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![BBiioollooggiiccaall NNiittrrooggeenn RReemmoovvaall
factors affecting nitrification
* temperature
* substrate concentration
* dissolved oxygen
* pH
* toxic and inhibitory substances
é
ù
NH N T
N O
m = m - -
( 0.095( 15) )[1 0.83(7.2 )]
DO
4 e pH
é
m K NH úû
- - N
K DO
4
ù
êë
+
× úû
êë
+ -](https://image.slidesharecdn.com/biologicalwastewatertreatmentprocesses-140920141105-phpapp01/85/Biological-wastewater-treatment-processes-22-320.jpg)
Uploaded byArvind Kumar
Biological wastewater treatment processes
The document summarizes a seminar on biological wastewater treatment processes, past, present, and future. It discusses various types of domestic and industrial wastewater and their characteristics. It then describes key biological processes involved in wastewater treatment like carbonaceous removal, nitrogen removal, and sulfate removal. Various treatment processes are discussed including pond treatment, activated sludge process, and biofilm processes. Ongoing research activities at the institute are also highlighted which include studies on nitrification kinetics, anaerobic sulfate reduction modeling, and membrane bioreactor processes.
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Biological wastewater treatment processes
- 1. SSeemmiinnaarr oonn BBiioollooggiiccaallWWaasstteewwaatteerr TTrreeaattmmeenntt PPrroocceesssseess PPaasstt,, PPrreesseenntt aanndd FFuuttuurree Dr. Ajit P. Annachhatre Environmental Engineering Program Asian Institute of Technology
- 2. KKeeyywwoorrddss Wastewater Biological Processes Treatment Processes Applications Ongoing Research Activities
- 3. 11..WWaasstteewwaatteerr DomesticWastewater Industrial Wastewater • Present State of Wastewater
- 4. DDoommeessttiicc WWaasstteewwaatteerr over 80 % - untreated in Asian mega cities major components- COD = 250-1000 mg/L Total N = 20-90 mg/L Total P = 4-15 mg/L effects of discharging into natural receiving bodies oxygen demand by carbon and nitrogen
- 5. IInndduussttrriiaall WWaasstteewwaatteerr...... Eg: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 COD - high suspended solids - cyanide exposure
- 6. IInndduussttrriiaall WWaasstteewwaatteerr...... Starchindustry wastewater ‡ factory with 300 T/d of starch ‡ wastewater generation 6000m3/d ‡ COD 14,000 mg/L ‡ population equivalent 1000,000
- 7. IInndduussttrriiaall WWaasstteewwaatteerr •present treatment method: Anaerobic ponds • typical loading rates: 800-1000kg COD /ha/d • area requirement: 100 ha
- 8. 22..BBiioollooggiiccaall PPrroocceesssseess aim: any form of life- ‘ survive multiply ’ need for energy organic molecules as building blocks made of C, H, O, N, S, P and trace elements
- 9. BBiioollooggiiccaall PPrroocceesssseess...... cell: derives energy from oxidation of reduced food sources (carbohydrate, protein fats)
- 10. MMiiccrroooorrggaanniissmmss Classification: Heterotrophic- obtain energy from oxidation of organic matter (organic Carbon) Autotrophic- obtain energy from oxidation of inorganic matter (CO2, NH4, H+ ) Phototrophic- obtain energy from sunlight
- 11. BBiioocchheemmiiccaall PPaatthhwwaayyss oxidation of organic molecules inside the cell can occur aerobic or anaerobic manner generalized pathways for aerobic anaerobic fermentation
- 12. BBiioocchheemmiiccaall PPaatthhwwaayyss Glucose EPM Pathway Pyruvic Acid ADP ATP Energy Lactic Acid TCA Cycle H+ Respiration H2O CO2 O2
- 13. BBiioocchheemmiiccaall PPaatthhwwaayyss C6H12O6+ 6O2 +38 ADP + 38 Pi 6 CO2 +38 ATP + 44 H2O aerobic pathways contains- EMP pathways, TCA cycle, respiration anaerobic pathways contains- EMP pathways released energy stored as ATP molecules excess food is stored as Glycogen
- 14. Biological growth -exponential growth (batch) - Monod kinetics - Haldane kinetics under toxic conditions
- 15. exponential growth Biologicalgrowth... dX dt = mX Log No. of Cells Time Lag phase Log growth phase Stationary phase Death phase
- 16. Biological growth... Monod kinetics m = mm S Ks +S Substrate Concentration (S) Specific growth rate ( μ) μ Max. rate m μm/2 ks
- 17. Biological growth... Haldane kinetics (under toxic conditions) m = mm S Ks +S +S.i / Ki Substrate Concentration (S) Specific growth rate ( μ) i
- 18. 33..AApppplliiccaattiioonnss 1. Carbonaceousremoval - aerobic - anaerobic 2. Nitrogen removal - nitrification - denitrification 3. Sulfide removal - anaerobic SO4 reduction - aerobic HS- oxidation
- 19. BBiioollooggiiccaall CCaarrbboonnaacceeoouuss RReemmoovvaall aerobic - oxidation bacteria CHONS + O2 + Nutrients CO2 + NH3 + C5H7NO2 (organic matter) (new bacterial cells) + other end products - endogenous respiration bacteria C5H7NO2 + 5O2 5CO2 + 2H2O + NH3 + energy (cells)
- 20. BBiioollooggiiccaall CCaarrbboonnaacceeoouuss RReemmoovvaall anaerobic 100% 20% 5% 60% 15% 15% 35% 17% 10% 13% 72% 28% Schematic of the Anaerobic Process Hydrolysis Acidogenesis Methenogenesis Complex Organics Intermediates Propionate H 2 Acetate CH 4
- 21. BBiioollooggiiccaall NNiittrrooggeenn RReemmoovvaall nitrification -energy Nitrosomonas NH4 + + 1.5 O2 NO2 - + H2O + 2 H+ + (240-350 kJ) (1) Nitrobacter NO2 - + 0.5 O2 NO3 - + (65-90 kJ) (2) -assimilation Nitrosomonas 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 + 1.98 H CO3 - 0.021 C5H7NO2 + 0.98 NO3 - + 1.04 1H2O + 1.88H2CO3
- 22. BBiioollooggiiccaall NNiittrrooggeenn RReemmoovvaall factors affecting nitrification * temperature * substrate concentration * dissolved oxygen * pH * toxic and inhibitory substances é ù NH N T N O m = m - - ( 0.095( 15) )[1 0.83(7.2 )] DO 4 e pH é m K NH úû - - N K DO 4 ù êë + × úû êë + -
- 23. BBiioollooggiiccaall NNiittrrooggeenn RReemmoovvaall denitrification * assimilatory denitrification - reduction of nitrate to ammonium by microorganism 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 proceeds through a series of four steps NO NO NO N O N 3 - 2 - 2 2 ¾¾® ¾¾® ¾¾® ¾¾®
- 24. BBiioollooggiiccaall NNiittrrooggeenn RReemmoovvaall 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 acid NO - + 1.08CH OH + H + 0.065C H O N 0.47N 0.76CO 2.44H O 3 3 5 7 2 2 2 2 ¾¾® + + +
- 25. BBiioollooggiiccaall NNiittrrooggeenn RReemmoovvaall factors affecting denitrification * temperature * dissolved oxygen * pH
- 26. BBiioollooggiiccaall SSuullffaattee RReemmoovvaall * Sulfate removal cycle anaerobic SO4 -- HS - S 0 (O2 deficient) (O2 excess)
- 27. 44..TTrreeaattmmeenntt PPrroocceesssseess pond treatment activated sludge process biofilm process
- 28. PPoonndd TTrreeaattmmeenntt -no biomass recirculation - high HRT - high land area - O2 transfer limitations - inadequate mixing - excess loading (anaerobic condition-H2S generation)
- 29. AAccttiivvaatteedd SSlluuddggee PPrroocceessss F PST AT SST E RAS SW SW
- 30. AAccttiivvaatteedd SSlluuddggee PPrroocceessss...... - aerobic - suspended-growth - Design equations 1 q c Yk k min = - q q d c c SF * min =
- 31. AAccttiivvaatteedd SSlluuddggee PPrroocceessss...... typical values of cell residence time (qc ) - qc for C removal ~ 3-10 days - qc for N removal ~ 5-30 days - loading rates ~ 2-3 kg COD/m3/d - drawbacks: O2 requirements, inlet conc.
- 32. BBiiooffiillmm PPrroocceesssseess advantagesof 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
- 33. BBiiooffiillmm PPrroocceesssseess...... •types of biofilms: aerobic, anaerobic, anoxic • process of biofilm formation - formation of diffuse electrical double layer due to electrostatic forces and thermal motion - transfer of microorganism to surface - microbial adhesion - biofilm formation
- 34. BBiiooffiillmm PPrroocceesssseess...... •biofilm operation X Y Liquid Biofilm Film Bulk Liquid Support Material (a) Physical concept Fully Penetrated SS Partially Penetrated Sb Substrate Concentration X Y (b) Substrate concentration profile
- 35. BBiiooffiillmm PPrroocceesssseess...... •biofilm operation - diffusion resistance - inadequate supply of nutrients to inner portions of Biofilm - limitations on product out diffusion - attrition of reaction conditions
- 36. BBiiooffiillmm PPrroocceesssseess...... •biofilm operation average rate of substrate consumption Effectiveness factor h = ---------------------------------------------- substrate consumption at biofilm surface • as biofilm thickness increases effectiveness factor (h) decreases
- 37. AAnnaaeerroobbiicc bbiiooffiillmm pprroocceesssseess Conversion of Ethanol to Methane Conversion Reaction DGo’ (kJ) Ethanol CH2CH2OH (aq) + H2O (l) = CH3COO- (aq) + H+ (aq) + 2H2 (g) +09.65 Hydrogen 2H2 (g) + ½ CO2 (g) = ½ CH4 (g) + H2O (l) - 65.37 Acetate CH3COO- (aq) + H+ (aq) = CH4 (g) + CO2 (g) - 35.83 Net CH2CH2OH (aq) = 3/2 CH4 + ½ CO2 (g) - 91.55
- 38. AAnnaaeerroobbiicc bbiiooffiillmm pprroocceesssseess...... • importance of H partial pressure • loading rates 10-15 kg COD/m3/d against 2-5 kg COD/m3/d in suspended growth processes
- 39. OOnnggooiinngg RReesseeaarrcchh AAccttiivviittiieess Biological Processes aerobic anoxic anaerobic nitrification denitrification SO4 2-- reduction HS- oxidation detoxification
- 40. OOnnggooiinngg RReesseeaarrcchh AAccttiivviittiieess aerobic nitrification HS- oxidation inhibition aniline modeling biofilm in ASP degradation processes in SBR Shabbir Jega Sunil Keshab Savapak Shabbir Shabbir
- 41. OOnnggooiinngg RReesseeaarrcchh AAccttiivviittiieess anaerobic SO4 2--reduction detoxification modeling modeling Savapak Amara
- 42. OOnnggooiinngg RReesseeaarrcchh AAccttiivviittiieess anoxic denitrification toxic chemicals membrane as C source bio reactor Krongtong Tran membrane processes Piyaputr
- 43. Study of nitrificationprocess inside a spherical biofloc particle based on biofilm kinetics. determination of effectiveness factor for substrate consumption and thus the substrate removal rates.
- 44. Mathematical model consistsof a system of second order differential equations based on steady state material balance and appropriate boundary conditions. Model is solved numerically using a computer program developed in Macsyma 2.3, which uses 4th order Runge-Kutta method for solving system of ODEs
- 45. Evaluation of concentrationprofile for the substrates r R dr inside a spherical biofloc Assumptions: Spherical biofloc Double substrate limited kinetics based on Michaelis - Menten equation Steady State conditions. Constant Kinetic and Diffusional parameters, and biomass density inside the floc.
- 46. Substrate : Oxygenand Ammonia-nitrogen Material Balance Equation: Mass transfer limitations due to diffusional resistances and biochemical reactions taking place inside the biofloc are considered. . f b . ( ) ( ) d s dr 2 r ds dr 9 Y s 1 s s 1 s 2 1 2 1 2 1 2 1 b b 1 1 2 2 2 + = + + . f b . ( ) ( ) d s dr 2 r ds dr 9 s 1 s s 1 s 2 2 2 2 2 2 1 1 b b 1 1 2 2 2 + = + +
- 47. Boundary Conditions: Dependon, ¨ Degree of penetration Partial or Full ¨ Limiting Substrate Substrate-1 (Oxygen) Substrate-2 (Ammonia) Case : Full Penetration at r = 1.00 , s1 = 1.0, s2 = 1.0 at r = 0, s1 = s1,0, s2 = s2,0, ds1/dr = 0, ds2/dr = 0 1 0 0 r s s2,0 s1,0 1
- 48. Fig. Variation ofeffectiveness factor with the size of biofloc and bulk DO to bulk NH 4 + conc. ratio for constant bulk DO conc = 4 mg/l 1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.00 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 Biofloc diameter (mm) Effectiveness factor ( ) 0.1 0.125 0.15 0.2 0.25 0.3 0.4 0.5 0.75 1 1.5 2 3 4 6 8 10
- 49. OOnnggooiinngg RReesseeaarrcchh AAccttiivviittiieess Gas Solid Liquid (GSL) Separator Effluent Outlet Feed Pump (peristaltic) Sampling Port Recirculation Pump (peristaltic) U Water Seal Biogas Gas Measurement Unit 10 cm dia. 300 cm tall Acrylic tube Effluent Settler Wash-out Biomass Sludge Blanket Glass Beeds Feeds Tank Cyanide Degradation in Ananerobic Processes
- 50. OOnnggooiinngg RReesseeaarrcchh AAccttiivviittiieess Gas solid liquid (GSL) separator Effluent Sludge blanket UASB Reactor For Biological Sulfate Removal Effluen Settler Wash-out biomass Feed tank Recycle 10.3 cm dia. 9.3 cm tall Acrylic tube Biogas Gas Measurement Unit Sampling port 10 cm 10 cm 10 cm 10 cm 10 cm Glass beads Feed pump (peristaltic) Recirculation pump (peristaltic) 8.5 Fludized Bed for Sulfide Oxidation Process HCl (NaOH)-pump Fluidized Bed For Sulfide Oxidation Process Na2S/NaHCO3 Solution Nutrients Aeration Tank Sand Air Effluen t pH electrode Recycle UASB for Sulfide Removal
- 51. OOnnggooiinngg RReesseeaarrcchh AAccttiivviittiieess Feed Pump Influent Feed Tank NaNO3 Solution C = 50 (mg NO3 -- N/L) V = 4.0 (L) Chitosan Membrane Stirrer Sampling Point Magnetic Stirrer Denitrifying Bacteria Weir Feed Side Recycle Pipe Permeate Side NaNO3 Solution V = 3.5 (L) C = 50 (mg NO3 -- N/L) V = 3.5 (L) Sampling Point Bio-Chitosan Membrane Reactor for Denitrification
- 52. OOnnggooiinngg RReesseeaarrcchh AAccttiivviittiieess Effluent Recirculate Recirculation tank Gas collection tank Wastewater Storage Tank Wastewater Pump Recirculation Pump Gas Clarifier Impeller Gravel Timer Sieve Effluent Sampling Point Influent Sampling Point 10 cm 10 cm 10 cm 10 cm 10 cm 10 cm 10 cm Denitrification of Toxic Nitrogenous Wastewater
- 53.