Overview and feasibility of advanced grey water treatment systems for single households

Although in recent years new developments for smaller applications have been made, investment costs have decreased and fresh water and sewage fees have increased, it has not been published so far if there are feasible grey water systems for single households with high quality effluent on the market. This paper gives a general overview of grey water treatment systems, a detailed comparison of available advanced grey water treatment for single households and a cost evaluation in view of onsite membrane bioreactor (MBR) systems for single households. The data and information were collected from demo units, publications, manufacturers and suppliers of these systems and were compared with experiences found in research literature. Results show that on-site MBR systems with daily grey water reclamation of more than 500 litres (10 persons) could be cost-effective. For single households the investment is still too high for a payback time of less than 15 years.