Systems
Environmental & sustainable water treatment by Marine Biologists
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Active Water Treatment Systems Environmental & sustainable water treatment by Marine Biologists |
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| | DrydenAqua homepage | AFM homepage | Water treatment homepage| swimming pools | Aquaculture & Aquaria | Drinking water | Sewage effluent | Aeration systems | Leachate treatment | Farm effluent | | ||
| Leachate home |
Nutrient balance in leachate & wastewater |
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| Relationship between Ammonium, BOD, Phosphate and alkalinity | |||
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Kgs of component required |
Ammonium nitrogen 1kg | COD/BOD 1 kg | Phosphate 1kg |
| Oxygen required in Kg ( 1 x diffuser 6.2.10, provides 10kg of oxygen per day) |
5 Kg |
2 Kg |
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| Ammonium nitrogen consumed in Kg |
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0.1 Kg |
10 Kg |
| COD/BOD consumed in Kg |
10 Kg |
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100 Kg |
| Phosphate required in kG |
0.1 Kg |
0.01 Kg |
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| Alkalinity required | Buffers to provide pH and alkalinity stability are available from Dryden Aqua. We also provide molasses to assist heterotrophic bacterial assimilation of ammonium. This is normally required when the leachate temperature is below 8 deg C. | ||
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Sodium hydroxide, or |
4 kg (12 litres) |
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Sodium bicarbonate, or |
12 kg |
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Calcium carbonate, or |
7 kg |
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Magnesium oxide |
3 kg |
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| Nitrification equations | |
Alkalinity buffering equation1. H20 + CO2 <=> H2CO3 <=> HCO3 + H+ <=> CO3 + 2H+ Nitrification equations 2. NH4+ + 1.5O2 => 2H+ + 2H2O + NO2- 3. NO2- + 0.5O2 => NO3- 4. NH4+ + 1.83 O2 + 1.98 HCO3- => 0.021 C5H702N + 0.98 NO3- + 1.041 H2O + 1.88 H2CO3- 5. NH4+ + 1.9O2 + 2HCO3- => 1.9 CO2 + 2.9 H2O + 0.1 CH2 from 1 gram of ammonium. 8.59 grams of carbonic acid is produced (H2CO3) 0.17 grams of autotrophic nitrifying bacteria cells are produced. |
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Heterotrophic bacterial assimilation of organic matter
8CH2O + NH3 + 3O2 ----------------> C5H7NO2 + 3CO2 + 6H2O + energy organic matter + ammonium + oxygen ---> bacterial cell biomass + carbon dioxide + water + energy (ATP)
When the bacteria in an exponential growth phase with a low bacterial cell biomass ( less than approx 3000 mg/l) the above equation applies, however if the MLSS ( mixed liquor suspended solids) concentration is high and the residence time of the effluent is to short a period, then Endogenous Respiration occurs and the bacteria start to consume themselves in accordance to the following equation;
C5H7NO2 + 5O2 -----------------------> 5CO2 + 2H2O + NH3 + energy bacterial cell biomass + oxygen --------------> carbon dioxide + water + ammonium + energy (ATP)
If the system is in endogenous respiration and there is a long residence time of the effluent in the system, then autotrophic bacteria can become established and convert the ammonia to nitrate.. However in most cases it is more efficient to split the system up into a number of tanks operating in series to give the autotrophic nitrifying bacteria a better chance of surviving digestion by the heterotrophic bacteria.
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