Effect Of Two-sludge SBR Short-range Denitrifying Phosphorus And Nitrogen Removal

There are so many shortcomings that the nitrogen and phosphorus removal can not be carried out smoothly,including two aspects:both denitrification and phosphorus release consume carbon, in inadequate conditions, denitrification and phosphorus release bacteria compete carbon source with each other, leading to the failure of denitrification and phosphorus removal^[1]; and phosphorus removal bacteria need to achieve phosphorus removal through excluding the sludge, the SRT is shorter, while the generation time of nitrifying bacteria is longer, excluding the sludge too often will make a huge loss of immature nitrifying bacteria. For these reasons, the ideal nutrient removal process should provide enough carbon source for denitrifying bacteria and phosphorus release bacteria, and make the nitrifying bacteria and PAOs grow independently to solve the competition on matrix and SRT^[2]. Short-range two-sludge SBR nutrient removal technology is a new technology developed on the basis of traditional biological nutrient removal technology that can effectively solve these problems.The experiment can provide technical basis for practical application of the two-sludge system through studying the best operating conditions and the treatment effect of continuous operation .The test used simulated domestic wastewater as the research object, and adopted two-sludge SBR reactor to make a study of pollutant removal efficiency. First the test obtain nitrification bacteria and bacteria which use NO₂-N as the electron acceptor through separate acclimation,and then make the study of nitrification and denitrification phosphorus removal effects and the accumulation mechanism of bacterial nitrification through reactor test and static test,finally, investigating the effect of phosphorus and nitrogen removal of the two-sludge SBR process by running continuousUsing a separate method of acclimation, after 47 days and 107 days acclimation,nitrification bacteria and denitrifying phosphate accumulating bacteria which use nitrite as electron acceptor can be obtained.In the aerobic reactor,the ammonia removal and nitrification rates were up to 96% and 95%,seperately;Hypoxia effluent phosphorus concentration of denitrifying removal reactor was up to 0.4mg/L.Studying NO₂-Naccumulation and factors with the method of intermittent aeration. The result showed that the temperature at 25℃, pH = 7.5, DO <1.0mg / L, NO₂-N accumulation has the best effect. After a period of stable operation, the NO₂-N concentration of effluent can reach 24mg / L.Study of factors of DPB used NO₂-N as the electron acceptor showed that, anoxic phosphorus uptake had the best effect in COD concentration of 150mg / L, phosphorus removal rate reached 96%; system best C / N should be controlled at around 3.3, when PO₄^3- average removal reached about 89%; the best MLSS should be 3000mg / L or so,with the SRT of 12d. Studying the SBR nitrification and denitrification and phosphorus removal system with simulated domestic wastewater found that with the influent COD of 100-150mg / L, NH+-N concentration of 90-110mg / L, PO₄^3- concentration of 5-8mg / L, the average removal rates were up to 85%, 93.24%, 91.56% seperately, the whole process run stably.Two-sludge SBR nitrification and denitrification nutrient removal process achieve "one-carbon dual-use", solving carbon source competion between denitrifying bacteria and PAOs in traditional biological nitrogen and phosphorus removal technology;Separating the nitrification bacteria and denitrifying phosphorus removing bacteria solved the problem of sludge age contradictions. Two-sludge SBR technology can effectively improve the defects and deficiencies of the traditional process , improve the treatment efficiency, reduce footprint and reduce costs, possessing good practical value and significance.