| Excess emissions of nitrogen and phosphorus is the main reason to cause eutrophication. As the water body eutrophication have became extremely prominent and the effluent discharge standards are becoming strict, wastewater treatment technology is gradually removed from one stage that removing organism to another stage that simultaneously nitrogen and phosphorus removal. The research on the nitrogen and phosphorus sewage treatment in order to control eutrophication has become one of the focus in the world. At present, the disadvantage of high energy consumption, low efficiency and unstable operation have existed in sewage treatment plant for nutrient removal normally. Therefore, no matter from saving money, improving water quality, or from the stability of operation effect as well as upgrading and reconstruction of sewage treatment plant, developing new carbon, nitrogen and phosphorus synchronous removal equipment, improving the traditional biological nutrient removal efficiency are of great significance at this stage.Biofilm-granular sludge coupling reactor is a double-sludge system that combines suspended biofilm with granular sludge water treatment technology (Patent application NO.201110293470, Publication NO.102372362A). The nitrifying bacteria are set in biofilms and placed in aerobic zone above the baffle, while denitrifying phosphorus bacteria which are rich in granular sludge are placed under the baffle. Nitrate produced in the nitrification process are used for denitrification and phosphorus removal as electron acceptor. The separation of them can resolve the competitive contradiction in the traditional process. Besides, the nitrifying biofilm and denitrifying phosphorus bacteria live in their respective environment, making selection according to the SRT operational requirements of biological membrane and nitrification and denitrification phosphorus bacteria, and have more conducive to high efficiency, stable of nitrogen phosphorus removal system.Sewage flows goes through the different regions of the coupling process in turn, from anaerobic,aerobic anoxic process in sequence.Thus completing the removal of nitrogen, phosphorus and other organic matter. The integration design of the craft has save floor space, simplify the process, shorten running time, reduce energy consumption and especially suit to disposing low C/N ratio of urban sewage.Through domestication,60cycles can be hung on the denitrifying bacteria in the suspended carrier film success. After the domestication, NH4+-N concentration is1.32mg/L water, the removal rate is as high as95.65%, effluent NO3--N concentration of19.14mg/L, is gradually activated sludge and suspended carrier surface closely. With flocculent sludge for the inoculation sludge, the use of three phase concentration strategy, successful enrichment of denitrifying phosphorus removal granular sludge, phosphate, ammonia nitrogen and COD removal rate is gradually increased, the trial period, are stable at more than90%. Adopt the method of instantaneous water test study of process and different nitrogen oxygen zone volume load/diminishing nitrogen volume load. For good/anaerobic zone volume proportion of inflow method was improved, forming biofilm/granular sludge coupling process after improvement, the improved coupling process of carbon nitrogen and phosphorus removal is the most has improved to a certain extent, COD and P, the removal rate of NH4+-N and TN increased respectively16.68%,26.10%,19.45%and19.64%.When the HRT for8h, the phosphorus release rate and phosphorus absorption rate is highest,0.47and0.97mg P/g SS/h, the largest carbon source utilization, denitrifying phosphorus removal efficiency is the most stable. When air were0.2,0.1and0.05m3/h, the removal rate of ammonia nitrogen by81.03%,74.42%and70.34%respectively, and the ammonia oxidation rate, on average,1.63,1.48and1.41mg/g N ss/h, according as the decreasing of oxygen, is significantly lower on PO43--P removal rate,80.40%,75.22%and69.19%respectively, the denitrification rate were1.04,0.92and0.81mg/g N ss/h, P uptake rate were1.00,0.94and0.89mg P/g ss/h. Temperature on the anaerobic phosphorus release amount and COD removal effect is not obvious, low temperature (20℃) did not worsen denitrifying phosphorus release effect. At20℃,28℃and33℃temperatures, the coupling process of ammonia nitrogen removal efficiency of76.09%,81.57%and83.07%respectively. Effluent concentration of phosphate were2.37,2.37and2.03mg/L, and anoxic phosphorus uptake were14.49,15.00and14.94mg/L. As temperatures rise, denitrifying phosphorus removal efficiency gradually decline,20℃denitrifying phosphorus removal efficiency, the largest is0.93mg P/mg NO3--N.Choose different carbon source (glucose and anhydrous sodium acetate), the coupling process of the removal rate of COD were77.23%and83.58%respectively, the removal rate of phosphate were59.91%and71.22%respectively.Compared with conventional nutrient and phosphoru removal process, biofilm-granular sludge couplling process with saving floor space, reduce energy consumption, process simplicity, and high pollutant removal, which seek for our economy, efficient and viable the new wastewater treatment process, water quality improvement and maintaining ecosystem balance providing new ideas and perspectives. |
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