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BIOLOGICAL PLANT SIZING

BIOLOGICAL PLANT SIZING. Ing. Alberto Scaunich. N. -. Number of values. M. -. Average Value. s. -. Standard Deviation. WHICHEVER. NORMAL. -. Typical Values. DISTRIBUTION. DISTRIBUTION. s. 68.3%. M+. s. 75%. 95.4%. M+2. s. 91%. 99,7%. M+. 3. STATISTIC ELABORATION.

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BIOLOGICAL PLANT SIZING

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  1. BIOLOGICAL PLANT SIZING Ing. Alberto Scaunich

  2. N - Number of values M - Average Value s - Standard Deviation WHICHEVER NORMAL - Typical Values DISTRIBUTION DISTRIBUTION s 68.3% M+ s 75% 95.4% M+2 s 91% 99,7% M+ 3 STATISTIC ELABORATION EXISTING PLANT(or available data flowrate and pollutants concentration) Generally are available data for: Flow Q [m3/d] Pollutant concentration c [mg/l]  Pollutant Load C [kg/d] = Q*c/1000

  3. When are available a lot of data, it’s better to eliminate single data (only flow or only concentration). Hence you proceed in statistic elaboration. At the end, when you have average values of flow and loads, calculate the value ratio: average load (concentration) average flow which generally is different from concentration average values and is more significant, representing the weighted average of concentrations. EXISTING PLANT(or available data flowrate and pollutants concentration)

  4. MUNICIPAL WASTE WATER • You have to refer your design to the SPECIFIC CONTRIBUTION PER CAPITA, which generally result prudential values. • 2. INDUSTRIAL WASTE WATER • You have to refer your design to the available SPECIFIC CONTRIBUTION PER UNIT OF PRODUCTS, adopting some security factors. NOTEXISTING PLANT

  5. POLLUTANTS BALANCE In biological plant sizing the ratio COD/BOD and BOD/TKN (or COD/TKN) are very important In Denitrification you need organic load to remove Nitrogen. assume: 3 kgBOD/kg(N-NO3)DENsizing oxidation 4 kgBOD/kg(N-NO3)DENsizing post-denitrification (methanol requirements) Calculate Pollutants balance for these following cases (to verify section sizing): M (BOD) + M(TKN) M(BOD) + M+2s (TKN) M+2s (BOD) + M(TKN)

  6. NITROGEN BALANCE TKNin+(N-NO2)in+(N-NO3)in = = TKNSED+(N-NO3)DEN+TKNox+TKNout+(N-NO2)out+(N-NO3)out Where: TKNin = inlet Nitrogen (organic ed ammonia) (N-NO2)in = inlet Nitrogen (nitrite): generally absent (N-NO3)in = inlet Nitrogen (nitrate): present only in industrial wastewater TKNSED = organic Nitrogen removed in primary sedimentation: 10÷15% TKNin TKNin(N-NO3)DEN = nitrogen to remove by denitrification TKNox = TKN removed by bacterial metabolism (5% BOD removed in biological treatment = 0,05 (BODin Den – BODout) TKNout = outlet Nitrogen (organic ed ammonia) - assume: 1 mg/l (N-NO2)out = outlet Nitrogen (nitrite) - negligible (N-NO3)out = outlet Nitrogen (nitrate) - project requirement(10÷15 mg/l) Normally you can’t have in the same time significant values of (N-NH3)out and(N-NO3)out

  7. DENITRIFICATION DESIGN DENITRIFICATION VELOCITY (municipal effluents) (nD)T = (nD)20 * qT-20 Where: (nD)T [gN-NO3/kgVSS*d] = Denitrification velocity:actual operative conditions (temperature = T); (nD)20 [gN-NO3/kgVSS*d] = Denitrification velocity: max value at T = 20 °C, without any limiting factor; q= Temperature correction coefficient (higher value, higher T dependence)

  8. DENITRIFICATION VELOCITY

  9. DENITRIFICATION VOLUME CALCULATION (N-NO3)DEN V= ------------------- (nD)T * X Where: V [m3] = Minimum design Denitrification volume T [°C] = Minimum design Temperature (N-NO3)DEN [kg N-NO3/d] = nitrogen to remove by denitrification X [kgSSV/m3]: = Volatile Suspended Solids concentration in biological basins (Denitrification – Nitrification) Note: It’s opportune to assure a minimum residential time of 3÷4 h at the maximum flow, to give to mixed liquor enough time to reduce its O2 content (DO concentration of 0,5 mg/l reduce denitrification efficiency to 10%)

  10. MIXED LIQUOR TO RECYCLE CALCULATION 1000 * (N-NO3)DEN QML = ------------------------- - QR 24 * N-NO3 out Where: QML [m3/h] = flowrate of recirculated Mixed Liquor QR [m3/h] = return sludge flowrate (N-NO3)DEN [kg N-NO3/d] = nitrogen to remove by denitrification N-NO3 out[g/m3] = concentration of nitrogen in outlet stream (design value) 1000 = conversion factor (kg  g) 24 = conversion factor (d  h)

  11. MIXING - DENITRIFICATION Above 8÷10 W/m3 energy density is required (normal submersible mixers) Mixer rotation velocity must be chosen as low as possible (< 700 rpm)

  12. OXIDATION DESIGN PRELIMINARY SIZING BODin V= --------------- X * F/M Where: BODin [kgBOD/d] = Inlet BOD, coming from Denitrification X [kgSST/m3] = Total Suspended Solids concentration in biological basins (Denitrification – Nitrification): Values: 4÷6 SSV/SST = Organic fraction: typical = 0,7 F/M [kgBOD/kgSST*d] = Ratio Food/Mass: Typical values range - extended aeration0,075 (0,06÷0,09) - nitrification (according T) 0,15 (0,12÷0,18) - carbon removal only (h=85-90%) 0,25 (0,2÷0,35)

  13. OXIDATION DESIGN NITRIFICATION VERIFING Where: (nn)T= Nitrification velocity: actual operative conditions (temperature = T [gTKN/kgSSV/d]; (nn)20= Nitrification velocity: max value at T = 20 °C, without any limiting factor; [gTKN/kgSSV/d]; q= Temperature correction coefficient; KTKN, KO = semisaturation constants, relating to TKN and DO [mg/l]; TKN, O.D.= TKN and Oxygen concentrations in biological basins [mg/l]

  14. OXIDATION DESIGN NITRIFICATION VERIFING

  15. OXIDATION DESIGN CALCULATIONOF NITRIFICANT BACTERIA FRACTION Where: y N = nitrificant bacteria cellular yield coefficient [kgSSV/kg/TKN] y = heterotrophicbacteria cellular yield coefficient[gSSV/gBOD] S0 = inlet organic matter [mg/l] Se = outlet organic matter [mg/l] TKN0 = inlet TKN [mg/l] TKNe = outlet TKN [mg/l] y/yN = 4,72 (Bonomo, 2008)

  16. OXIDATION DESIGN NITRIFICATION VOLUME CALCULATION Where: x =Total Suspended Solids concentration in biological basins [kgSST/m3] XN = Total nitrificant bacteria in nitrification basins [kgSST]

  17. OXIDATION DESIGN RETURN SLUDGE FLOWRATE Where: xr =Total Suspended Solids concentration in return sludge [kgSST/m3]

  18. OXIDATION DESIGN RETURN SLUDGE FLOWRATE – IMHOFF CONE (Q + Qr)Va = Qr Vr Qr Va -------------- = --------------- Q Vr - Va If Vr =1 l/l Qr Va -------------- = --------------- Q 1 - Va

  19. OXIDATION DESIGN Imhoff cone – 30 min [ml/l] or [cc/l] Imhoff SVI = --------------- x RETURN SLUDGE FLOWRATE SVI (sludge volume index) Where: x =Total Suspended Solids concentration in biological basins [g/l] Qr x -------------- = --------------- Q 1000/SVI - x

  20. OXIDATION DESIGN EXCESS SLUDGE FLOWRATE CALCULATION

  21. OXIDATION DESIGN ACTUAL OXYGEN REQUIREMENTS (AOR) & STANDARD OXYGEN REQUIREMENTS (SOR) Where: a = Carbon removal coefficient = 0,5 kgO2/kgBOD b = Endogenous respiration coefficient = 0,08 kgO2/kgSST/d N da nitrificare = N to remove in nitrification [kgN-NH4/d] 2,86 KgO2/KgNDEN = Oxygen recovery

  22. OXIDATION DESIGN ACTUAL OXYGEN REQUIREMENTS (AOR) & STANDARD OXYGEN REQUIREMENTS (SOR) Where: a= rapporto tra il coefficiente di trasferimento relativo al liquido reale a 20°C e quello relativo alle condizioni standard, fissato pari a 0,70; b = rapporto tra la concentrazione di ossigeno a saturazione nel liquido reale in condizioni di esercizio e quella in acqua pulita in condizioni di esercizio; Cs,T = concentrazione di ossigeno a saturazione in acqua pulita alla temperatura di esercizio T; Cw,T = concentrazione di ossigeno nel liquido reale alle condizioni di esercizio, fissata pari a 2 mg/l; Cs,* = concentrazione di saturazione in acqua pulita in condizioni standard (20 °C); T = Temperatura nelle condizioni di esercizio

  23. OXIDATION DESIGN AIR DEMAND Where: 24 = days hours; 0,28 = Kg O2 / mc air in standard conditions (20°C – 0 m a.s.l.); h = transfer efficiency O2 = 5% / m depth.

  24. SEDIMENTATION DESIGN

  25. WASTEWATER TREATMENT PLANT BIOLOGICAL TREATMENTS

  26. BIOLOGICAL TREATMENTS PIATTELLI PER AERAZIONE AD ALTA EFFICIENZA

  27. BIOLOGICAL TREATMENTS PIATTELLI PER AERAZIONE AD ALTA EFFICIENZA

  28. BIOLOGICAL TREATMENTS PIATTELLI PER AERAZIONE AD ALTA EFFICIENZA

  29. BIOLOGICAL TREATMENTS PIATTELLI PER AERAZIONE AD ALTA EFFICIENZA

  30. BIOLOGICAL TREATMENTS DENITRIFICAZIONE - OSSIDAZIONE

  31. BIOLOGICAL TREATMENTS OSSIDAZIONE E TUBAZIONI RICIRCOLO

  32. BIOLOGICAL TREATMENTS OSSIDAZIONE

  33. BIOLOGICAL TREATMENTS OSSIDAZIONE

  34. BIOLOGICAL TREATMENTS DENITRIFICAZIONE - OSSIDAZIONE

  35. BIOLOGICAL TREATMENTS OSSIDAZIONE - OKI

  36. BIOLOGICAL TREATMENTS OSSIDAZIONE

  37. BIOLOGICAL TREATMENTS OSSIDAZIONE - OKI

  38. BIOLOGICAL TREATMENTS OSSIDAZIONE A BOLLE MEDIE

  39. BIOLOGICAL TREATMENTS BIODISCHI

  40. BIOLOGICAL TREATMENTS SEDIMENTAZIONE

  41. BIOLOGICAL TREATMENTS SEDIMENTAZIONE

  42. BIOLOGICAL TREATMENTS SEDIMENTAZIONE – CARROPONTE ASPIRATO

  43. BIOLOGICAL TREATMENTS SEDIMENTAZIONE

  44. BIOLOGICAL TREATMENTS SEDIMENTAZIONE

  45. BIOLOGICAL TREATMENTS SEDIMENTAZIONE

  46. BIOLOGICAL TREATMENTS SEDIMENTAZIONE

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