Comparing performance of activated sludge systems in tropical climates : a case of the Crowborough Wastewater Treatment Plant in Harare (Zimbabwe) and the Tung Kru Wastewater Treatment Plant in Bangkok (Thailand) | |
| Author | Mbiza, Happymore |
| Call Number | AIT Thesis no.UWEM-14-03 |
| Subject(s) | Sewage disposal plants--Thailand Sewage disposal plants--Zimbabwe |
| Note | 74 leaves : ill. |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. UWEM-14-03 |
| Abstract | This researchsummarizes work that was done towards making recommendations in rehabilitation of the CWWTP in Harare, Zimbabwe. The study focused on modeling activated sludge process in CWWTP (Harare) and TKWWTP (Bangkok) to evaluate treatment efficiencies.Modeling resultswere then compared and recommendations were made basing on this comparison. BioWin was used for system evaluation following the systematic activated sludge process modeling protocol developed by STOWAand the parameters of concern in the model were COD, TKN and TP.The research showed that the 5 stage Bardenpho at CWWTP has the potential to perform well under normal circumstances. In its non-functional state, the plant was also reasonably likely to contribute to disease outbreaks in Harare. CWWTP did not meet effluent discharge standards in December from 1994 to 2014, a period of (20 years). It was also found thatCWWTP had a bigger loading rate than the TKWWTP and that they had different wastewater characteristics. There was evidence for system overdesign and or wrong treatment system selection with special emphasis on erection of a 5 stage Bardenpho plant to treat 2mg/l of phosphorusat CWWTP.Chemical precipitation was recommendedfor CWWTP just as it was found to be effective in removal of such a TP concentration at TKWWTP. Total system dilapidation at CWWTP was found to be a reason of lack of system monitoring and subsequent failure to react on time to fix identified challenges in the plant therefore automation was suggested. Land based treatment systems like ponds were also suggested.Industry was encouraged to take part in wastewater treatment and privatization of the water sector could reap good service provision. This study also suggested that both TKWWTP and CWWTP look into possibilities of removing personal care products and pharmaceuticals from their wastewater as none of them had put in place measures to remove these micro pollutants.CWWTP was recommended to reduce aeration from 4mg/l to 2mg/l in the BNR plant as concentration increase didn’t increase system efficiency above 2mg/l, also energy generation at the plants was suggested. A revamp was suggested on the national legislation in Thailand concerning a high allowable TKNconcentration in effluent discharge to the environment.35mg/l was regarded too high in comparison to EPA standard of 25mg/l. The standard is even lower in other countries like Zimbabwe at about 10mg/l.Finally a technology selection matrix should be created toaide in treatment system selection. Political andsocio-economic factorsshould be included in wastewater treatmentdecision making. |
| Year | 2014 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. UWEM-14-03 |
| Type | Thesis |
| School | School of Engineering and Technology |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Urban Water Engineering and Management (UWEM) |
| Chairperson(s) | Anachathre, Ajit P.;Hooijmans, Tineke |
| Examination Committee(s) | Shrestha, Sangam;Thammarat Koottatep |
| Scholarship Donor(s) | Bill and Melinda Gates Foundation (BMGF)and Dutch Development Cooperation -UNESCO-IHE Programmatic Cooperation (DUPC) |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology - UNESCO-IHE, 2014 |