Study On Performance Of Novel Rotating Biological Contactor Based On Separation Treatment Of Black Water And Grey Water Of Rural Domestic Sewage

At present,Dispersion of discharge,obvious fluctuation of water quality and low treatment rate are the characteristics of rural domestic sewage in China,which brings great challenges to the comprehensive water environment management in rural areas.In this situation,it is particularly important to develop a suitable treatment technology for rural domestic sewage.Considering the utilization of nitrogen and phosphorus resources and sustainable development,the concept of "source separation treatment" was proposed on the basis of the existing rural distributed sewage treatment technology,and a new biological ecological combination process of "black water anaerobic treatment-mixed sewage anoxic treatment-aerobic treatment-nitrogen and phosphorus resource utilization of constructed wetlands" was adopted.Specifically,small volume blackwater after anaerobic period of treatment mixed with a large volume of gray water into the anaerobic pool.Waterwheel driven rotating biological contactor as aerobic unit for further treatment of anoxic tank effluent,which partial nitrification fluid backflow to the anoxic pool for denitrification.economical artificial wetland at the end of biological purification section of the tail water depth N and P utilization.Economical constructed wetlands deeply purify the tail water of the biological section to achieve the recycling of N and P.The "aerobic unit" of the combined process was the main research object of this paper,aiming at strengthening the practical engineering problems and improving the hydraulic flow pattern and treatment effect of the traditional rotating biological contactor,the rotating biological contactor driven by the waterwheel with a deflector was proposed for the first time,that was,the novel rotating biological contactor.In order to provide reference for the development of traditional water treatment devices and equipment innovation,and to contribute new ideas,new processes and new approaches to the promotion of rural domestic sewage treatment technology,the performance of the novel rotating biological contactor was comprehensively investigated by combining theoretical analysis with experimental research.According to the results of the clear water experiment,after the improvement of the rotating biological contactor,the backmixing degree was reduced,and the residence time distribution was more concentrated.The hydraulic retention time was closer to the theoretical hydraulic retention time.The dead zone rate was greatly reduced.HRT affected the residence time distribution curve of the novel rotating biological contactor.When HRT was 50 min～70min,the influence of reactor structure on residence time distribution was consistent.When HRT was 1 h～3 h,with the increase of HRT,the hydraulic flow pattern became worse.The novel rotating biological contactor hanging film had good performance and its excellent hydraulic flow pattern was conducive to the growth of various microorganisms.The effects of HRT and rotating speed on the treatment efficiency of novel and traditional rotating biological contactor were investigated in different seasons,and the appropriate operating parameters were optimized by balancing engineering economy and treatment efficiency.The results showed that when the same treatment effect is achieved,the hydraulic retention time of the novel first-grade rotating biological contactor was shorter and the speed was lower than that of the traditional rotating biological contactor.The effect of both on TN is characterized by low treatment rate.The back-flow ratio of nitrifying solution had a great influence on the removal of pollutants in the "anoxic reactor/ novel waterwheel driven rotating biological contactor "(AR-nwd RBC)system.In order to achieve a better treatment effect,the back-flow ratio of nitrifying solution needed to be increased in winter and spring.In winter and spring,when the reflux ratio of nitrification liquid was 200%,the system achieved the highest removal rate of COD and ammonia nitrogen(about 80%).In summer and autumn,when the reflux ratio of nitrification liquid was 150%,the system achieved the highest removal rate of COD and ammonia nitrogen(about 88%).For the removal of TN,summer and autumn were significantly higher than winter and spring.Under optimal operating parameters,the COD and ammonia nitrogen in the effluent of the novel rotating biological contactor meat the grade A standard of(GB 18918—2002),while TN needed further treatment of subsequent constructed wetland.AR-nwd RBC system had obvious pollutant removal rule.In winter and spring,the removal rate of COD and TN decreased step by step,and the contribution rate of anoxic tank and first-stage rotating biological contactor to COD removal was the highest.The contribution rate of anoxic pool to TN removal rate was the highest.After removing the dilution effect of the anoxic tank,the contribution rate of the three-stage rotating biological contactor was the highest.The grading removal rate of the pollutants in four seasons is consistent.