Présentations Colloques

The Maltese islands are one of the most water-stressed countries in the world, where the annual mean national water demand is around double the sustainable naturally renewable water supply. As part of the implementation of the EU’s Water Framework Directive Malta is considering wastewater treatment and re-use as one of the main measures required for the environmental objectives of the Directive.**Three polishing plants have been commissioned with a production capacity of 7Mm3 year (12% of national demand). The water treatment (polishing) strategy adopted in Malta is centered on a four barrier process supplementing conventional treatment with membrane technology. The intended primary use of this water is its supply to the agricultural and commercial sectors. However within a comprehensive water management framework, the use of this highly polished water is also being considered for managed aquifer recharge (MAR) in periods of low water demand.**In preparation for the availability of this new water resource, a pilot MAR scheme was developed around the main Malta-south wastewater treatment plant. This pilot enabled the assessment of the quality of the polished wastewater, an assessment of the potential significance of MAR for aquifer protection purposes and the development of a regulatory framework based on the requirements of the EU’s Water Framework and Groundwater Directives.**Initial results from this pilot project show that the quality of the highly polished water is sufficient to achieve the prevent and limit objectives of the EU’s Groundwater Directive and thus permit its use for direct MAR purposes. The process of replenishing groundwater with high quality treated wastewater also proved beneficial at the pilot level when it comes to aquifer protection from saline intrusion. It is envisaged that the results of this pilot project will enable the replication of the MAR scheme along a 2km corridor in the southern region of the Malta Mean Sea Level aquifer for the development of a seawater intrusion barrier for the increased protection of this regional aquifer system.