Water Quality Protection Technology Research Of Renewable Water Recycling System On Biological Activated Carbon Following Ozonation

The paper is aimed to remove the renewable water recycle process may beenriched pollutants by using Ozone bio-activated carbon （O₃-BAC） and “enhancedcoagulation+sedimentation+filter” process. Comparing with the two processes, wediscussed the mechanism of the enriched pollutants by each one, especially O₃-BACprocess on the degradation process of organic matter and remove mechanism in water.By preliminary experiments and the best removal of organic matter in secondaryeffluent, we determined the best dosage of ozone was2mgO₃/mgTOC, and theoptimum contact time was20min. According to the secondary effluent turbidity removalefficiency, we determined the best dosage of PAC was25～35mg/L about conventionaladvanced treatment. In these conditions, we contrasted analysis of the two treatmentprocess. The research shows that TOC average removal rate was17.97%by O₃-BAC,and the effluent after O₃-BAC was6.78. And effluent color was3degrees or so byO₃-BAC, which is more less than by conventional deep treatment（23degrees）.To the enriched pollutants that may exist in circulating water, we comprehensiveinvestigated the removal rate of pollutants by O₃-BAC after ozonation, activated carbonbed microbial degradation and activated carbon adsorption synergy, and analysis of theorganic matter change trend by quantitative and qualitative. The results showed that theproportion of polymer organic matter （molecular weight2000⁶000Da） wassignificantly reduced by ozonation; Low molecular organic matter was increasedespecially, and the molecular weight mainly concentrated in less than500Da（35.89%）and2000～3000Da（29.18）. The study found that the renewable water recycling in the wastewater treatmentplant influent nitrogen and phosphorus enrichment. To compare the two the two deeptreatment of nitrogen and phosphorus removal efficiency, we found that, when theammonia nitrogen （NH₃-N） concentration less than2mg/L, the average removal ofNH₃-N reached65%by O₃-BAC; when NH₃-N concentrations greater than2mg/L, theaverage removal of it was just about40%.Comparing the removal rate of NH₃-Nremained35%⁴5%by conventional treatment process. However, the O₃-BAC to totalnitrogen （TN） removal efficiency of nearly20%, and the conventional depth treatmentof TN removal rate in about10%. And the removal of total phosphorus （TP） was betterthan conventional advanced treatment by O₃-BAC.O₃-BAC process has good organic matter, color, nitrogen and phosphorus removalefficiency, and it is suitable for renewable water recycle water quality guarantee systemof sewage deep treatment.