UASB-MFC Coupling System Research On The Treatment Effect And Operation Characteristics Of High Ammonia Nitrogen Wastewater

The harm of high ammonia nitrogen waste water is high.Compared with other treatment methods,the treatment effect of biological method on ammonia nitrogen wwastewater was the best.In addition,the high ammonia nitrogen concentration in the high ammonia nitrogen wastewater will reduce the carbon and nitrogen ratio in the anaerobic system.In the process of microbial growth,a large number of carbon sources are needed.These carbon sources are partly oxidized by carbon dioxide in the process of microbial metabolism,and the other is used for the synthesis of raw biomass and transformed into protoplasm carbon.Therefore,the ratio of carbon and nitrogen is an important factor in the nutritional requirements of microbes.As an influencing factor,C/N can take part in bacteria productivity metabolism process,mainly in the process of microbial self synthesis,metabolism and organic transformation in microorganism.When a lot of ammonia in the anaerobic process,it is easy to product the anammox process,but need to nitrite in anaerobic ammox process,and the start-up process of ammox is very slow,so this study for treatment of high ammonia nitrogen wastewater in UASB,inhibit the anammox process by controlling the concentration of nitrite in the water of UASB-MFC,explore the treatment effect in the coupling system of high ammonia wastewater of different concentration and MFC electricity production performance.According to the experimental research and analysis of the subject,the following conclusions are drawn.1.The proper reduction of C/N can promote the degradation of organic matter.When C/N was reduced from 70 to 35 and 20,the COD removal rate was 83%and 84.3%from 65.42%and 67.42%,respectively.A certain amount of nitrogen was added to reduce C/N in a certain range,which was conducive to providing more balanced nutrients for microbial growth and making the anaerobic digestion system run better.But when the dosage was too large and the C/N was too low,the anaerobic digestion efficiency can be reduced by the inhibition of the high concentration of ammonia nitrogen on the growth of microbial flora.In addition,the reduction of C/N can promote the granulation of sludge.At the time of 30 day,R1 average particle size of granular sludge by 48.38?m increased to 587.36?m,while the increase of ammonia dosage for the sludge particle size change effect was more obvious,which was 20 C/N when the best effect,the average particle size from 46.38?m increased to run for 30 days when 1182.36?m.2.The reduction of C/N can promote the increase of total gas production and methane production in the system.C/N decreased from 70 to 50 and 35,and the methane production in the system increased from 1.59 and 1.45L/d to 4 and 5.11L/d,respectively.In the process of reducing C/N from 70 to 35,the amount of hydrogen increased gradually.When C/N was 70,the amount of hydrogen production increased from 202.71mL/d to 458.28mL/d during the anaerobic digestion for 30 days.When the C/N was reduced to 50,35,20,and 10,the hydrogen production increased by 271.08,388.61,621.41 and 586.14mL/d,respectively.3.The regulation of C/N can optimize the type of acid producing fermentation.in the process of reducing C/N from 70 to 35,the type of acid producing fermentation in the system was converted from propionic acid to acetic acid fermentation.And the total yield of volatile fatty acids in the anaerobic system could be inhibited by the reduction of C/N.In addition,C/N can regulate the oxidation-reduction potential of anaerobic digestion.When C/N was 70,it was basically kept at about-180V.When C/N=35,the redox potential in the system was reduced to-398V.It was indicated that in the process of reducing C/N from 70 to 35,the redox potential decreases continuously and helps the growth of anaerobic microorganism.4.Reducing C/N could improve the efficiency of MFC production.When C/N was 70,the MFC voltage rose gradually within 24 h,and then tends to be stable,the maximum voltage was 0.241V.When C/N was reduced to 10,the MFC voltage rose to 0.48V.The regulation of C/N can regulate the electrochemical properties of MFC.The internal resistance of MFC in R1 was 282?,obviously lower than 554?in R2 and 777?in R3;its Kulun efficiency was also lower than R2 and R3.It shows that MFC has the largest internal resistance in R3.At this time,the electricity generation was weak,and continues to decrease the C/N ratio.It was found that with the decrease of C/N ratio,the Kulun efficiency of MFC increased and the internal resistance decreased.