Characterization of disposable effluent from filters washing at a water treatment plant aiming its reuse

Abstract This paper deals with the characterization of the disposable liquid effluent (supernatant from sludge ponds and water from filter washing) at the ETA/Gramame (water treatment plant) in João Pessoa, Paraíba State, aiming at its reuse in the treatment process. The results obtained showed that the physicochemical characteristics of effluent had behavior similar to original natural water from the Gramame River impounded at the ETA/Gramame, with the exception of aluminium, which had high concentration in the effluent. Thus, the reuse of water volumes employed for washing filters and cleaning decanters in an ETA (water treatment plant) must be under more effective control when aluminium sulphate is added to the water treatment process.