Minimal adverse impact of discharging polluted effluents to rivers with selective locations
Abstract The disposal of sewage from human activities remains a challenge in developing countries due to relatively high treatment costs. Untreated or poorly treated sewage is therefore commonly discharged to streams, lakes, and coastal oceanic waters. The location of discharges of polluted effluents to rivers can be managed to reduce adverse environmental impacts. This study presents a relative preference method for siting sewage discharge locations on a river considering biochemical oxygen demand (BOD) impacts. River water quality is simulated for different levels of BOD concentration using the QUAL 2 K water quality model. Results of these simulations are compared to each other with a relative preference function that selects polluted effluent discharge locations to lessen the degradation of riverine water quality. The selection of the discharge locations takes into account input from regulatory agencies and other pertinent environmental organizations to achieve the least damage to receiving waters. The relative preference method is applied to the Karoon river between Gotvand dam and Shooshtar city, Iran. The results show the best locations for discharging the new polluted effluent are at the upstream and downstream portions of the considered river reach. Locations at kilometer 35 and its vicinity had the lowest values of the relative preference function making them the most unsuitable points for discharging the sewage effluent.
Sustainable Cities and Society