Substrate body for activated sludge water-treatment tanks - composed of watertight closed-pored material, remains buoyant during operational periods

摘要

Substrate material bodies whose vol. is less than 1 litre and whose specific gravity remains less than one during extended periods of operation are proposed for use in activated sludge water treatment tanks. Up to 40% of the surface area of bodies may project above the liq. surface in the tank, similar bodies of specific gravity down to 0.6 may also be used. As well as zones of open-pored material, the bodies have zones of material which is closed-pored, water tight and impervious to water-vapour diffusion. Buoyancy is provided by this second material. USE/ADVANTAGE - In activated-sludge tanks as a substrate for activated and unactivated sludge. The long-term buoyancy of the proposed substrate bodies avoids the problems experienced with currently used clarifier tanks, in which the substrate material tends to sink to the bottom of the tank when the tank is not being agitated or aerated. Operational problems are therefore avoided and the energy required for aeration is reduced.