The Screen Of High Efficient Nitrogen And Phosphorus Removal Strain And The Evaluate Of Application Potential In Wastewater Treatment

In this study,denitration and phosphorous removal strains were screened from the activated sludge which used in the sugar refinery waste water.According to the results of preliminary screening and secondary screening,two strains with excellent performance in denitrification and phosphorus removal were selected,and they were named LY-3 and ZL-6.In order to further understand the characteristics of the two strains,bacteria morphology observation and physiological and biochemical characteristics analysis were carried out,and LY-3 and ZL –6 were preliminary determined as bacillus.To further determine the strain classes,molecular biological technique was used(16SrDNA),compared with blast and build the evolutionary tree,two strains of bacteria was determined: LY-3 was Bacillus cereus,and ZL-6 Bacillus megaterium,respectively.In order to further determine the growth curves of 2 strains and its characteristics of nitrogen and phosphorus removal,we systematic studied the LY-3 and ZL-6 strains respectively.LY-3 strain’s corresponding nitrogen removal ability are relatively weak in lag phase.After the strain grew into the exponential phase,the efficiency of removing nitrogen has been increased rapidly.And its denitrification ability reached maximum which the total nitrogen removal rate reached at 94.42%,when the pH of 7,temperature of 35℃,8% inoculated quantity,speed is 210 r/min;For the strain ZL-6,when the pH is 8,temperature is 32 ℃,phosphorous removal ability reached maximum which the total phosphorous removal rate reached at 94.87%,when the pH of 8,temperature of 32℃,8% inoculated quantity,speed is 210 r/min.We simulated treatments system under the aerobic condition.In this experiments,we used several different methods with strains,sludge and mixture to processed sewage,and COD removal rate,total phosphorus rate and total nitrogen rate were compared,finally,we determined an solution,that is LY-3 + ZL-6 + sludge.Under this solution,the removal rate of COD,total nitrogen removal rate and total phosphorus rate were 78.0%,82.61%,83.75%,respectively.we also studied the load resistance under the high COD contents with this solutions,and it was found that the sludge still have a strong ability of denitrifying and phosphorus removal capacity under the high COD conditions,and it will have a broad application prospect.