Long-term operating data of a full-scale SWRO desalination plant. Performance analysis

Abstract

The RO technology is the most extended for seawater desalination purposes. The operating data in long-term of full-scale plants is key to analyse its performance under real conditions. This seawater reverse osmosis (SWRO) desalination plant had a production capacity of 5,000 m3/d for irrigation purposes. The operating data such as conductivities, flows and pressures were collected for around 27,000 h from 2001 to 2004. The plant had sand and cartridge filters without chemical dosing in the pre-treatment stage, a RO system with one stage, 56 pressure vessels, 7 RO membrane elements (TorayTM SU820) per pressure vessel and Pelton turbine as energy recovery device. The operating data allowed to calculate the average water and salt permeability coefficients (A and B) of the membrane as well as the specific energy consumption (SEC) along the operating period. The calculation of the average A in long-term operation allowed to fit the parameters of three different models used to predict the mentioned parameter. The results showed a 30% decrease of A, parameter B increase around 70%. The SEC was between 3.75 and 4.25 kWh/m3. The three models fitted quite well to the experimental data with standard deviations between 0.0011 and 0.0015.