Treating waste water, esp. from cess pits, with flocculants - then gravity filtration through textile to reduce solids and BOD

摘要

A proces for purifying waste water with reduction in COD and BOD values which requires a preliminary sepn. before a further purification comprises the following. Flocculating agents are added to the waste water and the greater part of the colloidal constituents are eliminated by passing the water through a gravity filter comprising a support material in an appts. contg. it to form a filter consisting of the support material and a layer of sepd. solids, which removes the colloidal constituents. The appts. forms the first part of water-treatment stations which also includes a further purification means comprising either a biological or a physico-chemical treatment followed by means for the sepn. of the resultant sludge. The process is partic. used to treat effluent from cess-pits and sludges collectors. The process has the advantage of reducing the COD (up to 20,000 mg/l.) in a preliminary sepn. stage. It is also cheaper and more adaptable than current first sepn. methods which require expensive concrete tanks with long sepn. times.