Study On Optimization Of Emulsion Liquid Wastewater Treatment Process

Emulsions are widely used in the metal processing industry and the mechanical processing industry,and they produce spoilage and deterioration during use,resulting in emulsion wastewater.Emulsion wastewater contains high COD and direct emissions can cause severe environmental pollution.In this experiment,coagulation and demulsification and biological contact oxidation were used to treat emulsion wastewater.In the process,acid-soluble coagulation and flocculating sludge was used as a coagulant,and bio-modulators were used to improve the biodegradability of the wastewater.Finally,the emulsion wastewater will be discharged up to standard.The concentration of COD in the emulsified wastewater was about 8.46×104 mg/L.The COD concentration was milk yellow and the emulsification was stable.The beaker experiment was used to screen three different coagulants and three different flocculants to selectively treat the emulsion.The amount of coagulant used was 3.75 g/L of aluminum sulfate at room temperature,and the flocculant was anionic polyacrylamide 0.08 g/L,when the optimal reaction pH is 6.5,the COD removal rate of the emulsion wastewater can reach 90%,and the SS removal rate can reach 85%.Sulfuric acid solution can reduce or even eliminate the coagulation produced by the slag,so that the mixture of the coagulant recovered,the use of sulfuric acid 30 mL/L.The direct economic benefits reach 2,500 yuan/t,which is feasible in practical engineering applications.The recycled coagulant still has the value of recycling.The emulsion can be recycled and the cycle number is about 3 times.Coagulated emulsion wastewater is treated at room temperature with a self-developed,direct-flow,fixed-bed bio-contact oxidation unit,using polyurethane packing.Under the premise of successful biofilm culture and acclimation,continuous aeration was performed intermittently.By examining the removal of COD and ammonia nitrogen in the water and determining the optimal residence time of 9 days?the best dissolved oxygen content was 5 mg/L?the optimum filler ratio was 50%?and the suspended sludge concentration was 5500 mg/L,the COD removal rate could be achieved 98%?ammonia nitrogen removal rate of up to 93%.In view of the poor biodegradability of the coagulation effluent,three kinds of self-developed biological regulators were selected to improve the biodegradability.Experiments showed that the biological regulator 3(main component alcohol)has good removal effect with the coagulation effluent.When the amount of 5%is added,the wastewater B/C(biodegradability)is increased from 0.124 to 0.350,and the residence time of the same removal of COD is reduced to 5 days.Experiments show that the system has strong anti-shock load ability,can withstand the impact of large influent COD and ammonia nitrogen,and the system can resume operation within 1 to 2 weeks when subjected to COD impact,while the impact of ammonia nitrogen will cause irreversible consequences.The final effluent meets the Class C standard of "Sewage discharge into urban sewer control project limits”(GB/T 31962-2015).