Ponds at Hawkwood deal with sewage

It was a Hawkwood College Open Day last Saturday and I took the opportunity to see how the ponds were progressing - these ponds have been put in to manage the college's sewage.

Hawkwood College is an independent adult education centre offering courses in creative exploration to people of all ages and from all walks of life. The College ethos includes access for all and a commitment to sustainable land use, hence the decision to build a state-of-the art ecological sewage system in 2005.

Simon Charter, the designer of the system (right in photo above), who lives in Ruscombe and is a member of the Ruscombe Brook Action Group showed us around. We walked down the grass paths that wind down past pond-side benches through wildflowers, trees and shrubs.

Sewage and waste water from the house is piped into two digestion tanks, where solids settle and separate (see photo left). The liquids flow into a distribution chamber, from where about 10 bucket loads of dirty water are sent 4-5 times a day into each of four primary treatment ponds. The water is then pumped through a cascade in each pond and gravel beds planted with aquatic & marginal plants.

Three of the cascades are Flowforms (See more re Flowforms here) which induce a rhythmical vortex movement in the water, replicating the swirls and eddies found in a slow moving river (photo of one of the ponds left). The fourth cascade, in the control pond, is like a natura but without the vigorous movement created by the Flowforms.

Cleansed overflow from the primary treatment ponds joins together in the maturation pond, also with planted gravel beds, but no cascade. After this comes the water absorption area, in the form of a meandering ditch planted with willows, dogwood and other water-hungry plants. This area allows a final polishing of the water before discharging into the natural watercourse below.

The water from the roof of the college is diverted into a small stream area where water cress is growing (see photo - college in background and water cress in foreground).

The whole project won a 2005 Stroud District Council Award for Sustainable Design. Dragonflies, water boatmen, newts, ducks and wagtails have already been observed, providing new habitat to increase biodiversity - indeed we could see much in the ponds when we were there.

Ponds are also one of the options to help improve the Ruscombe brook - other options include reed beds.