| Iron-reducing bacteria(Iron-reducing bacteria, IRB) participates the process of dissimilatory Fe(III) reduction. Dissimilatory of Fe(III) reducing microorganisms widely found in nature, can take advantage of Fe(III) as a terminal electron acceptor, oxidized electron donor and obtain energy. Studies have shown that microbes alienation Fe(III) reduction process can not only participate in the cycle of iron in nature, and promote the removal of nitrogen and phosphorus,it has attracted widespread attention in recent years. Dissimilatory of Fe(III) reduction of microorganisms,can account for about 3% of the total amount of activated sludge microorganisms.Therefore, strengthen the dissimilatory Fe(III) reduction process can not only improve the efficiency of the sewage treatment system to remove a variety of pollutants but also can use product Fe(II) to improve phosphorus removal in wastewater treatment system,to achieve combination of chemical phosphorus removal and biological phosphorus removal. Carbon source as an important factor have an impact of iron reduction rate and the nitrogen and phosphorus removal. Studying the effects of Carbon source has important meaning for improving dissimilatory Fe(III) reduction efficiency, strengthening the activated sludge systems to remove nitrogen and phosphorus.Fe(III) reducing bacteria taken from the activity of oxidation ditch is cultivated under the condition of constant temperature in anaerobic environment.Then,the anaerobic activated sludge is inoculation sludge. The research need continuous monitor physical and chemical indicators of the reactor, to explore different carbon source and its concentration effect on activated sludge dissimilatory Fe(Ⅲ) reductive coupling with denitrification of nitrogen removal effect. At the same time, dissimilatory Fe(Ⅲ) reduction technology combined with anaerobic sequencing batch reactor, the reactor was investigated in the dissimilatory of Fe(III) reduction coupling denitrification and phosphorus. The following conclusions:(1) The ability of activated sludge dissimilatory Fe(III) reduction microorganism using different carbon sources are different. It is easier to use glucose,and methanol with.However, organic acid salt is more difficult to use. At the same time, the different carbon source for activated sludge alienation iron reduction also has effect on the synergy effect of nitrogen and phosphorus. Best denitrification effect is sodium acetate group, until the end of the reaction, the removal rate of ammonia nitrogen and total nitrogen were 98.61% and 98.05% respectively, iron reduction ability of glucose and methanol group, nitrogen phenomenon is not obvious.(2) Glucose as the carbon source, investigate the impact of three different glucose concentrations for activated sludge dissimilatory Fe(Ⅲ) reduction with removal nitrogen and phosphorus. The results show that the conditions of iron reduction rate of each concentration group were: high concentration(5.6mmol/L)>low concentration(2.8mmol/L)>blank(0mmol/L) under the same experimental conditions. But each concentration group performance is not satisfactory in terms of denitrification, until the end of the reaction, the residual volume of ammonia concentrations is 50mg/L. Phosphorus removal preformance better, the phosphorus concentrations of each concentration group have been reduced to 0.5mg/ L at the eighth day.(3) Acetate as the carbon source, investigate the impact of three different acetate concentrations for activated sludge dissimilatory Fe(Ⅲ) reduction with removal nitrogen and phosphorus. The results show that the conditions of iron reduction rate of each concentration group were: Blank(0mmol/L)> low concentration(4.2mmol/L)> concentration(8.4mmol/ L)> high concentration(16.8mmol/L)under the same experimental conditions. High concentrations of acetate suppression iron reduction process.the effect of various concentrations of although ammonia degradation is more thorough, the order in which they appear degradation is low concentrations prior to the high concentration group. Phosphorus removal rate was worse than glucose, but the phosphorus concentrations of each concentration group have been reduced to 0.5mg/ L at the tenth day.(4) Combined the dissimilatory of Fe(III) reduction technique with ASBR reactors, investigate dissimilatory of Fe(III) reduction capability with removal nitrogen and phosphorus. The results showed that the removal efficiency of CODcr and total phosphorus stabilized at around 90%, So it provides a new way of strengthening nitrogen and phosphorus removal for the sewage treatment plant. |
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