Study On Techique For The Treatment Of Coal-to-liquids Low Denisity Oil Wastewater

While coal-to-liquids profession fast development in recent years, water environmental pollution is serious day by day. According to pertinent data demonstration coal-to-liquids profession, 1 ton oil needs to consume 4-5 tons coals and 8-9 tons water, simultaneously will emissions the massive waste water. The coal-to-liquids enterprise to reduce the amount of fresh water, all carries on processing and recycling use to the waste water. This project in view of some coal-to-liquids enterprise wastewater disposal cannot attain a designated standard, in this present situation, conducts the improvement research to pretreatment and the biological treatment craft, the goal is enhances entire wastewater disposal craft the processing efficiency, the waste water can reach to standard and recycling use.In the pretreatment technical study first used the coagulation static testing to contrast polymerization aluminum chloride (PAC) and the polymerization iron sulfate (PFS) two kind of coagulants to the coal system oil low concentration oily wastewater effect, The test result indicated that:the coagulation effect of PAC surpasses PFS. The optimalconditions of PAC: flocculant dosing quantity 3.6mg/L, pH 7.0, sedimentation time 30 min, mixing speed 90 r/min; On the optimal condition of PAC the removal rate of CODcr of coal-to-liquids wastewater is 42.33%, turbidity 90%, oil 51.04%. The dynamic testing research of coagulation - air floatation carries on the coal-to-liquids low denisity oil wastewater in the static experiment's foundation, the result indicated: while water leakage pH 7-8, CODcr 197-235 mg/L, NH₃-N 28-35 mg/L, oil 29-35 mg/L, SS 38-42 mg/L, removing rate is 52%, 30%, 65% and 35%.The pretreatment waste water enters the biological treatment craft, has contrasted the ordinary active sludge process, the acidified - good oxygen biology process and the PACT three biological treatment system's processing effect in the biological treatment technical study. The findings indicated: Acidified - good oxygen biology process and ordinary active sludge process elimination pollutant biology effect basic consistent,in the resident time is under 16 conditions CODcr, Oil, SS, NH₃-N elimination rate respectively is 49%, 50%, 32%, 46%. However, the elimination rate of PACT is 75.5%, 70%, 69%, 60%. The contrastive analysis may be known that the PACT process to CODcr, Oil and SS elimination effect surpasses the ordinary active sludge process obviously, therefore to include difficultly to degrading the organic matter the low concentration coal-to-liquids wastewater biological treatment to select the PACT process to be appropriate. Uses the coagulation - gas to float the pretreatment and the PACT two crafts carries on the combination to carry on processing to the coal-to-liquids low concentration oil wastewater, CODcr, Oil, NH₃-N, the SS water leakage density is 45-50mg/L, 3-5mg/L, 8-10mg/L, 8-12mg/L, achieved third-level enters the water standard, CODcr and Oil achieves the recycling use stardard, after continuing the advanced treatment can achieve the recycling use stardard of wastewater.