Design of a tertiary system of purification for residual saline waters

Abstract

The following paper proposes a tertiary treatment system for the recycling of wastewater to be used as irrigation water for crops such as the banana tree that require water of a high quality. A physical-chemical system is proposed followed by Electrodialysis Reversal (EDR) desalination. The aim is to lower the overall levels of chlorides and dissolved solids present in the water. Using this process it is possible to reduce the product water conductivity from 2000 μS/cm to 700 μS/cm, with a salinity reduction of around 88% and NO 3- reduction of 85%. The use of a RO system is rejected due to the high silica content and in order to avoid the loss of valuable nutrients required for irrigation water. In this way, water of a high quality is produced for the growing of particularly sensitive species such as the banana tree, while at the same time contributing to a reduction in the excessive overuse of the region's aquifers.