Phosphorous Removal From Wastewater
The most common treatment mechanism for the removal of phosphorous from wastewater involves the use of metal salt based coagulants:
M3+ + PO43-→ MPO4 ↓ (Where M is the metal ion)
A known amount of coagulant is applied to the wastewater. A coagulated solid is formed and phosphate is precipitated out as a settled solid. The amount of Phosphorous present is expressed as unit mass in kilogrammes, ie. mg/l phosphate x m3 daily flow. Therefore an increase/decrease in wastewater phosphorous load would generally require an adjustment to the coagulant application rate in order to maintain the optimum dose concentration.
Typical products used for phosphorous removal include:
- Aluminium Sulphate
- Aluminium Chloride
- Ferric Chloride
- Ferric Sulphate
- Ferrous Salts
- Polymer blended with metal salts
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