The Study Of Nitrogen Removal By Heterotrophic Nitrification And Aerobic Denitrification Bacillus Sp. AY01

Heterotrophic nitrification and aerobic denitrification(HNAD) is a new technology of biological nitrogen removal, it can remove carbon and nitrogen in wastewater simultaneously, and without adding additional carbon for the denitrification process, and the reactor can achieve a complete nitrification and denitrification process, and the ammonia will be discharged from the system in gaseous nitrogen compounds, thus overcoming the conflicts of in handling efficiency and economical aspects for the traditional wastewater treatment process, and nitrification and denitrification also produces acids and bases, and they can respectively be partially neutralize each other, thereby reducing to join the buffering agent, but there are some problems for HNAD technology, such as aerobic denitrifying process is difficult to consume completely the products from heterotrophic nitrification, which tends to lead to the accumulation of intermediates, which will difficult to control the operation process, and HNAD mechanism and high concentration of ammonia wastewater treatment also need to be further explored.In order to get HNAD strain to remove high concentration ammonia wastewater, a strain bacteria was isolated from sludge, and with the aid of morphological observation and the16S rDNA sequencing identification, the strain was proved and named, and the HNAD performance was proved through the experiments of aerobic and anaerobic, carbon and no carbon, cell and cell fluid, and the influence factors of carbon sources, C/N ratio and DO was investigated about HNAD strains, and explored high concentration ammonia wastewater HNAD properties and different initial high concentration of ammonia nitrogen wastewater degradation.The colony morphology was rod-shaped, Gram-positive, spores about isolated strain, and the16S rDNA maximum similarity was93%of Bacillus licheniformis SCD113020(JN998739.1), named as Bacillus sp. AY01. When the strain was cultivated in the initial ammonia concentration of600mg/L medium, ammonia degradation rates were14.90%and5.95%in aerobic/anaerobic conditions, ammonia degradation rates were96.59%and44.03%with carbon and non-carbon sources, ammonia degradation rates were99.80%and72.34%about cell/cell fluid, so AY01strain had the synchronous heterotrophic nitrification and aerobic denitrification performance. The main impact factors of strain AY01HNAD included organic carbon source, C/N ratio and the DO concentration, when cultivated at a temperature of30℃,120rpm conditions, sodium citrate had the maximum conversion rate of total nitrogen and it was99.44%, when the C/N ratio was10, ammonia degradation rate was97.30%, and when DO was50%, the maximum degradation rate of ammonia per unit time was46.67%. When strain AY01disposed of high ammonia nitrogen wastewater, the initial ammonia concentration was990.74mg/L, the ammonia concentration decreased to22.50mg/L after10days, the ammonia concentration decreased to minimum3.76mg/L after17days, so strain AY01able to synchronize HNAD removed efficiently high concentration of ammonia nitrogen wastewater and ultimately detectable ammonia concentration was low relatively, the original high concentration of ammonia nitrogen wastewater and1/2original high concentration of ammonia nitrogen wastewater degradation rates were99.21%and72.23%, so the initial concentration affected strains AY01degradation efficiency, it need to be considered to adjust timely initial ammonia concentration so that improving degradation efficiency.