Advanced Treatment of Wastewater from an Ethylene Chemical Enterprise by a Biological Aerated Filter-Ultrafiltration-Reverse Osmosis Process

摘要

This work focused on the advanced treatment of the secondary treated ethylene chemical plant effluent, which contained high conductivity and high organic concentration. To reduce the cost and improve operation stability, a biological aerated filter-ultrafiltration-reverse osmosis (BAF-UF-RO) process was proposed. The feasibility and effectiveness of the BAF loaded with a novel non-sintered fly-ash ceramsite (NSFC) as pretreatment method were investigated in detail. The results showed that the COD, turbidity, NH_3-N and SDI_(15) in the effluent from the BAF were reduced largely. The BAF-UF-RO process was stable with the recovery rate of 75%, and the desalination rate was up to about 97.5%. Moreover, the operating pressure and backwash frequency of RO maintained 0.94-0.98 MPa and 2 times/d, respectively. After continuous operation for four months, there appeared to be no need for chemical cleaning of the RO membrane.