Surface Water Pre-treatment

Surface water from rivers or lakes is the most variable source of raw water and the most easily accessible.Even though the salinity is normally moderately low because of reduced contact with the soil, it happens sometimes that water treatment plants located on rivers estuaries have to face important sea water reflux thus highly affecting the salinity of the feed water.In a river, in particular, turbidity and the content of micro-organisms could be impressively affected by seasonal variations or storm conditions.Following the above concepts, treatment of surface water may consist of a sequence of different stages.Basically water treatment may consist of chemical physical treatment with coagulation and flocculation in order to destabilise and precipitate colloids and solids into gravity settlers.Chemical physical treatment is normally followed by filtration on media filters in order to effectively remove the residual suspended solids.