Pilot On Enrichment Of High Activity Nitrification Sludge And Nitrification Enhancement

Membrane bioreactor(MBR)pilot device was used to enrich nitrifying sludge with urban sewage after pretreatment and ammonium sulfate,the influence of such factors for enrichment of nitrifying bacteria such as :the temperature,DO,ammonia and COD volume load volume,free ammonia were studied.The production of nitrifying bacteria was calculated through two methods(kinetic method and maximum specific consumption rate method)during two sludge discharge stages and the cost of nitrifying sludge enrichment was also calculated.The effect of nitrification sludge on the recovery of high ammonia and high temperature was studied,The variation of population abundance and enrichment factors were studied by high throughput PCR sequencing.The experiment results show that:The max nitrification activity of MBR pilot device was 98.41 mg·(L·h)-1;When SRT = 20 d,the average nitrification activity could be stabilized at 72.39 mg·(L·h)-1;The cost of enrichment of nitrifying sludge per kilogram is 3.52 yuan;Two methods were used to calculate the yield of nitrifying bacteria in the two stages during the enrichment process.The results were 14.96 mg nitrifiers·(d·L)-1,12.35 mg nitrifiers·(d·L)-1 and 18.85 mg nitrifiers·(d·L)-1,21.72 mg nitrifiers·(d·L)-1.The pilot study on the impact of high ammonia showed that the addition of 2% enriched nitrification sludge could restore the pilot scale nitrification system with good effect.After 48 h,the removal rate of ammonia nitrogen was reduced from 29.4% to 83.2%.;The high temperature impact test showed that the addition of nitrifying sludge has a good effect on the recovery of the system,there was a positive correlation in recovering the collapse of nitrifying sludge which caused by high temperature and high ammonia impact.The bacteria(Proteobacteri)and Bacteroides(Bacteroidetes)were the dominant bacteria in all the samples,and the content of them was about 90% of the total bacteria.In the enrichment process,nitrification bacteria rich up to 17.44%,but its large fluctuations,and little correlation in nitrification activity;effects of various environmental factors under the same genus correlation variations between different species and different environmental factors.