Rain collection and recycling

Design aims: groundhouse harvests all water needed for washing and recycles grey water for food growing

• rainwater is collected, filtered and stored in underground tanks and supplies all bathing and washing water for the house.
• grey water (from washing) is filtered into reed beds and used on the gardens.
• no black water is produced by the house.

Rain water – the groundhouse roof is designed to harvest a large amount of rainwater which runs, through a vortex pre filter, into underground storage tanks.  Two side by side rainwater harvesting tanks provide a 10,000 litre storage capacity.  The tanks, the vortext pre filter and the water pumps are from the German company Wisy, selected because of the ‘over engineered’ quality of their products.

The groundhouse has a dual water system.  It is connected to mains water which is permanently available from the small drinking water taps fitted in both the kitchen and bathroom.  All other water for washing is, by default, filtered rainwater, making mains water consumption and running costs very low.  The rainwater is cleaned by the vortex filter and then, in the utility room, it pass through a secondary filter and then a carbon filter.  It is then pressurised into and expansion tank specified for drinking water by Altecnic. The whole water system for the house can be switched over to mains water in the utility room.  This is a useful back up for cleaning the tanks and if the tanks run dry during periods of low rainfall.

Grey Water and Toilet – we recycle all ‘grey‘ water (water from washing) through a primary straw filter (grease trap), then through a series of reed beds, for final use in watering the gardens.  To ensure no water pollution is created by the groundhouse and to return nutrients to the land, we have fitted a dry toilet from Separret in Sweden.  This separates urine which enters the grey water system and keeps solids dry and odour free until the collecting chamber needs emptying (around 2 weeks).  This is transfered to the toilet composter outside the building.  All plumbing is conventional in the groundhouse, and blank pipe runs are fitted for installation of a fosse septique.