Deep Treatment Of Domestic Sewage In Expressway Service Area Based On Multi-stage A/O Process Based On Physicochemical And Biochemical Coupling

Based on the investigation of the water quality characteristics and treatment status of the expressway service area,this paper uses the self-developed composite active catalytic carrier as the process basis to couple the microbial denitrification with the chemical catalysis to develop a suitable depth of sewage for the expressway service area.Processed system process.Through the long-term stable operation verification of different parameters(HRT,DO,reflux ratio)in laboratory small test and on-site process pilot test,the physicochemical and biochemical coupling multi-stage A/O system realizes high-efficiency nitrogen and phosphorus removal under low temperature conditions.In addition,based on the laboratory test data,a dynamic model was established for the physicochemical and biochemical coupled multi-stage A/O system.The calculation of the gray correlation degree of the order of impact of each pollutant was used to quantify the nitrogen and organic matter in the process.The process of mutual conversion,consumption,and the simultaneous denitrification and dephosphorization mechanism of physicochemical and biochemical coupling technologies.Finally,the economic analysis of the composite active catalytic carrier and the physicochemical and biochemical coupling multi-stage A/O process was carried out.Research indicates:(1)In the laboratory pilot study,the physicochemical and biochemical coupling multi-stage A/O system was started for 38 days.The optimal operating parameters were HRT=16 h(7.2 h for the oxygen reactor and 9 h for the aerobic reactor).In the aerobic reactor,DO=6.0-6.5 mg L-1,the reflux ratio is 5:1,the C/N ratio is 2.82～3.37,and the effluent quality of the system NH4+-N,COD,TN and TP reaches the town.Class I A emission standards in the Pollutant Discharge Standard for Wastewater Treatment Plants(GB18918-2002).(2)The denitrification rate of the physicochemical and biochemical coupling system based on the Eckenfelder equation is obtained K(TN)=0.000 37 min 1,K(COD)=0.000 000 64 min-1,K(NH4+-N)=0.000 000 107 min-1.Based on the Monod equation,the kinetic constants QNH4+-N=2.4295,KNH4+-N=0.29737.The results show that the physicochemical properties and catalytic properties of the composite active catalytic carrier in the physicochemical and biochemical systems are very suitable for microbial growth and adhesion.Through the gray correlation analysis,the order of influence of the multi-level A/O system of materialized and biochemical coupling on the removal factors of various pollutants is obtained,and it can be used for optimization of operating parameters in actual engineering and targeted removal of pollutants.(3)The optimal HRT of physicochemical and biochemical coupling multi-stage A/O system in actual engineering is 7.5 h(4.5 h for anaerobic reactor and 3.0 h for aerobic reactor),and the optimal DO concentration is 4.0 mg L-1,the best reflux ratio is 4:1.Under the best working conditions,all pollutants have reached the Class A emission standard in the Pollutant Discharge Standard for Urban Sewage Treatment Plants(GB18918-2002).The physicochemical and biochemical coupling of the multi-stage A/O system in the field test runs 64.5%of the total denitrification.The physicochemical and biochemical coupling biofilm reactor has autotrophic denitrification based on the composite active catalytic carrier.Contribution rate>35%.In summary,the research and development of materialized and biochemical coupled multi-stage A/O technology provides new ideas and concepts for deep nitrogen and phosphorus removal and energy reduction in domestic sewage in the service area of expressway.It provides theoretical basis and technical support for the reduction of ammonia nitrogen and total nitrogen in sewage in the service area of the expressway and the upgrading of existing treatment technologies.The full text has a total of 35 groups,36 tables,and 98 references.