Chemical-Physical Enhanced Biological Treatment Of Seasonal Heavy Polluted Huaihe Raw Water

It is essential to ensure the safety of potable water and improve the potable water quality forthe water treatment. While water source pollution is tending to become more and more serious,the drinking water source pollution has presented the unstable high-risk seasonal heavypollution characteristic because of the influences of seasonal change and pollution group fromupstream cities. Especially in winter, the conventional water treatment process can not ensurethe water quality because of the low water temperature and the high concentrations ofammonia nitrogen and organic pollution in water source. As a result, it has become animportant development direction for suiting the situation of our country to explore new watertreatment technology on the basis of traditional process to adapt the ceaseless water qualityand assure the good water quality.According to the Huaihe raw water with the unstable high-risk seasonal heavy pollutioncharacteristic, it was put forward to use the adsorption type filler biological reactor to removethe pollutants efficiently and completely, which constructing the chemicaladsorption-biological oxidation multiphase medium system on the surface of the filler, andusing the rapid response characteristic of adsorption effect, the environmental friendlyproperty of biological effect, meanwhile the substrate concentration of adsorption effect formicroorganism and the regeneration effect for adsorption. Through the adsorption andoptimizing test, the activated charcoal, zeolite and actived zeolite were selected as theexperiment materials to improve the treatment effect. This paper discussed the tests ofbiological activated carbon circulating fluidized bed （BACCFB）, strengthening ultrasonicenhanced biological aerated filter, and actived zeolite/carbon combination bed; researched thecontamination removal effects of the adsorption-biological reactors; probed the key influencefactors and determined the parameters for the transformation of water treatment plant.The activated carbon, natural zeolite and anthracite adsorption tests results showed thatthe active carbon adsorption effect was the best on organic matter, and natural zeolite had thebest adsorption efficiency for ammonia nitrogen. The activated carbon removal rates ofpermanganate index, UV254and ammonia nitrogen were respectively39.44%,53.46%and8.18%; natural zeolite were respectively11.28%,5.34%and56.18%, and anthracite wererespectively19.68%,10.21%and11.60%. Disussing the zeolite adsorption ammonia nitrogenkinetics characteristic, it corresponded with Freundlich isothermal adsorption equation, which wasQ=0.916C。^0.0385e e. The activated zeolite removal efficiency of contamination was betterthan the natural zeolite, the adsorption balance time was shorter, and the adsorption ammonianitrogen speed was faster.The results showed that the BACCFB process had a promising performance for theremoval of organic matter and ammonia nitrogen, but was not effective at the removal ofturbidity. It was observed that the average removal rates of permanganate index, UV254andammonia nitrogen were28.84%,27.86%and65.01%respectively. And, the pilot plant testresults showed that the average removal rates of permanganate index, UV₂₅₄, UV₄₁₀andammonia nitrogen were25.88%,27.78%,80.78%and62.88%respectively. The besthydraulic retention time （HRT） and air-water ratio of the BACCFB were45min and1:1. Theadvantages of this process included long using time of adsorbing material, high removalefficiency, better oxygen transfer efficiency, shorter the startup time, better resistanceperformance for shock loading and so on.The test results showed that the performance of the pollutants removed by thestrengthening ultrasonic enhanced biological aerated filter was excellent. The average zeolitebiological aerated filter （ZBAF）removal rates of turbidity, permanganate index, UV₂₅₄andammonia nitrogen were respectively71.36%、24.51%、9.27%and95.37%, anthracitebiological aerated filter （ABAF） were respectively69.80%,33.38%,25.86%and81.02%, andactivated carbon biological aerated filter （ACBAF） were respectively70.46%,49.87%,42.71%and90.89%. Appropriate hydraulic retention time （HRT） and air-water ratio had amajor influence on organic matter removal for ZBAF, and ammonia nitrogen removal forABAF. In this experiment condition, the best HRT and air-water ratio of the BAF are30minand1:1. The water temperature had certain influence on the treatment effect of BAF, but theZBAF showed a good ammonia nitrogen removal efficiency at low water temperature. TheBAF had a high resistance to shock loading, and the ZBAF had the best effect for theresistance to ammonia nitrogen loading. The ultrasonic had certain effect on the remocel ofpermanganate index and UV₂₅₄, but no effect on ammonia nitrogen. The combination processof strengthening ultrasonic enhanced biological aerated filter could improve effectively thepollutans treatment effect, the organic matter removel effect by which was better than theBAF process, but had no improving for ammonia nitrogen.The actived zeolite/carbon combination bed process had a good performance for theremoval of Huaihe raw water contaminants. When the inflow of the pilot scale was8m³/m²·h,the results showed that the average removal rates of permanganate index, UV₂₅₄, ammonia nitrogen and UV410were respectively90.78%,45.54%,49.37%,94.82%and89.54%. Thisprocess had a high resistance to shock loading. Appropriate backwash had little influence onthe treatment effect of zeolite/carbon combination bed, but the content of dissolved oxygen inwater had certain influence on the treatment effect.