Dealing with waste water

Water is so crucial to our existence that it seems incredible how we take it for granted. If we do stop and think we often tend to think first of the quality of drinking water. That is a reasonable consideration as it is closely knit with survival. Having secured survival, the next step is how to enhance the quality of our lives. It is therefore at this second stage of thinking that one worries of waste water being cast untreated into the sea that surrounds us. We are at a stage in our development when it is high time to think about this issue, and deal with it effectively.

Parliament recently discussed the financial estimates of the Water Services Corporation for the current financial year. While a fair review was made of the financial figures being presented, most deputies focused their remarks on the effect which EU directives will have on the corporation in the coming years. And rightly so!

While many would think that the EU directives having the largest impact on the corporation were those relating to the quality of water, few realise that following the migration of the Drainage Department to the Water Services Corporation last October, all directives relating to urban waste will now also have a direct impact on the corporation.

An integral part of the responsibilities inherited by the corporation following the migration of the Drainage Department were those of the Sewage Master Plan Implementation Unit (SMPIU). The unit is responsible for the setting up of the sewage treatment infrastructure and to plan, design and implement the required sewage treatment plants for Malta and Gozo.

The mandate of the SMPIU is to implement the recommendations of the Sewage Master Plan for Malta and Gozo, a study carried out in 1992. The scope of this plan was to identify and assess the current sewerage infrastructure of the Maltese islands, highlight problem areas and bottlenecks of the network and propose a series of upgrades and improvements to overcome these deficiencies. The improvements and upgrades required can be subdivided into the following categories:

¤ New relief mains and galleries;

¤ Retention basins and galleries to be used for retention;

¤ Pumping stations and rising mains;

¤ Sewage outfalls; and

¤ Construction of urban waste treatment plants.

All the categories mentioned above are of paramount importance, however, the construction of three sewage treatments plants in Malta and Gozo as indicated in the Sewage Master Plan deserve particular attention. The plan indicates the need for the construction of three urban waste water treatment plants: one in Gozo and two in Malta; one in the northern region and one in the southern region. These plants are intended for full tertiary treatment capability, availing the treated effluent for irrigation purposes.

Gozo waste water treatment plant

This proposed plant has been identified in the Sewerage Master Plan as a priority measure for approximation to the Urban Wastewater Directive 91/271/EC. The area earmarked for the construction of this treatment plant is at Ta' Mgarr ix-Xini in the south of Gozo. The objectives of this project include:

¤ The discharge of treatment effluent to a non-sensitive area through an existing marine sewage outfall;

¤ Reduction of the impact of raw sewage discharge to the marine environment in the area; and

¤ To ensure that the treated effluent is suitable for irrigation and for selected industrial re-use applications.

Apart from the construction of the plant, the project will include the setting up of the necessary infrastructure to support the plant's operation. The ancillary infrastructure works include:

¤ One sewage intake pumping station;

¤ One treated effluent pumping station; and

¤ Two rising mains, and access roads leading to the intake pumping station and sewage treatment plant.

It is expected that once in operation the plant will handle an average flow of 6,000 cubic metres per day with a peak flow of 630 cubic metres per hour. The discharge from the plant is expected to contain the following pollution concentrations: BOD5: 5mg/litre, total ammonia Nitrogen: 2mg/litre and total suspended solids: 10mg/litre.

On a macro level, it is expected that results achieved through the operation of this new plant will lead to an improvement in the tourism potential of the area in view of the improved land and marine based environment achieved through the reduction in the existing pollutant load. On a longer term one would also expect higher productivity of land in the vicinity of the plant through the provision of second class water for irrigation purposes.

The whole project is estimated to cost €7.2 million, out of which €3.5 million will be financed through the EU pre-accession funds.

It is expected that the plant will be commissioned in 2006. The project implementation schedule is on time with the tender for the project having been issued on April 28, 2004.

The chemistry is just the detail. The effect is cleaner waters, a healthier environment and a better quality of life.

Mr Carabott is Policy Manager (Utilities), Ministry of Information Technology and Investment.