FB RAITA  measures the phosphorus precipitating chemical and feeds it into the wastewater, precipitating the phosphorus in the precipitation well. The amount of effluent is measured in batches (80 l) by at the same time, RAKE phosphorus precipitation chemical is dosed into the precipitation well. Dosing takes place in the first part of the precipitation well so that the chemical is mixed and acts on the precipitation for the maximum time. The chemical reacts with phosphate and precipitates in the slurry. Phosphorus that precipitates in the slurry is discharged by normal slurry drainage. The amount of sludge increases by about 30%. We recommend a retention of 48 hours for the precipitation process.