Economic feasibility study for MF system as a pretreatment of SWRO in test bed desalination plant

Abstract

The test bed for seawater reverse osmosis (SWRO) desalination plant having a capacity of 10 million imperial gallons per day, located in the southeast of South Korea, is under construction by Doosan Heavy Industries and Construction. The feed water for first pass SWRO train will be pretreated by a microfiltration (MF) membrane system and conventional dual media filtration system. For the MF pretreatment system, it is necessary to evaluate the economic feasibility between the submerged and the pressurized membrane systems to apply the filtration mode of membrane modules. This article evaluates the economics using the life cycle cost (LCC) analysis method. Although many researchers reported that the submerged MF system has economic advantages over the pressurized system because the submerged system consumes lower energy, the result of this article presents on the contrary to this. The result shows that the total capital cost and operation cost of the pressurized system are lower than those of the submerged system, because the pressurized system can use the hydraulic pressure generated from the seawater supply pump and air consumption is much lower than that of the submerged system. In addition, the result of LCC estimation shows that the pressurized system has the lower cost compared with the submerged system, by approximately 13%. This represented that the pressurized MF pretreatment system has economic advantage over the submerged system especially in SWRO desalination plant.