This study evaluated the effect of potassium ferrate(PF)and low-temperature thermal hydrolysis co-pretreatment on the promotion of sludge hydrolysis process and the impact on acid production in the subsequent anaerobi...This study evaluated the effect of potassium ferrate(PF)and low-temperature thermal hydrolysis co-pretreatment on the promotion of sludge hydrolysis process and the impact on acid production in the subsequent anaerobic digestion process.The analytical investigations showed that co-pretreatment significantly facilitated the hydrolysis process of the sludge and contributed to the accumulation of short-chain fatty acids(SCFAs).The pretreatment conditions under the optimal leaching of organic matter from sludge were hydrothermal temperature of 75℃,hydrothermal treatment time of 12 h,and PF dosage of 0.25 g g^(−1)TSS(total suspended solids),according to the results of orthogonal experiments.By pretreatment under proper conditions,the removal rate of soluble chemical oxygen demand(SCOD)achieved 71.8%at the end of fermentation and the removal rate of total phosphorus(TP)was 69.1%.The maximum yield of SCFAs was 750.3 mg L^(−1),7.45 times greater than that of the blank group.Based on the analysis of the anaerobic digestion mechanism,it was indicated that the co-pretreatment could destroy the floc structure on the sludge surface and improve organic matter dissolving,resulting in more soluble organic substances for the acidification process.Furthermore,microbial community research revealed that the main cause of enhanced SCFAs generation was an increase in acidogenic bacteria and a reduction of methanogenic bacteria.展开更多
[Objective] The aim was to study on effect of sludge from different sources on biogas yield efficiency through anaerobic digestion of corn straw. [Method] The present research studied on daily biogas yield and the acc...[Objective] The aim was to study on effect of sludge from different sources on biogas yield efficiency through anaerobic digestion of corn straw. [Method] The present research studied on daily biogas yield and the accumulated biogas amount through anaerobic digestion of corn straw and sludges from four sources. [Result] The accumulated biogas yields produced from sludges in four sources from high to low were granular sludge, river sediments, concentrated sludge and filtered sludge. The first one proved the highest at 3.73 and 56.29 L/kg VS in daily biogas yield and the accumulated biogas. [Conclusion] The research laid foundation for full utilization of straw, improvement of energy utilization and sustainable development.展开更多
The synergetic effect and underlying mechanism of potassium ferrate(PF)with tea saponin(TS,a biosurfactant)in producing short chain fatty acids(SCFAs)from anaerobic fermentation of waste activated sludge(WAS)were expl...The synergetic effect and underlying mechanism of potassium ferrate(PF)with tea saponin(TS,a biosurfactant)in producing short chain fatty acids(SCFAs)from anaerobic fermentation of waste activated sludge(WAS)were explored in this work.Experimental results showed that 0.2 g PF(g TSS)^(-1)(total suspended solid)combined with 0.02 g TS(g TSS)^(-1) could further improve SCFAs’production,and the maximum SCFAs content reached 2008.7 mg COD L^(-1),which is 1.2 and 4.5 times higher than those with PF and TS individually added,respectively,and 5.3 times higher than that of blank WAS on Day 12.In the model substrates experiments,the degradation rates of bovine serum albumin and dextran with combination of PF and TS were 41.3%±0.1% and 48.5%±0.06%,respectively,on Day 3,which are lower than those in blank WAS(with degradation rates of 72.3%±0.5%and 90.3%±0.3%).It was revealed that the oxidative effect of PF and the solubilization of TS caused more organic matters to be dissolved out from WAS,providing a large number of biodegradable substances for subsequent SCFAs production.While WAS pretreated with the combination of PF and TS,the relative abundances of Firmicutes increased from 6.4%(blank)to 38.6%,and that of Proteobacteria decreased from 41.8%(blank)to 21.8%.The combination of PF and TS promoted the hydrolysis process of WAS by enriching Firmicutes,and then increased acetic acid production by inhibiting Proteobacteria that consumed SCFAs.Meanwhile,at the genus level,acidogenesis bacteria(e.g.,Proteiniclasticum and Petrimonas)were enriched whereas SCFAs consuming bacteria(e.g.,Dokdonella)were inhibited.展开更多
Effect of ultrasonic pretreatment on sludge dewaterability was determined and the fate of extracellular polymeric substances （EPS） matrix in mesophilic anaerobic digestion after ultrasonic pretreatment was studied. ...Effect of ultrasonic pretreatment on sludge dewaterability was determined and the fate of extracellular polymeric substances （EPS） matrix in mesophilic anaerobic digestion after ultrasonic pretreatment was studied. Characteristics of proteins （PN）, polysaccharides （PS）, excitation-emission matrix （EEM） fluorescence spectroscopy and molecular weight （MW） distribution of dissolved organic matters （DOM） in different EPS fractions were evaluated. The results showed that after ultrasonic pretreatment, the normalized capillary suction time （CST） decreased from 44.4 to 11.1 （sec·L）/g total suspended solids （TSS） during anaerobic digestion, indicating that sludge dewaterability was greatly improved. The normalized CST was significantly correlated with PN concentration （R2 = 0.92, p 〈 0.01） and the PN/PS ratio （R2 = 0.84, p 〈 0.01） in the loosely bound EPS （LB-EPS） fraction. Meanwhile, the average MW of DOM in the LB- EPS and tightly bound EPS （TB-EPS） fractions also had a good correlation with the normalized CST （R2 〉 0.66, p 〈 0.01）. According to EEM fluorescence spectroscopy, tryptophan-like substances intensities in the slime, LB-EPS and TB-EPS fractions were correlated with the normalized CST. The organic matters in the EPS matrix played an important role in influencing sludge dewaterability.展开更多
Objective To investigate the effect of chemical oxygen demand （COD） concentrations on the anaerobic ammonium oxidation （ANAMMOX）. Methods An Expanded Granular Sludge Bed （EGSB） reactor was used to cultivate the ...Objective To investigate the effect of chemical oxygen demand （COD） concentrations on the anaerobic ammonium oxidation （ANAMMOX）. Methods An Expanded Granular Sludge Bed （EGSB） reactor was used to cultivate the granular sludge and to perform the ANAMMOX reaction in the bench scale experiment. NH4^＋-N and NO2^--N were measured by using colorimetric method. NO3^＋-N was analyzed by using the UV spectrophotometric method. COD measurement was based on digestion with potassium dichromate in concentrated sulphuric acid. Results When the COD concentrations in the reactors were 0 mg/L, 200 mg/L, 350 mg/L, and 550 mg/L, respectively, the NH4^＋-N removal efficiency was 12.5%, 14.2%, 14.3%, and 23.7%; the removal amount of NO2-N was almost the same; the nitrate removal efficiency was 16.8%, 94.5%, 86.6%, and 84.2% and TN removal efficiency was 16.3%, 50.7%, 46.9%, and 50.4%, moreover, the COD removal efficiency was 85%, 65.7%, and 60%; the COD removal rate was 27.42, 61.88, and 97.8 mg COD/（h·L）. Conclusion COD concentrations have a significant influence on anaerobic ammonium oxidation by granular sludge.展开更多
The present study deals with the performance evaluation of the UASB reactor under varied organic loading rate(OLR) for the treatment of paper mill wastewater. The sludge granulation process started after 120 days from...The present study deals with the performance evaluation of the UASB reactor under varied organic loading rate(OLR) for the treatment of paper mill wastewater. The sludge granulation process started after 120 days from the start-up period. Sludge granules size was found to be 0 8 mm at OLR of 1 72 kgCOD/(m 3·d), which reached maximum size of about 1 0 to 1 2 mm at OLR of 2 1 kgCOD/(m 3·d). At the end of initial OLR of 1 0 kgCOD/(m 3·d) the VSS concentration was 12 86 gVSS/L, which got increased to 38 05 gVSS/L at the end of an OLR 2 1 kgCOD/(m 3·d). Most of the times VFA recorded were well within the limit of VFA reported in anaerobic fermentation process. Many times the pH observed was between 6 5 and 7 8, which is more favorable for any anaerobic process. It is also found that pH within the reactor increases along with the height of reactor. The total maximum biogas production was found to be 0 40 L/gCOD removals at OLR of 2 1 kgCOD/(m 3·d) and the maximum BOD removal at this stage was observed to be 90%.展开更多
This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L^-1（Na^＋）, on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At ...This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L^-1（Na^＋）, on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At the optimum sodium ion concentration [1000-2000mg·L^-1（Na^＋）] for hydrogen production at 37℃, the maximum sucrose degradation rate, the specific hydrogen production yield and the specific hydrogen production rate were 393.6-413.1mg·L^-1.h^-1, 28.04-28.97ml·g^-1, 7.52-7.83ml·g^-1.h^-1, respectively. The specific production yields of propionate, butyrate and valerate decreased with increasing sodium ion concentration, whereas the specific acetate production yield increased, meanwhile the specific production yields of ethanol and caproate were less than 55.3 and 12.6mg·g^-1, respectively. The hybrid fermentation composition gradually developed from acetate, propionate and butyrate to acetate with the increase in sodium ion concentration.展开更多
A series of batch experiments were conducted in 125 mL serum bottles to assess the toxicity of different concentrations of ammonia nitrogen to the specific methanogenic activity of anaerobic granular sludge from upflo...A series of batch experiments were conducted in 125 mL serum bottles to assess the toxicity of different concentrations of ammonia nitrogen to the specific methanogenic activity of anaerobic granular sludge from upflow anaerobic sludge bed（UASB） and expanded granular sludge bed（EGSB） reactors. The effects of pH value and temperature on toxicity of ammonia nitrogen to anaerobes were investigated. The results show that the specific methanogenic activity of anaerobic granular sludge suffers inhibition from ammonia nitrogen, the concentrations of ammonia nitrogen that produce 50 % inhibition of specific methanogenic activity for sludge from UASB and EGSB reactor are 2.35 and 2.75 g/L, respectively. Hydrogen utilizing methanogens suffers less inhibition from ammonia mtrogen than that of acetate utilizing methanogens. Hydrogen-producing acetogens that utilize propionate and butyrate as substrates suffer serious inhibition from ammonia nitrogen. The toxicity of ammonia nitrogen to anaerobic granular sludge enhances when pH value and temperature increase. Anaerobic granular sludge can bear higher concentrations of ammonia nitrogen after being acclimated by ammonia nitrogen for 7 d.展开更多
Sludge granulation is considered to be the most critical parameter governing successful operation of an upflow anaerobic sludge blanket and expanded granular sludge bed （EGSB） reactors. Pre-granulated seeding sludge...Sludge granulation is considered to be the most critical parameter governing successful operation of an upflow anaerobic sludge blanket and expanded granular sludge bed （EGSB） reactors. Pre-granulated seeding sludge could greatly reduce the required startup time. Two lab-scale and a pilot-scale EGSB reactors were operated to treat Shaoxing Wastewater Treatment Plant （SWWTP） containing wastewater from real engineering printing and dyeing with high pH and sulfate concentration. The microbiological structure and the particle size distribution in aerobic excess sludge, sanitary landfill sludge digested for one year, and the granular sludge of EGSB reactor after 400 d of operation were analyzed through scanning electron microscopy （SEM） and sieves. The lab-scale EGSB reactor seeded with anaerobic sludge after digestion for one year in landfill showed obviously better total chemical oxygen demand （TCOD） removal efficiency than one seeded with aerobic excess sludge after cation polyacrylamide flocculation-concentration and dehydration. The TCOD removed was 470.8 mg/L in pilot scale EGSB reactor at short hydraulic retention time of 15 h. SEM of sludge granules showed that the microbiological structure of the sludge from different sources showed some differences. SEM demonstrated that Methanobacterium sp. was present in the granules of pilot-scale EGSB and the granular sludge produced by landfill contained a mixture of anaerobic/anoxic organisms in abundance. The particle size distribution in EGSB demonstrated that using anaerobic granular sludge produced by sanitary landfill as the seeding granular sludge was feasible.展开更多
In this study,an up-flow anaerobic sludge blanket(UASB) reactor was applied to treat the high salinity wastewater from heavy oil production process.At a HRT of ≥24 h,the COD removal reached as high as 65.08% at an in...In this study,an up-flow anaerobic sludge blanket(UASB) reactor was applied to treat the high salinity wastewater from heavy oil production process.At a HRT of ≥24 h,the COD removal reached as high as 65.08% at an influent COD ranging from 350mg/L to 640mg/L.An average of 74.33% oil reduction was also achieved in the UASB reactor at an initial oil concentration between 112mg/L and 205mg/L.These results indicated that this heavy oil production related wastewater could be degraded efficiently in the UASB reactor.Granular sludge was formed in this reactor.In addition,two models,built on the back propagation neural network(BPNN) theory and linear regression techniques were developed for the simulation of the UASB system performance in the oily wastewater biodegradation.The average error of COD and oil removal was-0.65% and 0.84%,respectively.The results indicated that the models built on the BPNN theory were wellfitted to the detected data,and were able to simulate and predict the removal of COD and oil by the UASB reactor.展开更多
This paper presents the results obtained for the effluent dewatering properties of anaerobic digestion of secondary sludge （SS） and anaerobic co-digestion of mixture of this sludge with the distillery wastewater （D...This paper presents the results obtained for the effluent dewatering properties of anaerobic digestion of secondary sludge （SS） and anaerobic co-digestion of mixture of this sludge with the distillery wastewater （DW） under thermophilic （55±1 ℃）, 5 L of working volume, three parallel lab-scale conditions. Its mixtures were prepared with a DW content of 25%and 50% and the C/N ratios of mixtures are 13.1 and 17.6, respectively. The effluent dewatering properties were evaluated under stable conditions which the biogas yield and the effluent pH were steady. The natural settleability, biogas yield, centrifugal dewatering, centrifugal supernatant turbidity and specific resistance filtration （SRF） were investigated. The results showed that the effluent dewatering properties of anaerobic co-digestion of mixtures between SS and DW were better than that of anaerobic digestion of SS alone. In the anaerobic digestion system with the feed were SS, mixture of SS and a DW content of 25%and 50% in order, the net biogas yield of secondary sludge in ADSA,ADSB and ADSC were 0.42 0.507 and 0.511 m3 biogass/kg.VS.d ; compared with the biogas yield in anaerobic digestion system A （ADSA）, the biogas yield in anaerobic digestion system B （ADSB） and anaerobic digestion system C （ADSC） had been increased by more than 20% respectively; the SRF of three digested sludge are（were） from 6.8×10^13, 1. 1×10^13 to 5.1×10^12 m/Kg, natural settling rates of 12 h are 26, 37 and 56% and that of 24 h are 32%, 45% and 59% respectively; the centrifugal dewatering rate of 3 min at speed of 1000 rpm were 16%, 31% and 51% respectively; the turbidity of centrifugal supernatant were 804, 754 and 678FTU simultaneously.展开更多
The anaerobic digestion of septic sludge was studied through inoculating effective microorganisms (EMs) under mesophilic condition (35 ℃). The variation of COD,total solid (TS),volatile solid (VS),pH value and the ga...The anaerobic digestion of septic sludge was studied through inoculating effective microorganisms (EMs) under mesophilic condition (35 ℃). The variation of COD,total solid (TS),volatile solid (VS),pH value and the gas production rate during the digestion process were presented,and the optimal adding concentration of EMs was determined by comparing the reduction effectiveness of septic sludge. The results show that proper addition of EMs can enhance acid buffering capacity of the system,and the NH3-N concentration is lower than inhibition concentration of 2 g/L reported in the literature and maintain the range of pH value which is suitable for both hydrolysis-acidification and methanogenesis. However,overdose of EMs can reduce the initial pH value of septic sludge and decrease the effects of the anaerobic digestion. EMs can increase the quantity of microbe in septic sludge and improve the gas production and generation rate over a period of time. But overdosing EMs can lead to low pH,restrain activity of methanogenic bacteria and affect the quantity and the generation rate of gas. Adding 0.01% EMs achieves the highest sludge reduction with the removal rates of TS,VS and COD by 32.51%,42.34% and 40.97%,respectively.展开更多
The maximum specific sludge activity of granular sludge from large scale UASB, IC and Biobed anaerobic reactors were investigated by batch tests. The limitation factors related to maximum specific sludge activity (dif...The maximum specific sludge activity of granular sludge from large scale UASB, IC and Biobed anaerobic reactors were investigated by batch tests. The limitation factors related to maximum specific sludge activity (diffusion, substrate sort, substrate concentration and granular size) were studied. The general principle and procedure for the precise measurement of maximum specific sludge activity were suggested. The potential capacity of loading rate of the IC and Biobed anaerobic reactors were analyzed and compared by use of the batch tests results.展开更多
This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L-1(Na+), on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At the op...This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L-1(Na+), on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At the opti- mum sodium ion concentration [1000—2000mg·L-1(Na+)] for hydrogen production at 37℃, the maximum sucrose degradation rate, the specific hydrogen production yield and the specific hydrogen production rate were 393.6— 413.1mg·L-1·h-1, 28.04—28.97ml·g-1, 7.52—7.83ml·g-1·h-1, respectively. The specific production yields of propionate, butyrate and valerate decreased with increasing sodium ion concentration, whereas the specific acetate production yield increased, meanwhile the specific production yields of ethanol and caproate were less than 55.3 and 12.6mg·g-1, respectively. The hybrid fermentation composition gradually developed from acetate, propionate and butyrate to acetate with the increase in sodium ion concentration.展开更多
Municipal sludge was rich in organic matter, period of natural degradation was long and low efficiency, leachate would pollute underground water. In this paper, a comparative study of the ways of pretreatment with aci...Municipal sludge was rich in organic matter, period of natural degradation was long and low efficiency, leachate would pollute underground water. In this paper, a comparative study of the ways of pretreatment with acid alkali treatment, heat digestion and ultrasonic treatment were done. The results showed that The dehydro-genase activity were increased, the SCOD (soluable chemical oxygen demand, SCOD) in-creased more than 2.47~2.83, 1.70~1.76, 2.6~ 2.77 times respectively. The hydrogen yield in-creased more than 11.5~12.2, 24.1~24.7, 34.2~ 34.9 mL.g-1 (VS) respectively. The period of pro- hydrogen was shorten to 7.5, 8.0, 6.5 d respec-tively. The degradation rate was up to 72.04%, 81.4%, 80% respectively, the methane concen-tration in the gas was close to “zero” and ul-trasonic treatment was better than others. Gompertz model curve fitting on hydrogen production was carried out. All the values of correlation factor R2 were more than 0.97.展开更多
The aim of the research was to obtain both an excellent effluent for reuse and a reduced sludge production simultaneously by a combination process of anaerobic phase and Membrane bioreactor （MBR） technology in treat...The aim of the research was to obtain both an excellent effluent for reuse and a reduced sludge production simultaneously by a combination process of anaerobic phase and Membrane bioreactor （MBR） technology in treating domestic wastewater. During the experimental period of three months, excellent removals for COD, NH3-H, TN were obtained, and mean removals were 91.87%, 96.13%, and 69. 23%, respectively. Whereas, at first 20 days, the removal for TP was only about 15.87%. In the following days, about 30% of raw water was introduced into the anaerobic reactor to supply organics for denitrificatien and release of polyphosphate, then a significant improvement for TP removal was observed, and mean removal of TP increased to 76.35%. During the operational period, it was investigated that the permeate could meet the requirements of several water criteria for reuse except free chlorine, and a mean excess sludge yield coefficient of 0.137 g MLSS/g COD was obtained. Therefore, the predicted goals of permeate for reuse and excess sludge reduction could be both achieved after dosing a certain quantity of disinfectant into the permeate.展开更多
Taking the anaerobic digestion products of sludge as the object, through the analysis on the development of garden substrate market at home and abroad and the development status of horticultural products from the anae...Taking the anaerobic digestion products of sludge as the object, through the analysis on the development of garden substrate market at home and abroad and the development status of horticultural products from the anaerobic digestion products, the direction for the utilization of the anaerobic digestion products of sludge was pointed out. Based on the demand of Chongqing’s garden market, this paper analyzed the potential utilization of sludge anaerobic digestion products in Chongqing, and briefly introduced the research status of landscaping utilization of sludge anaerobic digestion products in Chongqing, in order to provide reference for the industry.展开更多
Anaerobic granular sludge is of key importance for highly effective operation of hybrid anaerobic baffled reactor(HABR).An observation and analysis on the composition of anaerobic granular sludge in each separation co...Anaerobic granular sludge is of key importance for highly effective operation of hybrid anaerobic baffled reactor(HABR).An observation and analysis on the composition of anaerobic granular sludge in each separation compartment of HABR was conducted by using scanning electron microscope(SEM)and molecular biotechnology,and specific methanogenic activity(SMA)and coenzyme F420 content were determined.It was indicated that the disparity of microbial composition was significant among these separation compartments of HABR,and the HABR encouraged phase separation.The results show the understanding of microbiological characteristics of anaerobic granular sludge in HABR is helpful for cultivating granular sludge,which ensures the effective operation of the reactor.展开更多
In 2010, Brazil endorsed a new national policy of solid wastes, which has a very ambitious target to close up all the dumping areas and to manage adequately all the municipal solid waste, disposing in landfills only t...In 2010, Brazil endorsed a new national policy of solid wastes, which has a very ambitious target to close up all the dumping areas and to manage adequately all the municipal solid waste, disposing in landfills only the refuse of treated municipal solid waste after 2019. Food waste is the largest representative of organic waste produced in Brazilian municipalities, which can produce both fertilizer and biogas through anaerobic digestion （AD） process, reducing in both cases greenhouse gases emissions. AD assays of some samples of restaurant food wastes were performed in batch laboratory, 500 mL reactors for determination of optimized start-up conditions. The tests were conducted in triplicate, using anaerobic sludge from a poultry slaughterhouse wastewater treatment as inoculum to start up the anaerobic biodigestors. The effect of three different substrates to inoculum mixing ratios 10：90 （S1）, 20：80 （S2） and 30：70 （S3） was evaluated. The food waste used as substrate was previously homogenized and submitted to aerobic mechanical mixing for four days before it was fed in the reactors in anaerobic conditions at the mentioned proportions with the inoculum. The reactors were maintained at 35 ℃ and under mechanical mixing at 60 rpm. The methane production was monitored until its stabilization. Results showed that S1 presented the best performance during the initial 12 d, when it totalized 526 NmLCH4/gVSsubstrate.展开更多
Recently microbial fuel cells (MFCs) have been considered as an alternative power generation technique by utilizing organic wastes. In this study, an experiment was carried out to generate bioelectricity from co-diges...Recently microbial fuel cells (MFCs) have been considered as an alternative power generation technique by utilizing organic wastes. In this study, an experiment was carried out to generate bioelectricity from co-digestion of organic waste (kitchen waste) and sewage sludge as a waste management option using microbial fuel cell (MFC) in anaerobic process. A total of five samples with different sludge-waste ratio were used with zinc (Zn) and cupper (Cu) as cell electrodes for the test. The trends of voltage generation were different for each sample in cells such as 350 mV, 263 mV, 416 mV maximum voltage were measured from sample I, II and III respectively. It was observed that the MFC with sewage sludge showed the higher values (around 960 mV) of voltages with time whereas 918 mV obtained with organic waste. Precisely comparing cases with varying the organic waste and sewage sludge ratio helps to find the best bioelectricity generation option. Using MFCs can be appeared as the solution of electricity scarcity along the world as an efficient and eco-friendly manner as well as organic solid waste and sewage sludge management.展开更多
基金supported by the National Natural Science Foundation of China(No.41276067)the Air Liquide(China)R&D Co.,Ltd.(No.20200216).
文摘This study evaluated the effect of potassium ferrate(PF)and low-temperature thermal hydrolysis co-pretreatment on the promotion of sludge hydrolysis process and the impact on acid production in the subsequent anaerobic digestion process.The analytical investigations showed that co-pretreatment significantly facilitated the hydrolysis process of the sludge and contributed to the accumulation of short-chain fatty acids(SCFAs).The pretreatment conditions under the optimal leaching of organic matter from sludge were hydrothermal temperature of 75℃,hydrothermal treatment time of 12 h,and PF dosage of 0.25 g g^(−1)TSS(total suspended solids),according to the results of orthogonal experiments.By pretreatment under proper conditions,the removal rate of soluble chemical oxygen demand(SCOD)achieved 71.8%at the end of fermentation and the removal rate of total phosphorus(TP)was 69.1%.The maximum yield of SCFAs was 750.3 mg L^(−1),7.45 times greater than that of the blank group.Based on the analysis of the anaerobic digestion mechanism,it was indicated that the co-pretreatment could destroy the floc structure on the sludge surface and improve organic matter dissolving,resulting in more soluble organic substances for the acidification process.Furthermore,microbial community research revealed that the main cause of enhanced SCFAs generation was an increase in acidogenic bacteria and a reduction of methanogenic bacteria.
基金National Basic Research Program of China (973 Program) (2009CB724700,2011CBA00800)National Natural Foundation of China (31101269)+4 种基金Scienc & Technology Plotform Construction Programof Jiangxi Province (2010DTZ01900)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education InstitutionsNatural Science Foundation of Jiangsu Department of Education (07KJD350034)High-level Talents Foundation of Jiangsu University (07JDG020)Supported by International Foundation for Science (F 4930-1)~~
文摘[Objective] The aim was to study on effect of sludge from different sources on biogas yield efficiency through anaerobic digestion of corn straw. [Method] The present research studied on daily biogas yield and the accumulated biogas amount through anaerobic digestion of corn straw and sludges from four sources. [Result] The accumulated biogas yields produced from sludges in four sources from high to low were granular sludge, river sediments, concentrated sludge and filtered sludge. The first one proved the highest at 3.73 and 56.29 L/kg VS in daily biogas yield and the accumulated biogas. [Conclusion] The research laid foundation for full utilization of straw, improvement of energy utilization and sustainable development.
基金supported by the National Natural Science Foundation of China(No.41276067)the Air Liquide(China)R&D Co.,Ltd.(No.20200216).
文摘The synergetic effect and underlying mechanism of potassium ferrate(PF)with tea saponin(TS,a biosurfactant)in producing short chain fatty acids(SCFAs)from anaerobic fermentation of waste activated sludge(WAS)were explored in this work.Experimental results showed that 0.2 g PF(g TSS)^(-1)(total suspended solid)combined with 0.02 g TS(g TSS)^(-1) could further improve SCFAs’production,and the maximum SCFAs content reached 2008.7 mg COD L^(-1),which is 1.2 and 4.5 times higher than those with PF and TS individually added,respectively,and 5.3 times higher than that of blank WAS on Day 12.In the model substrates experiments,the degradation rates of bovine serum albumin and dextran with combination of PF and TS were 41.3%±0.1% and 48.5%±0.06%,respectively,on Day 3,which are lower than those in blank WAS(with degradation rates of 72.3%±0.5%and 90.3%±0.3%).It was revealed that the oxidative effect of PF and the solubilization of TS caused more organic matters to be dissolved out from WAS,providing a large number of biodegradable substances for subsequent SCFAs production.While WAS pretreated with the combination of PF and TS,the relative abundances of Firmicutes increased from 6.4%(blank)to 38.6%,and that of Proteobacteria decreased from 41.8%(blank)to 21.8%.The combination of PF and TS promoted the hydrolysis process of WAS by enriching Firmicutes,and then increased acetic acid production by inhibiting Proteobacteria that consumed SCFAs.Meanwhile,at the genus level,acidogenesis bacteria(e.g.,Proteiniclasticum and Petrimonas)were enriched whereas SCFAs consuming bacteria(e.g.,Dokdonella)were inhibited.
基金supported by the National Natural Science Foundation of China (No. 20977066)the National Key Project for Water Pollution Control (No.2008ZX07316-002, 2008ZX07317-003)the Specialized Research Found for Doctoral Program of Higher Education of China (No. 200802470029)
文摘Effect of ultrasonic pretreatment on sludge dewaterability was determined and the fate of extracellular polymeric substances （EPS） matrix in mesophilic anaerobic digestion after ultrasonic pretreatment was studied. Characteristics of proteins （PN）, polysaccharides （PS）, excitation-emission matrix （EEM） fluorescence spectroscopy and molecular weight （MW） distribution of dissolved organic matters （DOM） in different EPS fractions were evaluated. The results showed that after ultrasonic pretreatment, the normalized capillary suction time （CST） decreased from 44.4 to 11.1 （sec·L）/g total suspended solids （TSS） during anaerobic digestion, indicating that sludge dewaterability was greatly improved. The normalized CST was significantly correlated with PN concentration （R2 = 0.92, p 〈 0.01） and the PN/PS ratio （R2 = 0.84, p 〈 0.01） in the loosely bound EPS （LB-EPS） fraction. Meanwhile, the average MW of DOM in the LB- EPS and tightly bound EPS （TB-EPS） fractions also had a good correlation with the normalized CST （R2 〉 0.66, p 〈 0.01）. According to EEM fluorescence spectroscopy, tryptophan-like substances intensities in the slime, LB-EPS and TB-EPS fractions were correlated with the normalized CST. The organic matters in the EPS matrix played an important role in influencing sludge dewaterability.
基金The work was supported by the National Natural Science Foundation of China (Grant No. 59978020).
文摘Objective To investigate the effect of chemical oxygen demand （COD） concentrations on the anaerobic ammonium oxidation （ANAMMOX）. Methods An Expanded Granular Sludge Bed （EGSB） reactor was used to cultivate the granular sludge and to perform the ANAMMOX reaction in the bench scale experiment. NH4^＋-N and NO2^--N were measured by using colorimetric method. NO3^＋-N was analyzed by using the UV spectrophotometric method. COD measurement was based on digestion with potassium dichromate in concentrated sulphuric acid. Results When the COD concentrations in the reactors were 0 mg/L, 200 mg/L, 350 mg/L, and 550 mg/L, respectively, the NH4^＋-N removal efficiency was 12.5%, 14.2%, 14.3%, and 23.7%; the removal amount of NO2-N was almost the same; the nitrate removal efficiency was 16.8%, 94.5%, 86.6%, and 84.2% and TN removal efficiency was 16.3%, 50.7%, 46.9%, and 50.4%, moreover, the COD removal efficiency was 85%, 65.7%, and 60%; the COD removal rate was 27.42, 61.88, and 97.8 mg COD/（h·L）. Conclusion COD concentrations have a significant influence on anaerobic ammonium oxidation by granular sludge.
文摘The present study deals with the performance evaluation of the UASB reactor under varied organic loading rate(OLR) for the treatment of paper mill wastewater. The sludge granulation process started after 120 days from the start-up period. Sludge granules size was found to be 0 8 mm at OLR of 1 72 kgCOD/(m 3·d), which reached maximum size of about 1 0 to 1 2 mm at OLR of 2 1 kgCOD/(m 3·d). At the end of initial OLR of 1 0 kgCOD/(m 3·d) the VSS concentration was 12 86 gVSS/L, which got increased to 38 05 gVSS/L at the end of an OLR 2 1 kgCOD/(m 3·d). Most of the times VFA recorded were well within the limit of VFA reported in anaerobic fermentation process. Many times the pH observed was between 6 5 and 7 8, which is more favorable for any anaerobic process. It is also found that pH within the reactor increases along with the height of reactor. The total maximum biogas production was found to be 0 40 L/gCOD removals at OLR of 2 1 kgCOD/(m 3·d) and the maximum BOD removal at this stage was observed to be 90%.
基金Supported by the National Natural Science Foundation of China （No.20122203）.
文摘This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L^-1（Na^＋）, on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At the optimum sodium ion concentration [1000-2000mg·L^-1（Na^＋）] for hydrogen production at 37℃, the maximum sucrose degradation rate, the specific hydrogen production yield and the specific hydrogen production rate were 393.6-413.1mg·L^-1.h^-1, 28.04-28.97ml·g^-1, 7.52-7.83ml·g^-1.h^-1, respectively. The specific production yields of propionate, butyrate and valerate decreased with increasing sodium ion concentration, whereas the specific acetate production yield increased, meanwhile the specific production yields of ethanol and caproate were less than 55.3 and 12.6mg·g^-1, respectively. The hybrid fermentation composition gradually developed from acetate, propionate and butyrate to acetate with the increase in sodium ion concentration.
文摘A series of batch experiments were conducted in 125 mL serum bottles to assess the toxicity of different concentrations of ammonia nitrogen to the specific methanogenic activity of anaerobic granular sludge from upflow anaerobic sludge bed（UASB） and expanded granular sludge bed（EGSB） reactors. The effects of pH value and temperature on toxicity of ammonia nitrogen to anaerobes were investigated. The results show that the specific methanogenic activity of anaerobic granular sludge suffers inhibition from ammonia nitrogen, the concentrations of ammonia nitrogen that produce 50 % inhibition of specific methanogenic activity for sludge from UASB and EGSB reactor are 2.35 and 2.75 g/L, respectively. Hydrogen utilizing methanogens suffers less inhibition from ammonia mtrogen than that of acetate utilizing methanogens. Hydrogen-producing acetogens that utilize propionate and butyrate as substrates suffer serious inhibition from ammonia nitrogen. The toxicity of ammonia nitrogen to anaerobic granular sludge enhances when pH value and temperature increase. Anaerobic granular sludge can bear higher concentrations of ammonia nitrogen after being acclimated by ammonia nitrogen for 7 d.
基金Project supported by the Major Scientific Key Problem Program of Scientific Commission of Zhejiang Province,China(2004C13027).
文摘Sludge granulation is considered to be the most critical parameter governing successful operation of an upflow anaerobic sludge blanket and expanded granular sludge bed （EGSB） reactors. Pre-granulated seeding sludge could greatly reduce the required startup time. Two lab-scale and a pilot-scale EGSB reactors were operated to treat Shaoxing Wastewater Treatment Plant （SWWTP） containing wastewater from real engineering printing and dyeing with high pH and sulfate concentration. The microbiological structure and the particle size distribution in aerobic excess sludge, sanitary landfill sludge digested for one year, and the granular sludge of EGSB reactor after 400 d of operation were analyzed through scanning electron microscopy （SEM） and sieves. The lab-scale EGSB reactor seeded with anaerobic sludge after digestion for one year in landfill showed obviously better total chemical oxygen demand （TCOD） removal efficiency than one seeded with aerobic excess sludge after cation polyacrylamide flocculation-concentration and dehydration. The TCOD removed was 470.8 mg/L in pilot scale EGSB reactor at short hydraulic retention time of 15 h. SEM of sludge granules showed that the microbiological structure of the sludge from different sources showed some differences. SEM demonstrated that Methanobacterium sp. was present in the granules of pilot-scale EGSB and the granular sludge produced by landfill contained a mixture of anaerobic/anoxic organisms in abundance. The particle size distribution in EGSB demonstrated that using anaerobic granular sludge produced by sanitary landfill as the seeding granular sludge was feasible.
基金the support provided by the Research & Technology Development Project of China National Petroleum Corporation (06A0302)Postdoctor Innovation Funds in Shandong Province (201002039)the Fundamental Research Funds for the Central Universities (27R1204023A)
文摘In this study,an up-flow anaerobic sludge blanket(UASB) reactor was applied to treat the high salinity wastewater from heavy oil production process.At a HRT of ≥24 h,the COD removal reached as high as 65.08% at an influent COD ranging from 350mg/L to 640mg/L.An average of 74.33% oil reduction was also achieved in the UASB reactor at an initial oil concentration between 112mg/L and 205mg/L.These results indicated that this heavy oil production related wastewater could be degraded efficiently in the UASB reactor.Granular sludge was formed in this reactor.In addition,two models,built on the back propagation neural network(BPNN) theory and linear regression techniques were developed for the simulation of the UASB system performance in the oily wastewater biodegradation.The average error of COD and oil removal was-0.65% and 0.84%,respectively.The results indicated that the models built on the BPNN theory were wellfitted to the detected data,and were able to simulate and predict the removal of COD and oil by the UASB reactor.
文摘This paper presents the results obtained for the effluent dewatering properties of anaerobic digestion of secondary sludge （SS） and anaerobic co-digestion of mixture of this sludge with the distillery wastewater （DW） under thermophilic （55±1 ℃）, 5 L of working volume, three parallel lab-scale conditions. Its mixtures were prepared with a DW content of 25%and 50% and the C/N ratios of mixtures are 13.1 and 17.6, respectively. The effluent dewatering properties were evaluated under stable conditions which the biogas yield and the effluent pH were steady. The natural settleability, biogas yield, centrifugal dewatering, centrifugal supernatant turbidity and specific resistance filtration （SRF） were investigated. The results showed that the effluent dewatering properties of anaerobic co-digestion of mixtures between SS and DW were better than that of anaerobic digestion of SS alone. In the anaerobic digestion system with the feed were SS, mixture of SS and a DW content of 25%and 50% in order, the net biogas yield of secondary sludge in ADSA,ADSB and ADSC were 0.42 0.507 and 0.511 m3 biogass/kg.VS.d ; compared with the biogas yield in anaerobic digestion system A （ADSA）, the biogas yield in anaerobic digestion system B （ADSB） and anaerobic digestion system C （ADSC） had been increased by more than 20% respectively; the SRF of three digested sludge are（were） from 6.8×10^13, 1. 1×10^13 to 5.1×10^12 m/Kg, natural settling rates of 12 h are 26, 37 and 56% and that of 24 h are 32%, 45% and 59% respectively; the centrifugal dewatering rate of 3 min at speed of 1000 rpm were 16%, 31% and 51% respectively; the turbidity of centrifugal supernatant were 804, 754 and 678FTU simultaneously.
基金Project(2008BB7048) supported by Natural Science Foundation of CQ CSTC
文摘The anaerobic digestion of septic sludge was studied through inoculating effective microorganisms (EMs) under mesophilic condition (35 ℃). The variation of COD,total solid (TS),volatile solid (VS),pH value and the gas production rate during the digestion process were presented,and the optimal adding concentration of EMs was determined by comparing the reduction effectiveness of septic sludge. The results show that proper addition of EMs can enhance acid buffering capacity of the system,and the NH3-N concentration is lower than inhibition concentration of 2 g/L reported in the literature and maintain the range of pH value which is suitable for both hydrolysis-acidification and methanogenesis. However,overdose of EMs can reduce the initial pH value of septic sludge and decrease the effects of the anaerobic digestion. EMs can increase the quantity of microbe in septic sludge and improve the gas production and generation rate over a period of time. But overdosing EMs can lead to low pH,restrain activity of methanogenic bacteria and affect the quantity and the generation rate of gas. Adding 0.01% EMs achieves the highest sludge reduction with the removal rates of TS,VS and COD by 32.51%,42.34% and 40.97%,respectively.
文摘The maximum specific sludge activity of granular sludge from large scale UASB, IC and Biobed anaerobic reactors were investigated by batch tests. The limitation factors related to maximum specific sludge activity (diffusion, substrate sort, substrate concentration and granular size) were studied. The general principle and procedure for the precise measurement of maximum specific sludge activity were suggested. The potential capacity of loading rate of the IC and Biobed anaerobic reactors were analyzed and compared by use of the batch tests results.
基金Supported by the National Natural Science Foundation of China (No.20122203).
文摘This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L-1(Na+), on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At the opti- mum sodium ion concentration [1000—2000mg·L-1(Na+)] for hydrogen production at 37℃, the maximum sucrose degradation rate, the specific hydrogen production yield and the specific hydrogen production rate were 393.6— 413.1mg·L-1·h-1, 28.04—28.97ml·g-1, 7.52—7.83ml·g-1·h-1, respectively. The specific production yields of propionate, butyrate and valerate decreased with increasing sodium ion concentration, whereas the specific acetate production yield increased, meanwhile the specific production yields of ethanol and caproate were less than 55.3 and 12.6mg·g-1, respectively. The hybrid fermentation composition gradually developed from acetate, propionate and butyrate to acetate with the increase in sodium ion concentration.
文摘Municipal sludge was rich in organic matter, period of natural degradation was long and low efficiency, leachate would pollute underground water. In this paper, a comparative study of the ways of pretreatment with acid alkali treatment, heat digestion and ultrasonic treatment were done. The results showed that The dehydro-genase activity were increased, the SCOD (soluable chemical oxygen demand, SCOD) in-creased more than 2.47~2.83, 1.70~1.76, 2.6~ 2.77 times respectively. The hydrogen yield in-creased more than 11.5~12.2, 24.1~24.7, 34.2~ 34.9 mL.g-1 (VS) respectively. The period of pro- hydrogen was shorten to 7.5, 8.0, 6.5 d respec-tively. The degradation rate was up to 72.04%, 81.4%, 80% respectively, the methane concen-tration in the gas was close to “zero” and ul-trasonic treatment was better than others. Gompertz model curve fitting on hydrogen production was carried out. All the values of correlation factor R2 were more than 0.97.
文摘The aim of the research was to obtain both an excellent effluent for reuse and a reduced sludge production simultaneously by a combination process of anaerobic phase and Membrane bioreactor （MBR） technology in treating domestic wastewater. During the experimental period of three months, excellent removals for COD, NH3-H, TN were obtained, and mean removals were 91.87%, 96.13%, and 69. 23%, respectively. Whereas, at first 20 days, the removal for TP was only about 15.87%. In the following days, about 30% of raw water was introduced into the anaerobic reactor to supply organics for denitrificatien and release of polyphosphate, then a significant improvement for TP removal was observed, and mean removal of TP increased to 76.35%. During the operational period, it was investigated that the permeate could meet the requirements of several water criteria for reuse except free chlorine, and a mean excess sludge yield coefficient of 0.137 g MLSS/g COD was obtained. Therefore, the predicted goals of permeate for reuse and excess sludge reduction could be both achieved after dosing a certain quantity of disinfectant into the permeate.
基金Supported by Project "Synergistic Anaerobic Digestion Technology of Municipal Sewage Sludge and Incineration Plant Landfill Leachate and Its Productivity Test" of Chongqing Water Asset Management Co.Ltd
文摘Taking the anaerobic digestion products of sludge as the object, through the analysis on the development of garden substrate market at home and abroad and the development status of horticultural products from the anaerobic digestion products, the direction for the utilization of the anaerobic digestion products of sludge was pointed out. Based on the demand of Chongqing’s garden market, this paper analyzed the potential utilization of sludge anaerobic digestion products in Chongqing, and briefly introduced the research status of landscaping utilization of sludge anaerobic digestion products in Chongqing, in order to provide reference for the industry.
基金Innovation Foundation of Donghua University for PhD Candidates,China(No.BC200828)Shanghai Leading Academic Discipline Project,China(No.B064)
文摘Anaerobic granular sludge is of key importance for highly effective operation of hybrid anaerobic baffled reactor(HABR).An observation and analysis on the composition of anaerobic granular sludge in each separation compartment of HABR was conducted by using scanning electron microscope(SEM)and molecular biotechnology,and specific methanogenic activity(SMA)and coenzyme F420 content were determined.It was indicated that the disparity of microbial composition was significant among these separation compartments of HABR,and the HABR encouraged phase separation.The results show the understanding of microbiological characteristics of anaerobic granular sludge in HABR is helpful for cultivating granular sludge,which ensures the effective operation of the reactor.
文摘In 2010, Brazil endorsed a new national policy of solid wastes, which has a very ambitious target to close up all the dumping areas and to manage adequately all the municipal solid waste, disposing in landfills only the refuse of treated municipal solid waste after 2019. Food waste is the largest representative of organic waste produced in Brazilian municipalities, which can produce both fertilizer and biogas through anaerobic digestion （AD） process, reducing in both cases greenhouse gases emissions. AD assays of some samples of restaurant food wastes were performed in batch laboratory, 500 mL reactors for determination of optimized start-up conditions. The tests were conducted in triplicate, using anaerobic sludge from a poultry slaughterhouse wastewater treatment as inoculum to start up the anaerobic biodigestors. The effect of three different substrates to inoculum mixing ratios 10：90 （S1）, 20：80 （S2） and 30：70 （S3） was evaluated. The food waste used as substrate was previously homogenized and submitted to aerobic mechanical mixing for four days before it was fed in the reactors in anaerobic conditions at the mentioned proportions with the inoculum. The reactors were maintained at 35 ℃ and under mechanical mixing at 60 rpm. The methane production was monitored until its stabilization. Results showed that S1 presented the best performance during the initial 12 d, when it totalized 526 NmLCH4/gVSsubstrate.
文摘Recently microbial fuel cells (MFCs) have been considered as an alternative power generation technique by utilizing organic wastes. In this study, an experiment was carried out to generate bioelectricity from co-digestion of organic waste (kitchen waste) and sewage sludge as a waste management option using microbial fuel cell (MFC) in anaerobic process. A total of five samples with different sludge-waste ratio were used with zinc (Zn) and cupper (Cu) as cell electrodes for the test. The trends of voltage generation were different for each sample in cells such as 350 mV, 263 mV, 416 mV maximum voltage were measured from sample I, II and III respectively. It was observed that the MFC with sewage sludge showed the higher values (around 960 mV) of voltages with time whereas 918 mV obtained with organic waste. Precisely comparing cases with varying the organic waste and sewage sludge ratio helps to find the best bioelectricity generation option. Using MFCs can be appeared as the solution of electricity scarcity along the world as an efficient and eco-friendly manner as well as organic solid waste and sewage sludge management.
