Retrofitting assessment of the Lanzarote IV seawater reverse osmosis desalination plant

Water resources available in the island of Lanzarote, the furthest east of the Canary Islands Archipelago, come mostly from sea water desalination. Desalted water demand in the island has grown considerably in the last decade forcing managers to adapt desalinated water supply constantly. Additionally, the energy dependence of the water cycle in the island is relevant, so any corrective measures over the water supplies will be welcome if it gets more resource with the lowest energy cost. In this way, the authors described in detail and simulate the possible use of hybrid interstage element design of pressure vessels and Pelton retrofits in the Lanzarote IV SWRO plant by comparing the current situation. This desalination plant, one of the largest public desalination plants of the island, has an installed capacity of 30,000 m3/day and more than 8 years of operation. It is an excellent example to propose changes in order to reduce the process energy consumption, as well as to obtain another series of operation and maintenance advantages. This paper is focused on capital costs savings through the use of new generation membranes and replacing the existing Pelton turbines by other more efficient energy recovery systems based on isobaric chambers.

Research Highlights
► Retro-fitting assessment of an existing desalination plant in Lanzarote island.
► Some suitable interstage membrane combination are analyzed and it is chose the most adequate.
► The main adequate and feasible configurations for Pelton turbines retrofitting are discussed. The best option is proposed for the desalination plant.
► Capital costs savings and higher capacity through the use of new elements and devices are obtained.