Study On Treatment Of Gas Production Wastewater By Combination Processes

The water quality of high salinity gas production wastewater was complex and harmful to the environment and human body.It was difficult to satisfy the discharge standards after using a single treatment process.Thence,a new physical-chemical combination process was used to treat the gas production wastewater.The removal rate of COD is taken as the target of the process treatment,and the optimum process parameters was explored through experiments.This paper mainly studied the feasibility of combined process of Chemical Coagulation-Persulfate Advanced Oxidation-activated carbon adsorption which was used to deal with the gas production wastewater from a gas well in western Sichuan,and according to the influence of various factors on the removal efficiency of COD in the experiment,the optimal reaction conditions of the ultimate combination of technology were determined.First of all,the gas production wastewater was tested by Chemical Coagulation.The results showed that the removal rates of COD,SS,oil and chroma were 38.09%?93.21%?39.51%and 79.9%respectively and we could get the more effective oil-water separation at the optimum technological conditions:dosage of 1100 mg/L,pH 8,reaction temperature 35?and reaction time 15 min.Secondly,we defined the optimum operating conditions of Persulfate Advanced Oxidation by orthogonal experiments,and the main factors affecting the removal rates of COD were investigated individually.The results showed that the optimal operating conditionwere as follows:activation temperature was 90?,reaction time was 120 min,and the removal rates of COD,SS,oil and chroma could reach 93.98%?21.08%?89.89%and 50%,and the effluent was very remarkable.Then the molecular probe experiment showed that the dominant radical in this process was·OH.The wastewater oxidized by the Persulfate Advanced Oxidation was tested via the activated carbon adsorption.The result indicated that the removal rates of COD,SS,oil and chroma can reach 58.72%?87.61%?32.74%and 90.07%after210 min treatment of the 15g/L activated carbon at room temperature.Under the optimum treatment conditions,the effluent of gas production wastewater treated by the combined process can reach the first class standard of the“Integrated Wastewater Discharge Standard”(GB8978-1996).The estimated cost of the combined process of treating gas production wastewater was53.46~85.68 yuan/m~3.In conclusion,chemicalcoagulation-PersulfateAdvanced Oxidation-activated carbon adsorption process is technically and economically feasible and has great research value.