Phosphorous Removal
Ensen have extensive experience in the development of site specific programmes for the treatment of phosphorous in waste waters, primarily using chemistry together with our in depth knowledge of physical, chemical and biological activities within the treatment processes.
The principal involves the use of metal salt coagulants for phosphorous removal as follows:
M3+ + PO4(3)- → MPO4 ↓(Where M is the metal ion)
A known amount of coagulant is applied to precipitate out a specific amount of phosphorous. The amount of Phosphorous present is expressed as unit mass in kilogrammes, i.e.. mg/l phosphate x m3 daily flow. Therefore an increase/decrease in wastewater load would require the dose rate of coagulant to also be adjusted in order to maintain the optimum dose concentration.
Chemical phosphorous removal can be achieved in a number of locations:
- Pre-Precipitation- Chemical addition to raw wastewater and precipitate is removed with primary sludge.
- Simultaneous Precipitation- Chemical addition so that the precipitation is removed with the waste biological sludge. Can be added either to primary effluent or to mixed liquor, prior to secondary sedimentation.
- Post-Precipitation- Chemical addition after both primary and secondary treatment processes, where an additional solid separation device is needed (DAF, clarifier or filter).
