Wastewater Treatment Plant: Modelling and Validation of an Activated Sludge Process
Abstract
1. Introduction
2. Method
2.1. System Layout
2.2. Calibration and Validation Procedure
3. Results and Discussion
3.1. Sensitivity Analysis
3.2. Energy Analysis
4. Conclusions
Author Contributions
Funding
Conflicts of Interest
Appendix A
Appendix A.1. System Model
Parameter | Description | Unit | |
---|---|---|---|
1 | SI | Soluble inert organic matter: consists of organic compounds that do not take part in the wastewater treatment processes | mgCODl−3 |
2 | SS | Readily biodegradable substrate: simple organic carbon compounds that provide energy to heterotrophic bacteria | mgCODl−3 |
3 | XI | Particulate inert organic matter: undissolved organic particles such as soil organic matter or other particulates isolated by sieving or filtration | mgCODl−3 |
4 | XS | Slowly biodegradable substrate: consists of relatively complex compounds that must be hydrolysed to simple compounds by extracellular enzymes in order to be assimilated by microorganisms | mgCODl−3 |
5 | XBH | Active heterotrophic biomass: microorganisms using organic carbon for the formation of new biomass | mgCODl−3 |
6 | XBA | Active autotrophic biomass: microorganisms using carbon from carbon dioxide for the formation of new biomass | mgCODl−3 |
7 | XP | Particulate products arising from biomass decay: products which are inert to further biological attack after the decay of the biomass | mgCODl−3 |
8 | SO | Oxygen: the oxygen concentration for the biological process | mgl−3 |
9 | SNO | Nitrate and nitrite nitrogen: products obtained by autotrophic bacteria in aerobic condition and removed by heterotrophic bacteria in anoxic condition | mgNl−3 |
10 | SNH | NH4++ NH3 nitrogen: the soluble ammonia nitrogen, assumed to be the sum of the ionized (ammonium, NH4+) and un-ionized form (ammonia, NH3) | mgNl−3 |
11 | SND | Soluble biodegradable organic nitrogen: products formed by the hydrolysis of particular organic nitrogen by ammonification | mgNl−3 |
12 | XND | Particulate biodegradable organic nitrogen: products generated from decay of autotrophic and heterotrophic bacteria | mgNl−3 |
13 | Salk | Alkalinity | mol m−3 |
Process, j | Component, i | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | Process Rate | |
SI | SS | XI | XS | XBH | XBA | XP | SO | SNO | SNH | SND | XND | Salk | ρj | |
1. Aerobic growth of heterotrophs | 1 | |||||||||||||
2. Anoxic growth of heterotrophs | 1 | |||||||||||||
3. Aerobic growth of autotrophs | 1 | |||||||||||||
4. Decay of heterotrophs | 1-fP | −1 | fP | bHXB,H | ||||||||||
5. Decay of autotrophs | −1 | baXB,A | ||||||||||||
6. Ammonification of soluble nitrogen | 1 | −1 | kaSNDXB,H | |||||||||||
7. Hydrolysis of entrapped organics | 1 | −1 | ||||||||||||
8. Hydrolysis of entrappedorganic nitrogen | 1 | −1 | ρ7(XND/XS) |
- H = the maximum heterotrophic growth rate, equal to 4.0 (day−1).
- KS = the saturation (heterotrophic growth), equal to 10.0 (g COD m−3).
- KO,H = the half saturation (heterotrophic oxygen), equal to 0.2 (g O2 m−3).
- KNO = the half saturation (nitrate), equal to 0.5 (g NO3-Nm−3).
- bH = the heterotrophic decay rate, equal to 0.3 (day−1).
- ηg = the anoxic growth rate correction factor, equal to 0.8 (-).
- ηh = the anoxic hydrolysis rate correction factor, equal to 0.8 (-).
- kh = the maximum specific hydrolysis rate, equal to 3.0 (g, slowly biodegradable COD (g XBH COD day)−1).
- KX = the half saturation (hydrolysis), equal to 0.1 (g, slowly biodegradable COD (g XBH COD)−1).
- A = the maximum autotrophic growth rate, equal to 0.5 (day−1).
- KNH = the half saturation (auto: growth), equal to 1.0 (g NH3-Nm−3).
- KOA = the half saturation (auto: oxygen), equal to 0.4 (g O2 m−3).
- bA = the autotrophic decay rate, equal to 0.05 (day−1).
- ka = the ammonification rate, equal to 0.05 (m3 COD (g day)−1).
Appendix A.2. Aeration Energy Demand Evaluation
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Concentration of | Inflow | Anoxic Tank 1 Initial | Anoxic Tank 2 Initial | Aeration Tank 1 Initial | Aeration Tank 2 Initial | Aeration Tank 3 Initial |
---|---|---|---|---|---|---|
(gm−3) | ||||||
Readily biodegradable substrate | 69.500 | 3.732 | 2.061 | 1.454 | 1.226 | 1.067 |
Soluble inert organic | 30.000 | 30.000 | 30.000 | 30.000 | 30.000 | 30.000 |
Particulate inert organic matter | 51.200 | 814.301 | 813.912 | 813.393 | 812.874 | 812.354 |
Slowly biodegradable substrate | 202.320 | 83.073 | 81.401 | 68.023 | 57.215 | 49.092 |
Active heterotrophic biomass | 28.170 | 2085.021 | 2083.728 | 2088.379 | 2091.048 | 2091.868 |
Active autotrophic biomass | 0 | 69.621 | 69.535 | 69.839 | 70.152 | 70.382 |
Particulate products arising from biomass decay | 0 | 227.672 | 228.044 | 228.540 | 229.037 | 229.534 |
Dissolved oxygen | 0 | 0.012 | 0.000 | 2.938 | 3.752 | 1.076 |
Nitrate and nitrite nitrogen | 0 | 1.649 | 0.543 | 2.177 | 3.881 | 5.089 |
Ammonia nitrogen | 31.560 | 17.672 | 18.135 | 16.549 | 15.029 | 13.901 |
Soluble biodegradable organic nitrogen | 6.950 | 1.319 | 0.859 | 0.914 | 0.881 | 0.808 |
Particulate biodegradable organic nitrogen | 10.590 | 5.234 | 5.235 | 4.485 | 3.872 | 3.410 |
Concentration of | Results Obtained | Biowin [4] | Simba [19] | Stoat [5] |
---|---|---|---|---|
(gm−3) | ||||
Readily biodegradable substrate | 0.890 | 0.890 | 0.889 | 0.900 |
Soluble inert organic | 30.000 | 30.000 | 30.000 | 30.000 |
Particulate inert organic matter | 4.392 | 4.270 | 4.392 | 6.100 |
Slowly biodegradable substrate | 0.188 | 0.210 | 0.188 | 0.140 |
Active heterotrophic biomass | 9.782 | 9.510 | 9.782 | 6.600 |
Active autotrophic biomass | 0.573 | 0.560 | 0.573 | 0.400 |
Particulate products arising from biomass decay | 1.728 | 1.680 | 1.728 | - |
Dissolved oxygen | 0.491 | 0.500 | 0.491 | 0.500 |
Nitrate and nitrite nitrogen | 10.415 | 10.450 | 10.415 | 10.400 |
Ammonia nitrogen | 1.733 | 1.740 | 1.733 | 1.700 |
Soluble biodegradable organic nitrogen | 0.688 | 0.690 | 0.688 | 0.700 |
Particulate biodegradable organic nitrogen | 0.013 | 0.010 | 0.013 | 0.000 |
TSS Concentrations Along the Settler Height | Results Obtained | Biowin [4] | Simba [19] | Stoat [5] |
---|---|---|---|---|
(gSSm−3) | ||||
Layer 1 (effluent source) | 12.497 | 12.170 | 12.500 | 12.500 |
Layer 2 | 18.113 | n/a | 18.110 | 18.100 |
Layer 3 | 29.540 | n/a | 29.540 | 29.500 |
Layer 4 | 68.978 | n/a | 68.980 | 68.900 |
Layer 5 | 356.075 | n/a | 356.070 | 356.100 |
Layer 6 | 356.075 | n/a | 356.070 | 356.100 |
Layer 7 | 356.075 | n/a | 356.070 | 356.100 |
Layer 8 | 356.075 | n/a | 356.070 | 356.100 |
Layer 9 | 356.075 | n/a | 356.070 | 356.100 |
Layer 10 (activated sludge source) | 6393.984 | 6406.030 | 6393.980 | 6394.100 |
Volume Tank 1, 2 (m3) | Volume Tank 3, 4, 5 (m3) | kLa (day−1) | EQI (kg pollutions d−1) | Electric Demand (kW) | Primary Energy Consumption (MWh/y) | ΔPE (%) | CO2 (tCO2/y) | ΔCO2 (%) |
---|---|---|---|---|---|---|---|---|
1000 | 1333 | 240 | 5508 | 185 | 3520 | - | 782 | - |
1000 | 1666 | 144 | 5109 | 161 | 3061 | 13.0 | 680 | 13.0 |
1250 | 1666 | 144 | 4941 | 163 | 3105 | 11.8 | 690 | 11.8 |
1250 | 2000 | 120 | 4546 | 165 | 3145 | 10.7 | 699 | 10.6 |
1500 | 2000 | 108 | 4968 | 163 | 3103 | 11.8 | 689 | 11.9 |
2000 | 2666 | 84 | 4129 | 175 | 3339 | 5.1 | 742 | 5.1 |
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Calise, F.; Eicker, U.; Schumacher, J.; Vicidomini, M. Wastewater Treatment Plant: Modelling and Validation of an Activated Sludge Process. Energies 2020, 13, 3925. https://doi.org/10.3390/en13153925
Calise F, Eicker U, Schumacher J, Vicidomini M. Wastewater Treatment Plant: Modelling and Validation of an Activated Sludge Process. Energies. 2020; 13(15):3925. https://doi.org/10.3390/en13153925
Chicago/Turabian StyleCalise, Francesco, Ursula Eicker, Juergen Schumacher, and Maria Vicidomini. 2020. "Wastewater Treatment Plant: Modelling and Validation of an Activated Sludge Process" Energies 13, no. 15: 3925. https://doi.org/10.3390/en13153925
APA StyleCalise, F., Eicker, U., Schumacher, J., & Vicidomini, M. (2020). Wastewater Treatment Plant: Modelling and Validation of an Activated Sludge Process. Energies, 13(15), 3925. https://doi.org/10.3390/en13153925