The decentralised approach to sanitation offers an affordable solution without the need for electrical or chemical inputs, minimising the capital and operation costs associated with high-tech conventional WWTPs. Furthermore, it is located near the community serviced, eliminating the need for extended sewer lines and pump stations. Since 2010, eThekwini Water and Sanitation (EWS) has been investigating the approach to decentralised wastewater treatment in partnership with the Bremen Overseas Research and Development Association (BORDA), a German non-profit organisation who has installed many such systems around the world. Decentralised wastewater treatment systems designed by BORDA are constructed on-site and thus, by definition, not regarded as package plants.

A demonstration-scale system was constructed in Newlands East at a research site named Newlands Mashu (NM), for a design flow of 41.6 m3/d. Raw domestic wastewater is gravity fed and primarily treated anaerobically in a two-chambered settler, three-train anaerobic baffled reactor (ABR) and two-chambered anaerobic filter (AF). The ammonium-rich effluent (hereafter referred to as AF effluent) can be reused in agriculture. This is beneficial in terms of promoting subsistence farming in the serviced communities and reducing the potable water demand for irrigation. The AF effluent from Trains 2 and 3 of the ABR is used for agricultural trials on-site to test the growth effects and safety of irrigating with anaerobically treated domestic wastewater.