In this work,ofloxacin(OFL),a kind of frequently detected antibiotic in groundwater,was selected to explore its impact(at ng/L-μg/L-level)on denitrification performance in an autotrophic denitrification system driven...In this work,ofloxacin(OFL),a kind of frequently detected antibiotic in groundwater,was selected to explore its impact(at ng/L-μg/L-level)on denitrification performance in an autotrophic denitrification system driven by pyrite/sulfur(FeS2/S0).Results showed that OFL restrained nitrate removal efficiency,and the inhibition degree was positively related to the concentration of OFL.After being exposed to increased OFL(200 ng/L-100μg/L)for 69 days,higher inhibition of electron transport activity(ETSA),enzyme activities of nitrate reductase(NAR),and nitrite reductase(NIR)were acquired.Meanwhile,the extracellular protein(PN)content of sludge samples was remarkably stimulated by OFL to resist the augmented toxicity.OFL contributed to increased microbial diversity and sulfur/sulfide oxidation functional genes in ng/L-level bioreactors,whereas led to a decline inμg/L level experiments.With OFL at concentrations of 200 ng/L and 100μg/L,the whole expression of 10 key denitrification functional genes was depressed,and the higher the OFL concentration,the lower the expression level.However,no significant proliferation of antibiotic resistance genes(ARGs)either in 200 ng/L-OFL or 100μg/L-OFL groups was observed.Two-factor correlation analysis results indicated that Thiobacillus,Anaerolineae,Anaerolineales,and Nitrospirae might be the main hosts of existing ARGs in this system.展开更多
This study presents a novel approach,the Supercapacitor Microbial Electrolysis Cell(SCMEC),which utilizes a supercapacitor as an external power source to enhance the efficiency of autotrophic nitrogen removal in low C...This study presents a novel approach,the Supercapacitor Microbial Electrolysis Cell(SCMEC),which utilizes a supercapacitor as an external power source to enhance the efficiency of autotrophic nitrogen removal in low C/N ratio wastewater.The results demonstrated that the SC-MEC system,operating under anaerobic conditions and devoid of any organic carbon source,exhibited exceptional performance in ammonia oxidation and total nitrogen(TN)removal when solely relying on ammonia nitrogen as the electron donor.Operating at a voltage of 1.8 V with a capacitance capacity of 30 F,ammonium oxidation rated up to 56.51 mg/L/day and TN removal rated up to 54.64 mg/L/day,in which 97%of ammonium nitrogen was converted to gaseous nitrogen.Furthermore,the charging and discharging process of supercapacitors autonomously regulated the bipolar potentials.Cyclic voltammetry(CV)analysis showed the significantly enhanced electrochemical activity of the SCMEC system during the reaction process.Based on in-situ CV test results,itwas inferred that this enhancementwas associated with extracellular electron transfer mediators.Themicrobial community analysis revealed a process of synchronous nitrification and denitrification(SND)coupled with anammox,involvingmultiple genera,such as Candidatus Kuenenia,Nitrosomonas,Truepera,and Bosea.In conclusion,this study highlights the tremendous potential of SC-MEC in achieving efficient autotrophic nitrogen removal,offering more feasible and economical solutions for addressing low C/N water pollution issues.展开更多
Sulfur autotrophic denitrification technology is a low-carbon and environmentally friendly wastewater treatment technology.The effects of factors such as pH,temperature,S/N and salinity on the efficiency of sulfur aut...Sulfur autotrophic denitrification technology is a low-carbon and environmentally friendly wastewater treatment technology.The effects of factors such as pH,temperature,S/N and salinity on the efficiency of sulfur autotrophic denitrification reactions were discussed,and the community characteristics of microorganisms were summarized.This article also introduced the future research and development directions of this process.展开更多
Sulfur-limestone was used in the autotrophic denitrification process to remove the nitrate and nitrite in a lab scale upflow biofilter.Synthetic water with four levels of nitrate and nitrite concentrations of 10,40,70...Sulfur-limestone was used in the autotrophic denitrification process to remove the nitrate and nitrite in a lab scale upflow biofilter.Synthetic water with four levels of nitrate and nitrite concentrations of 10,40,70 and 100 mg N/L was tested.When treating the low concentration of nitrate-or nitrite-contaminated water（10,40 mg N/L）,a high removal rate of about 90% was achieved at the hydraulic retention time（HRT） of 3 hr and temperature of 20-25°C.At the same HRT,50% of the nitrate or nitrite could be removed even at the low temperature of 5-10°C.For the higher concentration nitrate and nitrite（70,100 mg N/L）,longer HRT was required.The batch test indicated that influent concentration,HRT and temperature are important factors afiecting the denitrification eficiency.Molecular analysis implied that nitrate and nitrite were denitrified into nitrogen by the same microorganisms.The sequential two-step-reactions from nitrate to nitrite and from nitrite to the next-step product might have taken place in the same cell during the autotrophic denitrification process.展开更多
In order to reduce the amount of NO_3^-–N generated by the Anammox process, and alleviate the competition between denitrification and Anammox for NO_2^-–N in a single reactor, the preference of S^0 for reacting with...In order to reduce the amount of NO_3^-–N generated by the Anammox process, and alleviate the competition between denitrification and Anammox for NO_2^-–N in a single reactor, the preference of S^0 for reacting with coexisting NO_2^-–N and NO_3^-–N in the sulfur autotrophic denitrifying(SADN) process and the coupling effect of short-cut SADN and the Anammox process were studied. The results showed that S^0 preferentially reacted with NO_3^-to produce NO_2^-–N, and then reacted with NO_2^-–N when NO_3^-–N was insufficient, which could effectively alleviate the competition between SADN bacteria(SADNB) and Anammox bacteria(An AOB) for NO_2^-–N. After 170 days of operation, coupling between short-cut S^0-SADN and the Anammox process was first successfully achieved. SADNB converted the NO_3^-–N generated by the Anammox process into NO_2^-–N, which was once again available to An AOB. The total nitrogen removal efficiency eventually stabilized at over 95%, and the effluent NO_3^-–N was controlled within 10 mg/L, when high NH_4^+–N wastewater was treated by the Anammox process. Microbial community analysis further showed that Candidatus Brocadia and Thiobacillus were the functional microorganisms for An AOB and SADNB.展开更多
A combined process consisting of a short-cut nitrification （SN） reactor and an anaerobic ammonium oxidation upflow anaerobic sludge bed （ANAMMOX） reactor was developed to treat the diluted effluent from an upflow ...A combined process consisting of a short-cut nitrification （SN） reactor and an anaerobic ammonium oxidation upflow anaerobic sludge bed （ANAMMOX） reactor was developed to treat the diluted effluent from an upflow anaerobic sludge bed （UASB） reactor treating high ammonium municipal landfill leachate.The SN process was performed in an aerated upflow sludge bed （AUSB） reactor （working volume 3.05 L）,treating about 50% of the diluted raw wastewater.The ammonium removal efficiency and the ratio of NO 2 N to NOx-N in the effluent were both higher than 80%,at a maximum nitrogen loading rate of 1.47 kg/（m 3 ·day）.The ANAMMOX process was performed in an UASB reactor （working volume 8.5 L）,using the mix of SN reactor effluent and diluted raw wastewater at a ratio of 1：1.The ammonium and nitrite removal efficiency reached over 93% and 95%,respectively,after 70-day continuous operation,at a maximum total nitrogen loading rate of 0.91 kg/（m 3 ·day）,suggesting a successful operation of the combined process.The average nitrogen loading rate of the combined system was 0.56 kg/（m 3 ·day）,with an average total inorganic nitrogen removal efficiency 87%.The nitrogen in the effluent was mostly nitrate.The results provided important evidence for the possibility of applying SN-ANAMMOX after UASB reactor to treat municipal landfill leachate.展开更多
Sulfur-driven autotrophic denitrification(SDAD),a process suited for the treatment of nitrogen and sulfur-polluted wastewater without extra supplement of organic carbon,is a promising biological nitrogen removal proce...Sulfur-driven autotrophic denitrification(SDAD),a process suited for the treatment of nitrogen and sulfur-polluted wastewater without extra supplement of organic carbon,is a promising biological nitrogen removal process.However,the SDAD process was affected by many factors such as various electron donors,organic carbon and exogenous substances(e.g.,antibiotics and heavy metal),which prevent further application.Thus,we conducted a detailed review of previous studies on such influence factors and its current application.Besides,a comparative analysis was adopted to recognize the current challenges and future needs for feasible application,so as to ultimately perfect the SDAD process and extend its application scope.展开更多
The stability and parameters of a bio-ceramic filter for completely autotrophic nitrogen removal were investigated. The completely autotrophic nitrogen removal over nitrite （CANON） reactor was fed with different con...The stability and parameters of a bio-ceramic filter for completely autotrophic nitrogen removal were investigated. The completely autotrophic nitrogen removal over nitrite （CANON） reactor was fed with different concentrations of ammonia （400, 300, and 200 mg N/L） but constant influent ammonia load. The results showed that the CANON system can achieve good treatment performance at ambient temperature （15-23℃）. The average removal rate and removal loading of NH4＋-N and TN was 83.90%, 1.26 kg N/（m3.day）, and 70.14%, 1.09 kg N/（m3.day）, respectively. Among the influencing factors like pH, dissolved oxygen and alkalinity, it was indicated that the pH was the key parameter of the performance of the CANON system. Observing the variation of pH would contribute to better control of the CANON system in an intuitive and fast way. Denaturing gradient gel electrophoresis analysis of microorganisms further revealed that there were some significant changes in the community structure of ammonium oxidizing bacteria, which had low diversity in different stages, while the species of anaerobic ammonium oxidizing （anammox） bacteria were fewer and the community composition was relatively stable. These observations showed that anaerobic ammonia oxidation was more stable than the aerobic ammonia oxidation, which could explain that why the CANON system maintained a good removal efficiency under the changing substrate conditions.展开更多
Eutrophication caused by high concentrations of nutrients is a huge problem for many natural lakes and reservoirs. Removing the nitrogen contamination from the low C/N water body has become an urgent need. Autotrophic...Eutrophication caused by high concentrations of nutrients is a huge problem for many natural lakes and reservoirs. Removing the nitrogen contamination from the low C/N water body has become an urgent need. Autotrophic denitrification with the sulfur compound as electron donor was investigated in the biofilter reactors. Through the lab-scale experiment,it was found that different sulfur compounds and different carriers caused very different treatment performances. Thiosulfate was selected to be the best electron donor and ceramsite was chosen as the suitable carrier due to the good denitrification efficiency, low cost and the good resistibility against the high hydraulic loads. Later the optimum running parameters of the process were determined. Then the pilot-scale experiment was carried out with the real micro-polluted water from the West Lake, China. The results indicated that the autotrophic denitrification with thiosulfate as electron donor was feasible and applicable for the micro-polluted lake water.展开更多
The importance of dissolved organic phosphorus(DOP) as a potential nutrient source for primary producers in marine systems has been recognized for up to eight decades, but currently, the understanding of the biogeoche...The importance of dissolved organic phosphorus(DOP) as a potential nutrient source for primary producers in marine systems has been recognized for up to eight decades, but currently, the understanding of the biogeochemistry of DOP is in its infancy. In the present study, monthly data between 2000 and 2014 were used to analyze the temporal and spatial distributions of DOP in the Mir Bay, the northern South China Sea. The DOP residence time(TDOP) was also investigated using a simple regression analysis in combination with chlorophyll a(Chl a) measurements while excess DOP(ΔDOP), produced by the biogeochemical processes of autotrophic production and heterotrophic removal, was determined using a two-component mixing mass-balance model in combination with salinity measurements. The results showed that the DOP concentration was(0.017±0.010) mg/L higher in the surface-water compared with the bottom-water and higher in the inner Tolo Harbour and waters adjacent to Shatoujiao compared with the main zone of the bay. Although seasonal changes and annual variability in the DOP were small, the surface DOP concentration was higher in the wet season(April–September)than in the dry season(October–March) due to the impacts of seaward discharges and atmospheric deposition into the bay. Measurement and regression results showed that the DOP release rate from phytoplankton production was about 1.83(gP)/(gChl a) and the TDOP was about 7 d, which implied that the DOP cycle in the bay was rapid. The ΔDOP was calculated from the model to be about 0.000 mg/L in the main zone of the bay and about 0.002 mg/L in the inner Tolo Harbour and waters adjacent to Shaotoujiao, suggesting that the autotrophic production of DOP was almost balanced by the heterotrophic removal in the main zone of the bay and dominated in the inner Tolo Harbour and waters adjacent to Shaotoujiao. In conclusion, the Mirs Bay is very productive and fairly heterotrophic.展开更多
Rapid formation of autotrophic partial denitrification(APD)granules is of practical interest to start up an expanded granular sludge bed reactor for wastewater treatment.This study demonstrates that methanogenic granu...Rapid formation of autotrophic partial denitrification(APD)granules is of practical interest to start up an expanded granular sludge bed reactor for wastewater treatment.This study demonstrates that methanogenic granules can be easily acclimated into autotrophic partial denitrification granules in one day,with the ability to remove 82%of 2.7 kg-S/(m^3·d)sulfide into S^0 and to convert 97%of 0.9 kg-N/(m^3·d)nitrate into nitrite,which can provide a promising feedstock for anaerobic ammonia oxidation process.Arcobacter sp.is essential for S^0 accumulation.Under high loadings,the abundance of Arcobacter sp.decreased,while on the contrary the abundance of unclassified_p_Firmicutes increased,leading to the deterioration of autotrophic partial denitrification performance.The granules performance could be recovered by adopting the strategies of properly reducing the influent loadings.展开更多
The removal of eight typical pharmaceuticals(Ph ACs)(i.e.,ibuprofen(IBU),ketoprofen(KET),diclofenac(DIC),sulfadiazine(SD),sulfamethoxazole(SMX),trimethoprim(TMP),ciprofloxacin(CIP)and enoxacin(ENO))in sulfur-driven au...The removal of eight typical pharmaceuticals(Ph ACs)(i.e.,ibuprofen(IBU),ketoprofen(KET),diclofenac(DIC),sulfadiazine(SD),sulfamethoxazole(SMX),trimethoprim(TMP),ciprofloxacin(CIP)and enoxacin(ENO))in sulfur-driven autotrophic denitrification(Sd AD)process were firstly investigated via long-term operation of bioreactor coupled with batch tests.The results indicated that IBU and KET can be effectively removed(removal efficiency>50%)compared to other six Ph ACs in Sd AD bioreactor.Biodegradation was the primary removal route for IBU and KET with the specific biodegradation rates of 5.3±0.718.1±1.8μg g^(-1)-VSS d^(-1)at initial concentrations of 25-200μg/L.The biotransformation intermediates of IBU and KET were examined,and the results indicated that IBU was biotransformed to three intermediates via hydroxylation and carboxylation.KET biotransformation could be initiated from the reduction of the keto group following with a series of oxidation/reduction reactions,and five intermediates of KET were observed in this study.The microbial community composition in the system was markedly shifted when long-term exposure to Ph ACs.However,the functional microbes(e.g.,genus Thiobacillus)showed high tolerance to Ph ACs,resulting in the high efficiency for Ph ACs,N and S removal during long-term Sd AD reactor operation.The findings provide better insight into Ph ACs removal in Sd AD process,especially IBU and KET,and open up an innovative opportunity for the treatment of Ph ACs-laden wastewater using sulfur-mediated biological process.展开更多
Nitrate is considered to be one of the most widely present pollutants leading to eutrophication of environment. The purpose of this work was to isolate and identify new anaerobic denitrifying bacteria from reservoir s...Nitrate is considered to be one of the most widely present pollutants leading to eutrophication of environment. The purpose of this work was to isolate and identify new anaerobic denitrifying bacteria from reservoir sediments and utilize different electron donors for isolates to improve nitrate removal efficiency. Using traditional enrichment approach,one purified anaerobic bacterium( Y12) capable of NO-3-N removal from sediments was obtained. The species identity of Y12 was determined via 16 S rRNA gene sequence analysis to be Acinetobacter. In this work,the fastest denitrification rates were observed with ferrous iron as electron donor.And,slightly slower rates were observed with hydrogen and sodium sulfide as electron donors. However,when used hydrogen gas, ferrous iron and sodium sulfide as electron donors, C / N ratios had little effect on autotrophic denitrification rate at the initial C / N ratio from 1.5 to 9.0. Meanwhile,when made use of hydrogen gas,ferrous iron and sodium sulfide as electron donors,a maximum nitrate removal ratio of 100.00%,91.43%and 87.99% at the temperature of 30 ℃,respectively. Moreover,maximum denitrification activity was observed at p H 6.0-7.0.展开更多
The characteristics of the start-up period of single-step autotrophic nitrogen removal process were investigated. The autotrophic nitrogen removal process used a sequencing batch reactor to treat wastewater of medium ...The characteristics of the start-up period of single-step autotrophic nitrogen removal process were investigated. The autotrophic nitrogen removal process used a sequencing batch reactor to treat wastewater of medium to low ammonia-nitrogen concentration, with dissolved oxygen （DO）, hydraulic retention time （HRT） and temperature controlled. The experimental conditions were temperature at （30±2） ℃, ammonia concentration of （60 to 120） mg/L, DO of （0.8 to 1.0） mg/L, pH from 7.8 to 8.5 and HRT of 24 h. The rates of nitrification and nitrogen removal turn out to be 77% and 40%, respectively, after a start up period going through three stages divided according to nitrite accumulation： sludge domestication, nitrifying bacteria selection and sludge adaptation, It is demonstrated that dissolved oxygen is critical to nitrite accumulation and elastic YJZH soft compound packing is superior to polyhedral hollow balls in helping the bacteria adhere to the membrane.展开更多
Carbon cycling research has increased over the past 20 years, but less is known about the primary contributors to soil respiration (i.e. heterotrophic and autotrophic) under dormant conditions. It is understood that s...Carbon cycling research has increased over the past 20 years, but less is known about the primary contributors to soil respiration (i.e. heterotrophic and autotrophic) under dormant conditions. It is understood that soil CO2 effluxes are significantly lower during the winter of temperate ecosystems and assumed microorganisms dominate efflux origination. We hypothesized that heterotrophic contributions would be greater than autotrophic under simulated dormancy conditions. To test this hypothesis, we designed an experiment with the following treatments: combined autotrophic heterotrophic respiration, heterotrophic respiration, autotrophic respiration, no respiration, autotrophic respiration in vermiculite, and no respiration in vermiculite. Engelmann spruce seedlings and soil substrates were placed in specially designed respiration chambers and soil CO2 efflux measurements were taken four times over the course of a month. Soil microbial densities and root volumes were measured for each chamber after day thirty-three. Seedling presence resulted in significantly higher soil CO2 efflux rates for all soil substrates. Autotrophic respiration treatments were not representative of solely autotrophic soil CO2 efflux due to soil microbial contamination of autoclaved soil substrates;however, the mean autotrophic contributions averaged less than 25% of the total soil CO2 efflux. Soil microorganism communities were likely the primary contributor to soil CO2 efflux in simulated dormant conditions, as treatments with the greatest proportions of microbial densities had the highest soil CO2 efflux rates. Although this study is not directly comparable to field dormant season soil CO2 effluxes of Engelmann spruce forest, as snowpack is not maintained throughout this experiment, relationships, and metrics from such small-scale ecosystem component processes may yield more accurate carbon budget models.展开更多
This study investigates the simultaneous accumulation of S^(0) and NO_(2)^(-)during short-cut sulfur autotrophic denitrification(SSADN)in response to 0-35 mg/L hydroxylamine(NH_(2)OH)addition.At a dosage of 15 mg/L NH...This study investigates the simultaneous accumulation of S^(0) and NO_(2)^(-)during short-cut sulfur autotrophic denitrification(SSADN)in response to 0-35 mg/L hydroxylamine(NH_(2)OH)addition.At a dosage of 15 mg/L NH_(2)OH,the accumulation of NO_(2)^(-)-N peaked at 32.49±1.33 mg/L,which is 1.65 times higher than that of the control.The addition of NH_(2)OH facilitates the retention of S^(0) in the system.Enzyme assays indicated significant discrepancies in the enhanced NO_(2)^(-)-N reductase(NAR)and NO_(2)^(-)-N reductase(NIR)activities induced by NH_(2)OH are responsible for the excellent NO_(2)^(-)-N production.These results are supported by the corresponding NO_(3)^(-)-N reduction genes(napA,narG)and NO_(2)^(-)-N reduction genes(nirS,nirK).In addition,the abundance of sulfur oxidation genes(soxB)decreases with increasing NH_(2)OH dosage,inhibiting further oxidation of S^(0) to SO_(4)^(2-).The accumulation of NO_(2)^(-)-N and S^(0) increases from 45.8% and 36.8% to 70.04% and 52.52%,respectively,with the addition of 2 mg/L NH_(2)OH in the continuous-flow up-flow anaerobic sludge blanket(UASB)reactor.展开更多
Due to the influence of human activities, such as improper discharge of domestic sewage and livestock manure, abuse and loss of chemical fertilizers and pesticides, nitrate pollution in water has become a major enviro...Due to the influence of human activities, such as improper discharge of domestic sewage and livestock manure, abuse and loss of chemical fertilizers and pesticides, nitrate pollution in water has become a major environmental problem. It has been reported that high nitrate concentration in water may lead to serious human health problems including methemoglobinemia and cancer, as well as ecological and environmental problems such as water eutrophication. Therefore, how to effectively remove nitrate has been the research focus in the field of water treatment. According to the mechanism of sulfur autotrophic denitrification, a large amount of sulfate will be produced while nitrate is reduced, which may cause the sulfate in effluent to exceed the standard;At the same time, the alkalinity in the system will be obviously consumed in the reaction process, resulting in a decrease in effluent pH value. In addition, when solid-phase sulfur source is used as electron donor, the mass transfer rate between bacteria and material is low, which is also an important factor limiting denitrification effect and efficiency. Therefore, the research status of sulfur autotrophic denitrification technology is reviewed in this paper, including microbial community structure and metabolic mechanism, selection of electron donors, application in water treatment, and synergistic denitrification with heterotrophic denitrification, etc. At the same time, the future development of this technology is prospected.展开更多
Carbon fixation by soil autotrophic microbes is an overlooked process in organic carbon anabolism,which is potentially affected by biochar.In this study,we quantified the abundance of functional genes cbbL and cbbM,ke...Carbon fixation by soil autotrophic microbes is an overlooked process in organic carbon anabolism,which is potentially affected by biochar.In this study,we quantified the abundance of functional genes cbbL and cbbM,key components of the widely distributed Calvin cycle,and combined this with Ribulose-1,5-bisphosphate carboxylase/oxygenase(RubisCO)enzyme activity assays and high-throughput sequencing of cbbL-and cbbM-harboring microbial communities to investigate the carbon fixation potential,activity,and community structure under biochar application in paddy and upland soils.Results showed that cbbL consistently dominated over cbbM in both paddy and upland soils,with higher abundances in paddy soils,driven by biochar amendment,rice growth stage,and rhizosphere effects.The rhizosphere acted as a hotspot for cbbL and cbbM genes and RubisCO activity in paddy soil.In upland soils,nitrogen availability(NH_(₄)^(+),dissolved organic nitrogen-DON),microbial biomass carbon,and labile carbon and nitrogen pools(dissolved organic carbon,N-acetyl-β-D-glucosaminidase)were consistently associated with cbbL abundance,underscoring their ecological role in soil CO_(2)fixation.In paddy soils,inorganic nitrogen(NH_(₄)^(+),NO_(3)^(⁻),NO_(2)^(⁻)),redox potential(Eh),and urease activity were the main predictors of cbbL abundance and the cbbL/16S ratio,while pH and nitrogen availability(NO_(2)^(⁻),DON)was mostly associated with cbbM/16S ratio.Biochar was the primary driver reshaping the structure of autotrophic microbial communities harboring cbbL and cbbM genes across different soil compartments,including surface soil,rhizosphere,and bulk soil.Pseudomonadota,Cyanobacteriota,Actinomycetota and Chloroflexota were dominant cbbL carriers,while Pseudomonadota,Actinomycetota and Myxococcota predominated in cbbM assemblages across soils.Biochar induced functional differentiation of facultative autotrophic taxa under different RubisCO forms by enhancing the abundance of Rhodopseudomonas in cbbM-bearing communities while decreasing it in cbbL-bearing ones.Furthermore,Calvin cycle-mediated CO_(2)fixation was found to couple with pathways including methylotrophy,methanotrophy,iron oxidation and respiration,nitrogen fixation and reduction,and arsenate reduction and detoxification.Collectively,the results of this study emphasize the importance of soil type,micro-environmental conditions,nitrogen status and the impact of biochar in shaping microbial carbon assimilation via the Calvin cycle pathway and the cbbL and cbbM-harboring microbial community.展开更多
Sulfur autotrophic denitrification(SAD)is a promising biological nitrogen removal technology without CO_(2)emissions.However,the impact of seasonal temperature variations on SAD performance,especially in the treatment...Sulfur autotrophic denitrification(SAD)is a promising biological nitrogen removal technology without CO_(2)emissions.However,the impact of seasonal temperature variations on SAD performance,especially in the treatment of actual municipal secondary effluent,remains unclear.To address this issue,a composite substrate SAD reactor(i.e.,SPSAD),where element S^(0)and pyrite(v:v/1:3)were uniformly mixed in hollow plastic balls that served as the filler,was developed in this paper.The performance of the SPSAD reactor was comprehensively evaluated under 190 d of seasonal variation.The results indicated that the nitrate removal loading(NRL),nitrate removal efficiency(NRE),and PO_(4)^(3-)-P removal rate decreased from 0.060 kg NO_(3)^(-)-N/(m^(3)·d),93.2%and 67.9%to 0.032 kg NO_(3)^(-)-N/(m^(3)·d),49.9%and 30.2%,respectively,when the temperature decreased from 35℃ to 9℃.The SPSAD reactor was effective at performing denitrification under temperature variations.Additionally,the ratio ofΔSO_(4)^(2-)toΔNO_(3)^(-)-N gradually decreased from 6.48 to 5.34 as the temperature decreased,revealing a shift in the predominant electron donor for denitrification from S^(0)to pyrite.Microbial analysis revealed that the average abundance of Proteobacteria was 53.11%,making it the dominant phylum in the reactor.Thiobacillus was significantly enriched as the predominant genus responsible for denitrification,with its abundance decreasing from 33.2%at Stage I(25-35℃)to 26.4%at Stage III(9-11℃).The feasibility and advantages of NO_(3)^(-)-N and PO_(4)^(3-)-P removal via the SPSAD reactor were discussed and demonstrated in practical applications.This study provides stakeholders with scientific support for the deep treatment of municipal secondary effluent in cold areas.展开更多
An innovative advanced wastewater treatment process combining biologic aerated filter （BAF） and sulfur/ ceramisite-based autotrophic denitrification （SCAD） for reliable removal of nitrogen was proposed in this pap...An innovative advanced wastewater treatment process combining biologic aerated filter （BAF） and sulfur/ ceramisite-based autotrophic denitrification （SCAD） for reliable removal of nitrogen was proposed in this paper. In SCAD reactor, ceramisite was used as filter and Ca （HCO3）2 was used for supplying alkalinity and carbon source. The BAF-SCAD was used to treat the secondary treatment effluent. The performance of this process was investigated, and the impact of temperature on nitrogen removal was studied. Results showed that the combined system was effective in nitrogen removal even at low temperatures （8℃）. Removal of total nitrogen （TN）, NH4＋ -N, NO3-N reached above 90% at room temperature. Nitrification was affected by the temperature and nitrification at low temperature （8℃） was a limiting factor for TN removal. However, denitrification was not impacted by the temperature and the removal of NO3 -N maintained 98% during the experimental period. The reason of effective denitrification at low temperature might be the use of easily dissolved Ca（HCO3）2 and high-flux ceramisite, which solved the problem of low mass transfer efficiency at low temperatures. Besides, vast surface area of sulfur with diameter of 2-6 mm enhanced the rate of microbial utilization. The removal of nitrate companied with the production of SO42-, and the average concentration of SO27 was about 240mg.L^-1. These findings would be beneficial for the application of this process to nitrogen removal especially in the winter and cold regions.展开更多
基金supported by the National Natural Science Foundation of China(No.42377083)the Natural Science Foundation of Sichuan Province,China(No.2025 ZNSFSC0433).
文摘In this work,ofloxacin(OFL),a kind of frequently detected antibiotic in groundwater,was selected to explore its impact(at ng/L-μg/L-level)on denitrification performance in an autotrophic denitrification system driven by pyrite/sulfur(FeS2/S0).Results showed that OFL restrained nitrate removal efficiency,and the inhibition degree was positively related to the concentration of OFL.After being exposed to increased OFL(200 ng/L-100μg/L)for 69 days,higher inhibition of electron transport activity(ETSA),enzyme activities of nitrate reductase(NAR),and nitrite reductase(NIR)were acquired.Meanwhile,the extracellular protein(PN)content of sludge samples was remarkably stimulated by OFL to resist the augmented toxicity.OFL contributed to increased microbial diversity and sulfur/sulfide oxidation functional genes in ng/L-level bioreactors,whereas led to a decline inμg/L level experiments.With OFL at concentrations of 200 ng/L and 100μg/L,the whole expression of 10 key denitrification functional genes was depressed,and the higher the OFL concentration,the lower the expression level.However,no significant proliferation of antibiotic resistance genes(ARGs)either in 200 ng/L-OFL or 100μg/L-OFL groups was observed.Two-factor correlation analysis results indicated that Thiobacillus,Anaerolineae,Anaerolineales,and Nitrospirae might be the main hosts of existing ARGs in this system.
基金supported by the National Natural Science Foundation of China(No.31970106).
文摘This study presents a novel approach,the Supercapacitor Microbial Electrolysis Cell(SCMEC),which utilizes a supercapacitor as an external power source to enhance the efficiency of autotrophic nitrogen removal in low C/N ratio wastewater.The results demonstrated that the SC-MEC system,operating under anaerobic conditions and devoid of any organic carbon source,exhibited exceptional performance in ammonia oxidation and total nitrogen(TN)removal when solely relying on ammonia nitrogen as the electron donor.Operating at a voltage of 1.8 V with a capacitance capacity of 30 F,ammonium oxidation rated up to 56.51 mg/L/day and TN removal rated up to 54.64 mg/L/day,in which 97%of ammonium nitrogen was converted to gaseous nitrogen.Furthermore,the charging and discharging process of supercapacitors autonomously regulated the bipolar potentials.Cyclic voltammetry(CV)analysis showed the significantly enhanced electrochemical activity of the SCMEC system during the reaction process.Based on in-situ CV test results,itwas inferred that this enhancementwas associated with extracellular electron transfer mediators.Themicrobial community analysis revealed a process of synchronous nitrification and denitrification(SND)coupled with anammox,involvingmultiple genera,such as Candidatus Kuenenia,Nitrosomonas,Truepera,and Bosea.In conclusion,this study highlights the tremendous potential of SC-MEC in achieving efficient autotrophic nitrogen removal,offering more feasible and economical solutions for addressing low C/N water pollution issues.
文摘Sulfur autotrophic denitrification technology is a low-carbon and environmentally friendly wastewater treatment technology.The effects of factors such as pH,temperature,S/N and salinity on the efficiency of sulfur autotrophic denitrification reactions were discussed,and the community characteristics of microorganisms were summarized.This article also introduced the future research and development directions of this process.
基金supported by the National Natural Science Foundation of China(No.50808121)the Chinese National Key Projects of Water Pollution Control and Reclamation(No.2008ZX07106-2-2)
文摘Sulfur-limestone was used in the autotrophic denitrification process to remove the nitrate and nitrite in a lab scale upflow biofilter.Synthetic water with four levels of nitrate and nitrite concentrations of 10,40,70 and 100 mg N/L was tested.When treating the low concentration of nitrate-or nitrite-contaminated water（10,40 mg N/L）,a high removal rate of about 90% was achieved at the hydraulic retention time（HRT） of 3 hr and temperature of 20-25°C.At the same HRT,50% of the nitrate or nitrite could be removed even at the low temperature of 5-10°C.For the higher concentration nitrate and nitrite（70,100 mg N/L）,longer HRT was required.The batch test indicated that influent concentration,HRT and temperature are important factors afiecting the denitrification eficiency.Molecular analysis implied that nitrate and nitrite were denitrified into nitrogen by the same microorganisms.The sequential two-step-reactions from nitrate to nitrite and from nitrite to the next-step product might have taken place in the same cell during the autotrophic denitrification process.
基金supported by the National Key Research and Development Programme of China(No.2016YFC 0401103)the National Natural Science Foundation of China(No.51408387)the Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment
文摘In order to reduce the amount of NO_3^-–N generated by the Anammox process, and alleviate the competition between denitrification and Anammox for NO_2^-–N in a single reactor, the preference of S^0 for reacting with coexisting NO_2^-–N and NO_3^-–N in the sulfur autotrophic denitrifying(SADN) process and the coupling effect of short-cut SADN and the Anammox process were studied. The results showed that S^0 preferentially reacted with NO_3^-to produce NO_2^-–N, and then reacted with NO_2^-–N when NO_3^-–N was insufficient, which could effectively alleviate the competition between SADN bacteria(SADNB) and Anammox bacteria(An AOB) for NO_2^-–N. After 170 days of operation, coupling between short-cut S^0-SADN and the Anammox process was first successfully achieved. SADNB converted the NO_3^-–N generated by the Anammox process into NO_2^-–N, which was once again available to An AOB. The total nitrogen removal efficiency eventually stabilized at over 95%, and the effluent NO_3^-–N was controlled within 10 mg/L, when high NH_4^+–N wastewater was treated by the Anammox process. Microbial community analysis further showed that Candidatus Brocadia and Thiobacillus were the functional microorganisms for An AOB and SADNB.
基金supported by the Special Fundof State Key Joint Laboratory of Environment Simulation and Pollution Control,China (No. 08Y03ESPCT)the Key Projects in the National Science & Technology Pillar Program in the Eleventh Five-Year Plan Period of China(No. 2006BACl9B01)
文摘A combined process consisting of a short-cut nitrification （SN） reactor and an anaerobic ammonium oxidation upflow anaerobic sludge bed （ANAMMOX） reactor was developed to treat the diluted effluent from an upflow anaerobic sludge bed （UASB） reactor treating high ammonium municipal landfill leachate.The SN process was performed in an aerated upflow sludge bed （AUSB） reactor （working volume 3.05 L）,treating about 50% of the diluted raw wastewater.The ammonium removal efficiency and the ratio of NO 2 N to NOx-N in the effluent were both higher than 80%,at a maximum nitrogen loading rate of 1.47 kg/（m 3 ·day）.The ANAMMOX process was performed in an UASB reactor （working volume 8.5 L）,using the mix of SN reactor effluent and diluted raw wastewater at a ratio of 1：1.The ammonium and nitrite removal efficiency reached over 93% and 95%,respectively,after 70-day continuous operation,at a maximum total nitrogen loading rate of 0.91 kg/（m 3 ·day）,suggesting a successful operation of the combined process.The average nitrogen loading rate of the combined system was 0.56 kg/（m 3 ·day）,with an average total inorganic nitrogen removal efficiency 87%.The nitrogen in the effluent was mostly nitrate.The results provided important evidence for the possibility of applying SN-ANAMMOX after UASB reactor to treat municipal landfill leachate.
基金the financial support from the National Natural Science Foundation of China(No.51878231)。
文摘Sulfur-driven autotrophic denitrification(SDAD),a process suited for the treatment of nitrogen and sulfur-polluted wastewater without extra supplement of organic carbon,is a promising biological nitrogen removal process.However,the SDAD process was affected by many factors such as various electron donors,organic carbon and exogenous substances(e.g.,antibiotics and heavy metal),which prevent further application.Thus,we conducted a detailed review of previous studies on such influence factors and its current application.Besides,a comparative analysis was adopted to recognize the current challenges and future needs for feasible application,so as to ultimately perfect the SDAD process and extend its application scope.
基金supported by the Trans-Century Training Program Foundation for Talents from the Ministry of Education of China (No. NCET-10-0008)the Open Project of State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology (No.QAK201005)the National Water Pollution Control and Management Technology Major Projects (No.2012ZX07202-005)
文摘The stability and parameters of a bio-ceramic filter for completely autotrophic nitrogen removal were investigated. The completely autotrophic nitrogen removal over nitrite （CANON） reactor was fed with different concentrations of ammonia （400, 300, and 200 mg N/L） but constant influent ammonia load. The results showed that the CANON system can achieve good treatment performance at ambient temperature （15-23℃）. The average removal rate and removal loading of NH4＋-N and TN was 83.90%, 1.26 kg N/（m3.day）, and 70.14%, 1.09 kg N/（m3.day）, respectively. Among the influencing factors like pH, dissolved oxygen and alkalinity, it was indicated that the pH was the key parameter of the performance of the CANON system. Observing the variation of pH would contribute to better control of the CANON system in an intuitive and fast way. Denaturing gradient gel electrophoresis analysis of microorganisms further revealed that there were some significant changes in the community structure of ammonium oxidizing bacteria, which had low diversity in different stages, while the species of anaerobic ammonium oxidizing （anammox） bacteria were fewer and the community composition was relatively stable. These observations showed that anaerobic ammonia oxidation was more stable than the aerobic ammonia oxidation, which could explain that why the CANON system maintained a good removal efficiency under the changing substrate conditions.
基金supported by the National Natural Science Foundation of China (No. 51478262)The Chinese National Key Projects of Water Pollution Control and Reclamation (No. 2012ZX07101-007-005)the Open Fund Project of Zhejiang Mariculture Research Institute (No. J2013005)
文摘Eutrophication caused by high concentrations of nutrients is a huge problem for many natural lakes and reservoirs. Removing the nitrogen contamination from the low C/N water body has become an urgent need. Autotrophic denitrification with the sulfur compound as electron donor was investigated in the biofilter reactors. Through the lab-scale experiment,it was found that different sulfur compounds and different carriers caused very different treatment performances. Thiosulfate was selected to be the best electron donor and ceramsite was chosen as the suitable carrier due to the good denitrification efficiency, low cost and the good resistibility against the high hydraulic loads. Later the optimum running parameters of the process were determined. Then the pilot-scale experiment was carried out with the real micro-polluted water from the West Lake, China. The results indicated that the autotrophic denitrification with thiosulfate as electron donor was feasible and applicable for the micro-polluted lake water.
基金The National Key Basic Research Special Foundation of China under contract No.2013CB965101the Marine Science and Technology Foundation of the South China Sea Sub-administration,SOA,China under contract No.1624
文摘The importance of dissolved organic phosphorus(DOP) as a potential nutrient source for primary producers in marine systems has been recognized for up to eight decades, but currently, the understanding of the biogeochemistry of DOP is in its infancy. In the present study, monthly data between 2000 and 2014 were used to analyze the temporal and spatial distributions of DOP in the Mir Bay, the northern South China Sea. The DOP residence time(TDOP) was also investigated using a simple regression analysis in combination with chlorophyll a(Chl a) measurements while excess DOP(ΔDOP), produced by the biogeochemical processes of autotrophic production and heterotrophic removal, was determined using a two-component mixing mass-balance model in combination with salinity measurements. The results showed that the DOP concentration was(0.017±0.010) mg/L higher in the surface-water compared with the bottom-water and higher in the inner Tolo Harbour and waters adjacent to Shatoujiao compared with the main zone of the bay. Although seasonal changes and annual variability in the DOP were small, the surface DOP concentration was higher in the wet season(April–September)than in the dry season(October–March) due to the impacts of seaward discharges and atmospheric deposition into the bay. Measurement and regression results showed that the DOP release rate from phytoplankton production was about 1.83(gP)/(gChl a) and the TDOP was about 7 d, which implied that the DOP cycle in the bay was rapid. The ΔDOP was calculated from the model to be about 0.000 mg/L in the main zone of the bay and about 0.002 mg/L in the inner Tolo Harbour and waters adjacent to Shaotoujiao, suggesting that the autotrophic production of DOP was almost balanced by the heterotrophic removal in the main zone of the bay and dominated in the inner Tolo Harbour and waters adjacent to Shaotoujiao. In conclusion, the Mirs Bay is very productive and fairly heterotrophic.
基金supported by the National Natural Science Foundation of China (21307160)the Natural Science Foundation of Shandong Province, China (ZR20192019MEE038)+3 种基金the Fundamental Research Funds for the Central Universities (19CX02038A)the Open Project of Key Laboratory of Environmental Biotechnology, CAS (Grant No. kf2018003)the Open Project Program of State Key Laboratory of Petroleum Pollution Control (Grant No. PPC2018006)the CNPC Research Institute of Safety and Environmental Technology
文摘Rapid formation of autotrophic partial denitrification(APD)granules is of practical interest to start up an expanded granular sludge bed reactor for wastewater treatment.This study demonstrates that methanogenic granules can be easily acclimated into autotrophic partial denitrification granules in one day,with the ability to remove 82%of 2.7 kg-S/(m^3·d)sulfide into S^0 and to convert 97%of 0.9 kg-N/(m^3·d)nitrate into nitrite,which can provide a promising feedstock for anaerobic ammonia oxidation process.Arcobacter sp.is essential for S^0 accumulation.Under high loadings,the abundance of Arcobacter sp.decreased,while on the contrary the abundance of unclassified_p_Firmicutes increased,leading to the deterioration of autotrophic partial denitrification performance.The granules performance could be recovered by adopting the strategies of properly reducing the influent loadings.
基金supported by the National Natural Science Foundation of China(Nos.52000186,51922110 and 52131001)。
文摘The removal of eight typical pharmaceuticals(Ph ACs)(i.e.,ibuprofen(IBU),ketoprofen(KET),diclofenac(DIC),sulfadiazine(SD),sulfamethoxazole(SMX),trimethoprim(TMP),ciprofloxacin(CIP)and enoxacin(ENO))in sulfur-driven autotrophic denitrification(Sd AD)process were firstly investigated via long-term operation of bioreactor coupled with batch tests.The results indicated that IBU and KET can be effectively removed(removal efficiency>50%)compared to other six Ph ACs in Sd AD bioreactor.Biodegradation was the primary removal route for IBU and KET with the specific biodegradation rates of 5.3±0.718.1±1.8μg g^(-1)-VSS d^(-1)at initial concentrations of 25-200μg/L.The biotransformation intermediates of IBU and KET were examined,and the results indicated that IBU was biotransformed to three intermediates via hydroxylation and carboxylation.KET biotransformation could be initiated from the reduction of the keto group following with a series of oxidation/reduction reactions,and five intermediates of KET were observed in this study.The microbial community composition in the system was markedly shifted when long-term exposure to Ph ACs.However,the functional microbes(e.g.,genus Thiobacillus)showed high tolerance to Ph ACs,resulting in the high efficiency for Ph ACs,N and S removal during long-term Sd AD reactor operation.The findings provide better insight into Ph ACs removal in Sd AD process,especially IBU and KET,and open up an innovative opportunity for the treatment of Ph ACs-laden wastewater using sulfur-mediated biological process.
基金Sponsored by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(Grant No.2012BAC04B02)Open Project of State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology(Grant No.QA201518)the Key Laboratory of the Education Department of Shaanxi Province(Grant No.12JS051)
文摘Nitrate is considered to be one of the most widely present pollutants leading to eutrophication of environment. The purpose of this work was to isolate and identify new anaerobic denitrifying bacteria from reservoir sediments and utilize different electron donors for isolates to improve nitrate removal efficiency. Using traditional enrichment approach,one purified anaerobic bacterium( Y12) capable of NO-3-N removal from sediments was obtained. The species identity of Y12 was determined via 16 S rRNA gene sequence analysis to be Acinetobacter. In this work,the fastest denitrification rates were observed with ferrous iron as electron donor.And,slightly slower rates were observed with hydrogen and sodium sulfide as electron donors. However,when used hydrogen gas, ferrous iron and sodium sulfide as electron donors, C / N ratios had little effect on autotrophic denitrification rate at the initial C / N ratio from 1.5 to 9.0. Meanwhile,when made use of hydrogen gas,ferrous iron and sodium sulfide as electron donors,a maximum nitrate removal ratio of 100.00%,91.43%and 87.99% at the temperature of 30 ℃,respectively. Moreover,maximum denitrification activity was observed at p H 6.0-7.0.
基金the Scientific and Technical Research Major Project Foundation of Educational Ministry of China (No. 308020)Natural Science Foundation of China (No. 50608071)Doctoral Fund of the Ministry of Education of China (No. 20050611010)
文摘The characteristics of the start-up period of single-step autotrophic nitrogen removal process were investigated. The autotrophic nitrogen removal process used a sequencing batch reactor to treat wastewater of medium to low ammonia-nitrogen concentration, with dissolved oxygen （DO）, hydraulic retention time （HRT） and temperature controlled. The experimental conditions were temperature at （30±2） ℃, ammonia concentration of （60 to 120） mg/L, DO of （0.8 to 1.0） mg/L, pH from 7.8 to 8.5 and HRT of 24 h. The rates of nitrification and nitrogen removal turn out to be 77% and 40%, respectively, after a start up period going through three stages divided according to nitrite accumulation： sludge domestication, nitrifying bacteria selection and sludge adaptation, It is demonstrated that dissolved oxygen is critical to nitrite accumulation and elastic YJZH soft compound packing is superior to polyhedral hollow balls in helping the bacteria adhere to the membrane.
文摘Carbon cycling research has increased over the past 20 years, but less is known about the primary contributors to soil respiration (i.e. heterotrophic and autotrophic) under dormant conditions. It is understood that soil CO2 effluxes are significantly lower during the winter of temperate ecosystems and assumed microorganisms dominate efflux origination. We hypothesized that heterotrophic contributions would be greater than autotrophic under simulated dormancy conditions. To test this hypothesis, we designed an experiment with the following treatments: combined autotrophic heterotrophic respiration, heterotrophic respiration, autotrophic respiration, no respiration, autotrophic respiration in vermiculite, and no respiration in vermiculite. Engelmann spruce seedlings and soil substrates were placed in specially designed respiration chambers and soil CO2 efflux measurements were taken four times over the course of a month. Soil microbial densities and root volumes were measured for each chamber after day thirty-three. Seedling presence resulted in significantly higher soil CO2 efflux rates for all soil substrates. Autotrophic respiration treatments were not representative of solely autotrophic soil CO2 efflux due to soil microbial contamination of autoclaved soil substrates;however, the mean autotrophic contributions averaged less than 25% of the total soil CO2 efflux. Soil microorganism communities were likely the primary contributor to soil CO2 efflux in simulated dormant conditions, as treatments with the greatest proportions of microbial densities had the highest soil CO2 efflux rates. Although this study is not directly comparable to field dormant season soil CO2 effluxes of Engelmann spruce forest, as snowpack is not maintained throughout this experiment, relationships, and metrics from such small-scale ecosystem component processes may yield more accurate carbon budget models.
基金supported by the Shandong Provincial Natural Science Foundation(No.ZR2019MEE038,ZR202110260011)the Scientific research project of Xinjiang oilfield company(No.2022C4004)the Qingdao West-Coast Economic New Area Scientific and Technological Project of the special open competition mechanism to select the best candidates(2022-14).
文摘This study investigates the simultaneous accumulation of S^(0) and NO_(2)^(-)during short-cut sulfur autotrophic denitrification(SSADN)in response to 0-35 mg/L hydroxylamine(NH_(2)OH)addition.At a dosage of 15 mg/L NH_(2)OH,the accumulation of NO_(2)^(-)-N peaked at 32.49±1.33 mg/L,which is 1.65 times higher than that of the control.The addition of NH_(2)OH facilitates the retention of S^(0) in the system.Enzyme assays indicated significant discrepancies in the enhanced NO_(2)^(-)-N reductase(NAR)and NO_(2)^(-)-N reductase(NIR)activities induced by NH_(2)OH are responsible for the excellent NO_(2)^(-)-N production.These results are supported by the corresponding NO_(3)^(-)-N reduction genes(napA,narG)and NO_(2)^(-)-N reduction genes(nirS,nirK).In addition,the abundance of sulfur oxidation genes(soxB)decreases with increasing NH_(2)OH dosage,inhibiting further oxidation of S^(0) to SO_(4)^(2-).The accumulation of NO_(2)^(-)-N and S^(0) increases from 45.8% and 36.8% to 70.04% and 52.52%,respectively,with the addition of 2 mg/L NH_(2)OH in the continuous-flow up-flow anaerobic sludge blanket(UASB)reactor.
文摘Due to the influence of human activities, such as improper discharge of domestic sewage and livestock manure, abuse and loss of chemical fertilizers and pesticides, nitrate pollution in water has become a major environmental problem. It has been reported that high nitrate concentration in water may lead to serious human health problems including methemoglobinemia and cancer, as well as ecological and environmental problems such as water eutrophication. Therefore, how to effectively remove nitrate has been the research focus in the field of water treatment. According to the mechanism of sulfur autotrophic denitrification, a large amount of sulfate will be produced while nitrate is reduced, which may cause the sulfate in effluent to exceed the standard;At the same time, the alkalinity in the system will be obviously consumed in the reaction process, resulting in a decrease in effluent pH value. In addition, when solid-phase sulfur source is used as electron donor, the mass transfer rate between bacteria and material is low, which is also an important factor limiting denitrification effect and efficiency. Therefore, the research status of sulfur autotrophic denitrification technology is reviewed in this paper, including microbial community structure and metabolic mechanism, selection of electron donors, application in water treatment, and synergistic denitrification with heterotrophic denitrification, etc. At the same time, the future development of this technology is prospected.
基金the National Natural Science Foundation of China(Grant No.42177107,42307043,21607125)Natural Science Foundation of Anhui Province,China(Grant No.2108085MC85).
文摘Carbon fixation by soil autotrophic microbes is an overlooked process in organic carbon anabolism,which is potentially affected by biochar.In this study,we quantified the abundance of functional genes cbbL and cbbM,key components of the widely distributed Calvin cycle,and combined this with Ribulose-1,5-bisphosphate carboxylase/oxygenase(RubisCO)enzyme activity assays and high-throughput sequencing of cbbL-and cbbM-harboring microbial communities to investigate the carbon fixation potential,activity,and community structure under biochar application in paddy and upland soils.Results showed that cbbL consistently dominated over cbbM in both paddy and upland soils,with higher abundances in paddy soils,driven by biochar amendment,rice growth stage,and rhizosphere effects.The rhizosphere acted as a hotspot for cbbL and cbbM genes and RubisCO activity in paddy soil.In upland soils,nitrogen availability(NH_(₄)^(+),dissolved organic nitrogen-DON),microbial biomass carbon,and labile carbon and nitrogen pools(dissolved organic carbon,N-acetyl-β-D-glucosaminidase)were consistently associated with cbbL abundance,underscoring their ecological role in soil CO_(2)fixation.In paddy soils,inorganic nitrogen(NH_(₄)^(+),NO_(3)^(⁻),NO_(2)^(⁻)),redox potential(Eh),and urease activity were the main predictors of cbbL abundance and the cbbL/16S ratio,while pH and nitrogen availability(NO_(2)^(⁻),DON)was mostly associated with cbbM/16S ratio.Biochar was the primary driver reshaping the structure of autotrophic microbial communities harboring cbbL and cbbM genes across different soil compartments,including surface soil,rhizosphere,and bulk soil.Pseudomonadota,Cyanobacteriota,Actinomycetota and Chloroflexota were dominant cbbL carriers,while Pseudomonadota,Actinomycetota and Myxococcota predominated in cbbM assemblages across soils.Biochar induced functional differentiation of facultative autotrophic taxa under different RubisCO forms by enhancing the abundance of Rhodopseudomonas in cbbM-bearing communities while decreasing it in cbbL-bearing ones.Furthermore,Calvin cycle-mediated CO_(2)fixation was found to couple with pathways including methylotrophy,methanotrophy,iron oxidation and respiration,nitrogen fixation and reduction,and arsenate reduction and detoxification.Collectively,the results of this study emphasize the importance of soil type,micro-environmental conditions,nitrogen status and the impact of biochar in shaping microbial carbon assimilation via the Calvin cycle pathway and the cbbL and cbbM-harboring microbial community.
基金supported by the National Natural Science Foundation of China(Nos.52400145,51974314,and 52270171)the Special Project on Bases and Talents of the Ministry of Science and Technology of China(No.2022XJKK1004)the Fundamental Research Funds for the Central Universities of China(No.2019XKQYMS79).
文摘Sulfur autotrophic denitrification(SAD)is a promising biological nitrogen removal technology without CO_(2)emissions.However,the impact of seasonal temperature variations on SAD performance,especially in the treatment of actual municipal secondary effluent,remains unclear.To address this issue,a composite substrate SAD reactor(i.e.,SPSAD),where element S^(0)and pyrite(v:v/1:3)were uniformly mixed in hollow plastic balls that served as the filler,was developed in this paper.The performance of the SPSAD reactor was comprehensively evaluated under 190 d of seasonal variation.The results indicated that the nitrate removal loading(NRL),nitrate removal efficiency(NRE),and PO_(4)^(3-)-P removal rate decreased from 0.060 kg NO_(3)^(-)-N/(m^(3)·d),93.2%and 67.9%to 0.032 kg NO_(3)^(-)-N/(m^(3)·d),49.9%and 30.2%,respectively,when the temperature decreased from 35℃ to 9℃.The SPSAD reactor was effective at performing denitrification under temperature variations.Additionally,the ratio ofΔSO_(4)^(2-)toΔNO_(3)^(-)-N gradually decreased from 6.48 to 5.34 as the temperature decreased,revealing a shift in the predominant electron donor for denitrification from S^(0)to pyrite.Microbial analysis revealed that the average abundance of Proteobacteria was 53.11%,making it the dominant phylum in the reactor.Thiobacillus was significantly enriched as the predominant genus responsible for denitrification,with its abundance decreasing from 33.2%at Stage I(25-35℃)to 26.4%at Stage III(9-11℃).The feasibility and advantages of NO_(3)^(-)-N and PO_(4)^(3-)-P removal via the SPSAD reactor were discussed and demonstrated in practical applications.This study provides stakeholders with scientific support for the deep treatment of municipal secondary effluent in cold areas.
基金Acknowledgements Authors thank the financial supports from the National Natural Science Foundation of China （Grant Nos. 51278489 and 51278143） and Program of International Science and Technology Cooperation （2010DFA92090）.
文摘An innovative advanced wastewater treatment process combining biologic aerated filter （BAF） and sulfur/ ceramisite-based autotrophic denitrification （SCAD） for reliable removal of nitrogen was proposed in this paper. In SCAD reactor, ceramisite was used as filter and Ca （HCO3）2 was used for supplying alkalinity and carbon source. The BAF-SCAD was used to treat the secondary treatment effluent. The performance of this process was investigated, and the impact of temperature on nitrogen removal was studied. Results showed that the combined system was effective in nitrogen removal even at low temperatures （8℃）. Removal of total nitrogen （TN）, NH4＋ -N, NO3-N reached above 90% at room temperature. Nitrification was affected by the temperature and nitrification at low temperature （8℃） was a limiting factor for TN removal. However, denitrification was not impacted by the temperature and the removal of NO3 -N maintained 98% during the experimental period. The reason of effective denitrification at low temperature might be the use of easily dissolved Ca（HCO3）2 and high-flux ceramisite, which solved the problem of low mass transfer efficiency at low temperatures. Besides, vast surface area of sulfur with diameter of 2-6 mm enhanced the rate of microbial utilization. The removal of nitrate companied with the production of SO42-, and the average concentration of SO27 was about 240mg.L^-1. These findings would be beneficial for the application of this process to nitrogen removal especially in the winter and cold regions.
