In order to reduce the amount of NO_3^-–N generated by the Anammox process, and alleviate the competition between denitrification and Anammox for NO_2^-–N in a single reactor, the preference of S^0 for reacting with...In order to reduce the amount of NO_3^-–N generated by the Anammox process, and alleviate the competition between denitrification and Anammox for NO_2^-–N in a single reactor, the preference of S^0 for reacting with coexisting NO_2^-–N and NO_3^-–N in the sulfur autotrophic denitrifying(SADN) process and the coupling effect of short-cut SADN and the Anammox process were studied. The results showed that S^0 preferentially reacted with NO_3^-to produce NO_2^-–N, and then reacted with NO_2^-–N when NO_3^-–N was insufficient, which could effectively alleviate the competition between SADN bacteria(SADNB) and Anammox bacteria(An AOB) for NO_2^-–N. After 170 days of operation, coupling between short-cut S^0-SADN and the Anammox process was first successfully achieved. SADNB converted the NO_3^-–N generated by the Anammox process into NO_2^-–N, which was once again available to An AOB. The total nitrogen removal efficiency eventually stabilized at over 95%, and the effluent NO_3^-–N was controlled within 10 mg/L, when high NH_4^+–N wastewater was treated by the Anammox process. Microbial community analysis further showed that Candidatus Brocadia and Thiobacillus were the functional microorganisms for An AOB and SADNB.展开更多
An innovative advanced wastewater treatment process combining biologic aerated filter （BAF） and sulfur/ ceramisite-based autotrophic denitrification （SCAD） for reliable removal of nitrogen was proposed in this pap...An innovative advanced wastewater treatment process combining biologic aerated filter （BAF） and sulfur/ ceramisite-based autotrophic denitrification （SCAD） for reliable removal of nitrogen was proposed in this paper. In SCAD reactor, ceramisite was used as filter and Ca （HCO3）2 was used for supplying alkalinity and carbon source. The BAF-SCAD was used to treat the secondary treatment effluent. The performance of this process was investigated, and the impact of temperature on nitrogen removal was studied. Results showed that the combined system was effective in nitrogen removal even at low temperatures （8℃）. Removal of total nitrogen （TN）, NH4＋ -N, NO3-N reached above 90% at room temperature. Nitrification was affected by the temperature and nitrification at low temperature （8℃） was a limiting factor for TN removal. However, denitrification was not impacted by the temperature and the removal of NO3 -N maintained 98% during the experimental period. The reason of effective denitrification at low temperature might be the use of easily dissolved Ca（HCO3）2 and high-flux ceramisite, which solved the problem of low mass transfer efficiency at low temperatures. Besides, vast surface area of sulfur with diameter of 2-6 mm enhanced the rate of microbial utilization. The removal of nitrate companied with the production of SO42-, and the average concentration of SO27 was about 240mg.L^-1. These findings would be beneficial for the application of this process to nitrogen removal especially in the winter and cold regions.展开更多
Sulfur-limestone was used in the autotrophic denitrification process to remove the nitrate and nitrite in a lab scale upflow biofilter.Synthetic water with four levels of nitrate and nitrite concentrations of 10,40,70...Sulfur-limestone was used in the autotrophic denitrification process to remove the nitrate and nitrite in a lab scale upflow biofilter.Synthetic water with four levels of nitrate and nitrite concentrations of 10,40,70 and 100 mg N/L was tested.When treating the low concentration of nitrate-or nitrite-contaminated water（10,40 mg N/L）,a high removal rate of about 90% was achieved at the hydraulic retention time（HRT） of 3 hr and temperature of 20-25°C.At the same HRT,50% of the nitrate or nitrite could be removed even at the low temperature of 5-10°C.For the higher concentration nitrate and nitrite（70,100 mg N/L）,longer HRT was required.The batch test indicated that influent concentration,HRT and temperature are important factors afiecting the denitrification eficiency.Molecular analysis implied that nitrate and nitrite were denitrified into nitrogen by the same microorganisms.The sequential two-step-reactions from nitrate to nitrite and from nitrite to the next-step product might have taken place in the same cell during the autotrophic denitrification process.展开更多
基金supported by the National Key Research and Development Programme of China(No.2016YFC 0401103)the National Natural Science Foundation of China(No.51408387)the Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment
文摘In order to reduce the amount of NO_3^-–N generated by the Anammox process, and alleviate the competition between denitrification and Anammox for NO_2^-–N in a single reactor, the preference of S^0 for reacting with coexisting NO_2^-–N and NO_3^-–N in the sulfur autotrophic denitrifying(SADN) process and the coupling effect of short-cut SADN and the Anammox process were studied. The results showed that S^0 preferentially reacted with NO_3^-to produce NO_2^-–N, and then reacted with NO_2^-–N when NO_3^-–N was insufficient, which could effectively alleviate the competition between SADN bacteria(SADNB) and Anammox bacteria(An AOB) for NO_2^-–N. After 170 days of operation, coupling between short-cut S^0-SADN and the Anammox process was first successfully achieved. SADNB converted the NO_3^-–N generated by the Anammox process into NO_2^-–N, which was once again available to An AOB. The total nitrogen removal efficiency eventually stabilized at over 95%, and the effluent NO_3^-–N was controlled within 10 mg/L, when high NH_4^+–N wastewater was treated by the Anammox process. Microbial community analysis further showed that Candidatus Brocadia and Thiobacillus were the functional microorganisms for An AOB and SADNB.
基金Acknowledgements Authors thank the financial supports from the National Natural Science Foundation of China （Grant Nos. 51278489 and 51278143） and Program of International Science and Technology Cooperation （2010DFA92090）.
文摘An innovative advanced wastewater treatment process combining biologic aerated filter （BAF） and sulfur/ ceramisite-based autotrophic denitrification （SCAD） for reliable removal of nitrogen was proposed in this paper. In SCAD reactor, ceramisite was used as filter and Ca （HCO3）2 was used for supplying alkalinity and carbon source. The BAF-SCAD was used to treat the secondary treatment effluent. The performance of this process was investigated, and the impact of temperature on nitrogen removal was studied. Results showed that the combined system was effective in nitrogen removal even at low temperatures （8℃）. Removal of total nitrogen （TN）, NH4＋ -N, NO3-N reached above 90% at room temperature. Nitrification was affected by the temperature and nitrification at low temperature （8℃） was a limiting factor for TN removal. However, denitrification was not impacted by the temperature and the removal of NO3 -N maintained 98% during the experimental period. The reason of effective denitrification at low temperature might be the use of easily dissolved Ca（HCO3）2 and high-flux ceramisite, which solved the problem of low mass transfer efficiency at low temperatures. Besides, vast surface area of sulfur with diameter of 2-6 mm enhanced the rate of microbial utilization. The removal of nitrate companied with the production of SO42-, and the average concentration of SO27 was about 240mg.L^-1. These findings would be beneficial for the application of this process to nitrogen removal especially in the winter and cold regions.
基金supported by the National Natural Science Foundation of China(No.50808121)the Chinese National Key Projects of Water Pollution Control and Reclamation(No.2008ZX07106-2-2)
文摘Sulfur-limestone was used in the autotrophic denitrification process to remove the nitrate and nitrite in a lab scale upflow biofilter.Synthetic water with four levels of nitrate and nitrite concentrations of 10,40,70 and 100 mg N/L was tested.When treating the low concentration of nitrate-or nitrite-contaminated water（10,40 mg N/L）,a high removal rate of about 90% was achieved at the hydraulic retention time（HRT） of 3 hr and temperature of 20-25°C.At the same HRT,50% of the nitrate or nitrite could be removed even at the low temperature of 5-10°C.For the higher concentration nitrate and nitrite（70,100 mg N/L）,longer HRT was required.The batch test indicated that influent concentration,HRT and temperature are important factors afiecting the denitrification eficiency.Molecular analysis implied that nitrate and nitrite were denitrified into nitrogen by the same microorganisms.The sequential two-step-reactions from nitrate to nitrite and from nitrite to the next-step product might have taken place in the same cell during the autotrophic denitrification process.
