Many waters in Tanzania exhibit high concentrations of organic matter and dissolved contaminants such as fluoride. Due to bacteria and virus removal, ultrafiltration (UF) is an attractive option for drinking water treatment, and when coupled with adsorbents, may compete with other established processes like nanofiltration (NF) for lower contaminant concentrations. The results presented here examine the characteristics and treatability of tropical natural organic matter (NOM) by UF as a function of seasonal variation. The Tanzanian river Maji ya Chai was sampled monthly during one year. The composition of NOM in Maji ya Chai River is influenced strongly by precipitation. Total organic carbon (TOC), specific ultraviolet absorbance (SUVA) and concentration of allochthonous organics substances (such as humic substances (HS)) are elevated in periods following high precipitation, while TOC is lower and contains more biopolymers in the dry seasons. UF experiments with two regenerated cellulose membranes of different molecular weight cut-off (MWCO, 5 and 10 kDa) were conducted. UF is able to remove 50–95% of TOC with a seasonal variability of 10–20%. Due to the remaining NOM in the water that would contribute to disinfection by-product formation and bacterial regrowth, the physically disinfected water is more applicable for point of use systems than distribution or storage.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The German Academic Exchange Service (DAAD) and Gesellschaft von Freunden der TU Berlin e.V. is acknowledged for a travel scholarship for G.A., and the Energy Technology Partnership (ETP) with the Drinking Water Quality Regulator for Scotland (DWQR) for a PhD Scholarship for J.S. Leverhulme Royal Society Africa Award SADWAT-Tanzania is thanked for project funding and Merck Millipore (Bedford, USA) for membrane provision. NM-AIST LiSE has made the UV instrument available for usage. Bryce Richards is greatly appreciated for all-round project and logistics support. Anthony Szymczyk (University Rennes, France) has provided streaming potential measurements and Meteoblue AG (Basel, Switzerland) very kindly performed precipitation data modeling for the research. TANAPA is acknowledged for allowing Godfrey Mkongo to collect samples for this research in Arusha National Park. Technicians Julius (metal works) and Suleiman (wood work) are thanked for their qualified and creative support from makeshift workshops.
ASJC Scopus subject areas
- Water Science and Technology
- Ecological Modeling
- Waste Management and Disposal