Effects Of Tourmaline Enhanced SBR On Nitrogen And Phosphorus Removals And Microbial Community Structure

Municipal wastewater treatment plants in China are the main source of eutrophication in rivers,especially in winter.Therefore,the main way to solve eutrophication is to improve the treatment efficiency of Municipal wastewater treatment plants.At present,the problems have become the research focuses,including the way to improve the treatment efficiency of municipal wastewater treatment plants and the way to increase the stability of biological treatment process in winter.This project studied the characteristics of tourmaline on activated sludge and the effects of tourmaline on the start-up process and the running period of SBR reactor.The study contents included the performance of biological phosphorus removal system,biological nitrogen and phosphorus removals system,sludge characteristics and microbial community structure,and so on.This study solved the problems of high energy consumption,poor shock load resistance and low treatment efficiency at low temperatures in activated sludge treatment system.It is hoped that the principle of tourmaline bio-enhancement will be enriched and perfected,and the application and process development of tourmaline in sewage treatment will be explored.Firstly,the effects of tourmaline on start-up process of SBR at room temperatures were studied,and the effects of tourmaline on the removal efficiency of pollutants in typical cycle were studied.The results showed that tourmaline could shorten the start-up period of SBR and increase the removal rates of COD,SOP,NH₄⁺-N,NO₃^--N and TN in typical cycle after start-up process at room temperatures.The final effluent concentrations of COD,SOP,NH₄⁺-N,NO₂^--N and NO₃^--N were lower than 25 mg/L,0.3 mg/L,0.15 mg/L and 8.70 mg/L,respectively in each group.Secondly,the effects of tourmaline on the community structure and function of activated sludge were investigated.DGGE technology was used to analyze the community structures of bacteria and ammonia oxidizing bacteria?AOB?in activated sludge.The results showed that tourmaline could promote the species of AOB and increase the relative abundance of specific AOB by the analysis of the fingerprints of bacteria and AOB in activated sludge.However,tourmaline did not affect the biodiversity of each community significantly.The effects of tourmaline on the running period of SBR were further studied after adjusting the cycle,and the effects of tourmaline on the removal rates of SOP,NH₄⁺-N,NO₃^--N,NO₂^--N and TN in typical cycle were investigated.The results showed that the removal rates of SOP,NH₄⁺-N,NO₂^--N and NO₃^--N were accelerated by tourmaline particles in running period at room temperatures.At the end of aerobic stage,the formation rates of NO₃^--N were 2.43 mg/?g·h?in the test group and 1.99 mg/?g·h?in the control group,the oxidation rates of NH₄⁺-N were 4.34 mg/?g·h?in the test group and 3.93 mg/?g·h?in the control group,and the absorption rates of phosphate were10.73 mg/?g·h?and 10.04 mg/?g·h?,respectively.The effluent concentrations of NH₄⁺-N and TN in the test group were significantly higher than those in the control group,while the effluent concentration of SOP in the test group was basically the same as that in the control group.The final effluent concentrations of SOP,NH₄⁺-N,NO₂^--N,NO₃^--N and TN were lower than 0.3 mg/L,1.4 mg/L,0.12 mg/L,11.2 mg/L and 12.2mg/L in the test group respectively,and 0.3 mg/L,4.5 mg/L,0.12 mg/L,9.4 mg/L and13.2 mg/L in the control group respectively.The effects of tourmaline on the structure and function of microbial community in activated sludge were also studied.DGGE analysis showed that tourmaline had no effects on the community structure of bacteria and AOB in running period.Shannon index showed that the diversity of microbial communities were not changed in running period with tourmaline.The effects of tourmaline on the nitrogen and phosphorus removals were investigated in short-term period for preventing the deterioration of effluent at low temperatures.The effects of tourmaline on SOP,NH₄⁺-N,NO₃^--N,NO₂^--N and TN of SBR at low temperatures were investigated,and the effects of tourmaline on pollutants removal rates were investigated.The results showed that tourmaline could significantly reduce the effect of sudden temperature drop on effluent,including the effluent concentrations of SOP,TN and NH₄⁺-N in short-term period,and the effluent concentrations of SOP,TN,NO₃^--N and NH₄⁺-N in running period at low temperature.The final effluent concentrations of SOP,TN,NO₂^--N,NO₃^--N and NH₄⁺-N in the test group were 0.34 mg/L,14.01 mg/L,8.12 mg/L,0.08 mg/L and 5.81 mg/L,respectively.Tourmaline promoted the increase of nitrite accumulation rate,and the nitrite accumulation rate reached to 88.18%in the test group at the end of aerobic stage.On the basis of the above study,the effects of tourmaline on microbial community structure in short-term and running period were studied at low temperatures.The results showed that tourmaline changed the relative abundance of the dominant bacteria,while did not significantly change the dominant bacterial species at the levels of phylum and genera in short-term period at low temperatures.During running period at low temperatures tourmaline partially changed the dominant bacteria species at the levels of phylum and genera,and significantly changed the relative abundance of the dominant bacteria.The analysis of functional microorganisms at low temperatures showed that tourmaline reduced the relative abundance of GAOs,while had no significant effects on the relative abundance of PAOs,tourmaline realized short-cut nitrification by promoting AOB proliferation and reducing NOB proliferation,tourmaline promoted DNB proliferation by regulating FNA,tourmaline promoted DPBs proliferation by regulating carbon source and pH value.