Development of the most adequate pre-treatment for high capacity seawater desalination plants with open intake

Abstract

Pre-treatment systems in reverse osmosis seawater desalination plants can be relatively simple or complex depending upon the direct function of the physical, chemical and microbiological quality of the water which is fed through the reverse osmosis membranes which separate the salts and the other disperse matter (colloids and micro-organisms) which are present in the processed water which, according to type and quantity, will produce a progressive or accelerated process of fouling of the same. Thus, the less quality of water to be desalinated, the greater or more intensive will be the pre-treatment system. The process water which is the result of systems of open intake is less recommendable since the characteristics are lower in quality, above all, the micro-biological parameters (the worst). All of this has a basic repercussion by increasing the cost per unit of the cubic metre of water produced and supplied to the end consumer or by reducing the profits for the companies exploiting the seawater desalination plant.As a result, it is enormously important to carry out a study designed at ensuring the optimisation of the pretreatment system for seawater desalination plants with open intake in order to optimise the quality of the water fed through the reverse osmosis membranes to guarantee the highest performance and to minimise the number of shutdowns for chemical cleansing which produce losses in turnover together with other operational costs which reduce the life cycle of the membranes significantly, resulting in the need for these to be replaced prematurely. This article attempts to show how important the adequate system for optimisation of the pretreatment system of seawater desalination plants of open intake is. These desalination plants are not necessarily either highly complicated or sophisticated in their use of diverse chemical products but merely require a new system of pre-treatment which is more simplified and coherent in order to ensure that the membranes function highly satisfactorily