Immobilization And Performance Of Aerobic Denitrification Bacterum

In recent years, people pay more attention to environmental issues, the sewagetreatment plant effluent quality requirements gradually increased, which cause thenew biological technology of wastewater treatment becomes a hot research area.This article focused on new biological nitrogen removal technology-aerobicdenitrification technology and combined microbial augmentation of aerobicdenitrificans and immobilization technology to solve the problem of aeribicdenitrification bacterium easily loss and difficult to be dominant flora when appliedas engineering microbial agents. The main purpose is to find the efficient carrierfor aerobic denitrificans and enhanced the performance of SBR base on aerobicdenitrificans immobilized and microbial physiological characteristics to achievemore efficient and stable performance of simultaneous nitrification anddenitrification. The future application of the theory is to further improve aerobicdenitrification technology system and provide theoretical support for processapplications.The aerobic denitrificans named T13can not only use nitrate through aerobicdenitrification but also ammonia through heterotrophic nitrification simultaneously.In addition, T13has the excellent removal efficiency of nitrate which is up to98%,and when there is sufficient organic carbon in the enviroment the removal rate ofammonia could be very high. However, since the accumulation of nitrite, theremoval efficiency of TN is only22.5%. The initial nitrate concentration androtating speed are the key factors that affect the accumulation of nitrite in aerobicdenitrification process.The TN removal efficiency of T13was increased successfully by11.1%,11.9%and25.8%and the nitrate removal rate as high as90%which was achievedthrough immobilizing by mycelial pellets, polyurethane foam and sodium alginatemixed activated carbon respectively. The reason is immobilization eased theproblem of the accumulation of nitrite, since the carrier can repress the transfer ofdissolved oxygen. Moreover, the immobolized carriers could provide protection toT13under weak acidic or low temperature condition, and the optimal aerobicdenitrification conditions of T13immobilized were30℃, pH=7and100r/min.However, due to the weaker mechanical strength of sodium alginate mixedactivated carbon carrier and longer immobilization period of polyurethane foam,mycelial pellets was choosed to be the best carrier for aerobic denitrificans.More stable aerobic denitrification was achieved in SBR enhangced bymycelial pellets immobilized T13, and the TN removal efficiency was increased to 49.81%under the condition of C/N=7, pH=7and DO=2mg/L. A/O-SBR enhancedby immobilized T13not only ensured the high COD and ammonia removalefficiency, but also maintained the higher TN removal efficiency rate of77%,average removal rate increased by22%. Based on the analysis of microbialcommunities by DGGE, mycelial pellets immobilization T13can persist long-termstability in the system to become dominant species, which successfully overcomethe problem of free state agents easily drained during strengthening process.