Treatment Of Produced Water By Electrochemical Preoxidation & Rotating Biological Contactor

With the continuous improvement of Oil extraction technology, the increasing complexity of produced water components, direct injection or discharge will not only pollute the environment, but also cause great waste. Therefore, the oilfield produced water must be properly treated then reinjected or let.This text was based on oilfield produced sewage, first of all, by electrochemical preoxidation process to improve biodegradability of the sewage, inspected the electrolysis voltage, pH value, electrolysis time, plate spacing, the anode material, and the number of the anode plate on the decontamination effect.Using Orthogonal experiment design and single-factor authentication determine the best electrochemical preoxidation process parameters: electrolysis voltage 15V, pH 5, plate spacing 2.0cm, anode materials for the Ti/Ir dimensionally stable electrode, the anode is 2 board, under these conditions, the removal rate of COD achieve 61% after electrolyzing 30 min, SRB killing rate was 99.89%. The biochemical capacity of sewage treated and untreated was studied by BOD₅/COD_Cr and microbial respiration rate method. Both experimental methods show that the former produced water biodegradability is poor, and the electrochemical oxidation treatment can be the biological treatment of sewage, at the same time, on the basis of microbial respiration rate, the microbial reaction kinetics results show that under the experimental conditions microbial respiration rate are strictly abide by a kinetic relationship lnC(O) = lnC₀(O)-Kt.Then rotating biological contactors biofilm carrier - the surface of activated carbon was modified by the chemical oxidation method - Fe³⁺ coverage technology and HF treatment. In virtue of chemical analysis, analysis of surface morphology characterization studied the changes of surface morphology, surface groups, hydrophilic and specific surface area activated carbon treated.Contrasted the two methods to impact on film properties of rotating biological contactor. Activated carbon dealt with the two surface oxidation was cranked out disces of rotating biological contactorsΙandΠ.Using them to dispose the produced water of being pretreated by electrochemical oxidation.The results showed that the use of chemical oxidation-Fe³⁺ coverage technology modification of activated carbon have greater specific surface area, high levels of acidic functional groups, as well as better link hydrophilic The microbe phase are very abundant of the two rotating biological contactor after attaching biofilm, but the biofilm of II is much thicker and attaching rate is faster. The microbe content are 2.20×10⁹cfu/g, 2.60×10⁹cfu/g respectively, and the dried weight of biofilm are 12.7858g/m²,16.9096 g/m² respectively of the two rotating biological contactor.The COD removal rates of all the three-stages rotating biological contactor are above 80% with the disc speed of 4rpm, water temperature 20℃, HRT for 6h, pH 6 to 8, the highest level achieves 92.36%, and rotating biological contactorsΠis better thanΙ. Rotating biological contactors are always aerobic running. Also the results show that the electrochemical pretreatment united rotating biological contactors is much better than the separate use of rotating biological contactors on the removal effects. The COD content of sewage disposed is 65.8mg/L and reaches the second-grade standard of the national discharge.