The Design And Operation Of Fine Chemical Wastewater By UASB-Biocontact Oxidation

With the fast development of fine chemical industries in China, more and more un-degradable and harmful wastewater were discharged to environment. The chemical wastewater contains NH4+-N, CODcr and un-degradable substances with high concentration and low pH value, which makes wastewater treatment more difficult by conventional biochemical processes. In this paper, the combined treatment of Pretreatment, UASB and biological contact oxidation was used in a fine chemical factory in Dalian. By practical engineering commissioning and stable operation, the results show that:1.Conventional activated sludge could be used as inocula fine chemical wastewater treatment through acclimatization. The surplus sludge from a municipal wastewater treatment plant were inoculated into UASB tank and biological contact oxidation tank, at the same time, cultivation and bio-film attachment were accomplished separately in each tank. Then the whole system was started up.2. In the practical engineering, the UASB reactor was inoculated with surplus sludge of 15 kg VSS/m3. The start-up was accomplished by increasing influent flow and volumetric load stepwise in 90 days.3. After start-up, with the volumetric load of 0.69 kg COD/(m3·d) and influent pH of 7.2-8.0, the CODcr removal was about 60%, with the effluent CODCr ranged from 1000 to 1500 mg/L.4.In the biocontact oxidation reactor, with the volumetric load of 0.7 kg COD/m3·d,the average CODcr removal was about 80%with the effluent CODcr of 190 mg/L.