| Epoxy propane(PO) saponification wastewater with high-salinity,high COD,high pH and low BOD/COD in a certain chlor-alkali industry limited company was proposed to treat by using combined treatment process which consisted of coagulant sedimentation process,activated sludge process together with aerobic submerged fixed-film process and oxidation process.In the process of coagulant sedimentation,we neutralized the mixture of PO wastewater and washing flue water to keep pH within the range of 8-9.The kind of flocculent agent and its dosage,together with the mix time and the mix strenghth were considered in the unit of coagulant sedimentation process.Experimental results showed that the COD and Ca2+ removal rate could reach 29.5% and 27.5% when we put 10mg/L PAM(the best flocculent agent) in the water sample and mixed it with the rotate speed of 300rpm for 1min and then with the rotate speed of 90 rpm for 15min.In the process of activated sludge process and aerobic submerged fixed-film process,we increased the salinity of effluent to acclimate the activated sludge and biofilm and get the halophine.The influence of the parameters such as hydraulic retention time(HRT),pH,and salinity on the COD removal were researched.We also compared the the COD removal of acclimated activated sludge with unacclimated activated sludge in the activated sludge process. In addition,we researched the ability of the bio-system to resist sudden impacts. Experimental results showed that it was feasible to get halophile by acclimating activated sludge and biofilm.The COD removal rate of bio-system came to a head as 80.7% when its total HRT reached 18 hours,and at that time the load of activated sludge was 0.56kgCOD/kgMLSS?d.When pH of influent water ranged from 8~9,pH of effluent water ranged from 6~7.And when pH of influent water exceeded 9,the COD removal rate descended sharply.The dissolved oxgen amount of both the activated sludge reactor and the biofilm reactor ought to range from 2 to 5 mg/L.The COD removal rate of acclimated activated sludge excelled the COD removal rate of unacclimated activated sludge distinctly.The sudden change of influent sanility influenced the COD removal. After the sudden change of high salinity,high COD and high pH impacted the bio-system for 24 hours ,the COD removal rate descended sharply,then it ascended gradually and resumed the normal level a week later.At the same time we researched the influence of calcium chloride salinity on the microbe activeness of the bio-system. Experimental results showed that when the salinity ascended from 1.4% to 3.2%,the COD removal rate of wastewater descended from 88.0% to 80.7% and MLVSS/MLSS descended because the inorganic part of activated sludge increased.As the result of the consistency of wastewater increased,the sedimental speed of activated sludge became slower,and it was necessary to increase the quantity of return activated sludge.The kinds of bacteria in the zoogloea decreased as the salinity ascended,and the protozoa and metazoa such as rotifers and eelworms died away when the salinity exceeded 2.0%.Furthermore we researched the COD removal of the chemical oxidation process in which we put chlorine in the wastewater after the biological treatment process. Experimental results showed that the COD decreased as much as 100mg/L when we put 1.5L chlorine in 1L effluent wastewater.Finally we set up the treatment process flowchart of the reconstructive project and figured out design parameters.
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