Thesis (M.S. - Hydrology and Water Resources)--University of Arizona, 1982. / Includes bibliographical references (leaf 52).

Thesis (Ph. D.)--University of Washington, 1990. / Vita. Includes bibliographical references (leaves [215]-237).

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 278-283). Available also in a digital version from Dissertation Abstracts.

Thesis (DTech (Chemical Engineering))--Cape Peninsula University of Technology, 2017. / The process of anaerobic digestion (AD) is one of the most cost-effective and environmentally sustainable technologies to treat wastewater in the agricultural sector. In South Africa, in some industries in the agricultural sector, such as the poultry industry in particular, slaughterhouses have the highest consumption of potable water, culminating in the production of a large quantity of high strength wastewater. This high consumption of potable water has become a concern in South Africa due to water scarcity and reduced rainfall attributed to global warming, including weather changes. Furthermore, the generation of a large volume of wastewater poses environmental pollution concerns. The wastewater from poultry slaughterhouses can be quite easily treated to a suitable quality for reuse, using various bioreactor systems that utilise low cost anaerobic digestion processes. However, as this wastewater contains a high quantity of biodegradable organic matter – with the primary pollutants being proteins, blood, fats, oil and grease (FOG) – selecting a suitable anaerobic reactor configuration (up-flow vs down-flow) plays an important role in achieving high reactor performance. In this study, both the up-flow, (i.e. Expanded Granular Sludge Bed Reactor) and the down-flow (i.e. Static Granular Static Granular Bed Reactor), were studied to quantitatively determine their performance in treating poultry slaughterhouse wastewater. Firstly, the feasibility of treating poultry slaughterhouse wastewater with an up-flow Expanded Granular Sludge Bed Reactor (EGSB) coupled with anoxic and aerobic bioreactors was investigated at an HRT of 7 (168 hr), 4 (96 hr) and 3 (72 hr) days using organic loading rates of 0.5, 0.7 and 1.0 gCOD/L.day. The averaged tCOD removal for the EGSB reactor was 40%, 57% and 55%, respectively, at the various OLRs and HRTs investigated. The overall tCOD removal of the system (EGSB-anoxic/aerobic) at high OLR of 1.0 gCOD/L.day was increased to 65%. The redundant performance of the up-flow EGSB reactor was attributed to the periodical sludge washout experienced during its operation due to high FOG and TSS concentrations in the influent. Due to the periodic sludge washout, the reactor required continuous re-inoculation resulting in the EGSB being operated for a short period (i.e. 26 days). As a result of such system deficiency, it was recommended that to improve the performance of the up-flow EGSB reactor in treating poultry slaughterhouse wastewater, a pre-treatment system – such as a Dissolved Air Floatation system (DAFs) or a FOG skimmer – is required to reduce the FOG and total suspended solids (TSS) load prior to the wastewater fed to the EGSB. This will minimise system failure and the need for a continuous re-inoculation of the system (see Appendix C for improved operation strategy of the EGSB reactor). Furthermore, a system redesign was recommended, thus the use of the SGBR. Secondly, after the EGSB system evaluation, the performance of a down-flow system (i.e. SGBR) for the new design, the following were deemed appropriate for improved system (SGBR) design: 1) reduced HRT for high wastewater treatment through-put rates; 2) the ability to adequately treat the wastewater with higher organic loading rates; and 3) reduction of the plant footprint by using a membrane filtration system (i.e. a single process unit) to effectively reduce process requirements needed for the anoxic/aerobic bioreactors (i.e. n=2 process unit) used with the EGSB. Similarly, for large-scale operations, it is advisable to have a backwash system to adequately handle declogging processes (i.e. these systems modifications were evaluated in the SGBR). The SGBR, coupled with an ultra-filtration (UF) membrane system, was then investigated for treating the poultry slaughterhouse wastewater at an HRT of 55 hrs and 40 hrs, including average OLRs of 1.01 and 3.14 gCOD/L.day, respectively. The average maximum performance of the SGBR in terms of tCOD, TSS and FOG removal was > 90% at the OLRs and HRTs investigated. The UF membrane system used as a post-treatment system further yielded a system performance improvement for tCOD, TSS and FOG of 64%, 88% and 60%, respectively. The overall performance of the combined system (SGBR and UF membrane system) in terms of tCOD, TSS and FOG removal was 98%, 99.8% and 92.4%, respectively. The highest performance for the down-flow SGBR was attributed to its ability to retain granulated sludge in the reactor while maximizing the digestion of the organic matter fed into the reactor, even at higher OLRs. Furthermore, for effective declogging, the implementation of a periodic backwash system to effectively remove dispersed fine sludge particles in the underdrain and excessive suspended solids entrapment was observed to ease the system operational deficiencies.

Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2017. / In the recent past, the poultry industry in South Africa has grown due to an increased demand of poultry products as a result of population growth and improved living standards. Furthermore, this has led to poultry slaughterhouses generating high strength wastewater which is laden with a high concentration of organic and inorganic pollutants from the slaughtering process and sanitation of equipment and facilities. As a result, South Africa has promulgated restrictions and a set of quality standards for effluent discharged into the environment to minimize ecological degradation and human health impact. Hence, there is a need for improved Poultry Slaughterhouse Wastewater (PSW) pre-treatment prior to either discharge into municipal wastewater treatment plants (WWTP) or on-site secondary treatment processes such as anaerobic digesters. Additionally, amongst the pre-treatment methods for Fats, Oil and Grease (FOG) laden wastewater, flotation remains the most popular with Dissolved Air Flotation (DAF) system being the most applied. However, modelling and optimization of a biological DAF system has never been attempted before in particular for a bioflocculant supported DAF (BioDAF) for PSW pre-treatment. Process modelling and optimization involves process adjustment to optimize influential parameters. In this study, Response Surface Methodology (RSM) was used to develop an empirical model of a BioDAF for pre-treatment of PSW, for which a bioflocculant producer including production conditions, flocculant type and its floc formation mechanism, were identified. Twenty-one (n = 21) microbial strains were isolated from the PSW and their flocculation activity using kaolin clay suspension (4g/L) was quantified, with a mutated Escherichia coli (mE.coli) [accession number LT906474.1], having the highest flocculation activity even in limited nutrient conditions; hence, it was used for further analysis in other experiments. Furthermore, the optimum conditions for bioflocculant production achieved using RSM were pH of 6.5 and 36°C conditions which induced instantaneous bioflocculant production with the highest flocculation activity. The bioflocculant produced by the mE.coli showed the presence of carboxyl/amine, alkyne and hydroxyl functional groups, which was indicative that the bioflocculant contained both polysaccharides and some amino acids.

In this study white-rot fungi were investigated for their efficiency at distillery wastewater remediation and the production of laccase as a valuable by-product. Distillery wastewaters are high in organic load and low in pH. The presence of phenolic compounds can lead to extremely colour-rich wastewaters and can be toxic to microorganisms. The presence of the inorganic ions may also affect biological treatment. White-rot fungi are unique among eukaryotic or prokaryotic microbes in possessing powerful oxidative enzyme systems that can degrade lignin to carbon dioxide. These ligninolytic enzymes, such as lignin peroxidase, manganese peroxidase and laccase, are capable of degrading a vast range of toxic, recalcitrant environmental pollutants and this makes the white-rot fungi strong candidates for the bioremediation of polluted soils and waters. The laccase enzyme alone has shown remediation potential in wastewaters such as beer production effluent, olive mill wastewater, alcohol distillery wastes, dye-containing wastewaters from the textile industry as well as wastewaters from the paper and pulp industry. It has been shown to be capable of remediating soils and waters polluted with chlorinated phenolic compounds, polyaromatic hydrocarbons, nitrosubstituted compounds and fungicides, herbicides and insecticides.

No abstract available. / Dissertation (MSc (Water Utilization))--University of Pretoria, 2006. / Chemical Engineering / unrestricted

Studies were undertaken to determine the effect of Kraft mill effluent (KME) on a representative species of the aquatic environment. By transplanting a population of Pacific oysters (Crassostrea gigas) to the Port Mellon area (the site of a Kraft mill), the effect of varying concentrations (on a distance from the mill basis) of the pulp mill waste was monitored in terms of changes in shell dimension, body mass (meat) weight, visual observation of the oysters' physiological state and oyster mortality. A seasonal hydrographic survey was conducted at three regions within the study area to monitor changes in water quality imposed by the effluent. In the areas of effluent imposition (oyster stations 1, 2 and 3) the oysters decreased or showed little gain in shell dimension. The body mass of those oysters nearest the mill outfall began to decline (on a weight basis) shortly after placement. At Station 2 and 3 the deterioration in body mass due to changes in water quality began a short time after the decline at Station 1. Changes in the physiological state of the oyster expressed as a darkening of the gills and mantle edge and variations in body mass texture, can be correlated to an oyster's distance from the mill for each collection timei A mortality rate was calculated at each station for all collection times. The mortality rates at Station 1 (100% in 12 months), Station 2 (50% in 20 months), and Station 3 (20% in 24 months) were extensive and proportional to effluent levels. Several of the changes in water quality (increased temperature, reduced salinities, low oxygen contents, variable pH, dissolved and particulated organic matter and chemical additions) imposed by the effluent were individually tested as the major cause of oyster deterioration. Firstly, the critical oxygen tension (the P02 where V02 declines below the routine rate) was determined as 40 mmHg. Correlating this to the range of 02 levels at each station during a tidal cycle, the oxygen demand of the effluent was not considered as a major cause of oyster mortality. A range of filtered, neutralized (pH 7.0 at 22°C) and aerated percentage KME/volume (0-50%) test solutions were monitored in terms of their effect on the percentage time of shell closure. In these experiments percentages above 20 greatly increased the time of shell closure. The effect of shell closure on oysters was tested by continual (up to 28 days) periods of air exposure. In these experiments the P02, zC02 and pH of the pallial fluid was monitored (from time 0 to 28 days) to determine if anaerobic metabolism was undertaken and if it was, the time span of anaerobic life in juvenile oysters. Anaerobic metabolism was concluded to maintain life in juvenile oysters for 22 days. These results were consistent with the hypothesis that KME is deleterious to oyster populations. At high concentrations of effluent the duration of shell closure is extensive such that an anaerobic death results. At lower concentrations the effluent imposed changes in water quality are responsible for the gradual decline in oyster well-being. / Science, Faculty of / Zoology, Department of / Graduate

No description available.

This thesis presents the development of a numerical model for one-dimensional pollutant transport in a porous medium. A computer program POLUTE1D has been developed. The numerical model is based on the flow and mass transport equations and the finite element method has been used for its formulation. The problem involves unsaturated flow and convective dispersive transport of a contaminant species. A literature survey on the evaluation of the dispersion coefficient is included. A waste disposal dump site is analysed as a one-dimensional problem by using this model. The effect of the liner thickness, the liner permeability, the ponding head and the initial condition of the porous domain on the spread of the contaminant is studied. Conclusions are presented based on a parametric study. / M. Eng.