Study On The Rapid Start-up Technology Of Nitrogen-containing Wastewater By CANON Process

The CANON technology is a new high efficiency and low consumption biological nitrogen removal process,which requires only a single reactor to complete short-range nitrification and anaerobic ammonia oxidation,its unique advantages is widely popular.However,its requirements on external temperature,pH,alkalinity and other conditions are harsh,and the operation process is vulnerable.In particular,the long start-up time results in the slow and serious limitation of the engineering application.In this paper,the influence of alkalinity,load and dissolved oxygen on the fast start process of CANON technology was systematically studied within the appropriate range of temperature and pH conditions.To explore the conditions and methods for the formation and effective growth of granular sludge.The initiation method of carbon-nitrogen synchronous removal process was preliminarily explored.The main content is as follows:(1)In the first stage,the control method to gradually improve the alkalinity was adopted to explore the optimal operating conditions of CANON technology start-up.After 220 days of operation,the alkalinity gradually increased from 300 mg/L to 2000 mg/L.By controlling the concentration of dissolved oxygen,the removal rate of ammonia nitrogen and total nitrogen reached 98%and 80%respectively,and the volume load of nitrogen removal was 0.394 kg/(m3·d).The experiment shows that under the condition of 200 mg/L concentration of ammonia nitrogen in water,the key factor for fast start of CANON is to control the alkalinity of 1600 mg/L,and the concentration of nitrite in the system is always lower than 25 mg/L.(2)The second stage always maintain 1600 mg/L alkalinity,the research results of the first stage for validation.By controlling the air system and the nitrate nitrogen concentration is lower than 25 mg/L,system running 90 days,99%and 85%total nitrogen removal rate of ammonia nitrogen removal rate,the start-up speed is much higher than current level of common research.(3)In the third stage,under the condition of 1600 mg/L,the water inflow rate was increased by 1.5 times of the second stage,and the influence of increasing water inlet load on the formation speed of CANON system was discussed.The system can reach 97%ammonia nitrogen removal rate and 80%total nitrogen removal rate after 66 days of operation,and the volume load of nitrogen removal is 0.588 kg/(m3·d),indicating that the optimized inlet load can promote the start-up speed.(4)After the successful start-up of CANON in the first and second stages,the water inlet load was strengthened by gradually increasing the water inlet flow,and granular sludge was cultivated to increase the handling capacity.The two systems operate stably for 80 days,with the maximum nitrogen removal load reaching 1.188 kg/(m3·d),and the particle size of sludge reaching about 1200 um,with dark red color and decreased microbial abundance.The anaerobic ammonia-oxidized population accounts for 15.7%and 28.7%respectively,including Candidatus Brocadia,Candidatus Jettenia and Candidatu Kuenenia.(5)Finally,the removal of carbon and nitrogen by anaerobic-CANON combined method was studied.This technique is to explore the treatment of different carbon and nitrogen ratio wastewater and expand the application scope of this technology.