Decentralised Wastewater Treatment System
Funded by: BORDA
January 2013 - December 2015
Partner organisations: eThekwini Water and Sanitation,
Project description
Bremen Overseas Research & Development Association (BORDA) and The Pollution Research Group (PRG) have been collaborating on sanitation projects since 2007, when the PRG was tasked by BORDA to direct its scientific activities on decentralised sanitation systems worldwide. Currently, PRG, eThekwini Water and Sanitation, and BORDA are investigating the viability of a modularised DEWATS for on-site waterborne sanitation and the usefulness of the treated water for agriculture. A DEWATS plant was built in Newlands-Mashu for technical evaluation as part of a Memorandum of Understanding between EWS and BORDA signed in 2009.
A DEWATS plant usually caters for settlements from 20 to 2,000 households. The modularised wastewater treatment plant at Newlands-Mashu consists of a biogas/settler pre-treatment step, an anaerobic baffled reactor, two anaerobic filter chambers and effluent polishing in a constructed wetland. The plant receives up to 40 m3/d of domestic wastewater from the surrounding residential area. The envisaged application for the DEWATS in eThekwini is to provide wastewater treatment to areas with relatively high population density that are beyond the sewer network of the city, such as informal settlements, development and transport nodes, and schools and clinics. The DEWATS process offers an additional benefit of producing nutrient-rich greywater useful for agriculture.
Although BORDA has constructed DEWATS plants in several places in Asia and Africa, no formal evaluation of the DEWATS operations has been conducted. In 2010, an evaluation of the Newlands-Mashu DEWATS plant began, with funding from Water Research Commission. BORDA’s primary responsibility was to commission the design and construction of the plant and to fund master’s and Ph.D. students to conduct the research. The DEWATS evaluation intended to assess the systems operations and load performance conditions, and determine the viability of using treated wastewater for agriculture. In addition to providing scientific oversight to the evaluation, PRG is currently supervising a PhD student working on the modeling of anaerobic baffled reactors (ABR) in a Decentralised Wastewater Treatment System (DEWATS).
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