| The study of sulfur autotrophic denitrification has been developed in recent years, because of its no carbon source, simple equipment, easy operation, mild conditions and other characteristics. The sulfur autotrophic denitrification system has good nitrogen removal effect in the treatment of low C/N municipal sewage, but it has been rarely reported on the phosphorus removal study. In this thesis, the research mainly focused on two aspects:①In order to investigate the performance of nitrogen and phosphorus removal of the sulfur/limestone system from low C/N municipal sewage, a sulfur/limestone packed column reactor was constructed, which was fed with synthetic wastewater and operated in the way of anaerobic biological filter. The effects of HRT, pH, temperature, NO3--N and P on nitrogen and phosphorus removal was studied.②The effects of HRT, pH, temperature, NO3--N, NH4+-N, HCO3-,P and Mg2+ on the pyrite autotrophic denitrification system was studied. At the same time, performance of nitrogen and phosphorus removal of the pyrite denitrification system and the pyrite/limestone denitrification system were also studied respectively. The main studies include:(1) The results showed that the optimal HRT value was 6 h, and removal rate of TN and phosphorus was 100% and 44.64% respectively in the sulfur/limestone packed column reactor with influent of NO3--N 30 mg/L, PO43--P 15 mg/L. Initial concentration of NO3--N had significant influence on nitrogen and phosphorus removal. When the initial NO3--N was 60mg/L, the highest removal velocity of TN was 8.38 mg/L-h. Initial concentration of phosphate and initial pH had significant influence on nitrogen and phosphorus removal. In order to keep nitrogen removal rate higher than 90%, initial concentration of phosphate and NH4+ should not be below 0.4mg/L and 0.6mg/L respectively. The optimal pH value was 6.5 and removal rate of TN and phosphorus was 91.51% and 47.68% respectively. Temperature had a positive impact on that system and the nitrogen and phosphorus removal rate decreased with temperature decreasing. The nitrate removal efficiency was high in the temperature range of 18-30℃and the efficiency of phosphorus removal rate reached about 50%, when the temperature was between 25-30℃.(2) The pyrite denitrification system actually included the denitrification of T.d.a. using pyrite as sulphur source. With influent of NO3--N 80 mg/L, PO43--P 15 mg/L, the optimal HRT value was 7d. The removal rate of TN and phosphorus was 61.38% and 100% respectively. The optimum denitrification pH was not neutral. There were high removal rates at pH 3.5 and 8.5. The temperature had great effect on the pyrrhotite denitrification system and the optimal temperature value was 30℃. The nitrate removal was inhibited at high concentration of NO3--N and the highest removal velocity of TN was 4.71mg/L·d. The limiting concentration of NH4+-N was 2mg/L. The limiting concentrations of P and Mg2+ were 4mg/L and 0.2mg/L respectively. The pyrite denitrification system had a high removal efficiency of P. Using the tannery wastewater of Zhengzhou Plant as experimental wastewater, the residual NO3--N was 1.18mg/L after 6d and NO2--N was alway lower than 1 mg/L.(3) The results showed that the optimal HRT value was 6d and removal rate of TN and phosphorus was 86.12% and 43.65% respectively in the pyrite packed column reactor with influent of NO3--N 30 mg/L, PO43--P 15 mg/L. Initial concentration of NO3--N had significant influence on nitrogen and phosphorus removal. When the initial NO3--N was 30mg/L, the highest removal velocity of TN was 3.46mg/L·d. The concentration of P should not below 4.96mg/L in order to keep a high removal rate (>75%). The optimum pH and temperature of pyrite denitrification were 7.5-9 and 30℃. (4) The results showed that the optimal HRT value was 5d and removal rate of TN and phosphorus was both 100% in the pyrite/limestone packed column reactor with influent of NO3--N 30 mg/L, PO43--P 15 mg/L. Initial concentration of NO3--N had significant influence on nitrogen and phosphorus removal. At NO3--N 60mg/L or above, however, the nitrate removal was markedly inhibited. In order to keep nitrogen removal rate over 90%, initial concentration of phosphate should not be below 7.12mg/L. The optimum denitrification pH was not neutral. There were high removal rates at pH 5.11-10.62. Temperature had a positive impact on that system. The nitrate removal efficiency was high in the temperature of 30℃. The phosphorus removal efficiency have little relations with temperature. The pyrite/limestone system had a high removal efficiency of P. When the initial of P was 250mg/L, the phosphorus removal was still higher than 93.75%.(5) The sulfur/limestone, pyrite and pyrite/limestone packed column reactor had the performance of nitrogen and phosphorus removal from low C/N municipal sewage. The dephosphorization behavior correlated closely with autotrophic denitrification process and the mechanism of phosphate removal was chemical precipitation mainly. With influent of NO3--N 30 mg/L, PO43--P 15 mg/L, the order of the three system denitrification velocity was sulfur/limestone packed column reactor (the removal velocity of NO3--N was 8.38mg/L'h)> pyrite/limestone packed column reactor (the removal velocity of NO3--N was 5.93mg/L·d)> pyrite packed column reactor (the removal velocity of NO3--N was 3.53mg/L·d). The order of the three system phosphate removal velocity was pyrite/limestone packed column reactor (the phosphorus removal was about 100%)> pyrite packed column reactor (the phosphorus removal was about 70%)> sulfur/limestone packed column reactor (the phosphorus removal was about 50%).
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