820.

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Abstract Biogas production is an anaerobic waste-to-energy technology, involving waste degradation and stabilization. The sustainable, cheap and clean nature of biogas has led to the unprecedented rise in its use as an alternative energy source. Due to the increased interests, availability of conventional biodegradable organics has shrunk enormously over the years, necessitating the aggressive search for novel energy crops and substrate enhancement options. These novel options ensure feedstock security, optimize conventional biomass feedstocks, improve feedstock degradability and increase in biogas yield. Low biodegradability of most lignocellulosic wastes like okra waste, limits their use as a viable substrate in the anaerobic digestion process. Over the years, several elements, compounds and nanoparticles have been applied to anaerobic digestion systems as supplementary nutrients with a view to enhancing substrate degradation. Such supplements like iron-based additives have gained prominence in anaerobic digestion processes of wastes, owing to their electron donation abilities, promotion of solubilization, hydrolysis, acidification, and hydrogenotrophic methanogenesis. In a bid to enhance substrate degradation, reduce inhibitions, increase both biogas yield and methane content, a comparative study on the influence of four different iron-based additives (nanoscale zero-valent iron (nZVI), Polypyrrole-magnetic nanocomposite (Ppy-Fe3O4), Iron powder (Fe) and Hematite (Fe2O3)) on the entire anaerobic digestion of okra waste was done. Previously determined optimum doses, 20 mg, 20 mg, 750 mg, 750 mg and 0 respectively for nZVI, Ppy-Fe3O4, Fe, Fe2O3 and control were added to the bioreactors containing okra wastes in a 500 mL biomethane potential bioreactors under mesophilic temperature (37°C) for 20 days. The cumulative volumes of the biogas from different reactors were recorded and analyzed. The morphological deformation, structures and analysis of the undigested substrate, digestates of substrate supplemented with iron-based additives and the control were evaluated with scanning electron microscopy (SEM). Artificial neural network (ANN) model and the modified Gompertz model were validated with the experimental data. The ANN model showed better goodness of fit and was better correlated with the experimental data. Experimental data were subjected to analysis of variance at a 95% confidence level. Results showed that Ppy-Fe3O4 additives better enhanced both biogas yield and methane contents significantly when compared to the control. It was also observed that all iron-additive supplemented processes were more degraded when compared with the control.

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West, Teno A. "Procurement of Emerging Waste-to-Energy Technologies." In 18th Annual North American Waste-to-Energy Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/nawtec18-3533.

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The City of Taunton, MA (City) has undertaken a competitive procurement process to consider proposals for a private company to develop, design, permit, finance, construct and operate a Solid Waste Management Facility (SWMF), which may be sized up to 1800 tons per day (TPD), to serve both the City’s and region’s needs for long term solid waste management. A comprehensive Request for Qualifications and Proposals (RFQP) for the SWMF was issued in June 2008. The City initiated the procurement process because its current landfill is scheduled to reach capacity in 2013. The procurement process focused on conversion technologies capable of recovering materials and producing electricity or fuels, and maximizing diversion of waste from landfilling. Technologies considered included both traditional and emerging technologies; e.g., composting, co-composting, thermal gasification, aerobic and anaerobic digestion, hydrolysis and mechanical means of waste separation into useful products. Landfilling and traditional waste-to-energy technologies were not considered.

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Ma, Na, Ping Liu, Chao Chen, Aili Zhang, and Lisa X. Xu. "Thermal Environmental Effect on Breast Tumor Growth." In ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206229.

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Tissue hypoxia is a common and important feature of rapidly growing malignant tumors and their metastases. Tumor cells mainly depend on energy production thru anaerobic glycolysis rather than aerobic oxidative phosphorylation in mitochondria [1]. Intervening the tumor metabolic process via thermal energy infusion is worthy attempting. And hyperthermia, mildly elevated local temperature above the body temperature, is one of such kind. Previously, after being heated for a short period of time, tumor glucose and lactate level increased and ATP level decreased, which suggested energy metabolism was modified following hyperthermia through increased ATP hydrolysis, intensified glycolysis and impaired oxidative phosphorylation [2]. Many researchers designed experiments to determine thermal dose in hyperthermia [3], but few focused on the relationship between tumor and energy, especially for a long-term local hyperthermia treatment. One clinical trial indicated the effective long-term hyperthermo-therapy for maintaining performance status, symptomatic improvement, and prolongation of survival time in patients with peritoneal dissemination [4].

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Звіти організацій з теми "Anaerobic hydrolysis"

Morrison, Mark, and Joshuah Miron. Molecular-Based Analysis of Cellulose Binding Proteins Involved with Adherence to Cellulose by Ruminococcus albus. United States Department of Agriculture, November 2000. http://dx.doi.org/10.32747/2000.7695844.bard.

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At the beginning of this project, it was clear that R. albus adhered tightly to cellulose and its efficient degradation of this polysaccharide was dependent on micromolar concentrations of phenylacetic acid (PAA) and phenylpropionic acid (PPA). The objectives for our research were: i) to identify how many different kinds of cellulose binding proteins are produced by Ruminococcus albus; ii) to isolate and clone the genes encoding some of these proteins from the same bacterium; iii) to determine where these various proteins were located and; iv) quantify the relative importance of these proteins in affecting the rate and extent to which the bacterium becomes attached to cellulose. BARD support has facilitated a number of breakthroughs relevant to our fundamental understanding of the adhesion process. First, R. albus possesses multiple mechanisms for adhesion to cellulose. The P.I.'s laboratory has discovered a novel cellulose-binding protein (CbpC) that belongs to the Pil-protein family, and in particular, the type 4 fimbrial proteins. We have also obtained genetic and biochemical evidence demonstrating that, in addition to CbpC-mediated adhesion, R. albus also produces a cellulosome-like complex for adhesion. These breakthroughs resulted from the isolation (in Israel and the US) of spontaneously arising mutants of R. albus strains SY3 and 8, which were completely or partially defective in adhesion to cellulose, respectively. While the SY3 mutant strain was incapable of growth with cellulose as the sole carbon source, the strain 8 mutants showed varying abilities to degrade and grow with cellulose. Biochemical and gene cloning experiments have been used in Israel and the US, respectively, to identify what are believed to be key components of a cellulosome. This combination of cellulose adhesion mechanisms has not been identified previously in any bacterium. Second, differential display, reverse transcription polymerase chain reaction (DD RT-PCR) has been developed for use with R. albus. A major limitation to cellulose research has been the intractability of cellulolytic bacteria to genetic manipulation by techniques such as transposon mutagenesis and gene displacement. The P.I.'s successfully developed DD RT- PCR, which expanded the scope of our research beyond the original objectives of the project, and a subset of the transcripts conditionally expressed in response to PAA and PPA have been identified and characterized. Third, proteins immunochemically related to the CbpC protein of R. albus 8 are present in other R. albus strains and F. intestinalis, Western immunoblots have been used to examine additional strains of R. albus, as well as other cellulolytic bacteria of ruminant origin, for production of proteins immunochemically related to the CbpC protein. The results of these experiments showed that R. albus strains SY3, 7 and B199 all possess a protein of ~25 kDa which cross-reacts with polyclonal anti-CbpC antiserum. Several strains of Butyrivibrio fibrisolvens, Ruminococcus flavefaciens strains C- 94 and FD-1, and Fibrobacter succinogenes S85 produced no proteins that cross-react with the same antiserum. Surprisingly though, F. intestinalis strain DR7 does possess a protein(s) of relatively large molecular mass (~200 kDa) that was strongly cross-reactive with the anti- CbpC antiserum. Scientifically, our studies have helped expand the scope of our fundamental understanding of adhesion mechanisms in cellulose-degrading bacteria, and validated the use of RNA-based techniques to examine physiological responses in bacteria that are nor amenable to genetic manipulations. Because efficient fiber hydrolysis by many anaerobic bacteria requires both tight adhesion to substrate and a stable cellulosome, we believe our findings are also the first step in providing the resources needed to achieve our long-term goal of increasing fiber digestibility in animals.

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