| Methyltin mercaptide is one of the most important heat stabilizer for PVC products for its high stability and dissolvability. However, the wastewater generated from methyltin mercaptide's production process consists of large quantities of organic pollutants, ammoniacal nitrogen and toxic substance, such as organotin and organic sulfur, and the pollution caused by the wastewater has drawn more and more attentions. At present, the method for methyltin mercaptide wastewater treatment is immature. It is necessary to explore a stable and effective method to treat the wastewater. The wasterwater got from methyltin mercaptide production process of 081 base can't be treated by biochemical plants directly for its high concentration of organics, toxicity and bad biorefractory. Therefore, this experiment mainly studied pretreated wastewater's aerobic biodegradability. Cometabolism and membrane bioreactor (MBR) are combined to treat the pretreated wastewater by different method. A series of research were carried on based on removal effect of the organic contaminants, changing of sludge characteristic, membrane fouling process and mechanism and membrane washing method. Furthermore, fitful bioreactor (FBR) is used to evaluate aerobic biodegradability of the wastewater in order to know wastewater's characteristic in a relatively short time to instruct biochemical treatment. Experimental results showed:The biodegradations of effluents from MBR, UV-03, Fenton, internal electrolysis and adsorption were evaluated by the innovative FBR, measuring COD instead of OUR, whose influent is a intermittent mixture of a starch solution in the first 80 minutes and the 081 wastewater in the later 100 minutes. And It was concluded that FBR could be used to evaluate the aerobic biodegradations of different waters of different qualities under the same condition of sludge characteristics and experimental conditions. When it was used to evaluate the aerobic biodegradation of a single water, the sludge characteristics influent little on the result got from the FBR.When the COD ratio of additional carbon and wastewater varies from 5/1 to 1/1, removal rate of pollutants is not ideal in every single condition and declined gradually from 60% to -84% because the accumalation of toxic substances make the micoorganisms inhibited.When the MBR is operating normally without sludge discharge, sludge concentration is 8.6～9.2g/L, VSS/SS is in a low level between 0.64 and 0.72, and SV is 100/100 because the accumalation of toxic substances make the sludge characteristic bad.The membrane fouling became more serious when the slugde concentration gets higher. The accumalation of toxic substances in the reactor worsen the sludge property and contributes a lot to the membrane fouling. Sedmentary deposit resistance is the main pollute resistance in membrance fouling process and mainly caused by these substances which exist in supernatant.Compared with physical washing, chemical washing can improve membrane's filtration capability thoroughly whose life-span is longer. 1 minute' osillation could increase the flux by 60% but declined 30% after 80 minutes' operation. While the chemical washing could increase the flux by 60%, and had performed normally for 20 days with quite a serious membrane fouling. Chemical washing was carried out in the sequence of acid liquor, lye and oxidizer whose flux recovering indexes were respectively 0.86-0.97, 0.98-1.13, 1.15-1.42. A better washing result can be obtained in the combination of lye, acid liquor and oxidizer than applying only one of them. More than 100% of the flux was recovered because the old membrane was not cleaned thoroughfully.
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