MSc Thesis / A dissertation submitted in partial fulfilment of the requirements for the degree Master of Science in Engineering to the Faculty of Engineering and the Built Environment, School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg, 2018 / This work aims at designing and simulating on Aspen Plus process simulator a process that can recover valuable chemicals from a High Organic Waste (HOW) stream produced at Sasol Secunda plant, South Africa. The waste is made up of low boiling point organic components such as pyridine, acetonitrile and Methyl Ethyl Ketone and water. Currently, the waste is incinerated without energy recovery. This practice serves to exacerbate the already high greenhouse gases emissions from the plant, but more importantly, it results in the missed opportunity to maximize revenues through resale of recycled valuable chemicals. The recovery of valuable chemicals from the HOW is made difficult by the formations of azeotrope between organic components and water; at least 6 azeotropes exist in the HOW stream. In this work the emphasis is on pyridine because of its established market value and demand. Pyridine market size is about 400 million USD in 2017 and is expected to increase to over 600 million USD by 2021 mainly due to increased usage in the agrochemical industry. Water integration strategy was also assessed demand because of the reported need to improve water utilization efficiency at Sasol Secunda plant. The recovery was achieved in 2 separate steps: 1) water-pyridine mixture was separated from the rest of the HOW stream using fractional distillation and 2) pyridine enrichment section which was designed using thermodynamic tools such as residue curve maps and isovolatility curves. The rest of the HOW stream (light fractions) was sent to the currently used incinerator. Liquid-liquid extraction and azeotropic distillation were considered for the pyridine enrichment step. Results showed that the combination of liquid-liquid extraction and distillation offered the benefit of a lower entrainer to azeotropic mixture ratio (EA) compared to azeotropic distillation. This gave the lowest recorded EA at 0.320:1. The comparison between the proposed process and the incineration of the whole HOW stream showed that the implementation of the process proposed reduced the incineration load by 60wt% and CO and CO2 emissions by 50%. Dividing Wall column process integration technique was implemented to reduce the number of distillation columns in the proposed process and 10% reduction in the reboiler and condenser duties was observed. Implementation of DWC further improved the purity of the recovered pyridine from 96mol% to over 99.9mol%. Preliminary economic evaluation carried out on Aspen Plus showed that the proposed recovery process was profitable with an Internal Rate of Return (IRR) of 20% and a payback period of 4.5 years. / MT 2018

Three major microbial subpopulations from an industrial leachate system were characterized with respect to their bioremediation potential, and particular aspects of a cometabolically active subpopulation were determined.

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No description available.

"Sewer System Evaluation Surveys Conducted in Industrial Sewers," describes the methods employed and the results of Sewer System Evaluation Survey studies conducted at two industrial complexes. The procedural techniques for locating and quantifying infiltration and inflow into sewer systems represented to provide a basic understanding of the steps required to complete such studies. Case studies of actual surveys conducted at two privately operated industrial plants in Tennessee are presented to illustrate the utilization of the investigative techniques. The results of the studies are compared with each other and with similar studies conducted in municipal sewer systems.

The objective of this investigation was to assess the potential of a titration bioassay i.e.: The Methanogenic Activity and Inhibition Analyser (MAlA), to determine the biodegradability of complex industrial effluents and wastewaters. Specifically, the project aimed to provide an alternative experimental method to the serum bottle method so that hazardous effluents can be pre-screened for treatment in under-utilised anaerobic digesters at sewage treatment plants in KwaZulu-Natal, South Africa. This study also aimed to provide a protocol and a simple mathematical model as experimental tools that could contribute to the development of future pre-screening studies. MAIA was used to conduct biodegradability and toxicity studies on semi-hazardous landfill leachate and textile size effluent. Thereafter, selected studies were repeated using a conventional screening method i.e.: serum bottle method. The investigation with MAlA revealed that both effluent substrates had potential for anaerobic treatment. However, the studies highlighted certain intrinsic limitations of the MAIA apparatus to effectively pre-screen complex substrates. The existing titrimetric system is too coarse to accurately track the biochemical pathways leading from the breakdown of complex compounds to methane gas production. Further, temperature interferences and gas phase diffusion limitations associated with the existing design make the assessment of activity difficult. The titrimetric method is comparable to the serum bottle method only if a qualitative assessment of toxicity and biodegradability is needed. However, the titrimetric method produces results in a much shorter period of time compared to the serum bottle method. Evaluated in this way the titrimetric method is the better alternative. However, the current system cannot challenge the reliability of the serum bottle method to provide good quantitative results. A mathematical model was developed which is much less detailed than the existing one provided by Remigi (2001). It comprises only two significant anaerobic processes namely hydrolysis and acetogenesis. Simulation trials have suggested that the model is a necessary and beneficial component ofthe titrimetric pre-screening protocol. This investigation has also led to the development of a more refined operating manual for MAIA.The manual provides a step-wise method for the preparation and conduction of pre-screening tests. Specifically, it highlights the need for a suitable biomass acclimation period and the importance ofnutrient use for better pre-screening assessments. / Thesis (M.Sc.Eng.)-University of Natal, Durban, 2003.

Thesis (MA (Hons.)) -- University of Western Sydney, Nepean, 1999. / Includes bibliographical references.

Thesis (M. Sc.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 45-47).

Thesis (M. Sc.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 59-62).

This pilot plant study evaluated the pretreatment capabilities of a “Sessil” media for an undiluted high strength industrial wastewater (from a cellulose acetate manufacturing plant) over a ten-month period from May 1989. The Sessil media used consisted of 20 feet long 1.15 inch wide polyethylene strips hanging from wooden slats at the top of a 26 feet tall tower. The effects of organic and hydraulic loadings on the performance of the tower were examined. The characteristics of the influent wastewater on treatment performance were also determined. The wastewater, comprised mainly of waste acetic acid, some acetone, other organic solvents such as isopropyl alcohol, and some cellulose acetate fibers, had an average COD of 2300 mg/l, BOD of 1600 mg/l, influent suspended solids of 200 mg/l, SO₄ of 3000 mg/l, and an influent pH of 4.5, at an influent temperature of 40 C. The tower was found to consistently reduce the chemical oxygen demand (COD) of the wastewater even under adverse conditions as experienced during the shock loading phase when glacial acetic acid was added to the influent stream. During steady-state conditions, net total COD (TCOD) removals ranged from 28 to 52%, with an overall mean of 39%. For organic loads ranging from 164 to 374 lb TCOD/1000ft³day, the net removals (i.e. TCODinfluent-TCODeffluent) were between 81 to 104 lb TCOD, while biological removals (TCODinfluent-Soluble CODeffluent) ranged between 113 to 184 lb. COD removal was found to be an exponential function of the organic loading rate. The COD removals were not directly dependent on the hydraulic loadings, which ranged from 673 to 1738 gallons/day/ft². However, high hydraulic loading rates increased the rates of biomass sloughing and the variability of the tower effluent suspended solids (SS). The hydraulic retention time in the tower averaged 31 minutes and appeared insensitive to the hydraulic loading rates over the range studied. Volatile organic compounds did not appear to be a significant problem and there was insignificant volatilization of the compounds during its passage through the tower. Reductions in COD during volatilization tests were a result of biological stabilization. Tower influent organic constituents (viz. acids and alcohols) were reduced during passage through the tower. Acetic acid and acetone (the major components of the wastewater) were significantly reduced but incompletely removed. The other constituents (e.g. isopropyl and other alcohols) were more completely removed. Most of the removals appeared to have occurred in the upper one-third portion of the tower. / Master of Science