Single/Multi Waste Load Allocation in Gheshlagh River; Simulation-Optimization Approach

In this research, single/multi waste load allocation problems are assessed with QUAL2Kw and multi objective particle swarm optimization (MOPSO) algorithm tools. Improving water quality in Gheshlagh River (minimizing DO violation from standard value) and minimizing the costs of construction and operation of municipal and industrial wastewater treatment plants are defined as objective functions in CBOD waste load allocation problem. Improving the integrated water quality index (which integrates the effects of T. Coliform, nitrogen concentration, phosphorous concentration, total suspended solid, and dissolved oxygen) in various monitoring stations is defined as water quality objective in multi waste load allocation problem. The results showed that in CBOD waste load allocation problem with no water treatment plant, the sum of DO violation in various monitoring stations was 4.5 mg/L. Also for no water quality standard violation, the construction and operation cost of wastewater treatment plant would be 290 ×109 Rials in 25 years. In multi waste load allocation problem the wastewater treatment plant costs increased considerably compared to the single waste load allocation problem.