WASTEWATER TREATMENT METHOD COMPRISING DECANTATION AND FINE SCREENING STAGES ET DEVICE FOR CARRYING OUT SAID METHOD

摘要

A method for removing helminth egg and other suspended solids from a wastewater stream includes directing the wastewater to a ballasted flocculation system and adding a coagulation agent, flocculation agent and a ballast into the wastewater. Sludge is settled from the wastewater in a settling tank at a rate of at least 10 meters per hour. The method further includes removing helminth egg by filtering the effluent through a fine screen having a mesh diameter of approximately 5 micrometers to approximately 25 micrometers. After passing through the fine screen, the filtered effluent has less than one helminth egg per liter.