The influence of ph, precipitant dosage and operational conditions (such as slow mixing and settling time) on the phosphorus removal using alum in low alkalinity wastewater (< 50 mg/l as caco3) was carried out by jar-test equipment. From the experiment it was found that the dosage of alum and removal of phosphorus depend on the ph of the wastewater after addition of precipitant. The optimum ph for efficient phosphorus removal was in the range of 5,7 – 5,9.The optimum time for slow mixing and settling was 20 minutes. In the present study, when an al:p mole ratio of 3:1 was applied at ph 7, total phosphorous in the effluent can be controlled at the low level of 0.3 mg/l.
Factor afecting Phosphorus precipitation
