Advanced treatment of petro-chemical wastewater with multifunction eco-ponds

The effluent of secondary sedimentation tank in a petro-chemical factory was treated with eco-ponds. The eco-ponds was constituted by the facultative pond, aerobic pond and hydrophyte pond, which was enhanced by the eco-concrete revetment, filter and floating bed of aquatic plants. Running results indicated that, HRT=45h, the removal rate for COD, TN and TP in the treated water was 28.3%-49.4%, 29.3%-45.5% and 21.3%-43.6% respectively. The process operates steadily with the treated water quality up to A standard of I-class criteria of the Chinese Discharge standard of pollutants for municipal wastewater treatment plant (GB 18918-2002).