Polder sludge draining process renders lagoon fit for agricultural use and water fit for release at low cost

摘要

A process de-waters sludge from standing waters especially lagoons. The lagoon sludge is sub-divided into a higher rinse polder zone and a lower rinse polder zone, allowing water to drain steadily from high to low on a quasi-continuous basis, and the steady removal of sludge. Each rinse polder is preferably 10 times longer than its width and has a gradient of preferably 0.5%. Water discharged from the rinse polder is admitted to the lower basin containing especially growing reeds which act as a biological filter. Before final release, treated water is subjected to the natural self-cleaning action of a waterway. Residual water is removed from sludge by wholly or partly covering the sludge with a material having strong suction properties. The suction material may be raised at one end by a post to form a 'sail', allowing the wind and sun to remove the water vapor which rises by capillary action.