Phosphorous recovery as calcium phosphate from UASB effluent after nitrification with or without subsequent denitrification

•After nitrification up to 80 % of phosphate can be recovered as calcium phosphate.•After nitrification the recovered phosphate contains only 2 m% magnesium phosphate.•During denitrification part of the phosphate precipitates in the reactor.•After denitrification phosphate can be reduced to the European discharge limit.•After denitrification the recovered phosphate is more contaminated with magnesium.