Side Stream Phosphorus Removal And Sludge Reduction Technology In Anao Process For Wastewater Treatment

As the increasingly serious of eutrophication, the treatment of nitrogen andphosphorus in the sewage get more and more attention, our country put forward morestrict requirements of urban sewage treatment about nitrogen and phosphorus index. TheANAO (Aerobic/Nitrification/Anoxic/Oxic) technology development by our group cansolve the problem of nitrogen and phosphorus, it effluent water quality can fully meetthe relevant national standards. But in order to ensure the system end phosphorusstandards often need to emit a large amount of surplus sludge, large amounts of excesssludge emission will produce secondary pollution, take up a lot of land, disposal cost ishigh, it is particularly important to sludge reduction. Although the effect of some currentreduction sludge methods is obvious, and these methods effectively control the emissionof the sludge, the contradictions between sludge reduction and phosphorus removaloften lead to the phosphorus and nitrogen removal capacity of system decreased.To solve above questions, this article have combined the ANAO technology whichinvented by our group with the side stream phosphorus removal technology to get thegoal that sludge reduction. Firstly, this article carried out a comparative study of the twoside stream phosphorus removal technologies. Secondly, this article made a optimizeresearch to the separation tank of sludge and water. At the last, this article made a studyof sludge reduction of this system.Return sludge side stream phosphorus removal technology need to build the tankwhich to release phosphorus. As it will take two hours to release out the phosphorus ofsludge, it will take a large area to build the tank of release phosphorus. If we use themechanical method to concentrate the sludge, capacity of phosphorus release willdecreased. So the technology of return sludge side stream phosphorus removal is noteasy to apply. We should apply the technology that Phosphorus-rich supernatant sidestream phosphorus removal. Lime should be used as the chemical phosphorus removalagents of phosphorus-rich supernatant side stream phosphorus removal technology, limehad advantages such as: the utilization is high, the treatment effect is good, andrelatively low cost. The optimization program of water separation tank is to dischargethe sludge with the power which stir from an anoxic pool, at the same time, increasedthe floor filled with inclined plate, which the distance between plate is10cm. The SS ofsupernatant from water separation pool are less than10mg/L after use this program.The maximum sludge reduction of ANAO side stream phosphorus removal pilot systemis80%, at this time the average removal rate of TP is82%, and the TP is0.46mg/L, itreach the level of an A standard. The removal rate of NH4-N and COD has increased,there is no change about the removal rate of TN. It can meet the water qualityrequirements when the sludge reduction is80%. At this time, phosphorus release capability and COD removal capability of anaerobic pool has increased, thedenitrification capacity of anoxic pool has increased. Other processing units lessaffected by the reduction.