Study On The Nitrogen Removal In The Treatment Of Sanitary Wastewater By Hydrolysis-Biological Aerated Filter

The usual type of municipal wastewater treatment is active sludge treatment. But the outplays of construction and running are huge, and the result of N,P removal is unsatisfactory. The treatment of Hydrolysis-acid—Biological Aerated Filter in municipal wastewater is discussed in this paper. With a small scale test, analyzing the water quality indexes in the influent and effluent, the theory and main affecting factors of pollutants removal are discussed. The kinetic relation of the Biological Aerated Filter is obtained.The main results are summarized as follows:1. The proposed hydraulic loading of the up-flow Biological Aerated Filter in treating municipal wastewater is 2.0m3/m2·h, the corresponding HRT is 0.75h, under this hydraulic loading, the removal rate of COD,NH4+-N and TN are respectively above 83.1%,75.9% and 37.3%. The effluent concentration could be respectively controlled below 30.5mg/L,7.8mg/L and 31.2mg/L.2. The simultaneous nitrification and denitrification rate of the up flow Biological Aerated Filter is about 25%.3. The rate of COD removing can reach 50% by hydrolysis and hydraulic retention time of hydrolysis pond, recycling ratio, nitrification of Biological Aerated Filter can affect the efficiency of denitrogenation. Efficiency of dephosphorization has been kept at a low level.4. Using the process of Hydrolysis-acid—Biological Aerated Filter and though recycling the effluent to the hydrolysis pond to undergoing denitrification, when the quantity is 0.054 m3/h and the recycling ratio is 300%, the removal rate of TN can reach 80%, the corresponding effluent TN is bellow 6.5mg/L , far low than when there is no recyling to the hydrolysis pond.5. Using the process of hydrolysis-acid—biological aerated filter to treat municipal wastewater, a better effluent is gained than the discharge standard of pollutants for municipal wastewater treatment plant (GB18918-2002,the first standard, B standard), in order to meet the first standard(A standard), two stages of the biological aerated filter is proposed.6. The kinetic formulate of the Biological Aerated Filter is: Se = S0 ?e?66.4θ.