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BIOLOGICAL PLANT SIZING Ing. Alberto Scaunich. EXISTING PLANT (or available data flowrate EXISTING PLANT (or available data flowrate and pollutants concentration)

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Presentation on theme: "BIOLOGICAL PLANT SIZING Ing. Alberto Scaunich. EXISTING PLANT (or available data flowrate EXISTING PLANT (or available data flowrate and pollutants concentration)"— Presentation transcript:

1 BIOLOGICAL PLANT SIZING Ing. Alberto Scaunich

2 EXISTING PLANT (or available data flowrate EXISTING PLANT (or available data flowrate and pollutants concentration) Generally are available data for: FlowQ[m3/d] Pollutant concentration c[mg/l] Pollutant Load C[kg/d]= Q*c/1000 STATISTIC ELABORATION

3 EXISTING PLANT (or available data flowrate EXISTING PLANT (or available data flowrate and pollutants concentration) When are available a lot of data, its 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.

4 NOT EXISTING PLANT NOT EXISTING PLANT 1.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.

5 POLLUTANTS BALANCE In biological plant sizing the ratio COD/BOD and BOD/TKN (or COD/TKN) are very important 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-NO 3 ) DEN sizing oxidation 4 kgBOD/kg(N-NO 3 ) DEN sizing post-denitrification (methanol requirements) (methanol requirements) Calculate Pollutants balance for these following cases (to verify section sizing): M (BOD) + M(TKN) M(BOD) + M+2 (TKN) M+2 BOD) + M(TKN)

6 NITROGEN BALANCE TKN in +(N-NO 2 ) in +(N-NO 3 ) in = TKN in +(N-NO 2 ) in +(N-NO 3 ) in = = TKN SED +(N-NO 3 ) DEN +TKN ox +TKN out +(N-NO 2 ) out +(N-NO 3 ) out Where: TKN in = inlet Nitrogen (organic ed ammonia) (N-NO 2 ) in = inlet Nitrogen (nitrite):generally absent (N-NO 3 ) in = inlet Nitrogen (nitrate):present only in industrial wastewater TKN SED = organic Nitrogen removed in primary sedimentation: 10÷15% TKN in TKN in (N-NO 3 ) DEN = nitrogen to remove by denitrification TKN ox = TKN removed by bacterial metabolism (5% BOD removed in biological treatment = 0,05 (BODi n Den – BOD out ) TKN out = outlet Nitrogen (organic ed ammonia) - assume: 1 mg/l (N-NO 2 ) out = outlet Nitrogen (nitrite) - negligible (N-NO 3 ) out = outlet Nitrogen (nitrate) - project requirement(10÷15 mg/l) Normally you cant have in the same time significant values of (N-NH 3 ) out and (N-NO 3 ) out

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

9 DENITRIFICATION VELOCITY DENITRIFICATION INTERNAL CARBON PRE-DEN Inizial velocity PRE-DEN Average vel. POST- DEN Average vel. VOCEUnità di misura Scaunich vecchio Scaunich attuale Forte influenza T Esercizio attuale Debole influenza T Organic fraction SSV/SST 0,7 Temperature correction coefficient 1,121,0651,2001,0801,030 Denitrification velocitya °C20 gN-NO3/kgSSTxd 70,056,0504,070,750,4 a °C18 gN-NO3/kgSSTxd 55,849,4350,060,647,5 a °C16 gN-NO3/kgSSTxd 44,543,5243,152,044,8 a °C14 gN-NO3/kgSSTxd 35,538,4168,844,642,2 a °C12 gN-NO3/kgSSTxd 28,333,8117,238,239,8 a °C10 gN-NO3/kgSSTxd 22,529,881,432,737,5 Denitrification velocitya °C20 gN-NO3/kgSSVxd 100,080,0720,0101,072,0 a °C18 gN-NO3/kgSSVxd 79,770,5500,086,667,9 a °C16 gN-NO3/kgSSVxd 63,662,2347,274,264,0 a °C14 gN-NO3/kgSSVxd 50,754,8241,163,660,3 a °C12 gN-NO3/kgSSVxd 40,448,3167,454,656,8 a °C10 gN-NO3/kgSSVxd 32,242,6116,346,853,6

10 DENITRIFICATION VOLUME CALCULATION (N-NO 3 ) DEN V = ( D ) T * X ( D ) T * XWhere: V [m 3 ] =Minimum design Denitrification volume T [°C] = Minimum design Temperature (N-NO 3 ) DEN [kg N-NO 3 /d] = nitrogen to remove by denitrification X [kgSSV/m 3 ]: = Volatile Suspended Solids concentration in biological basins (Denitrification – Nitrification) Note:Its 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 O 2 content (DO concentration of 0,5 mg/l reduce denitrification efficiency to 10%)

11 MIXED LIQUOR TO RECYCLE CALCULATION 1000 * (N-NO 3 ) DEN 1000 * (N-NO 3 ) DEN Q ML = Q R 24 * N-NO 3 out 24 * N-NO 3 outWhere: Q ML [m 3 /h] = flowrate of recirculated Mixed Liquor Q R [m 3 /h] = return sludge flowrate (N-NO 3 ) DEN [kg N-NO 3 /d] = nitrogen to remove by denitrification N-NO 3 out [g/m 3 ] = concentration of nitrogen in outlet stream (design value) 1000= conversion factor (kg g) 24 =conversion factor (d h)

12 MIXING - DENITRIFICATION Above 8÷10 W/m 3 energy density is required(normal submersible mixers) Mixer rotation velocity must be chosen as low as possible (< 700 rpm)

13 OXIDATION DESIGN PRELIMINARY SIZING BOD in V = X * F/M X * F/MWhere: BOD in [kgBOD/d] = Inlet BOD, coming from Denitrification X [kgSST/m 3 ] = 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 aeration 0,075 (0,06÷0,09) - nitrification (according T) 0,15 (0,12÷0,18) - carbon removal only ( =85-90%) 0,25 (0,2÷0,35)

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

15 OXIDATION DESIGN NITRIFICATION VERIFING

16 OXIDATION DESIGN CALCULATION OF NITRIFICANT BACTERIA FRACTION Where: y N = nitrificant bacteria cellular yield coefficient [kgSSV/kg/TKN] y = heterotrophic bacteria 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)

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

18 OXIDATION DESIGN RETURN SLUDGE FLOWRATE Where: x r = Total Suspended Solids concentration in return sludge [kgSST/m3]

19 OXIDATION DESIGN RETURN SLUDGE FLOWRATE – IMHOFF CONE (Q + Q r )V a = Q r V r Q r V a Q r V a = Q V r - V a Q V r - V a If V r = 1 l/l Q r V a Q r V a = Q 1 - V a Q 1 - V a

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

21 OXIDATION DESIGN EXCESS SLUDGE FLOWRATE CALCULATION

22 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/KgN DEN = Oxygen recovery

23 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; 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; C s,T = concentrazione di ossigeno a saturazione in acqua pulita alla temperatura di esercizio T; C w,T = concentrazione di ossigeno nel liquido reale alle condizioni di esercizio, fissata pari a 2 mg/l; C s,* = concentrazione di saturazione in acqua pulita in condizioni standard (20 °C); T = Temperatura nelle condizioni di esercizio

24 OXIDATION DESIGN AIR DEMAND Where: 24 = days hours; 24 = days hours; 0,28 = Kg O 2 / mc air in standard conditions (20°C – 0 m a.s.l.); h = transfer efficiency O 2 = 5% / m depth.

25 SEDIMENTATION DESIGN Hydraulic head (mc/mqxh) Hydraulic head (mc/mqxh) C i =Q/A 0,20 – 0,30 0,20 – 0,30 - Q (mc/h), flowrate - Q (mc/h), flowrate - A (mq), area - A (mq), area Solid load Solid load (kg SST/mqxd) (kg SST/mqxd) Cs = G/A < 5 a Q 24 < 5 a Q 24 <9 a Q max - G (kgSST/d), solid flowrate = 2,5 Qr X - G (kgSST/d), solid flowrate = 2,5 Qr X - X (kgSST/mc), activated sludge concentration - X (kgSST/mc), activated sludge concentration - Qr (mc/h), return sludge flowrate = 1 – 1,5 Q 24 - Qr (mc/h), return sludge flowrate = 1 – 1,5 Q 24 Height (m) Height (m)3m Bridge Bridge Suction bridge

26 BIOLOGICAL TREATMENTS WASTEWATER TREATMENT PLANT

27 PIATTELLI PER AERAZIONE AD ALTA EFFICIENZA BIOLOGICAL TREATMENTS

28 PIATTELLI PER AERAZIONE AD ALTA EFFICIENZA BIOLOGICAL TREATMENTS

29 PIATTELLI PER AERAZIONE AD ALTA EFFICIENZA BIOLOGICAL TREATMENTS

30 PIATTELLI PER AERAZIONE AD ALTA EFFICIENZA BIOLOGICAL TREATMENTS

31 DENITRIFICAZIONE - OSSIDAZIONE BIOLOGICAL TREATMENTS

32 OSSIDAZIONE E TUBAZIONI RICIRCOLO BIOLOGICAL TREATMENTS

33 OSSIDAZIONE

34 OSSIDAZIONE

35 DENITRIFICAZIONE - OSSIDAZIONE BIOLOGICAL TREATMENTS

36 OSSIDAZIONE - OKI BIOLOGICAL TREATMENTS

37 OSSIDAZIONE

38 OSSIDAZIONE - OKI BIOLOGICAL TREATMENTS

39 OSSIDAZIONE A BOLLE MEDIE BIOLOGICAL TREATMENTS

40 BIODISCHI

41 SEDIMENTAZIONE

42 SEDIMENTAZIONE

43 SEDIMENTAZIONE – CARROPONTE ASPIRATO BIOLOGICAL TREATMENTS

44 SEDIMENTAZIONE

45 SEDIMENTAZIONE

46 SEDIMENTAZIONE

47 SEDIMENTAZIONE


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