Treated sewage effluent : alternative uses

Abstract

The Water Services Corporation has to implement adequate measures in order to be compliant with the Urban Waste Water Treatment Council Directive 91/271/EEC, according to deadlines set in the Local Accession Treaty. This Directive, as amended by Commission Directive 98/15/EC, obliges European Union Member States to ensure that all wastewaters are properly collected and subjected to secondary or equivalent treatment before being discharged into estuaries or coastal waters. Transition periods for implementation of the Council Directive were agreed with the ten new Member States, with Malta having to comply by the year 2007. Local regulation, entitled 'Sewer Discharge Control Regulations, 2002', as amended by Legal Notice 378 of2005, was enacted. Treated sewage effluent, mainly used for non-potable purposes, is considered as the most common wastewater suitable for recycling since it is a constant year-round source of water available for this purpose. Numerous barriers to its reuse are present, including lack of standardized European guidelines having the only reference in Article 12 of the Council Directive. Wastewater management is surely an area relevant to the local context. In 2005, a high 68% or approx. 11.2 million m3 of the total water consumed in the Maltese Islands, was for domestic use, 38% of which was utilized for toilet flushings. In fact, three additional Sewage Treatment Plants have been designed with an inbuilt spare capacity of 20%. Recycled wastewater needs to be treated prior to use with the degree of treatment required mainly dependent on the intended use. Locally, the wastewater treatment process incorporates the primary, secondary and tertiary treatment. The activated sludge treatment process, with extended aeration, was chosen as the preferred treatment technology. Currently, merely 12% of sewage is treated at Sant' Antnin Sewage Treatment Plant which processes sewage prior to being used for irrigation purposes. To try to find out the general local perception of using treated sewage effluent as an alternative use, 100 face-to-face questionnaires were distributed across the Maltese Islands. Focused interviews were delivered to two Water Services Corporation's representatives in order to analyse the context from the Corporation's point of view. It emerged that Maltese support the concept of water reuse as a means of responsible water resources management, having an outstanding 97% of respondents agreeing to the concept that water produced by the Sewage Treatment Plants could be made use of effectively rather than being wasted. Intended uses mainly included gardening and toilet flushings, provided that 'odor' and 'color' are up to standard. However, there is still a general local unwillingness to buy vegetables grown with recycled water. On the basis of these findings, recommendations forwarded focused mainly on the fact that wastewater reuse should be locally viewed as an optimal alternative source of new water. Issues that local authorities need to consider in formulating policies, in consultation with the Maltese community, were also identified.