The study investigated the ability of granular activated carbon (F-400) to remove organic color, TOCk and THM precursors from a highly organic-laden recycled magnesium sludge without reducing the magnesium concentration. This treatment was attempted in order to render the sludge a more effective coagulant for surface water purification. Adsorption effectiveness was assessed through Freundlich isotherms and continuous-flow GAC columns, with both procedures conducted at three pH values. Color and TOC were adsorbed more effectively at lower pH values, while adsorption of THM precursors was inhibited at low pH. Magnesium was not significantly adsorbed by the carbon. The carbon treatment of magnesium sludge did little to improve its coagulation effectiveness.

Alum sludge from a Tampa water treatment plant was found to significantly reduce phosphorus release from anaerobic bottom sediments. The kinetics of phosphorus uptake by the sludge was evaluated in batch reactors. Further, the impact of the sludge on benthic organisms was determined in aquarium systems. Aquariums were set up with sediments and organisms from various lake habitats. Organisms were allowed to establish themselves and then test aquaria were dosed with alum sludge to cover the sediments. Benthic survival and heavy metal uptake were evaluated. Favorable phosphorus uptake was demonstrated in the batch reactors. The uptake kinetics were found to closely follow both Freundlich and Langmuir isotherms over a wide range of sludge dose and phosphorus concentrations. Benthic organisms typical of polluted environments were not adversely affected by the sludge additions. However, oligochaetes exposed to the sludge had elevated metal concentrations. Clean water organisms were somewhat less tolerant of the sludge and did not significantly concentrate heavy metals.

The treatment of municipal, industrial and agricultural wastewater produces a semi-liquid mixture known as sludge. The costs associated with pumping, transporting, treating, storing, and disposing of sludge are significant. Therefore, sludge dewatering techniques are employed to increase the solids content of the material by separating the solid and liquid components, thus reducing the overall volume requiring further handling. Non-mechanical dewatering methods require large areas of land and favorable climatic conditions, while mechanical dewatering technologies require significant capital investment and ongoing operation and maintenance by highly trained personnel. Due to these shortcomings, the conventional methods of sludge dewatering are not applicable to scenarios where: the quantity of sludge is small, there is limited budget, there are land restrictions, or dewatering is performed seasonally. An alternative approach that has recently attracted considerable attention is the use of dewatering fabrics; specially engineered textiles supplied in the form of very large bags into which the sludge is pumped. The concept itself is simple, pressure inside the bag pushes the free water through the fabric while the solid material is retained within. Unfortunately, these products have exhibited poor dewatering performance for certain feed materials. In this work, a series of ‘next-generation’ engineered dewatering fabrics featuring elongated ‘slit’ pores were produced using laser cutting techniques. A comprehensive analysis of the effect of the filter properties on dewatering performance was performed using sludge sourced from two different operations: municipal wastewater treatment and precious metal mining. / Thesis / Master of Applied Science (MASc) / In recent years, the use of engineered dewatering fabrics has emerged as a viable alternative to conventional methods of sludge dewatering in numerous application areas including municipal wastewater, mining, and pulp and paper. Previous studies have focused on the development of empirical ratios between dewatering performance and the porous properties of the textile material. The limitation of this approach is that the latter is difficult to characterize using currently available techniques due to the complex, nonuniform pore structure of conventional woven and nonwoven dewatering fabrics. In this study, a series of dewatering fabrics were produced using advanced microfabrication techniques featuring well-defined slit-pore geometries. Full-factorial design-of-experiment frameworks were employed to evaluate the effects of slit-pore dimensions and slit-pore spacing on cake layer development and key dewatering performance metrics. Laboratory scale dewatering performance tests were performed using both anaerobic digested sludge from the Woodward Avenue Wastewater Treatment Plant in Hamilton, Ontario and metal precipitate sludge from a nickel-copper mine in Ontario, Canada. The results from this study provide new insights into the importance of the cake layer in geotextile dewatering and the impact of pore geometry, porosity, and polymer performance on cake layer development.

Submitted in fulfillment for the Degree of Masters of Applied Sciences (Biotechnology), Durban University of Technology, Durban, South Africa, 2016. / Activated sludge (AS) flocs are paramount in biological treatment of wastewater, are comprised of microbial consortia with organic and inorganic material bound together by extra polymeric substances (EPS). The filamentous bacteria play a vital role in the floc formation process by providing the necessary structural support. Presence of epiphytic attachment on selected filamentous bacteria is a commonly occurring phenomenon in activated sludge samples. Different theories have been proposed to describe this phenomenon; however, not much research has been carried out to explore the profundity of the attachment. In this study, an attempt has been made to elucidate the intrinsic nature of the epiphytic attachment between the bacterial rods and filamentous bacteria based on microscopic (morphological and structural) analysis. Characterization of these epiphytes were performed using fluorescence in situ hybridization (FISH) at group level using Alpha, Beta and Gamma Proteo-bacterial probes. Morphological characteristics of filament hosts and the bacterial rods at the interface region was assessed using scanning electron microscopy (SEM). The SEM micrographs indicated that the attachment was facilitated by more than the EPS layer. Further ultrastructural examination using transmission electron microscopy (TEM) indicated a possible cell-to-cell interaction between epiphytes and the selected filaments. Fibrillar structures resembling amyloid-like proteins were observed within the filament cell targeted by the epiphytes. An interaction was apparent between the amyloid like proteins and the epiphytes as exhibited by the direction of fibrillar structures pointing towards the approaching epiphytes. Common bacterial appendages such as pili and fimbria were absent at the interface and further noted was the presence of cell membrane extensions on the epiphytic bacteria protruding towards the targeted filamentous cell. The sheath of host filaments however, remained intact and unpenetrated, during colonization. Amyloid-like fibrils at interface may potentially play the role of attachment sites for the attaching epiphytes, as attachment facilitating appendages were not visualized. / M

No description available.

No description available.

Abstract available in PDF file. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2012.

Thesis (M.S. - Soil, Water and Environmental Science)--University of Arizona. / Includes bibliographical references (leaves [64]-69).

Thesis (PhD (Chemical Engineering))--University of Pretoria, 2008. / Includes bibliographical references (p. 110-126)

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.