The Research On Optimal Operation Parameters Of Cyclica Ctivated Sludge Technology In Hailin Wastewater Treantment Lant

In order to start and operate CAST wastewater treatment successfully, pilotexperiment was studied. Simulating the characteristics of the wastewater treatment,factors such as influent model, C/N，MLSS and sludge reflux ratio, temperature, pHvalue, DO concentration, sludge retention time(SRT), drain ratio were researched. Theresults and conclutions were analysed to guide the operation of the treatment. Duringthe operation period, effluent concentrations and removal efficiencies of the COD,ammonia and TP were investigated.(1) Removal efficiencies were influenced by different influent model, the effluentindexes could meet the GB18918-20021st level B when entering2h(aerobic2h)-sediment0.5h-discharge0.5h. And it can be firmed that stir can promote thedenitrification process.(2) The denitrification efficiency could be strongly influenced by C/N value. Andthe denitrification efficiency can be improved as the C/N value increased. However, toohigher C/N value inhibited the denitrification process. In this experiment, the C/N valuewas7. MLSS and sludge reflux ratio could also influence the removal efficiencies whenthey were2500~3500mg/L and20%respectively in this experiment.(3) Removal efficiencies werealso influenced by temperature and pH.Denitrification process could be enhanced when pH was alkalinity. Removal efficienciescould be improved as the DO concentration increased. In this experiment, the C/N valuewas3.5~4.5mg/L.(4) SRT could impact the accumulation of special microorganism, which had adirect influence on ammonia and TP removals.15days had been chosen in thisexperiment.Drain ratio not only reflected the treatment efficiency but also thecontaminate load. The ratio of0.3had been chosen in this experiment.(5) Keeping the DO concentration by controlling the aerobic, suitable sludgereflux ratio and low SRT had been taken to solve the sludge resing. Lots of foam wasemerged during the previous stage, effluent water was sprayed on the surface of thefoam and sequencing spraying with sodium hypochlorite of low concentration had beentaken. Meanwhile, SRT was controlled to meet the generation time of nitrifyingbacteria.Referring to the pilot results, wastewater treatment had been tested and operated.The effluent indexes were COD＜40.0mg/L, ammonia＜2.0mg/L、TP＜1.0mg/L,whichcould meet the GB18918-20021st level B.