Excess sludge production and costs due to phosphorus removal.

Based on data collected from 35 French wastewater treatment plants and on published data, excess sludge production and chemical consumption associated with phosphorus removal is estimated for the three following phosphorus removal processes: chemical precipitation, Enhanced Biological Phosphorus Removal and hybrid process. The influence of wastewater characteristics on excess sludge production are assessed. Chemical costs and costs associated with sludge disposal were calculated and results for the three phosphorus removal processes are compared. The global costs for phosphorus removal are then estimated.