Development of an integrated wetland microbial fuel cell and sand filtration system for greywater treatment

This research focused on the design and operation of a system combining a constructed wetland microbial fuel cell (CW-MFC) and a biological sand filter (BSF) for the continuous treatment and recycling of handwashing greywater. The technology was assessed both in terms of its ability to treat the greywater and to generate bioelectricity. The performance was evaluated by regularly monitoring the organic material, nutrient and E. coli removal efficiencies as well as the power generation. The system was observed to achieve a complete bacterial removal for a 4-log E. coli influent load and a 99% COD removal was achieved with a 432 mg L-1 organic load. The final effluent quality was found to comply with South African standards for drinking water quality, illustrating the potential for reuse. Moreover, a maximum power density of 4.33 mW m(-3) was achieved by the system thus demonstrating the ability of the process to recover power from handwashing greywater. It was recommended that future investigations focus on determining the performance and maintenance requirements of a pilot-scale system operated using real handwashing greywater, appropriate methods for disinfection of the effluent, improved power generation and the expected life-cycle behaviour of the greywater treatment system.