Preparation Modification Of Sludge Coal Gangue Based Activated Carbon And Its Application In Anaerobic Ammonia Oxidation

Anaerobic ammonia oxidizing bacteria(AnAOB)are easily lost in the reactor,difficult to accumulate,and are easily affected by environmental factors such as pH and matrix concentration.The introduction of the carrier can effectively reduce the loss of AnAOB and increase the biomass,thereby speeding up the reactor start-up and improving the reactor's shock load resistance.Activated carbon is a commonly used microbial carrier,which can effectively enhance the microbial activity in the reactor,increase the biomass,shorten the reaction start-up time,and promote the stable operation of the reactor.This paper intends to use sludge and coal gangue as raw materials to prepare sludge coal gangue-based activated carbon(SCAC),which is activated and carbonized and applied to the start-up of the ASBR reactor that artificially simulates wastewater.After 155 d of operation,the following conclusions are obtained:(1)Using sludge and coal gangue as raw materials to prepare SCAC,through XRD,SEM,FT-IR and BET specific surface area,comparative analysis of the three,it is found that compared with the smooth surface of sludge,coal gangue,activated The SCAC prepared after carbonization has passivation and spongy protrusions are observed,which are mainly cubic Si O₂ crystal structure of P6222(No.180),indicating that SCAC has better adsorption performance and impact load resistance;sludge coal The C,H,O and other components in the gangue are activated and carbonized to form oxygen-containing functional groups such as hydroxyl,phenolic hydroxyl,carboxyl,lactone,etc.The surface functional group can promote the secretion of extracellular polymer(EPS)in the sludge and enhance the aggregation of microorganisms;after carbonization,the BET specific surface area of SCAC is 146.25 m²·g^-1,which is 75 and 50 times the BET specific surface area of sludge and coal gangue respectively.It is mainly microporous and mesoporous,which is rich in microorganisms.The set provides plenty of space for attachment.(2)Monitoring the NH₄⁺-N,NO₂^--N,NO₃^--N during the operation of the reactor by standard methods,comparing the R_SCAC with the SCAC reactor and the R_o without SCAC,it is found that R_SCAC has been maintained from 101d to 155d 94%±0.4%efficient and stable NH₄⁺-N removal rate;R_o removal rate stabilized at 81%±2%at 121 d.The removal rate of NO₂^--N of R_SCAC is almost maintained at 99%,the concentration of NO₃^--N effluent is also relatively stable at 1±0.5 mg·L^-1;the removal rate of NO₂^--N of R_o is between 93%?98%Fluctuations,the trend of NO₃^--N effluent concentration is related to the NO₂^--N concentration.The stoichiometric ratio in R_SCAC has stabilized on the 98th day,with a ratio of1:1.40:0.25,which is close to the theoretical value of 1:1.32:0.26.The stoichiometric ratio of R_o during this period is 1:(1.53?1.78):(0.27?0.44),with a large fluctuation range,but it has also approached the theoretical value.The pH value of R_SCAC effluent is stable at 7.95±0.06,and the pH value of R_o effluent fluctuates between 7.8?8.1,but the pH value of the effluent in the two reactors is close to 8.0,which is in line with the optimal pH value for the survival of anammox bacteria,Indicating that anammox bacteria dominate the reactor.(3)After the reactor was operated synchronously for 100 d,the microbial ACE,Chao1,Shannon,and Simpson indexes in R_o were all greater than R_SCAC,indicating that the species abundance and flora diversity in R_SCAC were lower than R_o,but R_SCAC functional flora AnAOB accounted for more than R_o.After the start of anammox,there are differences in the structure of the two bacteria.The number of bacteria detected in R_o and R_SCAC is 32 and 28,respectively,and the number of bacteria in total is 22.The two more abundant dominant bacteria phyla are similar,namely Planctomycetes,Proteobacteria,Chloroflxi,Armatimonadetes and Bacteroidetes.In R_o and R_SCAC,the relative abundance of Planctomycetes where AnAOB is located accounts for 20%and 29.28%of the total bacteria,respectively.Among them,the relative abundance of the detected anaerobic ammonia oxidation bacteria Candidatus Brocadia and Candidatus Jettenia in R_SCAC They are 22.07%and 2.64%respectively,which are twice the relative abundance in R_o;Nitrosomonas belonging to ammonia oxidizing bacteria(AOB),Denitratisoma,Thiobacillus etc.belonging to denitrifying bacteria(DB)are mainly detected in the phylum Proteobacteria.Among them,the relative abundances of Denitratisoma in R_o and R_SCAC were 7.50%and 5.64%,respectively,and that of Thiobacillus were 3.08%and 3.70%,respectively.It shows that SCAC is conducive to the enrichment of AnAOB in R_SCAC and becoming the dominant flora in the microbial community.(4)The EPS content in R_SCAC reactors was 69.41 mg·g VSS^-1 much higher than 44.23mg·g VSS^-1 in R_o.The EPS protein content in the R_o and R_SCAC reactors were 33.52mg·g VSS^-1 and 59.29 mg·g VSS^-1,and the polysaccharide content were 10.71 mg·g VSS^-1 and10.12 mg·g VSS^-1,respectively.The protein gain in R_SCAC is nearly 4 times than the protein gain in R_o.The PN/PS of R_o is 3.16,and the PN/PS of R_SCAC is 5.85.Compared with SEPS and LB-EPS,TB-EPS has the largest proportion in the total EPS content of R_o and R_SCACreactor sludge,accounting for 49.1%and 43.3%,respectively.Among in the SEPS,LB-EPS and TB-EPS layers,the sludge EPS and PN were increased in R_SCAC from adding SCAC.