Achieving Efficient Nitrogen Removal From Coal Chemical Wastewater In A Combining Simultaneous Partial Nitrification,anammox Process With An Algal-bacterial Consortium In A Photo-sequencing Batch Reactor

Coal chemical industry is developing rapidly of China for adapting to the rapid economic development,however,due to the high ammonia nitrogen,high COD and low C/N characteristics of coal chemical wastewater,the water environment pollution caused by this has become an important factor restricting the development of coal chemical industry.The current treatment process is expensive,and the effluent ammonia nitrogen concentration is high,therefore a new suitable treatment is urgently needed.The establishment of algal-bacterial consortium for nitrogen removal process has attracted much attention because of free requirement of organic carbon source and oxygen.In this paper,research was carried out in a combining simultaneous partial nitrification,anammox process with an algal-bacterial consortium photo-sequencing batch reactor fed with simulated coal chemical wastewater,the influence of illumination conditions and inoculation conditions on nitrogen removal was explored,investigated the performance of reactor running under high influent load.Finally,the microbial population structure of different stages was analyzed.The results showed that:(1)The influent ammonium concentration 100 mg/L,temperature 30±2?,pH 7.5~8.5,hydraulic retention time 24 h,the batch experiment results showed that when the initial intensity 4000 lux,illumination time 12h:12h,ammonia nitrogen removal rate was 92.58%,and the nitrate nitrogen maximum generation was 49.75 mg/L,the cumulative rate was68.93% in algal-bacterial system.(2)The effects of nitrogen removal in the reactor with different inoculation conditions were compared,and the effect of nitrogen removal was the best when the order of inoculation was: aerobic activated sludge,chlorella,anaerobic granular sludge.(3)After 97 days,the combining simultaneous partial nitrification,anammox process with an algal-bacterial consortium was successful started-up,with influent ammonium concentration 100 mg/L,temperature 30±2?,pH 7.5~8.5,hydraulic retention time 24 h,by adjusting illumination intensity to 3000 lux and illumination time 12h:12h.The ammonia nitrogen removal rate was stable above 85%,the total nitrogen removal rate was about 70%.(4)When the ammonia nitrogen in influent increased to 200 mg/L,the ammonia nitrogen removal rate was over 82%,the total nitrogen removal rate was about 68%.When theammonia nitrogen in influent increased to 300 mg/L,the ammonia nitrogen removal rate was about 85%,the total nitrogen removal rate was about 70%,reaching 75.25% at the highest.(5)High-throughput sequencing results showed that,the difference of microflora in different stages was obvious,and the microflora showed obvious succession.The analysis results of functional microflora showed that,when the dissolved oxygen content is high,NOB is the dominant bacteria in PN reactor.The reactor can not only maintain high ammonia nitrogen removal rate while can also ensure good nitrate nitrogen cumulative effect,AOB became the dominant bacteria.A large number of Planctomycetes which is belonging to anaerobic ammonia oxidizing bacteria were detected in MA-PN-ANA stage indicating occurring ANAMMOX.The characteristics and changes of microbial community structure in the reactor were confirmed by the analysis results of experimental data.