Study On Deodorization Technology And Mechanism Of Rural Domestic Wastewater Treatment Process

In recent years,according to the quantity and quality characteristics of rural domestic sewage and the background conditions of rural agriculture,some scholars have proposed"Biological+Ecological"combination process technology to deal with rural dispersion-based domestic sewage,and achieve better treatment.However,there is a problem that the biological unit surface structure exits the odor,affecting the living environment of surrounding residents,and does not match the idea of living environmental remediation in the current rural people.In this study,on the basis of"anoxic filter-waterwheel driving rotating biological contactor-artificial wetland"biological ecological combination process,the deodorization process and related mechanism of rural sewage in biological segments were studied.The biometric unit is combined with an oxygen aerobic process,and the short-range nitrification-denitrification process characteristics,the water-driven bio-carbide generated nitride refluxed to an oxygen-deficient reactor,using dissolved oxygen and nitrate in nitrification liquid as an electron receptor,and adopting appropriate reflow ratio to further dilute the main odorous substance sulfide in rural sewage.It effectively solves the problem of odor in the process of rural sewage treatment.It is in line with the 14th Five-Year Planning Rural Revitalization Mission to improve the rural homage environment,so that the rural cleaning and more responsive requirements are conducive to miniaturization,distributed,ecological,low cost,easy to maintain the promotion of rural sewage treatment technology.The main research contents and conclusions are as follows:（1）Three influencing factors of temperature,C/N and dissolved oxygen were investigated by small-scale batch trials.The results show that the temperature affects the effect of deodorizing system,the dissolved sulfide removal and denitrification of hypoxic unit is optimal at a higher ambient temperature（25°C）.The system sulfide removal efficiency with C/N lowered and significantly increased.When C/N is 2,the removal efficiency of the sulfide is the highest.The removal efficiency of the sulfide can reach 64.68%at 4 h,while the removal efficiency of nitrate and organic matter is relatively low.Higher dissolved oxygen level（DO:1.8～2.2 mg/L）can significantly increase the debris removal efficiency in the system,and the removal rate of organic matter is slightly improved,and the nitrogen is reduced.（2）The removal mechanism of sulfide is highly examined under different dissolved oxygen conditions.The release test results show that the DO content has a great influence on the removal of sulfides in water.As the concentration of DO increases,the desulfurization amount increases from 9.78 mg/g to 20.37 mg/g,and the release is increased from 1.03 mg/g to 3.05 mg/g.The increase of dissolved oxygen can promote the denitrification and deodorization process.The amount of sulfide release under higher DO concentration is more than the low DO concentration,which can be explained by adsorption behavior on the biofilm.In order to further explore the interaction of biological membranes and sulfides,the relevant test was carried out.The SEM/EDS test results show that the sulfide is indeed adsorbed to the biofilm during the mixing of the sulfide and the biofilm mixture.The XPS analysis showed that the existence of radicals and sulfide in the biofilm in the biofilm under higher DO concentration.The FTIR analysis showed that R-NH₂ should be one of the free radicals of sulfide bonding on the biofilm.（3）The optimum operating condition of the anoxic filter-waterwheel driving rotating biological contactor is determined by the trial experiment is:nitrification liquid reflux ratio of200%,rotation speed of 8rpm,anoxic hydraulic retention time of 10h,and waterwheel driving rotating biological contactor of 5h.During three and a half months,the average removal rate of S^2-,COD,TN,NH₄⁺-N,TP is 98.9%,85.41%,47.73%,80.74%,and 38.75%,respectively.The sulfide concentration of the overall water is less than 1 mg/L,which is in line with the"urban sewage treatment plant pollutant emission standard"（GB18918-2002）to select the sulfide of the control project;the effluent COD and NH₄⁺-N concentrations meet the emission requirements of the primary A standard in Jiangsu Province"Rural Domestic Wastewater Treatment Facilities"（DB32/3462-2020）;the effluent TN and TP concentration fluctuate respectively between 19.45～23.78mg/L,1.91 2.54 mg/L,and after the ecological unit is required to complete the nitrogen resource utilization process,the water quality can be achieved.