(学术讨论环境生物污水处理技术过去现在将来趋势)Biol课件.ppt

1、Dr.Ajit P.AnnachhatreEnvironmental Engineering ProgramAsian Institute of Technology+Wastewater+Biological Processes+Treatment Processes+Applications+Ongoing Research Activitiesc Domestic Wastewaterc Industrial WastewaterPresent State of Wastewater4 over 80%-untreated in Asian mega cities4 major comp

2、onents-COD=250-1000 mg/L Total N=20-90 mg/L Total P =4-15 mg/L4 effects of discharging into natural receiving bodies4oxygen demand by carbon and nitrogenEg:Starch industry wastewater major component-COD=10,000-20,000 mg/L effects of discharging into natural receiving bodies -20 m3/ton of starch-high

3、 COD-high suspended solids-cyanide exposureStarch industry wastewater factory with 300 T/d of starch wastewater generation 6000m3/d COD 14,000 mg/L population equivalent 1000,000 present treatment method:Anaerobic ponds typical loading rates:800-1000kg COD/ha/d area requirement:100 hac aim:any form

4、of life-survive&multiply c need for energy&organic molecules as building blocksc made of C,H,O,N,S,P and trace elements c cell:derives energy from oxidation of reduced food sources(carbohydrate,protein&fats)Classification:4 Heterotrophic-obtain energy from oxidation of organic matter(organic Carbon)

5、4 Autotrophic-obtain energy from oxidation of inorganic matter(CO2,NH4,H+)4Phototrophic-obtain energy from sunlight4 oxidation of organic molecules inside the cell can occur aerobic or anaerobic manner4 generalized pathways for aerobic&anaerobic fermentation GlucoseEPM PathwayPyruvic Acid ADP ATPEne

6、rgyLactic Acid TCA Cycle H+Respiration H2O CO2 O2D aerobic pathways contains-EMP pathways,TCA cycle,respirationD anaerobic pathways contains-EMP pathwaysD released energy stored as ATP moleculesD excess food is stored as GlycogenC6H12O6+6O2+38 ADP+38 Pi 6 CO2+38 ATP +44 H2O Biological growth-exponen

7、tial growth(batch)-Monod kinetics-Haldane kinetics under toxic conditionsc exponential growthBiological growth.dXdt=XLog No.of CellsTimeLag phaseLog growth phaseStationary phaseDeath phasec Monod kineticsBiological growth.=m SKsSSubstrate Concentration(S)Specific growth rate()Max.ratemm/2ksc Haldane

8、 kinetics (under toxic conditions)Biological growth.=m SKSS iKsi./Substrate Concentration(S)Specific growth rate()i1.Carbonaceous removal-aerobic-anaerobic2.Nitrogen removal-nitrification-denitrification3.Sulfide removal-anaerobic SO4 reduction-aerobic HS-oxidation4 aerobic-oxidation bacteria CHONS

9、+O2+Nutrients CO2+NH3+C5H7NO2(organic matter)(new bacterial cells)+other end products-endogenous respiration bacteriaC5H7NO2+5O2 5CO2+2H2O+NH3+energy (cells)4 anaerobicSchematic of the Anaerobic ProcessHydrolysisAcidogenesis MethenogenesisComplex OrganicsIntermediatesPropionateH2AcetateCH420%5%60%15

10、%35%10%13%17%15%72%28%100%4 nitrification-energyNitrosomonasNH4+1.5 O2 NO2-+H2O+2 H+(240-350 kJ)(1)NitrobacterNO2-+0.5 O2 NO3-+(65-90 kJ)(2)-assimilationNitrosomonas 15 CO2 +13 NH4+10 NO2-+3 C5H7NO2+23 H+4 H2O(3)Nitrobacter 5 CO2 +NH4+10 NO2-+2 H2O 10 NO3-+C5H7NO2+H+(4)-overall reaction NH4+1.83 O2+

11、1.98 H CO3-0.021 C5H7NO2 +0.98 NO3-+1.04 1H2O+1.88H2CO34 factors affecting nitrification*temperature*substrate concentration*dissolved oxygen*pH*toxic and inhibitory substances)2.7(83.01)15(095.044pHeDOKDONNHKNNHTONm4 denitrification*assimilatory denitrification-reduction of nitrate to ammonium by m

12、icroorganism for protein synthesis*dissimilatory denitrification-reduction of nitrate to gaseous nitrogen by microorganism-nitrate is used instead of oxygen as terminal electron acceptor-considered an anoxic process occurring in the presence of nitrate and the absence of molecular oxygen-the process

13、 proceeds through a series of four stepsNONONON ON 3-2-22 4 denitrification*heterotrophic denitrification-denitrifiers require reduced carbon source for energy and cell synthesis-denitrifiers can use variety of organic carbon source-methanol,ethanol and acetic acidNO +1.08CH OH+H 0.065C H O N 0.47N

14、0.76CO 2.44H O3-3+572222 4 factors affecting denitrification*temperature*dissolved oxygen*pH*Sulfate removal cycle anaerobicSO4-HS-S 0(O2 deficient)(O2 excess)c pond treatmentc activated sludge processc biofilm process-no biomass recirculation-high HRT-high land area-O2 transfer limitations-inadequa

15、te mixing-excess loading (anaerobic condition-H2S generation)PSTATSSTRASSWSWFE-aerobic-suspended-growth-Design equations1cdcYkkcSFminmin*typical values of cell residence time (c)-c for C removal 3-10 days-c for N removal 5-30 days-loading rates 2-3 kg COD/m3/d-drawbacks:O2 requirements,inlet conc.ad

16、vantages of biofilm processes:-higher process productivity (loading rates)-higher biomass holdup-higher mean cell residence time-no need for biomass recirculation-creates suitable environment for each type of bacteria-sustains toxic loads types of biofilms:aerobic,anaerobic,anoxic process of biofilm

17、 formation-formation of diffuse electrical double layer due to electrostatic forces and thermal motion-transfer of microorganism to surface-microbial adhesion-biofilm formation biofilm operationXYBiofilmLiquidFilmBulk LiquidSupport Material(a)Physical conceptFully PenetratedPartially PenetratedSSSbS

18、ubstrate ConcentrationXY(b)Substrate concentration profile biofilm operation-diffusion resistance-inadequate supply of nutrients to inner portions of Biofilm-limitations on product out diffusion-attrition of reaction conditions biofilm operationaverage rate of substrate consumptionEffectiveness fact

19、or =-substrate consumption at biofilm surface as biofilm thickness increases effectiveness factor()decreasesConversion of Ethanol to MethaneConversion Reaction Go(kJ)EthanolCH2CH2OH(aq)+H2O(l)=CH3COO-(aq)+H+(aq)+2H2(g)+09.65Hydrogen2H2(g)+CO2(g)=CH4(g)+H2O(l)-65.37AcetateCH3COO-(aq)+H+(aq)=CH4(g)+CO

20、2(g)-35.83NetCH2CH2OH(aq)=3/2 CH4+CO2(g)-91.55 importance of H partial pressure loading rates 10-15 kg COD/m3/d against 2-5 kg COD/m3/d in suspended growth processesBiological Processesaerobic anoxic anaerobic nitrificationdenitrification SO42-reductionHS-oxidation detoxificationaerobicnitrification

21、 HS-oxidationinhibition aniline modeling biofilm in ASP degradation processes in SBR ShabbirJega Sunil&Keshab Savapak Shabbir&Shabbir anaerobicSO42-reductiondetoxification&modeling&modeling Savapak Amaraanoxicdenitrificationtoxic chemicalsmembraneas C sourcebio reactor Krongtong Tran membrane proces

22、ses Piyaputrq Study of nitrification process inside a spherical biofloc particle based on biofilm kinetics.q determination of effectiveness factor for substrate consumption and thus the substrate removal rates.q Mathematical model consists of a system of second order differential equations based on

23、steady state material balance and appropriate boundary conditions.q Model is solved numerically using a computer program developed in Macsyma 2.3,which uses 4th order Runge-Kutta method for solving system of ODEsRrdrAssumptions:4Spherical biofloc4Double substrate limited kinetics based on Michaelis-

24、Menten equation4Steady State conditions.4Constant Kinetic and Diffusional parameters,and biomass density inside the floc.Evaluation of concentration profile for the substrates inside a spherical bioflocSubstrate:Oxygen and Ammonia-nitrogen.Material Balance Equation:Mass transfer limitations due to d

25、iffusional resistances and biochemical reactions taking place inside the biofloc are considered.()()d sdr2rdsdr9Ys1ss1s2121122111222+=+.()()d sdr2rdsdr9s1ss1s2222221111222+=+.Boundary Conditions:Depend on,Degree of penetration Partial or Full Limiting Substrate Substrate-1(Oxygen)Substrate-2(Ammonia

26、)Case:Full Penetrationat r=1.00,s1=1.0,s2=1.0 at r=0,s1=s1,0,s2=s2,0,ds1/dr=0,ds2/dr=0001rss2,0s1,01Effluent OutletFeed Pump(peristaltic)Recirculation Pump (peristaltic)Sampling PortGas Solid Liquid(GSL)SeparatorUWaterSealBiogasGas MeasurementUnit10 cm dia.300 cm tallAcrylic tubeEffluentSettlerWash-

27、outBiomassSludgeBlanketGlassBeedsFeedsTankCyanide Degradation in Ananerobic Processes UASB Reactor For Biological Sulfate Removal EffluenSettlerWash-outbiomassFeed tankRecycle10.3 cm dia.9.3 cm tallAcrylic tubeEffluent Gas solid liquid(GSL)separator BiogasGas Measurement Unit Sampling port10 cm10 cm

28、10 cm10 cm10 cm Glass beadsSludgeblanketFeed pump(peristaltic)Recirculation pump (peristaltic)8.5 Fluidized Bed For Sulfide Oxidation ProcessNa2S/NaHCO3 Solution Nutrients Aeration TankSandHCl(NaOH)-pump AirEffluentpH electrode RecycleFludized Bed for Sulfide Oxidation ProcessUASB for Sulfide Remova

29、lFeed TankNaNO3 SolutionC=50(mg NO3-N/L)V=4.0(L)Feed PumpInfluentChitosan MembraneStirrerMagnetic StirrerSampling PointDenitrifyingBacteriaWeirFeed SideRecycle PipePermeate SideV=3.5(L)NaNO3 SolutionC=50(mg NO3-N/L)V=3.5(L)Sampling PointBio-Chitosan Membrane Reactorfor DenitrificationEffluentRecirculateRecirculationtankWastewaterStorage TankGas collection tankWastewaterPumpRecirculationPumpGasTimerSieveGravelImpellerClarifierEffluentSampling PointInfluentSampling Point10 cm10 cm10 cm10 cm10 cm10 cm10 cmDenitrification of Toxic Nitrogenous Wastewater