环境工程专业英语优秀课件.ppt

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1、环境工程专业英语第1页，本讲稿共13页 An An anaerobic anaerobic hydrogen hydrogen fermentation fermentation system system with with a a thermophilic thermophilic flow-through flow-through reactor reactor(55(55o oC)C)for for hydrogen hydrogen production production and and a a boiling boiling retention retention vessel

2、 vessel(100(100o oC)C)for for continuous continuous heat heat treatment,treatment,was was studied studied for for enhanced enhanced continuous continuous hydrogen hydrogen fermentation fermentation using using sewage sewage sludge.sludge.The The performance performance of of the the hydrogen hydroge

3、n fermentation fermentation system system was was tested tested at at various various Hydraulic Hydraulic Retention Retention Times Times(HRTs)(HRTs)ranged ranged from from 1 1 to to 5 5 days.days.The The heat heat treatment treatment of of the the fermenting fermenting sludge sludge using using the

4、 the boiling boiling retention retention vessel vessel was was an an effective effective to to select select hydrogen hydrogen producing producing bacteria,bacteria,and and to to increase increase the the hydrolysis hydrolysis of of particulate particulate organics organics in in sewage sewage sludg

5、esludge。第2页，本讲稿共13页 Commercial hydrogen is almost produced from steam reforming of Commercial hydrogen is almost produced from steam reforming of natural gases and gasification of coal,but these require high-energy natural gases and gasification of coal,but these require high-energy inputs obtained

6、from non-renewable resources.With both advantages of inputs obtained from non-renewable resources.With both advantages of hydrogen production and stabilization of organic waste,the anaerobic hydrogen production and stabilization of organic waste,the anaerobic fermentation is relatively an efficient

7、and inexpensive method compared fermentation is relatively an efficient and inexpensive method compared to the physicochemical methods for hydrogen production.The objective to the physicochemical methods for hydrogen production.The objective of the study is to develop a continuous anaerobic hydrogen

8、 fermentation of the study is to develop a continuous anaerobic hydrogen fermentation system with stable hydrogen production by heat treatment,and with high system with stable hydrogen production by heat treatment,and with high yield of hydrogen by adopting thermophilic condition.yield of hydrogen b

9、y adopting thermophilic condition.第3页，本讲稿共13页Experimental ApparatusGas sampling potActivating reactorBiogasSludge tankInsutationHeating CoilThermophilic fermenterEfluent第4页，本讲稿共13页 Biogas production was monitored daily,and its composition was Biogas production was monitored daily,and its composition

10、 wasanalyzed by a gas chromatograph equipped with a thermal conductivity detector To analyzed by a gas chromatograph equipped with a thermal conductivity detector To analyze the methane and carbon dioxide in the biogas.with a flow rate of 40 analyze the methane and carbon dioxide in the biogas.with

11、a flow rate of 40 mL/min,and the temperatures of theinjector,detector,and column were 80,90,and mL/min,and the temperatures of theinjector,detector,and column were 80,90,and 5050o oC,respectively.The volatile fatty acid levels and their compositions C,respectively.The volatile fatty acid levels and

12、their compositions were analyzed by high-performance liquid chromatography.The mixed were analyzed by high-performance liquid chromatography.The mixed liquors were intermittently takenliquors were intermittently takenfrom both the flow-through and the retention reactor,and thefrom both the flow-thro

13、ugh and the retention reactor,and theproperties,including pH,alkalinity,COD,VSS,VS,and TS,ofproperties,including pH,alkalinity,COD,VSS,VS,and TS,ofthe samples were also analyzed according to the Standardthe samples were also analyzed according to the StandardMethods.The hydrolysis rate and VFA produ

14、ctionrate were calculated by Methods.The hydrolysis rate and VFA productionrate were calculated by Eqs.(1)and(2)respectively.Eqs.(1)and(2)respectively.(massSCOD/d)effluent(massSCOD/d)influent/(massSCOD/d)effluent(massSCOD/d)influent/(massPCOD/d)influent(massPCOD/d)effluent(1)(massPCOD/d)influent(mas

15、sPCOD/d)effluent(1)(massVFA/d)effluen(massVFA/d)influent/(massVFA/d)effluen(massVFA/d)influent/(massSCOD/d)effluen(massSCOD/d)influent(2)(massSCOD/d)effluen(massSCOD/d)influent(2)第5页，本讲稿共13页Hydrogen ProductionHydrogen ProductionHydrolysis and VS ReductionHydrolysis and VS ReductionVFA Production and

16、 Hydrogen YieldVFA Production and Hydrogen YieldResults and Discussion第6页，本讲稿共13页第7页，本讲稿共13页Hydrogen ProductionHydrogen Production第8页，本讲稿共13页 Hydrogen ProductionHydrogen Production the hydrogen production rate was quickly increased and approached the hydrogen production rate was quickly increased an

17、d approached to steady state within the 10th day of the operation at 1 day HRT to steady state within the 10th day of the operation at 1 day HRT the exposure of the fermenting sludge to heat is a good approach for both the exposure of the fermenting sludge to heat is a good approach for both the sel

18、ection of hydrogen production bacteria and the enhancement of the selection of hydrogen production bacteria and the enhancement of hydrolysis rate of particulate organic matter.However,a proper HRT is also hydrolysis rate of particulate organic matter.However,a proper HRT is also very important to o

19、btain higher hydrogen production.In the study,the very important to obtain higher hydrogen production.In the study,the proper HRT was 3 days,and the hydrogen production was limited by the proper HRT was 3 days,and the hydrogen production was limited by the hydrolysis rate for 1day HRT and by the hyd

20、rogen consumption activity for hydrolysis rate for 1day HRT and by the hydrogen consumption activity for 5 days HRT.5 days HRT.第9页，本讲稿共13页Hydrolysis and VS ReductionHydrolysis and VS Reduction The hydrolysis in the anaerobic degradation for organic sludge The hydrolysis in the anaerobic degradation

21、for organic sludge containing particulate matter is usually a rate limiting step,affecting on containing particulate matter is usually a rate limiting step,affecting on the whole performance of anaerobic process,and determining VS the whole performance of anaerobic process,and determining VS(Volatil

22、e Solids)removal of the sludge.(Volatile Solids)removal of the sludge.VS removal and hydrolysis rate were significantly affected by pH VS removal and hydrolysis rate were significantly affected by pH conditionIn the case of Run III with 5days HRT,VS removal was 37.9%,conditionIn the case of Run III

23、with 5days HRT,VS removal was 37.9%,which was higher than Run I or Run II.The effect of the exposure time of which was higher than Run I or Run II.The effect of the exposure time of the fermenting sludge to heatwas confirmed again by the increase of VS the fermenting sludge to heatwas confirmed agai

24、n by the increase of VS removal in Run IIIwith longer HRT.removal in Run IIIwith longer HRT.第10页，本讲稿共13页 HRT in the anaerobic hydrogen fermentation system with continuous heat treatment HRT in the anaerobic hydrogen fermentation system with continuous heat treatment is an important parameter in sele

25、cting hydrogen producing bacteria and determining the is an important parameter in selecting hydrogen producing bacteria and determining the pathways forming hydrogen.pH is another important parameter determining the pathways forming hydrogen.pH is another important parameter determining the metabol

26、ic pathway forming hydrogenmetabolic pathway forming hydrogenVFA Production and Hydrogen YieldVFA Production and Hydrogen Yield第11页，本讲稿共13页 higher maximum yield of hydrogen compared to previous studies higher maximum yield of hydrogen compared to previous studies was 3.07 mmol H2/g TS,which was obta

27、ined at 3 days HRT.The was 3.07 mmol H2/g TS,which was obtained at 3 days HRT.The hydrogen yield and hydrolysis rate were significantly affected by pH hydrogen yield and hydrolysis rate were significantly affected by pH condition,and proper pH for the hydrogen fermentation was from 5.5 to condition,

28、and proper pH for the hydrogen fermentation was from 5.5 to 6.5.The hydrogen production was limited by the hydrolysis for 1day 6.5.The hydrogen production was limited by the hydrolysis for 1day HRT and by the hydrogen consumption activity for 5days HRTHRT and by the hydrogen consumption activity for

29、 5days HRT第12页，本讲稿共13页 The continuous hydrogen fermentation system,consisted of a The continuous hydrogen fermentation system,consisted of athermophilic(55thermophilic(55)flow through reactor and a boiling retention)flow through reactor and a boiling retentionvessel(100vessel(100)for continuous heat

30、 treatment was a good process)for continuous heat treatment was a good processfor continuous hydrogen production from sewage sludge.Thefor continuous hydrogen production from sewage sludge.Thecontinuous heat treatment of the fermenting sludge using thecontinuous heat treatment of the fermenting slud

31、ge using theboiling retention vessel was an effective method for the selectionboiling retention vessel was an effective method for the selectionof hydrogen producing bacteria,and the increase of VS removalof hydrogen producing bacteria,and the increase of VS removalin virtue of the enhancement of hy

32、drolysis for particulate organicsin virtue of the enhancement of hydrolysis for particulate organicsin sewage sludge.The performance of hydrogen fermentationin sewage sludge.The performance of hydrogen fermentationwas significantly affected by the hydraulic retention time andwas significantly affect

33、ed by the hydraulic retention time andpH,and the optimal conditions were the HRT of 3days and pHpH,and the optimal conditions were the HRT of 3days and pH5.5-6.5,respectively.VS removal was increased according to5.5-6.5,respectively.VS removal was increased according toHRT and the maximum value was

34、37.9%at 5days of HRT.TheHRT and the maximum value was 37.9%at 5days of HRT.Themaximum hydrogen yield of the continuous hydrogen fermentationmaximum hydrogen yield of the continuous hydrogen fermentationsystem was 3.07 mmol H2 g TS-1 at 3 days of HRTsystem was 3.07 mmol H2 g TS-1 at 3 days of HRT第13页，本讲稿共13页