Environmental Impact and Cost Analysis of Desalination Systems

This study aims at studying the environmental effects of desalination byproducts and the cost analysis of desalination systems. Focus was made on the two widespread techniques of seawater desalination; the Multistage Flash (MSF) System and Reverse Osmosis (RO) system. These two technologies of thermal and membrane desalination have a substantial history and their industry is well established. MSF systems induce thermal pollution to its surrounding environment compared with the RO System. The temperature of the RO byproducts are at ambient compared with those of MSF that are typically (5-10) °C above ambient. Salinity of MSF concentrates are 15% higher than the influent raw seawater compared with that of the RO that reaches 100% higher in salinity. This study gives a detailed analysis of the environmental impact of each system, the effect of the byproducts on marine life and appropriate technology selection procedure. The economic analysis conducted was focused on land requirements, capital costs, operation and maintenance costs and depreciation costs. It was found that RO has lower capital and production cost than MSF. If membrane replacement rate is higher or energy cost is lower MSF then shows a slight economical advantage over RO especially in large capacity plants. MSF plants require land areas double that required for RO plants and more construction time for similar capacity plants.