Is there a future for the use of treated sewage effluent for irrigation in Malta?

Abstract

The Maltese Islands suffer from a chronic shortage of water resources. Over time, this has led to an increasing reliance on desalinated water to boost the limited groundwater supply. Treated sewage effluent use in agriculture can help to reduce the use of groundwater for irrigation, and if properly managed it can provide important nutrient inputs, thus lessening the need for fertilisers. Currently, only about 13% of raw sewage is treated and reused in Malta but, in order to comply with EU regulations, all sewage will have to be treated by 2007. This means that the volume of treated sewage available for reuse will increase considerably. With the help of interviews with those involved in the administration of treated sewage effluent, farmers, pitkala (fruit and vegetable wholesalers) and fruit and vegetable sellers, this research aimed to examine the current use of treated sewage effluent for irrigation, thus investigating the possibilities of reuse on a larger scale. Opinions of interviewees regarding crops irrigated with treated sewage effluent showed that those marketing agricultural products hold a very negative opinion of crops irrigated with treated sewage effluent; with most insisting that these spoil prematurely. On the other hand, farmers using treated sewage effluent said that their crops exhibited no such difference in quality. The study concluded that wider reuse of treated sewage effluent for irrigation is possible, but is closely tied with several other issues. These include the improvement of the quality of treated sewage effluent (especially regarding salinity levels), as well as the eradication of the currently rife illegal extraction of groundwater. The need for Maltese research on the effects of treated sewage effluent on crops, with special reference to the effects of salinity was also highlighted.