Friday, February 17, 2012


Grey Water Recycling System Drawing

Grey water room housing the filtration System. The green grass coers the underground system.  The cistern has a manhole for emergency trouble shooting.
Shown are the activated granular carbon filter (to remove contaminants and impurities) and the multi media filter (to Reduce the level of turbidity and suspended particles)

A glance at the opened cistern of grey water

One of my clients wants a green house. Initial plans were incorporation of solar roof, green roof, and recycled water, lots of ventillation, sun, etc.. With the cooperation of the Architect and experts,  we were able to execute everything xcept for the solar roof which turned out to be not feasible. (See  Our Rooftop farm and Vertical Garden )

Grey waste water recycling seemed too technical when I first heard about it. I though it would be too complicated to include in the renovation works in my client's home that I was skeptical - sanitary plans, multi media filter tanks, cisterns, alternate pipes etc. It all sounded complicated on paper but turned out very simple after the installation.

Our grey water source are  from the laundry, bathroom and rain water from downspouts (we have lots of rains throughout the year) and the backwash water coming from the main filtration system of the house - all of which have low level contaminants ( Note: we didn't include the sewer pipes). These pipes go to an underground cistern measuring 3x6x3 meters. The cistern has an overflow pipe in case we have too much grey water. Water then is pumped through a multimedia filter, then a carbon filter that purifies it from the contaminants. The resulting recycled water is used to water the garden and cleaning of outdoor areas. This filtration type does not make this water potable. (NOTE: some references do not recommend use of recycled grey water for some type of vegetable gardens due to possible contamination of laundry detergents or chlorine).

The grey water collected in the cistern must be consummed within 24 hours to 2 days to prevent putrefaction which can really smell bad. Maintenance requires two times a week backwashing, twice a month disinfection and replacement of filter every two months. These maintenance procedures must be strictly followed or the known complaint of developing foul smell of the resulting recycled water.
Maintenance Checklist posted inside grey water room

Maintenance Guidelines posted in grey water room
Benefits are lower water bills due to reduced fresh water use, healthier garden due to added natural nutrients in the recycled water, and of course responsible contribution to the environment.

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