THE PERFORMANCE OF BATCH STABILIZATION RESERVOIRS FOR WASTE-WATER TREATMENT, STORAGE AND REUSE IN ISRAEL

Stabilization reservoirs receive partially treated wastewater effluent s for storage and controlled release. They are used in Israel for two purposes: a) to upgrade the quality of the effluents during the long r esidence time within the reservoirs and, b) to store the effluents dur ing the rainy winter in order to perform agricultural irrigation durin g the dry summer. The improvement obtained in the quality of the efflu ents (i.e., the treatment capacity of the reservoirs) depends on the o perational regime of the reservoirs as reactors: continuous flow, in s eries, batch, etc. The performance of the reservoirs as batch reactors for wastewater treatment is herein analyzed based on outdoor experime nts carried out in real scale reservoirs with different hydraulic and organic loadings. The results of the experiments are compared with for ecasts obtained through statistical and kinetic models. Stabilization reservoirs working in batch mode, when properly designed and operated, are able to remove GOD, BOD, TSS and detergents by up to one order of magnitude, and Faecal coliforms by up to five orders of magnitude (be fore chlorination). A significant removal of heavy metals, bacteriopha ges and other pollutants is also obtained. The quality of the effluent s released from the reservoirs, added to the capabiblity for controlle d release, permits both wide crop rotation and easy management of irri gation. Copyright (C) 1996 IAWQ.