Grey water sanitation

The invent of waterborne sewage systems allowed society to transport faecal matter, in an underground network of pipes and tunnels to remote facilities to treat and dispense of this waste water in a proper manner. As societies advances all household liquid waste was channeled though these underground pipes and treatment plants were forced to deal with the surplus fluid that accompanied the effluent.

All wastewater treatment works are well designed to deal with the dirt and high quality faecal matter they receive but often struggle to cope with the quantity of fluids that are flushed down the pipe networks. This is not only a concern for municipal wastewater treatment plants but also household septic tanks. If the quantity of water that these facilities receive can be reduced, then many sewage spills can be prevented.

Water Rhapsody Second Movement uses grey water to flush toilets.

Grey water sanitation uses water from baths, showers, hand wash basins and the laundry to flush toilets. After the primary use of fresh water, the resulting grey water is passed through a filter where textile fluff, hair and other particles larger than 1mm are removed. The grey water is then treated to remove foul odours and to kill bacteria that may be present in the water. From the filter the water is sent to the holding tank, from where it is pumped to the individual toilets on demand. As the grey water is pumped directly to the pan there is no cistern and the flush handle, typically attached to the cistern is replaced with a bell push on the wall.

The average person produces more grey water a day than water used to flush toilets. This allows the reuse of grey water to lend itself very well to sanitation purposes. Not only does grey water sanitation bring with it a significant fresh water saving, as much as 50%, but it also reduces the quantity of wastewater produced.