Biological treatment of chemically flocculated agro-industrial waste from the wool scouring industry by an aerobic process without sludge recycle

A new agro-industrial effluent known as Sirolan CF effluent is the aqueous phase remaining after the chemical flocculation of wool scouring effluent by the Sirolan CF process. This effluent has been characterized, and shown to be effectively treated by biological degradation. It has a high concentration of organic material (5750 mg/L COD), with a low BOD5/COD ratio (0.29). Aerobic biological treatment was tested using laboratory and pilot scale reactors, and shown to remove essentially all BOD5, solvent extractable material and detergent activity. Maximum removal of the COD was 65% leaving a 2000 mg/L residual component of nonbiodegradable organic material. The combined processes of Sirolan CF and biological treatment removed over 90% of the COD and all solvent extractable material from raw wool scouring effluent. This compares favourably to existing treatment systems, and represents a viable and attractive alternative to treat this extremely polluted wastewater.