It was the purpose of this investigation to attempt to quantitate the microflora of the fields which receive the effluent from the Campbell Soup Plant, Paris, Texas, and to determine whether or not there is a correlation between the numbers and types of organisms present and the efficiency of purification of the system.

The following Thesis is comprised of two separate and individual parts, both of which relate to the disposal of hydrogen sulfide. Section One is an investigation into the possibility of developing a hydrogen sulfide decomposition process which would produce both hydrogen and elemental sulfur. Section Two deals with the speciation study of a catalyst used in a traditional process which converts hydrogen sulfide gas into elemental sulfur. / Section 1: <p> The disposal of hydrogen sulfide by electrolysis to produce both hydrogen and sulfur appears to an interesting alternative to the conventional Claus process which wastes the hydrogen content of hydrogen sulfide. The electrolysis at room temperature has been reported in the literature, however, the investigation was somewhat limited by the low conductivity displayed by the electrolysis solution (pyridine/hydrogen sulfide mixture). </p> <p> The primary goal of this research was to construct a suitable apparatus and carry out a series of conductivity measurements of liquid hydrogen sulfide at room temperature with and without the addition of possible electrolytes. The objective was to determine if an electrolyte could be found that would increase the conductivity to a suitably high level to warrant the further investigation of the electrolysis process. </p> <p> Of the six possible electrolytes, only tetrapropyl ammonium iodide increased the conductivity to a desirable level. A 0.4034 M solution of this alkyl ammonium iodide in liquid hydrogen sulfide increased the conductivity (at 23 C) from 7.00 X 10-8 ohm-1cm-1 for the pure solvent to 1.13 X 10-2 ohm-1cm-1. This increase was attributed to the formation of the corresponding hydrogen sulfide adduct and its subsequent dissociation in liquid hydrogen sulfide. </p> </p> Now that it has clearly been established that appropriately high conducting solutions of hydrogen sulfide can be prepared, the further investigation of the electrolysis of hydrogen sulfide as a viable industrial process is warranted. </p> Section 2: <p> This section deals with the investigation of species present in vanadium(IV): citrate solutions over a wide range of pH values. Various spectroscopic methods (UV/VIS, ESR, vanadium Sl FT-NMR) were used to probe this specific system. The accumulated spectroscopic data were rationalized on the basis of thirteen vanadium(IV) containing species, four of which were proposed to be vanadium(IV): citrate species. Based on the observed spectroscopic data an equilibrium diagram was prepared which illustrates the vanadium(IV) species present as a function of pH. </p> / Thesis / Master of Science (MSc)

The significant increase in the sewage sludge production in treatment plants makes anaerobic digestion more important as a stabilization process. However hydrolysis is the rate-limiting step of anaerobic digestion because of the semirigid structure of the microbial cells. Pretreatment of waste activated sludge (WAS) leads to disruption of cell walls and release of extracellular and intracellular materials. Therefore biodegradability of sludge will be improved in terms of more biogas production and sludge minimization. Among the pretreatment methods, alkaline, thermal and thermochemical pretreatments are effectual ones. Considering the effect of thermal pretreatment, microwave technology in which the sample reaches to elevated temperatures very rapidly is a very new pretreatment method. However no previous research has been conducted to test the effectiveness of microwave (MW) irradiation combined with alkaline pretreatment. Since both of these techniques seem to be highly effective, their combination can act synergistically and even more efficient method can be obtained. Therefore the main objective of this study was to investigate the effect of combination of a chemical method (alkaline pretreatment) and a physical method (microwave irradiation) in improving anaerobic digestion of WAS. In the first part of the study, alkaline and MW pretreatment methods were examined separately, then their combinations were investigated for the first time in the literature in terms of COD solubilization, turbidity and CST. Highest SCOD was achieved with the combined method of MW+pH-12. In the second part, based on the results obtained in the first part, alkaline pretreatments of pH-10 and pH-12 / MW pretreatment alone and combined pretreatments of MW+pH-10 and MW+pH-12 pretreated WAS samples were anaerobically digested in small scale batch anaerobic reactors. In correlation with the highest protein and carbohydrate releases with MW+pH-12, highest total gas and methane productions were achieved with MW+pH-12 pretreatment reactor with 16.3% and 18.9% improvements over control reactor, respectively. Finally the performance of MW+pH-12 pretreatment was examined with 2L anaerobic semi-continuous reactors. 43.5% and 53.2% improvements were obtained in daily total gas and methane productions. TS, VS and TCOD reductions were improved by 24.9%, 35.4% and 30.3%, respectively. Pretreated digested sludge had 22% improved dewaterability than non-pretreated digested sludge. Higher SCOD and NH3-N concentrations were measured in the effluent of pretreated digested sludge / however, PO4-P concentration did not vary so much. Heavy metal concentrations of all digested sludges met Soil Pollution Control Regulation Standards. Finally a simple cost calculation was done for a MW+pH-12 pretreatment of WAS for a fictitious WWTP. Results showed that, WWTP can move into profit in 5.5 years.

This research applies stochastic decision tree analytical techniques to a decision of the type a small community may face when choosing a solid waste disposal system from among several alternatives. Specifically targeted are those situations in which a community finds itself (1) lying at or near the boundary of a central planning area, (2) in a position to exercise one of several disposal options, and (3) has access to the data base on solid waste which has been systematically developed by a central planning agency. The options available may or may not be optimal in terms of total cost, either to the community or to adjacent communities which participate in centrally coordinated or jointly organized activities. The study suggests that stochastic simulation models, drawing upon a data base developed by central planning agencies in cases where local data are inadequate or not available, can be useful in evaluating disposal alternatives at the community level. Further, the decision tree can be usefully employed to communicate results of the analysis. Some important areas of further research on the small community disposal system selection problem are noted.

Ultrasonic sludge disintegration &ndash / the most commonly used mechanical pretreatment method- enables the occurrence of cavitation bubbles to extract intracellular material from the cell into aqueous phase. However, there is a lack of information on the volatile solids loading on the anaerobic digestion process performance of ultrasonically treated sludge. In this thesis work, the effect of sonication on disintegration of waste activated sludge (WAS) and an important parameter digester F/M (food to microorganism) ratio on ultrasonically treated WAS were investigated. First, preliminary studies were conducted. It was obtained that when the sonication power and time increased, soluble COD in the supernatant increased as well. Then, batch anaerobic digestion tests were conducted. Effect of F/M ratio in the digesters by using sonicated sludges at different powers was analyzed. For the sludge sonicated at high power, the methane content increased up to 55.1 % at F/M ratio of 10 compared to untreated sludge. On the other hand, methane generation rate slowed down with the increase in F/M ratio. Moreover, 10 % and 15 % increase in the destruction of MLVSS and total COD content was observed for sonicated sludges compared to the untreated sludges, respectively. In summary, both the sonication as a pretreatment method and the increase in digester F/M ratio increased the biogas production and the solids reduction during anaerobic digestion prosess. These results may have important implications for the operation of full scale systems in terms of system efficiency and operation.

Activated sludge systems are the most widely used biological wastewater treatment processes all over the world. The main working principles of an activated sludge system are the oxidation of biologically degradable wastes by microorganisms and the subsequent separation of the newly formed biomass from the treated effluent. Separation by settling is the most troublesome stage of an activated sludge process. A decrease in the efficiency of the separation of microbial biomass from the treated effluent causes a decrease in the overall efficiency of the treatment plant. The efficiency of the separation process is related to the bioflocculation, which can be briefly defined as the aggregation of the bacteria into flocs through flocculation. Bioflocculation depends on the extracellular polymers (EPS) that are produced by microorganisms. The operating conditions of the activated sludge system is a key determinant of the synthesis of EPS and bioflocculation. The main objective of this study is to find out the effect of magnesium ions on the bioflocculation process under phosphorus deficient and sufficient conditions. In order to achieve this aim, the effects of magnesium ion in 4 different concentrations (0.9, 5, 10 and 20 meq/L) are investigated in semi continuous reactors. The reactors are operated at a mean cell residence time of 8 days and 20&ordm / C temperature. When reactors are confirmed to be at steady state, several sets of analysis are conducted. In particular, the surface chemical parameters including EPS and its components, electrical charge, and hydrophobicity as well as physical properties such as settlability, filterability, viscosity, floc strength, and turbidity are examined. It has been understood that phosphorus deficiency causes severe filamentous bulking under magnesium rich conditions. Increasing the phosphorus concentration in the influent can cure this problem. After the sludges are cured some granular structures were observed in the microscopic investigations and they are thought to be polyphosphate granules in which microorganisms tend to accumulate phosphorus when they find the adequate source after a starvation period. To consider the reactors operated at phosphate present conditions, it has been found that EPS increases with increasing influent magnesium concentration. However, protein type EPS (EPSP) exhibits a sharper increase when compared to the carbohydrate type EPS (EPSC) indicating the selective attitude of magnesium ions to protein type of polymers. It has been understood that the increase in the influent magnesium concentration results in an increase in dewaterability and zone settling velocity, and a decrease in the viscosity. Hydrophobicity was found to exhibit a maximum value at 10 meq/L magnesium fed sludge and then it dropped back. Surface charge values also made a minimum at 10 meq/L reactor and then no change occurred at the increase of the magnesium concentration to 20 meq/L. Finally, COD values were found to increase with the increasing magnesium concentration due to the increasing EPS.