Research On The Technology Of Filtering And Adsorption In Reclaimed Water Reuse

With the rapid development of thel economy and society, the demand of the minicipal water supply has been increasd dramatically, but water resouces are limitted, In the other hand, with more stringent wastewater discharge standards implementation, many waeterwater treatment plants have been unable to meet wastewater discharge standards, and the indicators of secondary treatment effluent are often too high, So it is urgent to find the technology which can improve treatment porcess and meet discharge standards and recycle wastewater . Therefore, the technologies of wastewater recyling have become the focus of WWTPS. This topic comes from international cooperation projects in Qingdao, "The Researchof WasteWater Recyling," and it is the part of the researcht.As a new technology of wastewater treatment, filtration and absorption can effectively achieve discharge standards of WWTPS, and meet the requirements of wastewater recyling (Miscellaneous Domestic Water Quality Standards, CJ/T48-1999). In the thesis, CODCr and ammonia (NH₃-N) are the main evaluation indexs. The best activated carbon was selected as the experimental material, and producing biological activated carbon filter material. Research on the effects of particle size of activated carbon, and activated carbon dosage, and adsorption time, and temperature and pH have been done, meanwhile, the study on the removal of CODCr. And the comparative experiment in the use of activated carbon (GAC), fiber ball and zeolite have been taken. At the same time, the activated carbon using as the carrier and they were produced into biological activated carbon (BAC), in the use of filtration of returned sludge from secondary sedimentation tank of WWTPS. Then the biological activated carbon was uased to filter the secondary effluent of coking wastewater and the secondary effluent of minicipal sewage .Coagulation and multi-stage filter were uesd to treat secondary effluent of minicipal sewage, and study the results of the effluent making the analysis of feasibility and economy.Experimental results show that the adsorption of the smaller particle size of activated carbon is better. If increasing dosage of carbon, removal rate of CODCr was increased, but the scale of increase rate was decreased, eventually leveling off. With the increase of adsorption time, removal rate of CODCr significantly increased, but after 30min the removal rate of CODCr slowed down and became more stable. Temperature and pH have little influence on the removal rate of CODCr. Concluded by examinations of the orthogonal experiments, the CODCr removal rate of the influences by the factors of the primary and secondary relationshipunder using actived carbon is: adsorption time > activated carbon dosage > size > pH. The optimum adsorption conditions are: activated carbon particle size of 0.071mm, dosage of 10.0g/L, adsorption time of 30min, pH of 6.Using the aeration filter of biological activated carbon (BAC), coking wastewater effluent was treated. The resuils show that the best adsorption time is 8h. Treaed by the BAC filter, the CODCr value of effluent is 45.60mg/L and the removal rate was 49.56%. NH₃-N is 5.41mg/L, the removal rate was 81.12%. The CODCr effluent and the NH₃-N effluent have reached the national water reuse standards (Miscellaneous Domestic Water Quality Standards, CJ/T48-1999). PH and temperature have little influence on the effect of BAC aeration filter column, so they can be ignored.Using the process of coagulation and multi-stage filtration, the secondary effluent of urban sewagen hasbeen treated. CODCr of the effluent is 30.20mg/L, NH₃-N is 8.54mg/L, and both reached the national standards of water reuse requirements. Using BAC aeration filter column, the secondary of urban sewagewas treated, and the treatment time is 8h. CODCr of the effluent is 32.50mg/L, NH₃-N is 7.84mg/L, and both reached national standards for water reuse requirements (Miscellaneous Domestic Water Quality Standards, CJ/T48-1999).