Issue link: https://maltatoday.uberflip.com/i/963162
12 maltatoday SUNDAY 8 APRIL 2018 News JAMES DEBONO THE share of groundwater in Maltese tap water is set to decline further as a result of a proposed 9km underground tunnel that will channel water from the Pem- broke Reverse Osmosis plant to a reservoir in Ta' Qali. Groundwater accounts for 43% of Malta's drinking water, down from over 50% before 2000. The water supply consists of a mix of extracted water from the groundwater aquifer, and desali- nated sea water through reverse osmosis. The proposed water tunnel aims at reducing the amount of groundwater abstracted – the process to take out the water – to reduce the impact on the water table, and increase the amount of reverse osmosis mixed into the blend. But this will also increase Mal- ta's dependence on the more en- ergy-taxing reverse osmosis (RO) water. The quality of Malta's ground- water has been deteriorating over the years due to over-extraction and pollution from farms, neces- sitating that it be blended with RO water to reach EU standards. A reply to a parliamentary ques- tion in 2008, before the reduction in energy tariffs in 2014, had es- tablished that while it cost €13 to derive one cubic metre of water from the water table, it cost the Water Services Corporation €49 to produce the same amount of desalinated water. Groundwater, which today accounts for 43% of drinking wa- ter, is cheaper to produce as it is less energy consuming. An Environmental Impact As- sessment for the Pembroke tun- nel fails to quantify the increased energy costs which will come as a result of increasing reliance on RO water. According to the same EIA, since the infrastructural upgrade will involve the replace- ment of old pipes with new ones. The project is also expected to bring about a reduction in the current leakages, which are es- timated at 200,000 cb.m per an- num. With less water being wasted, energy costs are also expected to decrease, the EIA states. Energy costs will also be re- duced by lower pumping and electrical costs through a design which relies more on gravitation- al flows than on pumping. The EIA describes the extrac- tion of groundwater as "un- sustainable" and one which is "straining the Maltese aquifer systems". It refers to "the issue of uncon- trolled illegal extraction which leads to increased salinity levels within the aquifer." Ironically the problems of over extraction are also the result of rampant private extraction from boreholes. In fact it is estimated that more water is extracted by private operators like farmers than by the Water Services Cor- poration, which is the only body licensed to extract this water. The EIA concludes that groundwater is of "lower quality than RO water, since this origi- nates from the water table and tends to possess higher impurity and nutrient levels." Moreover, aquifer deterioration is also the result of nitrates re- sulting from slurry from livestock farms and the use of fertilisers. Better water quality water for central Malta Presently the water supply which feeds central Malta, which includes major urban centres like Birkirkara, mostly consists of groundwater which is temporar- ily stored in the Ta' Qali reser- voirs. On the other hand the water supply feeding the North Har- bour area which includes Pem- broke, St Julian's, Sliema, Swieqi mostly originates from the RO plant in Pembroke. Currently, the Pembroke RO directly feeds the North Harbour area (Sliema, St Julian's, Swieqi and San Gwann areas), before go- ing through the Ta' Qali group of reservoirs. That means that water distrib- uted from the Ta' Qali reservoirs is of inferior quality due to the low proportion of RO water in the blend. This will be resolved by supplying RO water directly to the Ta' Qali reservoirs which will then feed the other reservoirs across Malta. At Ta' Qali, water will be blend- ed with groundwater fed from the Naxxar reservoir and injected with a formulation of chemicals, to attain the desired blend. This water will be then distrib- uted to other reservoirs across Malta such as Fiddien, Naxxar and Qrendi. Neighbouring areas of San Gwann will be fed directly through the Misraħ Lewz, a res- ervoir which will be fed via the Ta' Qali reservoir through anoth- er underground side-tunnel. 122,000 cb.m of construction waste The project us expected to generate 122,000 cb.m of con- struction waste which amounts to nearly a tenth of construction waste generated in 2015. The EIA concludes that most of this material cannot be recycled, and thus the impact is considered to be adverse and irreversible. 4,100 truck trips will be neces- sary to transport all the excavated waste during the 20-month exca- vation phase. During the construction phase, natural areas including the Nat- ura 2000 site in Pembroke may also be affected by noise distur- bance and dust emissions. Water tunnel to increase national reliance on desalination MATTHEW VELLA SOME 170 farmers in the Mellieha area who have started using 'new water' from treated sewage for ir- rigation purposes are reporting better produce, according to the Water Services Corporation. The WSC said farmers' demand for the service has increased re- markably, leading to an increase in the supply network of so called second-class water. Tenders have now been issued for the trenching and pipe-laying of a distribution network in Mel- lieha and Mgarr. The water is treated in three phases – ultra-filtration, reverse osmosis, and advanced oxidifica- tion. "This three-phase treatment is indeed revolutionary, and Malta is amongst world leaders in the field such as Israel and Singapore," said WSC CEO Richard Bilocca. By using new water, farmers are benefitting from a stable sup- ply of low salinity water resulting in a very positive impact on their crops, giving them better shelf life and greater production flexibility. "Some farmers are even getting two crops a year, rather than one because the 'new water' does not have any negative impact on the fertility of the soil. Farmers are also minimising the strain on the aquifer that is caused by borehole extraction, exacerbated by the poor rainfall of the last years and helping the aquifer to replenish over time," Bilocca said. The quality of the water is above Food and Agriculture Organisa- tion (FAO) standards and under- goes strict testing regime at the WSC's laboratories. Farmers are given electronic cards to retrieve the water in pro- portion to the amount of land they farm, and the amount of water they take out is marked. The new distribution system will cover 400 hectares of agricultural land through a 20km distribution Malta's dependence on the energy-taxing reverse osmosis (RO) water is set to increase Farmers yielding two crops a year with 'new' second-class water Farmers are given electronic cards to retrieve the water in proportion to the amount of land they farm Farmers are benefitting from a stable supply of low salinity water resulting in a very positive impact on their crops