Purificn. of laundry effluent for recycling - by coagulating and decanting after adding aluminium sulphate and anionic polyelectrolyte

摘要

Wt. of aluminium sulphate employed is equal to the wt. of dry solids contained in the effluent. An anionic polyelectrolyte is also added at the rate of 0.5-10.0 ppm. The aluminium sulphate can be dehydrated or hydrated. The polyelectrolyte is pref. a polyacrylamide. The installation pref. comprises a reception tank for effluent to be treated. The effluent is then transferred e.g. pumped, to a coagulation and decantation vessel where additives are mixed in, sludge is drained off and clarified water decanted into a storage tank for water to be recycled to the laundry. Decanted water is pref. disinfected, e.g. by ultra-violet radiation or ozone, on its way to the recycling tank. The purificn. is now sufficiently effective to allow the water to be recycled in the laundry processes.