Studies On One-Stage Partial Nitritation And Anammox For Digested Liquid From Anaerobic Digestion With Thermal Hydrolysis Pretreatment

The sludge thermal hydrolysis anaerobic digestion(THP-AD)technology has become a highly concerned sludge treatment and disposal technology because of its economy,resources,and reduction,but the sludge produced by thermal hydrolysis anaerobic digestion Liquid(THPS)due to its high ammonia nitrogen content(1500-3000mg/L),low biodegradability,low COD/N and other characteristics increase the difficulty of treatment.Anaerobic ammonia oxidation(ANAMMOX)technology is favored as an economical and environmentally friendly autotrophic denitrification technology in the field of processing THPS,but the nitrosification(PN)-anaerobic ammonia oxidation(ANAMMOX)technology established based on this technology Slow start-up,difficulty in stable operation,and slow growth of the functional bacteria ammonia oxidizing bacteria(AOB)and anaerobic ammonia oxidizing bacteria(AMX),which are sensitive to the environment,have affected their research and development pace and practical engineering applications.The single-stage of PN-ANAMMOX technology has the advantages of high volume load,simple process,low engineering construction cost and low operating cost,and low N2O output.Therefore,this article focuses on the proposition of integrated ANAMMOX processing THPS.This topic focuses on One-Stage Partial Nitritation and Anammox to treat THPS.First,the nitrogen removal performance,sludge activity,particle size change,apparent morphology,and microbial community structure succession law during the start-up process were studied,and the reasons for system instability were analyzed and optimized on this basis.On this basis,a pretreatment-integrated ANAMMOX coupling process was proposed to explore the nitrogen removal performance during its start-up operation,and to analyze the sludge activity,particle size changes,apparent morphology,and microbial community structure succession laws with a view to To achieve pretreatment-integrated ANAMMOX coupling process for efficient and stable nitrogen removal when processing THPS.(1)In this study,a study was carried out to treat THPS with The PN and ANAMMOX sludge of the pilot PN-ANAMMOX process site were used as inoculums to control pH(7-8.5),temperature(33-35?),DO(0.01-0.2 mg/L),and intermittently aerated The proportion of aerobic time(12.5%-100%)is carried out by using water distribution to start and dilute THPS biogas slurry operation.After the 114d water distribution starts,the total nitrogen removal load(NRR)of the system is 0.4 kgN/m~3/d.After the THPS operation using the dilution method,the system experienced large NRR fluctuations(0.04–0.54 kgN/m3/d)and poor sludge settling performance.The demand for AOB inhibited the growth of AOB and also led to the proliferation of heterotrophic bacteria;the second is that THPS contains some complex organic matter,inhibiting the growth and reproduction of AOB and Anammox bacteria.On this basis,it is optimized,and the THPS entering the integrated ANAMMOX system is subjected to aerobic pretreatment.(2)The research of pretreatment-integrated ANAMMOX coupling process system was launched.The inoculum,pH,temperature,DO and other control strategies are similar to the integrated ANAMMOX process.The NRR of the integrated ANAMMOX reactor was 0.38kgN/m3/d after the 166d water distribution was started.In the pretreatment section,THPS uses its own alkalinity for aerobic digestion,and the supernatant is collected after the sediment is collected from its effluent.In the study of pretreatment-integrated ANAMMOX coupling process to treat THPS,the influent NH4+is about2050mg/L,the influent COD is about 3200mg/L,the effluent NH4+fluctuates around100mg/L,and NO2-keeps below 1mg/L The NRR is 1.65 kgN/m3/d,the total nitrogen removal rate is 95.12%,and the COD removal rate is about 70%,of which 47.49%of the COD is removed by the pretreatment section.(3)Study the microbial population structure characteristics through Illuminate high-throughput sequencing.The microbial populations of the two systems include Plantomycetes,Proteobacteria,Firmicutes,Bacteroidates and Chloroflexi at the phylum level.At the genus level,AMX bacteria mainly include Candidatus Brocadiaceae(type B)and Candidatus Kuenenia(type K).The water distribution starting environment is conducive to the growth of K-type AMX;during the operation of the integrated ANAMMOX process for THPS,the B-type and K-type AMX each account for about 50%;during the pretreatment-integrated ANAMMOX coupling process for the treatment of THPS,the AMX bacteria are K-type Main,accounting for 91.6%of the total number of AMX bacteria.The other functional bacteria AOB in the two processes are mainly Nitrosomonas and Betaproteobacteria.