Study On The Step-feed Characteristics Of The Nitrogen And Phosphorus Removal By SBR And Use In Municipal Wastewater Treatment

Effect of and factors having influence on biological removal nitrogen and phosphorus were studied during the experimental treatment of urban wastewater by SBR, because removal of nitrogen and phosphorus both demand carbon. But carbon not enough for nitrogen and phosphorus removal, at the same time, some wastewater treatment plant waster carbon which dissolved in the wastewater.This paper studied of step-feed carbon in different time (at the beginning of A/O and A/A) how can it affect removal of nitrogen and phosphorus of characteristics. It trying to use the step-feed resolve carbon unsatisfy the demand of nitrogen and phosphorus removing, then improving effect of nitrogen and phosphorus removing. And using the same way to study how can it work in the Xi'an wastewater treatment plant. The experiment results as follow:1. Step-feed in SBR for removal phosphorus concluded the following results: The ploy-phosphorus can meet the demand in the municipal wastewater activity sludge system treatment. Only 30% of the full carbon of the wastewater can be meet the phosphorus removal. At anaerobic input 30% carbon and aerobic input 70% carbon, the phosphorus release and uptake only need 45 minutes. But input 100% carbon at the anaerobic, the phosphorus release and uptake need 75 minutes. The phosphorus release 1mg at the anaerobic can uptake phosphorus 1.47mg at the aerobic.2. Step-feed in the SBR for studying DPB shows the following: It can be found DPB in the wastewater treatment. It can save carbon. The efficiency of DPB removing nitrogen and phosphorus are bond with consistency of nitrate-nitrogen. The rate of de-nitrification and phosphorus removing is 17.14%~37.82% when nitrate-nitrogen consistency is 6.6mg/L. The rate of de-nitrification and phosphorus removing is 31.52%~69.59% when nitrate-nitrogenconsistency is 19.8mg/L.3. Step-feed in SBR of municipal wastewater remove nitrogen and phosphorus concluded the following results: In SBR, the rate of nitrogen removal is 53%~67% when the full wastewater input SBR at once time. But make use of reasonable distribute carbon, the rate of removal nitrogen and phosphorus effect both advance. The rate of removal nitrogen is 83%~91%, and total phosphorus consistency in the outlet treated wastewater less than 0.5mg/L. DO concentration in the activity sludge system more than 2mg/L at the aerobic. The rate of ammonia-nitrogen nitrifying evidently slow down. The most of nitrate is that nitrite-nitrogen become nitrate-nitrogen. DO concentration in the activity sludge system higher than this can lead to energy waste. So DO concentration about 2mg/L can do work in the wastewater treatment.4. Basing on the results of the experiments, we put forward of utilizing step-feed and de-nitrification and phosphorus removal by DPB to improve the efficiency of nitrogen and phosphorus removal, resolving the lower efficiency of nitrogen and phosphorus removal, uncompleted de-nitrification which caused by the unreasonable distribution of carbon. By this way we meet the anticipated aim.