Research Of Bio-polluted Wastewater Treatment Method

In recent years, the biological technology provides great impulse both in economic and human progress.Meanwhile, the potential threaten and risk it brings has drawn people's attention increasingly. The waste produced by biological laboratory and bio-tech corporations, especially waste water, brings severe threaten to the environment.In order to select proper methods and reaction conditions, bench-scale experiment were carried out to the typical bio-hazardous wastewater from biological and pathological laboratories.After getting the optimized technical route, the full-scale treatment experiment will be taken.Six methods, such as coagulation, Fenton, electrochemistry, coagulation/Fenton, coagulation/electrochemistry and coagulation/ozone oxidation were tested. The result showed that a hybrid of coagulation and Fenton oxidation was the optimistic method for the treatment of a bio-hazardous wastewater. Optimal conditions for coagulation were 40mg/L of polymeric aluminum ferric chloride sulfate (PAFCS),1mg/L of polyacryl amide (PAM) and a [CaO]/[linear alkylbenzene sulfonates (LAS)]ratio of 0.75/1.The optimal parameters for Fenton oxidation were determined to be 3g/L H2O2, H2O2/Fe2+=20/1 with 4 hours at initial pH 3.5.The average COD was reduced from 387mg/L to 43mg/L. The COD was qualified for the GB8918-2002 in Level I B. The NH3-N,T-N,T-P were qualified for the GB8918-2002 in Level I A. The full-scale treatment instrument was designed and built according to the bench-scale experiment. Full-scale experiment was undertaken in order to find out the optimistic operation parameters and treatment effect. The overall process included three stages:disinfection, coagulation, Fenton oxidation and subsequent coagulation. The experimental results indicate that the optimal dosage for polymeric aluminum ferric chloride sulfate (PAFCS) in the coagulation-flocculation was 70mg/L and the dosage for PAM was lmg/L. The optimal parameters of Fenton process were chosen to be 1.5g/L of H2O2 at pH 3.5 and 12℃.The effluent quality was qualified for the GB8918-2002 in LevelⅡ,or better.If the T-P of the raw water is too high, for the overall process would included four stages:disinfection, coagulation, Fenton oxidation and subsequent coagulation. The first three steps was just like the previous method.In Stage 4,70mg/L PAFCS and lmg/L PAM were added to improve the removal effect of SS and total phosphorus T-P.Before the subsequent coagulation, the effluent quality was qualified for the GB8918-2002 in LevelⅡ,except for T-P and SS.The SS is 40mg/L, qualified for the GB8918-2002 in LevelⅢ.The T-P is 6.9mg/L, not qualified for any level of the GB8918-2002.After the subsequent coagulation, the SS is 13mg/L, qualified for the GB8918-2002 in levelⅠB.The T-P is 1.9mg/L, qualified for GB8918-2002 in LevelⅡ.Finally, this subject designed the treatment technology and instrument for the bio-hazardous wastewater. The result can provide technology support to the bio-hazardous waste management.