Application Research Of Mbr In Refining Sewage Depth Processing

Petrochemical refining sewage is seriously polluted and difficult to process, and the processing technology of some companies lags behind relatively in our country, so the effluent water quality is poor, and reuse of wastewater by deep processing is very difficult. MBR, a kind of new sewage treatment technics combining biodegradation and efficiency intercept effect of membrane, has many advantages, such as strong ability to resist impact load and good outlet water quality, which provides a possible method for reuse of wastewater by deep processing in the petrochemical refinery. Based on the condition of wastewater discharge in some company, MBR was used as deep treatment technics to take processing pilot test to three kinds of water quality (general oily water, high concentration oily water and alkaline water), to examine whether the effluent met the requirements for reuse as circulating cooling water. Meanwhile through the test, suitable membrane flux was determined and the chemical cleaning effect of the membrane was evaluated.Test results showed that for the general oily water, after fully preprocessing and MBR deep processing, the effluent turbidity average was0.05NUT, the ammonia nitrogen average was0.2mg/1, COD average was43mg/1, concentrations of volatile phenol was0.05mg/1, the average content of oil was1.27mg/1, and all these indicators met the requirements for using in circulating cooling water system. For high concentration oily water, due to the effects of high oil content of sewage, the ammonia nitrogen content of MBR effluent fluctuated and excess standard seriously. For alkaline water, due to its poor biodegradability, even if the pretreatment was enhanced, the removal rate of COD was very low, and the COD content of effluent did not meet the requirements of recycling after MBR deep processing. The experimental results indicated that it was feasible to reuse the general oily water as cold water filling water after MBR deep processing. In the operation, fully preprocessing was very necessary, which could not only enhance the impact resistance of the whole system, but also mainly removed substances harmful on microbe in petrochemical refining sewage, such as volatile phenols, ensuring good operation of the MBR system. However, high pollution wastewater, such as alkaline water, was not suitable to recycle in the processing.Test results of membrane flux demonstrated that, in the processing of petrochemical refining sewage, the integrated membrane bioreactor was used, with microfiltration membrane of0.1μm, and the suitable membrane flux was20L/m2.h. Chemical cleaning test results showed offline cleaning was superior to the online cleaning, and NaClO reagent had the best cleaning effect in the offline cleaning.