Thesis (Ph.D.)--University of Delaware, 2008. / Principal faculty advisors: Steven K. Dentel, Dept. of Civil & Environmental Engineering; and Diane S. Herson, Dept. of Biological Sciences. Includes bibliographical references.

Thesis (M. Phil.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 58-64).

Biological sulph ate reduction has been identi fied as a potentially valuable process for removing sulphate and heavy metals from indllstrial effluents. The role of sulphate reducing bacteria (SRB) in this process has attracted the attention of biotechnologists and recently of enzymologists due to its fundamental properties and possible role in AMD bioremediation. These obligatory anaerobic sulphate-reducing bacteria are commonly known to dissimilate sulphate for energy. Under anaerobic conditions SRB oxidize simple organic compounds such as lactic acid with the sulphate and thereby generate hydrogen sulphide (a stTong reducing agent) and bicarbonate ions. The hydrogen sulphide in turn reacts with contaminant metals contained in AMD and precipitates them out of solution as metal sulphides. Bicarbonate ions neutralize AMD by reaction with protons to form carbon dioxide and water. Organic matter in the municipal sewage sludge has been identified as a potential source of electron donors for su lphate reduction. However, this organic matter is in the polymeric form that cannot be util ised by SRB. The latter depend on the activities of other hydrolytic bacteria for the degradation of complex polymers. Hence the availability of these monomeric substrates is a major factor, which may constrain further process development and is considered a rate-limiting step. Thi s study is therefore undertaken to investigate the bacterial glucohydrolase enzymes involved in the digestion of the polysaccharides present in the sewage sludge with specific interest in cellulases and/or p-glucosidase enzymes. The goals of the research are to: isolate, identify, purify and quantify these enzymes; study their distribution with respect to time, pH, and temperature; maximize and quantify the hydrol ys is products; study whether sulphide and sulphate have an enhancing or an inhibitory effect on the activity of enzymes; optimize the enzyme activity against substrate and/or product inhibition and soluble heavy metal salts. / KMBT_363 / Adobe Acrobat 9.54 Paper Capture Plug-in

The purpose of this study was to investigate the qualitative and quantitative characteristics of high molecular weight exocellular materials (biopolymer) produced in biological waste treatment systems and examine the relationship between biopolymer and sludge settling and dewatering properties. The biopolymer that interfered with sludge filtration was a high molecular weight (>10⁵) anionic biocolloid composed partially of proteins, carbohydrates and humic acids. The relationship between supernatant biopolymer and sludge settling and dewatering characteristics is system specific. Sludge dewatering rates and supernatant biopolymer concentration vary drastically as sludge pH was increased from pH 3.0 to pH 10.0. Supernatant biopolymer and sludge specific resistance increased as sludge pH increased. Particle size analysis of biological sludge showed an increase in particles with mean size less than 10 microns as sludge pH was increased. No significant relationship was observed between sludge settling and biopolymer concentration in the sludge supernatant. / Master of Science

Stocking herbivorous aquatic organisms in wastewater treatment ponds specifically to control phytoplankton biomass and reduce suspended solids can provide small, rural communities with inexpensive, secondary wastewater treatment. The capability of several native fish species and the freshwater mussel, <i>Elliptio complanata</i>, to reduce suspended solids and phytoplankton was compared in laboratory and field enclosure experiments. Fathead minnows (<i>Pimephales promelas</i>), gizzard shad (<i>Dorosoma cepedianum</i>), and the common carp (<i>Cyprinus carpio</i>) had either no effect, or significantly increased suspended solids levels. None of the fish species consistently reduced concentrations of typical wastewater algal taxa. The ineffectiveness of fish was attributed to numerous algal characteristics such as cell size, shape, relative abundance, resistance to digestion, and palatability. In contrast, <i>E. complanata</i> consistently and substantially reduced both suspended solids and algae concentrations in wastewater. Small-sized algae and suspended particles were either directly assimilated, or removed from suspension as pseudofeces, further promoting clarification. The proportion of suspended solids and algae concentrations removed per individual mussel declined with increasing densities of mussels. Declines in suspended solids and algae attributable to mussel filtration were best described by semilogarithmic regression equations. Mean filtration rate of <i>E. complanata</i> ranged from 53 ml/h/mussel for colonial blue-green algae, to 134 ml/h/mussel for smaller green algae. The results of this study suggest that freshwater mussels can effectively control suspended solids and algae in eutrophic environments. / Master of Science

Submitted in partial fulfillment of academic requirements for the degree of Masters of Technology: Department of Chemical Engineering, Durban University of Technology, 2009. / The primary objective of this project was to establish a screening protocol which could be used to access high strength/toxic effluent for toxicity and degradability prior to being disposed in wastewater treatment works. The serum bottle method (materials and method section) is simple, makes use of small glass vials (125 mℓ-volume were used in this research) which do not require any stirring nor feeding device or other engineered tool: a serum bottle is sealed immediately after all components are poured inside and thereafter conducted in a batch mode and occasionally shaken to ensure adequate homogenisation of the components. The only variables which are regularly measured are the volume of biogas produced and gas composition. The two assays, originally developed by Owen et al. (1979) to address the toxicity and the biodegradability have been combined in a single test called AAT, Anaerobic Activity Test, which enables one to assess simultaneously the inhibitory effect on the methanogenic biomass and the biodegradability of the test material as well as the ability of the biomass to adapt to the test material and therefore to overcome the initial inhibition. The screening protocol is illustrated in Annexure A. The protocol consists of a sequence of assays which employ the serum bottle methodology. A first step of the procedure is aimed at rapidly estimating whether the effluent is potentially toxic to the methanogenic biomass and in what concentration. The second step is a more extensive screening, aimed at precisely characterising the toxicity of the effluent, the extent of biodegradation that can be achieved, as well as at establishing whether a potential for adaptation of the biomass exists upon exposure. If the sample passes the screening stage, the same serum bottle method will be used to conduct a series of batch co-digestion experiments aimed at evaluating a convenient volumetric ratio between the test material and the readily biodegradable substrate. Finally, a laboratory-scale codigestion trial could simulate the full-scale process, thus enabling the selection of appropriate operating conditions for the start-up of the full-scale implementation. This the protocol has been used to assess the amenability to be anaerobically (co)digested of four industrial effluents, i.e. size and distillery effluents which are classified as high strength and scour and synthetic dye effluents classified as toxic. From the biodegradability and toxicity assays the following conclusions were drawn. The size and distillery effluent were found to be ii degradable at 32 g COD/ℓ and 16 g COD /ℓ concentrations respectively. Concentrations higher than these stipulated above were found inhibitory. Scour effluent was found to be recalcitrant at all concentration tested and synthetic dye was 100 % degradable at 0.12 g COD/ℓ and lower and highly inhibitory at concentration higher than 1.1 g COD/ℓ. Co-digestion experiment using serum bottle AAT method were undertaken between effluents i.e. size + distillery, size + scour, distillery + synthetic dye in an attempt to verify whether the digestion performance benefits from simultaneous presence of the two substrates. The volumetric ratios between the effluents were 1:1, 1:2, 2:1. The presence of two mixtures in the case of size and distillery had better methane production compared to individual substrate i.e. size or distillery separate. The mixture with volumetric flow rate ratio of 2:1 (size: distillery) was preferable in terms of process performance as it had highest COD removal compared to the other mixtures /ratios and individual substrates. The mixture of size and scour (2:1) had highest degradation percentage compared to other ratios but not high enough to qualify as degradable (less than 50 %). The mixture of distillery and synthetic dye had the same pattern with ratio of 2:1 giving the best COD conversion. The pattern than can be drawn from the degradability of mixtures is: the degradability of mixtures increase with the increasing amount of the most biodegradable compound/effluent in the mixture. Serum bottle results provided the detailed information regarding the safe operating parameters which should be used during the starting point for the larger scale investigation i.e. lab-scale investigations. The lab scale investigations were conducted primarily to validate screening and monitor how the digestion progresses and also to provide data for future project i.e. pilot plant investigation. Other effluents i.e. scour and synthetic dye and their co-digestion mixture were excluded from the lab-scale investigations since they were found to be non- biodegradable i.e. their COD conversion was less the 50 % in the screening protocol. Due to time constrains and other technical difficulties in the laboratory, the co-digestion of size and distillery mixture trials we not conducted on the laboratory scale. Laboratory-scale digestion trials showed that the best organic loading rate for distillery effluent in terms of reactor performance and stability was 1.0g COD/ℓ with efficiency of about 45 %, and for size was 2.0g COD/ℓ with an efficiency of 40 %. The efficiencies obtained in both effluents trials could be greatly improved by acclimation; however these results showed that the digestion of these effluents on the bigger scale is possible. / Water Research Commission

No description available.

published_or_final_version / Civil and Structural Engineering / Master / Master of Philosophy

Submitted in partial fulfillment of academic requirements for the degree of Masters of Technology: Department of Chemical Engineering, Durban University of Technology, 2009. / The primary objective of this project was to establish a screening protocol which could be used to access high strength/toxic effluent for toxicity and degradability prior to being disposed in wastewater treatment works. The serum bottle method (materials and method section) is simple, makes use of small glass vials (125 mℓ-volume were used in this research) which do not require any stirring nor feeding device or other engineered tool: a serum bottle is sealed immediately after all components are poured inside and thereafter conducted in a batch mode and occasionally shaken to ensure adequate homogenisation of the components. The only variables which are regularly measured are the volume of biogas produced and gas composition. The two assays, originally developed by Owen et al. (1979) to address the toxicity and the biodegradability have been combined in a single test called AAT, Anaerobic Activity Test, which enables one to assess simultaneously the inhibitory effect on the methanogenic biomass and the biodegradability of the test material as well as the ability of the biomass to adapt to the test material and therefore to overcome the initial inhibition. The screening protocol is illustrated in Annexure A. The protocol consists of a sequence of assays which employ the serum bottle methodology. A first step of the procedure is aimed at rapidly estimating whether the effluent is potentially toxic to the methanogenic biomass and in what concentration. The second step is a more extensive screening, aimed at precisely characterising the toxicity of the effluent, the extent of biodegradation that can be achieved, as well as at establishing whether a potential for adaptation of the biomass exists upon exposure. If the sample passes the screening stage, the same serum bottle method will be used to conduct a series of batch co-digestion experiments aimed at evaluating a convenient volumetric ratio between the test material and the readily biodegradable substrate. Finally, a laboratory-scale codigestion trial could simulate the full-scale process, thus enabling the selection of appropriate operating conditions for the start-up of the full-scale implementation. This the protocol has been used to assess the amenability to be anaerobically (co)digested of four industrial effluents, i.e. size and distillery effluents which are classified as high strength and scour and synthetic dye effluents classified as toxic. From the biodegradability and toxicity assays the following conclusions were drawn. The size and distillery effluent were found to be ii degradable at 32 g COD/ℓ and 16 g COD /ℓ concentrations respectively. Concentrations higher than these stipulated above were found inhibitory. Scour effluent was found to be recalcitrant at all concentration tested and synthetic dye was 100 % degradable at 0.12 g COD/ℓ and lower and highly inhibitory at concentration higher than 1.1 g COD/ℓ. Co-digestion experiment using serum bottle AAT method were undertaken between effluents i.e. size + distillery, size + scour, distillery + synthetic dye in an attempt to verify whether the digestion performance benefits from simultaneous presence of the two substrates. The volumetric ratios between the effluents were 1:1, 1:2, 2:1. The presence of two mixtures in the case of size and distillery had better methane production compared to individual substrate i.e. size or distillery separate. The mixture with volumetric flow rate ratio of 2:1 (size: distillery) was preferable in terms of process performance as it had highest COD removal compared to the other mixtures /ratios and individual substrates. The mixture of size and scour (2:1) had highest degradation percentage compared to other ratios but not high enough to qualify as degradable (less than 50 %). The mixture of distillery and synthetic dye had the same pattern with ratio of 2:1 giving the best COD conversion. The pattern than can be drawn from the degradability of mixtures is: the degradability of mixtures increase with the increasing amount of the most biodegradable compound/effluent in the mixture. Serum bottle results provided the detailed information regarding the safe operating parameters which should be used during the starting point for the larger scale investigation i.e. lab-scale investigations. The lab scale investigations were conducted primarily to validate screening and monitor how the digestion progresses and also to provide data for future project i.e. pilot plant investigation. Other effluents i.e. scour and synthetic dye and their co-digestion mixture were excluded from the lab-scale investigations since they were found to be non- biodegradable i.e. their COD conversion was less the 50 % in the screening protocol. Due to time constrains and other technical difficulties in the laboratory, the co-digestion of size and distillery mixture trials we not conducted on the laboratory scale. Laboratory-scale digestion trials showed that the best organic loading rate for distillery effluent in terms of reactor performance and stability was 1.0g COD/ℓ with efficiency of about 45 %, and for size was 2.0g COD/ℓ with an efficiency of 40 %. The efficiencies obtained in both effluents trials could be greatly improved by acclimation; however these results showed that the digestion of these effluents on the bigger scale is possible.

Thesis (M.P.H.)--University of Michigan, 1944. / Cover title: The effect of certain industrial wastes on anaerobic decomposition.