WSC focuses on water quality

The setting up of a polishing plant to improve water quality in Gozo will mean that the sister island will no longer be self-sufficient in water production.

Improving water quality is one of the primary aims of the Water Services Corporation over the coming months, the corporation's chairman, Michael Falzon, says in the annual report published yesterday.

Mr Falzon said it was well known from reports published regularly by the corporation that water quality failed to meet EU standards on two counts - the level of nitrates and chlorides in some areas exceeded EU regulations.

In terms of an agreement reached between Malta and the EU, the level of nitrates has to be reduced to an acceptable level by this year in Malta and by next year in Gozo.

The chlorides parameter had to be reached by this year in Gozo and 2006 in Malta.

The water networks in the two islands were practically independent and the technical solutions for these standards to be achieved were therefore somewhat different, Mr Falzon said.

He explained that nitrates were present only in groundwater as a result of pollution from fertilisation of agricultural land and leaking drains.

This chemical was not present in water produced from reverse osmosis (RO) plants. Therefore, the required standard would be reached by blending groundwater with RO water after the former was collected in reservoirs. This would involve the laying of 8.5 km of new mains in Malta and 22.7 km in Gozo.

The technical problems to reduce chloride levels were more complex. Chloride was present in groundwater as a result of sea water infusion as well as in water produced by the reverse osmosis plants. In the latter case, chlorides tended to increase in proportion to the length of time the membranes in RO plants were used. The WSC would therefore be replacing the membranes more frequently, raising running costs, Mr Falzon said.

The corporation would also set up plants to "polish" groundwater, starting from Gozo, which is heavily reliant on groundwater extraction.

Mr Falzon said the WSC planned to commission the first phase of a polishing plant at Ta' Cenc next month, barring delays in the issue of the necessary Mepa permits.

He said that studies by WSC engineers had shown that after extracting the advisable maximum amount of groundwater in Gozo and polishing it, the WSC would no longer have enough water available from extraction to meet demand due to the 20 per cent reject that the polishing process demanded.

Water from the Cirkewwa RO plant would therefore have to be pumped to Gozo to make up for the shortfall. At present, groundwater extraction caters for all of Gozo's needs except for a few weeks during the summer peak tourist season.