Fecal Sewage Treatment By A Novel Functional Septic Tank Strengthed By Iron-based Bio-carrier

Black water has the characteristics of high pollutant load,unstable water quality and water quantity,and its treatment process often requires the combination of physical and chemical methods and biochemical methods.The traditional anaerobic septic tank has a good removal effect on COD in black water,but it has the defects of long start-up period,incomplete biodegradation,and poor removal effect of nitrogen and phosphorus.Common aerobic and anaerobic processes and simultaneous nitrification and denitrification processes can greatly reduce the concentration of NH4+-N in black water and reduce the total nitrogen concentration to a certain extent.However,due to the limitation of organic carbon source,this type of process often contains a large amount of NO3--N in the effluent,and the subsequent treatment process still needs to be added.At present,in the research of black water treatment technology,multi-technology combination is mostly used,and the research of new technology is rarely seen,which leads to the problems of complex black water treatment technology,large area,high investment and so on.Therefore,it is of great significance to develop new and effective treatment technologies suitable for the characteristics of black water quality.In view of the current problems in black water treatment,this paper applies iron-carbon micro-electrolysis to the enhancement of the functions of traditional septic tanks,using the self-developed iron matrix biological carrier as the core,coupling the combination of physical and chemical and biochemical reactions to achieve total nitrogen in black water,Simultaneous and efficient removal of total phosphorus and COD treatment,developed a new technology suitable for black water treatment.First,start the new functional septic tank.After the reactor has successfully hung the membrane,explore different dissolved oxygen(DO),hydraulic residence time(HRT),carbon to nitrogen ratio(C/N ratio)and other factors for the new functional septic tank.The impact of the treatment efficiency of the pond is based on the secondary treatment standard of the "Emission Standard for Pollutants in Urban Wastewater Treatment Plants"(GB18918-2002),and the best operating parameters of the new functional septic system are obtained.Under the parameters,explore the long-term operation effect of the new functional septic tank;then,based on the test results,perform a denitrification kinetic analysis on the new functional septic tank to explore the total nitrogen(TN)and dissolved organic matter under the optimal operating parameters The migration and transformation mechanism of nitrogen(DON),dissolved inorganic nitrogen(DIN),particulate organic nitrogen(PON)and adsorbed nitrogen(AN)in the system;finally,the microbial population structure in the system is analyzed and the system is established Degradation mechanism of major pollutants.the result shows:(1)DO,HRT and C/N have a greater influence on the NH4+-N and TN in the treatment of black water in the new septic tank,and the removal rate of COD and TP is relatively small.When the influent water quality is NH4+-N concentration is 160.0 ±20.Omg/L,COD concentration is 1600.0 ± 200.Omg/L,TP concentration is 30.0 ±5.0mg/L,control system DO=2.6mg/L,HRT=48h and The C/N is 6.8?8.1,and the removal rate of NH4+-N,TN,TP and COD by the new septic tank is 91.38%,84.63%,94.04%and 95.82%,respectively.(2)By establishing a material balance equation for the new functional septic tank reactor,the kinetic equation of the system's aerobic iron matrix bio-carrier pool is derived,and the kinetic parameters are solved to establish the system's biological denitrification kinetic model The kinetic equation of aerobic nitrification is:The kinetic equation of anoxic denitrification is NO3a=NO3bn-Cg-0.00389Xatcn.The nitrification and denitrification kinetic constants required in the denitrification process of the new functional septic tank in this study were 0.00757 and 0.00389,respectively,indicating that the system has a stronger effect on the removal of NH4+-N and NO3--N.(3)The distribution of TN in anaerobic tanks A and B is similar.NH4+-N is the main form of DN,accounting for 97.93%and 98.30%of DN,respectively.PON is the main component of PN,accounting for 96.23%and 97.26%of PN,respectively.The contribution rates of DN and PN to TN removal in systems A to B are-77.00%and 187.12%;NO2--N is the main form of DN in the aerobic iron matrix biocarrier pool,accounting for 64.95%of DN,and PON is PN The main form,accounting for 94.94%of PN,the contribution rate of DN and PN to TN removal is 79.93%and 21.34%;NH4+-N in the anoxic iron matrix bio-carrier pool is the main component of DN,accounting for 68.63%of DN,PON It is the main form of PN,accounting for 79.01%of PN,and the contribution rates of DN and PN to TN removal are 72.44%and 27.56%.The ammoniation in the anaerobic tanks A and B converts organic nitrogen to NH4+-N.The aerobic biological carrier pool is mainly based on nitrification,and the system NH4+-N is converted into NO3--N and NO2--N,iron The denitrification reaction in the matrix bio-carrier pool further removed NO3--N and NO2--N.(4)The microbial community structure was studied by high-throughput sequencing to further analyze the denitrification and dephosphorization of the system and the degradation mechanism of COD.The black water denitrification mechanism of Fe-C internal electrolysis and biological coupling mainly includes biological or chemical conversion and mass transfer processes.Microelectrolysis strengthens the ZVI electron donor reaction to accelerate the supply of[H]/Fe2+ and provide electrons for autotrophic denitrifying bacteria The donor promotes the process of hydrogen/iron autotrophic denitrification bacteria.At the systemic level,ammoniacal genus include Bacillus and Romboutsia;nitrifying genus include Nitrosomonas,Pseudomonas,Thauera,and not Acinetobacter;Denitrifying bacteria include Hydrogenopha,Thauera,Thiobacillus,Rhodanobacter,Pseudomonas.At the same time,the presence of Thiobacillus,Rhodanobacter,Acinetobacter,Bacillus,Pseudomonas,Enterobacter phosphorus-removing bacteria in the system realizes the removal of phosphorus in the system.The Fe3+produced by the electrolytic reaction significantly strengthens the system's fixation of phosphorus.There are degradation systems COD in the presence of Arenimonas and Erysiplothri.