Physical-Chemical And Biochemical Treatment For Refining Alkaline Residue Wastewater

Today, refining alkaline residue wastewater is recognized as a kind of industrial wastewater which is hard to degrade. This kind of waste water is high concentration of COD, high chroma, poor of biodegradation and toxic. If it was discharges directly without properly treatment, it will result to pollute the water environment and ecosystem, endanger human health and restrict economic sustainable development. So according to this kind of waste water, R&D new process which is high efficiency and low cost become the hotspot of wastewater treatment.In this paper, according to the refining alkaline residue wastewater, this experimental chooses coagulation-micro -electrolysis/Fenton-macroporous absorption resin as the pretreatment process, then the pretreatment effluent is disposed by phase of activated sludge. Through these processes in series,the effluent quality can meet the requirement. The lab experiment demonstrates that adopting coagulation-micro -electrolysis/Fenton-macroporous absorption resin and activated sludge process to treat the refining alkaline residue wastewater is feasible,and the optimun conditions are determined by studying these conditions of influencing the removal efficiency of pollutants. It can be drawn the following conclusion by analyzing experimental results:(1) The optimization operational parameters of coagulation as follows: the adding dose of PAC was 900 mg/L, the adding dose of CPAC was 30 mg/L, the pH value 8, the stirring time 15 min, the result of the study showed that the removal rate of CODcr and chroma should be 46.5%, 51.4% respectively.(2) The optimal conditions of Fe-C micro-electrolysis process as follows: the volume ratio of wastewater to Fe-C filler was 2:1, initial pH value was 3, reaction time was 2 h, under these conditions, the concentration of CODcr was between 16000 mg/L and 17000 mg/L, the removal rate reached to about 42.5%. The optimal conditions of Fenton reagent oxidation process as follows: pH value was between 2 and 3, reaction time was 2.5 h, Fe2+ concentration was about 800 mg/L, H2O2 concentration was 0.25 mol/L, the removal rate of CODcr reached to 42.5%. Micro-electrolysis/Fenton process on the total removal rate of CODcr was about 79.2%.(3) The paper studied the static absorption process of the pretreated wastewater. By experimenting with four different adsorption resins in this process, the study decided type LS-100 as best. In the 6-cycle adsorption-desorption experiments, when the average concentration of influent CODcr 6000 mg/L or so and the velocity of flow was 2 BV·h-1, the average concentration of effluent CODcr 1356 mg/L, run to resin penetration point, the average adsorption capacity of LS-100 resin to wastewater is 346 mg/mL, treatment of wastewater was 75 BV.(4) After activated sludge acclimation and at room temperature, concentration of influent CODcr was between 1278 and 1516 mg/L, hrt was 24 hours, the average concentration of effluent CODcr was 334 mg/L, The average removal rate of CODcr reached 76%.(5) The experiment results show that the combined pretreatment process of refining alkaline residue wastewater which put forward in this paper is cost-effective and technically feasible. The process is valuable to be consulted for pilot project.