A methodology of optimising the determination of multiple waste disposal sites in offshore waters using genetic algorithms

Abstract

In this paper we present a methodology of optimisation for the determination of the optimal locations of liquid waste dumping sites in the offshore waters. We try to minimise the waste disposal cost in marine waters for a finite number of sewage farms or accumulation sites from each ones starts off a pipeline, at the end of which there are a number, also finite, of submarine dumping sites. We also must verify that the concentration of a considered pollutant does not excess a pre-established limitation at a specific distance from the shore. The fitness function takes account of the location of every accumulation site, the location of every submarine dumping site and the flow of each ones. Also, for each sewage farm, we share the pipeline into three stretches, and for each one of these the cost function incorporates: The e cost /m3 of digging the trench, the cost /m of the used pipeline and the cost /m3 of covering the trench once placed the pipeline, also it incorporates the cost/m of each diffuser and the cost of each anchorage that is necessary to place in the last stretch each certain number of meters. On the one hand, as far away the submarine dumping sites are from the coast their construction will be more expensive, on the other hand, as nearer they are from the coast more difficult will be to keep the water quality within a desired level. The proposed optimisation tool to consider is the Genetic Algorithms with evaluation of the fitness function through finite volumes. We present one complete methodology and preliminary partial results. The implemented dispersion equation has been for coliform concentration and in this paper we propose a Taylor -Galerkin procedure adapted for the context of finite volumes.