Study On SBR Process In Cutting Emulsion Wastewater Treatment

Emulsion wastewater coming from machining industry is a kind of industry wastewater which contains much oil and has high COD value. If discharged directly, emulsion wastewater could pollutes the environment seriously. The wastewater is very stable and dissolved organics in it after oil/water separation is difficult to remove by chemical and physical methods. So it's difficult to discharge the wastewater which meets the national standards. Dissolved organics is usually treated by biological method, so it's necessary to research and develop methods to treat emulsion wastewater by biological methods.Emulsion wastewater treated by pretreatment methods such as demulsification to remove most of its oil is biodegradable easily. On the reconstruction project of high concentration emulsion wastewater treatment plant in a motor manufacturing company, we studied the decontaminating mechanism of SBR process, researched a small scale test using SBR activated sludge method to treat emulsion wastewater containing oil, adapted the result of small scale test to biological treatment unit of the wastewater treatment plant and achieved good resultIn small scale test, properties of influent wastewater were detected systematically, activated sludge was acclimated through asynchronous method, and the properties of sludge was detected. The results show that after pretreatment such as demulsification and coagulation, the main pollutant in emulsion wastewater is surface active agents and dissolved oil. The wastewater is biodegradable easily, and its B/C is about 0.5. The amount of N is enough, and P element is scarce. The oil content is about 40～50mg/L. The wastewater is alkaline and doesn't contain heavy metals. When the P element was added additionally, the COD of influent wastewater was 2000mg/L, the effluent COD was about 250mg/L, the removal rate approaches 90%. The effluent is limpid, and the turbidity is lower than 15 NTU. MLSS is 3000～4000mg/L, SV is in the range of 12～15%, SVI is in the span of 38～45mL/g. When the nutriment was not added, treating efficiency at first was good. But when the amount of wastewater reached 90% in the influent, treating efficiency became worse, SV low to 8% and...