Research On Hydrolysis Of Particulate Organic Matter And Influence On Nitrogen Removal Efficiency In The Denitrification Process

Aiming at the problem of the lack of carbon source in the process of removing nitrogen, particulate organic compounds as electron donor role is gradually paid more attention.Based on the basic principles of denitrification reaction, the hydrolysis process of particulate organic carbon source in the denitrification reaction is researched and the impacts of particulate organic carbon source on the removal process of nitrate are analysed in this paper, providing the theoretical basis for the rational use of particlate organic carbon source.The results show that:(1) During the denitrification process with the attendence of particulate organic matter, the contribution degree of particulate organic matter into dissolved organic matter is affected by the initial concentration of nitrate nitrogen, and nitrate nitrogen concentration is the main cause of the fluctuation of dissolved organic matter concentration.Compared to the reaction process that does not contain particulate organic matter, when the carbon-nitrogen ratio are 10.84 and 6.21, the concentration variation rate of dissolved organic matter are decreased by 55.88% ane 31.75% in turn; when the carbon-nitrogen ratio is 3.32, the concentration variation rate of dissolved organic matter is increased by 59.38%.(2) During the denitrification process with the attendence of particulate organic matter, the change trend of dissolved organic matter performances consistently in different ratios of carbon to nitrogen. The concentration of dissolved organic matter decreases significantly in the first hour, then reaches the highest value in second or third hour moment, in the end remaines stable or slowly downward trend. In the system of only using particulate organic matter as carbon source for denitrification reaction, the overall concentration of dissolved organic matter in the water is increased.(3) Particulate organic matter in the urban sewage water has a great influence on the nitrate nitrogen removal process of denitrification, when the carbon nitrogen ratios are respectively 10.84,6.21 and 3.32, increasing percentage of nitrate reduction rate is respectively 65.02%, 60.94% and 73.60%.(4)In the denitrification process of particulate organic compounds as sole carbon source, microorganisms can utilize the hydrolysis dissolving organic matter, and the denitrification reaction can be carried out smoothly. In the meanwhile,the removal effect of nitrate nitrogen is obvious. When the carbon-nitrogen ratio are 11.20,6.63,3.21 in turn, nitrogen removal rates are 66.64%,31.03% and 21.32%. But keeping the nitrogen removal rates steady state needs longer reaction time, and the accumulation rates of nitrite nitrogen are 18.08%,13.59% and 8.80%.(5) In the different conditions of carbon-nitrogen ratio and reaction ratio, the contribution rate of particulate organic matter into the dissolved organic matter is obviously different. The best dosing ratio of particulate organic matter is 90% when carbon-nitrogen ratio is 10, the best dosing ratio of particulate organic matter is 50% when carbon-nitrogen ratio is 6, the best dosing ratio of particulate organic matter is 50% when carbon-nitrogen ratio is 3.