Academic literature on the topic 'Sewage works'

The survival of three enteroviruses (polio 1, coxsackie B3 and echo 1) and a rotavirus (SA-11) was studied under laboratory conditions. The effects of temperature, dissolved oxygen, detention time, sludge source and virus type on virus inactivation were determined. Temperature was the single most important factor influencing the rate of virus inactivation. No significant differences were found for virus inactivation rates at dissolved oxygen levels between 0.9 and 5.8 mg/l. However, the inactivation rate of the viruses under aerobic conditions was found to be significantly greater than the inactivation rate under anaerobic conditions (−0.77log10/day vs −0.33 log10/day). Sludge source, detention time and virus type did not significantly influence the rate of virus inactivation.

Thesis (MTech (Environmental Management))--Cape Peninsula University of Technology, 2017.<br>¹Odour nuisance is increasingly becoming one of the major environmental problems in various countries across the world, especially odour associated with wastewater (Alfonsin et al., 2015; Schlegelmilch et al., 2005; Gostelow et al., 2001). As a result, the management of odour from Wastewater Treatment Works (WWTW) has become one of the environmental challenges besetting these facilities in recent times. The dispersion of odour across the physical boundary of wastewater treatment facilities presents not only negative environmental impacts to the natural environment, but also constitute a nuisance to surrounding populations. The Athlone (WWTW) located in the urban City of Cape Town with high demographics and adjacent to sensitive communities is thus not immune to poor air quality associated with WWTW activities (Walton, 2005). The population growth due to rural-urban migration has further put severe pressure on the facility and thus worsening the odour problem in the area. As a result, complaints have been received by the City Council from the surrounding communities over the last 20 years. In response to these complaints, the management of the WWTW introduced an odour management system with a particular focus on the use of a biotrickling filter coupled with the use of odour masking sprays. This management intervention was adopted in order to control the odour emitted to the atmosphere from the facility (WWTW). While these measures are said to reduce the prevalence of odour to the surrounding environment, it was, however, not clear whether or not such management interventions have reduced odour emitted from the treatment plant. This research was premised on two postulations as an approach to analyse the effect of the odour management plan adopted by the Athlone WWTW’s management and these are: 1) the perceived experience of odour by the adjacent neighbouring communities and, 2) the understanding of the inherent atmospheric dynamics (such as wind velocity, atmospheric stability, inversion layer and ventilation) which influence odour dispersal in the area. The research project argues that these two factors should be taken into account to ensure that the management of odour is sustainable. It is within this background that the research aimed at assessing the management of odour at the Athlone WWTW and to find out, if at all, the inherent local atmospheric conditions in the area and views of the surrounding communities are incorporated into the management of odour from the plant. The methodological design adopted in the study was case study approach. However, the atmospheric data (wind speed and direction) was obtained from the South African Weather Service (SAWS). These variables were analysed qualitatively and experimentally by the use of wind diagrams to provide insight on 2atmospheric stability conditions, surface inversion and topographical properties, and how these phenomenon influences odour dispersion. The study also reviewed previous odour management reports produced by the Althone WWTW management. This type of data was finally supported by data collected from the community by means of a community survey, face-to-face in-depth interviews and qualitative observation. Some major findings from the study revealed that the local weather of Athlone influences the dispersion of odour – facilitating dispersion in the summer through high wind velocities, while impeding dispersion during winter due to the presence of atmospheric stability conditions. Prevailing odours in this community has led to a general feeling of displeasure amongst community members especially since the management of the treatment plan does not include the local community in the decision-making process. In spite of these, the facility’s management approach was found to be more of a response driven nature even though it is ranked as a high-risk facility.

Surveys of UK rivers have shown a high incidence of sexual disruption in populations of wild roach (Rutilus rutilus) living downstream from sewage treatment works (STW). Moreover, the degree of intersex (gonads containing both male and female structural characteristics) has been correlated with the concentration of effluent in those rivers.

Sasol Chemical Industries (SCI) located in Sasolburg, South Africa (SA), have since the early fifties produced fuels and waxes commercially, and recently diversified to produce a wider range of other chemicals. The Sasol One processes as with all industrial processes generate various waste streams. One such waste stream in the case of the Sasol One Site, which was the main theme of this study is the so-called poor quality sewage sludge generated during the treatment of domestic and industrial effluent in biological oxidation ponds at the sewage works. The poor quality of the sludge is related to the metals and pathogenic organisms present in the sludge. Furthermore, the stockpiling area where the sludge is stored is running out of space thus creating an ongoing environmental and operational challenge to the management of the sewage works. The primary objective of the study was therefore to identify suitable sludge treatment options by means of comparing three sludge treatment techniques, viz; Composting, ASP (Activated Sludge Pasteurisation) and SLASH (treatment of sludge with ash and / or lime). It was anticipated that one or a combination of these three techniques would improve the quality of the sludge in terms of its metal and pathogenic content and furthermore, as a more beneficial sludge, possibly support the humus requirements for the revegetation efforts during the rehabilitation activities on the Sasol One waste site. In evaluating these possible treatment options the sludge was subjected to laboratory bench experiments and field plant trials. To arrive at an answer as to which treatment option was the best, a decision matrix was developed that compared and scored the treatment options using various weighted criteria. The criteria used considered (i) the present legal sludge treatment requirements in terms of the Water Research Commission guidelines;(ii) the sustainability of the option that would be the most likely one to succeed in the long term; (iii) the economic viability defined as a capital and operational expenditure required that would give an indication of the financial viability of the preferred option and; (iv) the technical feasibility being defined as the potential for the preferred option to achieve full scale operation and a measure of confidence to implement the option or not. The experiments conducted and results achieved indicated that all three treatment options significantly improved the quality of the sludge in terms of metal and pathogenic content. However the composted sludge scored the highest points followed by SLASH and lastly ASP. Based on these experiments and the decision matrix used, Composting performed best by achieving a satisfactory score based on the WRC classification guidelines including cost and technical feasibility. With respect to this outcome the Composting was recommended as the preferred treatment option.<br>Thesis (M. Environmental Management)--North-West University, Potchefstroom Campus, 2008.

The Upper Vaal Water Management Area (Upper Vaal WMA) lies in the eastern interior of South Africa. This WMA includes the Vaal, Klip, Wilge, Liebenbergsvlei and Mooi Rivers and extends to the confluence of the Mooi and Vaal Rivers. It also includes major dams such as the Vaal Dam, Grootdraai Dam and Sterkfontein Dam. The southern half of the WMA extends over the Free State province; the north-east mainly falls within Mpumalanga and the northern and western parts in Gauteng and North West provinces respectively (DWAF 2004). Several wastewater treatment works (WWTW) located in this area do not meet the standard set by the present legislation that addresses proper treatment of water. This results in number of problems that affect the quality of water in this catchment. It was noted by the WRC (2006b) that with the challenges of implementation in an environment of shared responsibility, it is increasingly recognised that public/government institutions must foster institutional cooperation and interaction for efficient provision of public services, both at the policy-strategy level and the operational-implementation level. According to WRC (2006b), poor cooperation between institutions in the implementation of their interrelated mandates has resulted in inefficient utilization of scarce resources and/or endless disputes. In order to address this shortcoming, a study that investigated the effects of cooperative governance in the Wastewater Treatment Works (WWTW) in the Upper Vaal Water Management Area was initiated. The results of the research indicate a lack of cooperation between the three spheres of governance that participate in the sustainable management of water treatment in this area.<br>Thesis (M. Environmental Management)--North-West University, Potchefstroom Campus, 2013.

There is worldwide concern over the possible estrogenic effects of organic chemicals on a variety of wildlife and indeed on humankind. In the U.K., estrogenic compounds in sewage treatment works (STW) effluents have been implicated in causing the increases in egg yolk protein production observed in caged male trout and other fish species. At the initiation of the present study, few of the estrogenic compounds in STW effiuents had been recognised, although circumstantial evidence suggested that steroidal hormones were primary candidates. Cholesterol is abundant in STW effluents and is the precursor of all steroidal hormones biosynthesised in mammalian systems. Thus, the aim of the present study was to examine the hypothesis that cholesterol might undergo A-ring aromatisation, during sewage treatment, producing estrone and 17β-estradiol via, intermediates such as l9-norcholest-l,3,5(10)-trien-3-ol (NCT). To study this hypothesis NCT was first synthesised via a known route and several of its chromatographic and mass spectral properties established for the first time. NCT itself was found to possess some estrogenic potential determined using an established assay but this was rather weak compared to 17β-estradiol - about 200,000 times less active at the minimum concentration needed to invoke a response. NCT also proved to be a much more hydrophobic compound than, for example, 17β-estradiol with a computed log octanol-water partition coefficient (Kow) of over 9 compared with a log Kow of about 4 for l7β-estradiol. The established analytical properties of NCT were then used to investigate possible NCT formation in sewage. Radiolabelled 14C-cholesterol was incubated aerobically and anaerobically in Semi-Continuous Aaivated Sludge (SCAS), Die Away (DA) or simple stand alone STW simulation vessels. The products of incubation in both aqueous and solid fractions were examined by radio-high performance liquid chromatography (r-HPLC), radio-thin layer chromatography (r-TLC) and radio-gas chromatography (r-GC). Aerobic studies showed that side chain cleavage and A-ring rupture of cholesterol occurred rapidly (~25 % of added activity within 24 hrs) as measured by 14C02 evolution. Gaseous evolution was not monitored from the anaerobic experiments. Most remaining activity was associated with the solids fractions in all experiments. In the aqueous experiments both SCAS and DA systems, r-HPLC revealed rapid production of polar products which were not identified further. r-HPLC also revealed non-polar components of which choIest-3,5-diene, an unknown cholestadiene, a cholestadienol (other than 5,7-dienol), cholest-4-en-3-one and possibly NCT were identified by r-GC in the products of DA experiments. Whilst r-HPLC and r-TLC also revealed several products of anaerobic digestion of cholesterol, no compounds were detected by r-GC. STW effluents from two wastewater plants in the North London area were monitored over 7 months for A-ring steroids and other suspected estrogenic chemicals. Both effluents had previously proved estrogenic to caged fish. Liquid and SPM samples were taken, extracted and analysed by GC-MS. The two main estrogens, l7β-estradiol and estrone were identified from all liquid samples but not in SPM extracts. Generally the concentration of estrone (maximum ca 3 ng Lˉ¹) was significantly higher than that for 17β-estradiol (maximum 1 ng fˉ¹). The third natural estrogen, l6a,l7β-estriol, was identified in all Harpenden effluent samples analysed up to a concentration ca 0.5 ng Lˉ¹. However, estriol was not found in Deephams effluent extracts. The phytoestrogen, daidzein, found in soya based products was intermittently found in aqueous effluents samples from both sites >1 ng Lˉ¹. SPM made up <0.001 % of the effluent. Extracts showed that there was a high percentage of steroidal based material with coprostanol>cholesterol=β-sitosterol>>stigmasterol. NCT was twice identified from SPM taken from Deephams with a concentration of 39 and 136 ng 1ˉ¹ but <LOD in Harpenden SPM extracts. In conclusion this study showed that formation of NCT from cholesterol in STW treatment under conditions monitored herein is not a major process. However, estrone, 17β-estradiol and 16a, 17β-estriol are relatively abundant and widespread components of the STW effluents tested. The origins of the components undoubtedly include direct inputs from female urine and faeces but other metabolic sources should not be entirely ruled out.