Study Of Biological Aerated Filter Process And Biological Contact Oxidation Process Used In Decentralized Wastewater Treatment

The urbanization of the Pearl River Delta region become faster and faster, while, the construction of pipe network lagged behind, therefore many decentralized pollution sources appeared. Urban water environment faces an unprecedented risk. In order to improve the urban water environment, enhance the economical and reusable faculty of the wastewater treatment, biological contact oxidation process and biological aerated filter process filled with new style medium were used in decentralized wastewater treatment in the pilot scale study. Firstly the aeration performance and the organic degradation performance of the new style medium used in the biological aerated filter were studied. The results shown that medium's filling can obviously improve the aeration performance of the system. And it is proved that the process microbe adsorbs and degrades organic matters in the reactor fall into first-order reaction; the adsorption and degradation rate is affected by medium filling percentage. Then in the pilot scale experiment, the contaminations removal efficiencies of the two biofilm process were studied under different hydraulic loads and aeration intensities; and the main factors which affect the removal efficiencies like hydraulic retention time, COD volumetric load, effluence DO were analyzed; then, the two systems were compared under different conditions. The results shown that two processes can achieve high contaminations removal efficiencies in most conditions, the effluent quality was stable, it was proved that the two processes were adapted to the decentralized wastewater treatment. Using of new style medium in the biological aerated filter enhanced the contaminations removal efficiencies, which makes biological aerated filter process better than biological contact oxidation process. Finally, by using of the pilot scale experiment results and the kinetics principles, we study the contamination degradation process in the two systems and gain the contamination degrade experimental kinetic modeling, which can be described as: Biological Aerated Filter S_e =S₀e^0.639t /(1+1.035t); Biological Contact Oxidation S_e= S₀/[(1+ 0.947t)(1+ 1.242t)]. Practice shows that, the modeling had effect in the effluent quality forecast in a certain range, and it can be used to determine appropriate hydraulic load according to the effluent quality demands, which have an instruct significance in the engineering practice.