Feasibility Study Of High Salinity Wastewater Treatment By Biological Contanct Oxidation Process

High concentration of inorganic ions in high salinity wastewater can inhibit thegrowth and metabolism of microorganisms, leading to low biological treatmentefficiency. So the high salinity wastewater has been considered to be one of themost difficult problems in wastewater treatment. Biological contact oxidationprocess is a new type of wastewater treatment technology with some capabilities ofresisting impact load, high concentration of microorganisms, and without sludgebackflow. So this technology has been widely used in wastewater treatment.According to the design principle, a phase biological contact oxidation process wasdesigned with seawater used in this paper to study the feasibility of high salinitywastewater teatmment by this thechnology.ReactorⅠsarted up by inoculating activated sludge is used to treat the commonhigh salinity wastewater without refractory compounds. The biofilm domesticationwas implemented by increasing the proportion of seawater in inflent. After48daysthe reactor can run smoothly. The study about effects of temperature, HRT, andsalinity on treatment efficiencies showed that the high treatment performance couldbe achieved when the temperature was at25~30℃, HRT was7hours, and thesalinity was less than7%. The impact and buffer experiment showed that thebiological contact oxidation system can recover over4~5cycles if it encounteredshock of high organic loading or high salinity.Three bacteria have been isolated from the seawater of fishing port in Weihaiwhich was polluted by petroleum with enrichment and domestication methods,named CTE762-2, CTE762-5and CTE762-10. The degradation performance ofisolations had been studied, reaching90%or so under optimum conditions. Throughthe identification by16S rDNA, that three bacteria were identified to beOceanimonas sp., Arthrobacter sp., and Vibrio sp. preliminarily. In order to study thetreatment of hypersaline wastewater containing phenol, reactorⅡwas used toconduct the experiment using the seawater sample mentioned as original waterresources. After60days, the system can run smoothly. The phenol removal rateunder different conditions had been studied, showing that when the operationparameters and inflent quality were controled under optimum conditions, theeffluent could meet the discharge standard. According to the characteristics of thisprocess, Monod equation has been used to study phenol degradation kinetics modelin order to provide some theretical basis for practical wastewater with phenoltreatment.These two reactors had been used to treat the practical wastewater from wastewater treatment plant of QingDao, chemical plant wastewater in Shanghai andWeihai. The efflent COD and ammonia nitrogen were68.05mg/L and11.57mg/L ofwastewater treatment plant in Qingdao, the effluent COD of Shanghai chemicalplant was333.26mg/L, and the phenol, COD, and ammonia nitrogen of chemicalplant in Weihai were1.83mg/L,946.32mg/L,21.58mg/L respectively which allmet the industry wastewater discharge standard.The study on the treatment of nomal high salinity wastewater and high salinitywastewater with phenol shows that the biological contact oxidation process isfeasible in high salinity wastewater treatment, showing preference in high capabilityof resisting impact load and high treatment efficency.