Pilot-scale Water Driven Rotating Biological Contactor With Drum In The Municipal Wastewater Treatment

Water is the most valuable natural resources for the living and development of human being, it also plays the key role in the social economical development and improving the living standards of mankind. However, with the development of our society, the pollution on water resources has become the bottleneck for our society's development. Nowadays, much attention was focused on the wastewater treatment technologies. Throughout one hundred years'development, these technologies were gradually maturity. Wastewater's treatment technologies methods are changed from separation treatment processing style to centralized treatment processing style. But with the rapid development of urbanization, centralized treatment processing style's weaknesses are appeared, such as large quantity energy loss in transferred wastewater to big treatment plants; large investment are needed in the wastewater network system construction; in rural area, such as vocation village and other places far away from cities, the wastewater can not be treated by centralized processing style. In this situation, separation treatment processing style became the hot field for researches and engineers again.A novel wastewater separation treatment reactor was introduced in this paper—Water Driving Rotation Biological Contactor with Drum(WDRBCD),experiments were conducted on the pilot-scale WDRBCD. To verify the best treatment ability of the reactor by adjusted the inflow wastewater quantity. Using the step-feeding and reflux processing flow to determine the best operation parameters of the reactor. Impulse loading experiments were conducted to confirm the reactor's ability on tolerance impulse loading.The experiments results indicated that the reactor can remove COD_Cr above 71%, BOD₅ above 79% and SS above 66.7%, the effluent water's pH values improved greatly when the inflow quantity is 10t/h. when the inflow quantity is 6t/h, the effluent water quality excluded TN-N values could reach our country's municipal wastewater discharge standards II. When the step-feeding and reflux processing were applied, in the condition of step-feeding (70%/30%)and reflux 50%(33%/17%), the COD_Cr removal ability increased by 15%, BOD₅ increased by 9%,NH₃-N increased by 17.4%,TP-P increased by 50%. The effluence water quality on COD_Cr,BOD₅,NH₃-N and TP-P could reach our country's municipal wastewater discharge standards I. The WDRBCD reactor has great tolerance ability on impulse loading. When the COD_Cr loading mutipled by 2.6 times, the action time is 12 hours, the effluence water quality can recover to best quality in 5 days.On the base of the experiments data, theoretical researches were conducted. The results shown that the degradation reaction of COD_Cr and BOD₅ were the first order reaction. When the wastewater treatment quantity is 144t/d, The reaction function are:COD_Cr, L_t = L₀ e^-0.227t,BOD₅, L_t = L₀ e^-0.264. The two stages WDRBCD's mathematical function isThe first stage's mathematical model is A/Q(L₀-L₁)=0.0109+0.5513/L₁, the second stage's mathematical model is A/Q(L₁-L₂)=0.0201+0.4973/L₂.