By Greta Muscat Azzopardi
First published on Times of Malta, March 5, 2015.
When we think of sewage, resource is perhaps not the first thing that comes to mind. Sewage is mostly considered a nuisance; a source of pollution and disease and at best, a hassle to dispose of. As the world’s clean freshwater supplies dwindle however, more and more countries are looking to sewage as a precious water and nutrient resource, making treated sewage reuse part of the overall water strategy. This is to be expected when one considers that domestic sewage is 99.9% (pure) water. Water scarcity is increasingly being recognised as a real and fast-growing human and geo-political issue having widespread consequences.
The degree of reuse varies by country. Large parts of Australia and the US make extensive use of treated wastewater for agriculture and industry while Singapore’s (rather unfortunately nicknamed) toilet-to-tap strategy aims to provide half of the nation’s water needs through purified wastewater by 2060. In Singapore, wastewater is treated to drinking quality and mixed in with other water sources and distributed to consumers as part of the potable water supply.
Malta very much stands among the water-poor nations.
Rainfall is scarce, unevenly distributed and generally not well harvested so that most of it just runs straight to the sea while causing flooding. The aquifer on the other hand is severely over extracted and with high levels of nitrates, making it a very much limited and dwindling resource if current practices continue.
With no other sources of freshwater, Malta looks to the sea to provide potable water and reverse osmosis provides over half of the municipal water supply, a proportion of which will continue to increase heavily unless major changes are made in the way we manage water.
Reverse osmosis comes at a cost: monetary, environmental and for our national security. A fuel crisis or an oil spill for example, could completely disrupt our ability to purify seawater and thus leave us without an adequate drinking supply.
In the recent past, treated sewage has been looked at and experimented with as a potential resource for agriculture. Malta’s first sewage plant, located in Marsascala, was sited to provide water for agriculture, feeding nearby fields that mostly did not have access to other water sources.
As time passed however, the water quality dwindled whilst rife, unregulated drilling of boreholes gave farmers a free, better quality alternative right at their doorstep. Illegal dumping of animal slurries into the sewerage system together with seawater infiltration into sewers meant treated effluent was of lower quality and higher salinity, leading farmers to essentially sideline this resource altogether.
Fast forward quite a few years to the present where we now new sewage treatment plants that process raw sewage and dump the treated effluent into the sea. Whilst this situation is a very welcome change for the quality and health of our seas and ensures that we comply with EU environmental laws, the system does not account for water reuse.
The question of reuse.
Unfortunately, reuse was not a determining factor in the siting of the new sewage treatment plants which were built at a cost of more than €110 million, and cost a few million euro to run every year.
The plants now are located in areas where there is little to no nearby agricultural demand for water. An extensive distribution system is required if this water is to be recovered and used.
Moreover, in their current configuration, the treatment plants are not capable of providing water for reuse because the quality of the water is such that while it is acceptable for disposal into the sea, it cannot be used for irrigation or any other use.
On its website, Water Services Corporation (WSC) quote plans to polish sewage water to even better quality and then have it “piped to a number of strategic locations where hydrants will be accessible for use”. No mention is made however of how the distribution system will work, how the water will be priced and who the targeted end users of this water are. It will be rather difficult for this water to compete with completely free, onsite borehole water (which most farmers have access to at the moment) and unless that source is controlled, there is little hope for real re-use by either agriculture or industry. The €22 million polishing plant project risks being a white elephant if a comprehensive plan for the take-up of this water is not in place.
Getting our (water) act together.
Whilst making the water available for reuse is a step in the right direction, the move will not be fruitful unless it is part of an integrated national water plan that adequately manages all local water resources as one system. Difficult decisions about aquifer extraction, water pricing, agricultural practices, storm water management and rainwater harvesting must be taken urgently if we wish to safeguard our national water resources.
Although both PN and PL committed to a water plan in their electoral manifesto, actual action has been scant. Following stakeholder engagement during the course of last year, news on the development of the Plan has been non-existent since then. The 2015 budget mentioned the ongoing development of a National Water Management plan with an aim of this being ready and adopted by next year. One strongly hopes this matter is being given the grave importance it is actually due.