Thesis (Ph. D.)--Lehigh University, 2004. / Includes vita. Includes bibliographical references (leaves 163-171).

Thesis (M.S.)--University of Tennessee, Knoxville, 2001. / Title from title page screen. Document formatted into manuscript-like pagination: x, 128 leaves : ill. (some col.). Vita. Includes bibliographical references (leaves 114-122).

Thesis (Ph. D.)--Colorado State University, 2004. / Includes bibliographical references.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 373-387). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 373-387). Also available on the Internet.

The environmental and agricultural viability of land disposal of a water treatment residue (WTR) from the Midmar Water Treatment Works of Umgeni Water was investigated by determining answers to four broad questions: 1. What effects would the application of the WTR have on plants growing on the treated soils? 2. What effects would application of the WTR have on soil chemical properties? 3. What effects would the WTR have on the soil solution composition (and by implication the quality of the groundwater)? 4. Could this material be used to reduce solubility of potential pollutants? To answer these questions, the following experiments were set up, and their respective results are reported. 1. Effects of the water treatment residue on plant growth This was investigated in a pot experiment and two field experiments. In the pot experiment five soils, two Huttons (Hu-M and Hu-T), an Inanda (la-C), a Namib (Nb-F) and a Shortlands (Sd) were used to grow perennial ryegrass ((Lolium perellne). All samples were fertilized with a basal dressing of N, P, K, Mg and S. Two lime levels were added to the Ia-C and Nb-F soils, the higher calculated to reduce acid saturation to 1%, and the lower being half of that. The WTR was applied at rates of 0, 40, 80 and 120 Mg ha-1. All treatments were in triplicate. Eight cuts in all were made of the perennial ryegrass. The dry matter (DM) yield of perennial ryegrass grown in the pot experiment increased with the WTR applied in all five soils although the highest increase was with the acidic Ia-C and Nb-F soils. The fact that the highest yields were on the strongly acid soils suggests that the liming effect of the WTR could have contributed, more so considering that lime also increased yields in these soils. It was, however, clear that no one factor was responsible for the increase in yield as the timing effect could not explain the results of the other three soils. At the two field experiments perennial ryegrass was grown at Brookdale Farm from 1998 to 2001, after which the site was re-seeded with tall fescue (Festuca arundinaceae). At Ukulinga Farm tall fescue was grown from the outset in 2000. In the two field experiments with both perennial ryegrass and tall fescue, no significant increase in yield was apparent. Importantly, however, from an environmental point of view there was no decrease in yield whether the WTR was incorporated or applied as a mulch. This was observed even at the highest rates of application, namely 1280 Mg ha-1. The growth on the mulched plots was often observed to be better than any of the other treatments, including the control. Analysis of the plant material from both pot and field experiments indicated that the WTR neither pollution of the groundwater by nitrates. However, analysis of saturated pastes from soils at both field experiments showed that the levels of nitrate were increased by application of the WTR in only the fallow plots. 4. The water treatment residue as a possible pollutant-reducing agent The effect of the water treatment residue on the sorption of P and heavy metals (Cd, Ni and Zn) was studied in the laboratory. Soils treated with WTR were equilibrated for 6 hours in 0.005 M calcium cWoride solution containing a known concentration of each element. For the coarse-textured soils, initial P concentrations ranged from 0 to 1000 mg kg-1 as opposed to 0 to 1800 mg kg-1 for the clay soils. Treatments of WTR used were 0, 80, 320 and 1280 Mg ha-1, both incubated and non-incubated. At high initial P solution concentrations, the WTR increased the extent of sorption in the coarser textured soils (Hu-T, Nb-A, Nb-F, Va and We), and decreased it in highly sorbing Av, Hu-M, la-C and la-W soils. In general though, the WTR greatly reduced soluble P. For Cd, Ni and Zn only one concentration, 50 mg kg-1, was studied using the incubated soil samples as affected by WTR rates from 0 to 1280 Mg ha-1. For all three metals, the amount sorbed increased with increase in amount of WTR for the nine soils studied, namely the Av, Hu-F, Hu-M, Hu-T, la-C, la-W, Nb-F, Va and We. In many cases the sorption was so high that more than 40 mg kg-1 of the initial concentration was removed from solution. Even for those soils with high sorption capacity e.g. the Va and We, the WTR still increased sorption by up to an average of more than 25% for Cd and more than 40% for Ni and Zn. Because for the Av and la-W soils liming also increased sorption, it could be assumed that the accompanying increase in pH as a result of the addition of WTR promoted precipitation of metals, and/or the resultant increase in negative charge increased their adsorption. These results show that where excess concentrations of soluble heavy metals may occur (especially in coarse-textured soils), and where there is concern about run-off with high P concentrations then this WTR could be considered to immobilize these elements and render them less harmful to the environment. General comments and management guidelines. Based on the results reported above, it is apparent that the WTR can be safely disposed of onto land. It has been demonstrated in the current investigation that rates of application can be as high as 1280 Mg ha-1. Rates of application to land higher than 1280 Mp; ha-1 could probably be acceptable - this was the highest rate tested in this investigation - where the residue is produced in large amounts at the plant, and land for disposal is somewhat limited. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 6, 2008) Includes bibliographical references.

Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 75-77). Also available on the Internet.

Thesis (M.Sc.) - University of KwaZulu-Natal, Pietermaritzburg, 2009. / Full text also available online. Scroll down for electronic link.

Thesis (PhD)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: Lignocellulose is the principal form of biomass in the biosphere and therefore the predominant renewable source in the environment. However, owing to the chemical and structural complexity of lignocellulose substrates, the effective and sustainable utilization of lignocellulose wastes is limited. Many environments where lignocellulose residues are ordinarily stored can be highly acidic (e.g. landfills), and under these circumstances biodegradation of the lignocellulose is slow and unhygienic. Owing to the metabolic activities of the micro-organisms, the initially acidified habitats rapidly undergoes self-neutralization. A number of pathogenic bacteria (coliforms and Salmonella sp.) are present during this slow degradation process and it is therefore imperative to improve the efficiency and hygienic effects of the biodegradation of the lignocellulose. Although the fundamentals of biodegradation of lignocellulose have been widely investigated, many issues still need to be resolved in order to develop commercially viable technology for the exploitation of these waste products. For example, owing to the complex, heterogeneous structure of lignocellulose, the degree of solubilization, modification and conversion of the different components are not clear. Likewise, the overall anaerobic degradation of lignocellulose is not understood well as yet. In this study, the emphasis was on the promotion of solid anaerobic digestion of lignocellulose wastes for environmental beneficiation and waste reutilization. The degradation of lignocellulose in landfill environments was first simulated experimentally. Once the microbial populations and the degradation products of the system were characterized, the promotion of anaerobic digestion by use of activated sludge was studied. This included acidogenic fermentation, as well as recovery of the methanogenic phase. Moreover, special attention was given to the further disposal of humic acids or humic acid bearing leachates formed in the digestive system, since these acids pose a major problem in the digestion of the lingocellulose. With ultrasonication, approximately 50% of the lower molecular weight fraction of humic acids could be decomposed into volatile forms, but the higher molecular weight fraction tended to aggregate into a colloidal form, which could only be removed from the system by making use of ultrasonically assisted adsorption on preformed aluminium hydroxide floes. This was followed by an investigation of the microbial degradation of humic acids and the toxicity of these acids to anaerobic consortia. Further experimental work was conducted to optimize the biological and abiological treatment of lignocellulose in an upflow anaerobic sludge blanket (DASB) reactor fed with glucose substrate. The humic acids could be partially hydrolysed and decomposed by the acid fermentative consortia of the granules in the DASB reactor. Finally, solid mesothermophilic lignocellulose anaerobic digestive sludge can be viewed as a humus-rich hygienic product that can improve the fertility and water-holding capacity of agricultural soil, nourish plants and immobilize heavy metals in the environment as a bioabsorbent. / AFRIKAANSE OPSOMMING: Lignosellulose is die hoofbron van biomassa in die biosfeer en is daarom ook die belangrikste hernubare bron in die omgewing. As gevolg van die chemiese en strukturele kompleksiteit van lignosellulose substrate, is die doeltreffende en volhoubare benutting van lignosellulose afval egter beperk. Die suurgehalte van die omgewings waar lignosellulose reste gewoonlik gestoor word, soos opvullingsterreine, kan hoog wees en onder hierdie omstandighede is die biodegradasie van die lignosellulose stadig en onhigiënies. As gevolg van die metaboliese aktiwiteite van die mikro-organismes ondergaan die aanvanklik aangesuurde habitatte vinnig self-neutralisasie. 'n Aantal patogeniese bakterieë (koliforme en Salmonella sp.) is deurgaans gedurende dié stadige natuurlike proses teenwoordig en dit is dus van die grootste belang om die effektiwiteit en die higiëne van die bioafbreking van die lignosellulose-substraat te verhoog. Alhoewel die grondbeginsels van die bioafbreking van lignosellulose reeds wyd ondersoek is, moet verskeie probleme nog opgelos word ten einde kommersieel haalbare tegnologie te ontwikkel vir die ontginning van afvalprodukte. Byvoorbeeld, as gevolg van die komplekse, heterogene struktuur van lignosellulose, is die graad van solubilisering en die modifikasie en omskakeling van verskillende komponente nog onduidelik. Net so word die algehele anaerobiese afbreking van lignosellulose ook nog nie ten volle verstaan nie. In hierdie ondersoek het die klem geval op die bevordering van soliede anaerobiese digestie van lignosellulose afval vir omgewingsverbetering en die benutting van die afval. Die afbreking van lignosellulose in opvullingsterreine is eers eksperimenteel gesimuleer. Nadat die mikrobiese populasies en die afbrekingsprodukte gekarakteriseer is, is die bevordering van anaerobiese digestie deur die gebruik van geaktiveerde slyk bestudeer. Dit het asidogeniese fermentasie ingesluit, sowel as herwinning van die metanogeniese fase. Spesiale aandag is gegee aan die verdere verwerking van humus sure en humussuurbevattende legate wat in die digestiewe stelsel gegenereer is, aangesien die sure probleme veroorsaak het met die vertering van die lignosellulose. Met ultrasoniese straling is nagenoeg 50% van die lae-molekulêre massafraksie van die humussure ontbind in vlugtige vorm, maar die hoë-molekulêre massafraksie het geneig om in 'n kolloïdale vorm te aggregeer, wat slegs uit die stelsel verwyder kon word deur middel van ultrasonies ondersteunde adsorpsie op voorafgevormde aluminiumhidroksiedvlokkies. Dit is gevolg deur 'n ondersoek na die mikrobiese afbreking van humus sure en die toksisiteit van die sure ten opsigte van anaerobiese konsortia. Verdere eksperimentele werk is gedoen ten opsigte van die biologiese en abiologiese behandeling van lignosellulose in 'n opwaartsvloeiende anaerobiese slikkombersreaktor (OASK) gevoer met glukosesubstrate. Die humus sure kon gedeeltelik gehidroliseer en ontbind word deur die suurgistende konsortia van die granules in die OASK reactor. Ten slotte kan die vaste termofiliese-mesofiliese anaerobiese lignosellulose verteringslik ook gesien word as 'n humusryke higiëniese produk wat die vrugbaarheid en die waterhoudende vermoë van landbougrond kan verhoog, plante kan voed en kan funksioneer as bioabsorbeerder van swaarmetale in die omgewing.