This activity is targeted towards older students and/or adults. The activity focuses on the provision of water services (drinking water and wastewater treatment). This activity creates linkages between the cost and energy use of different measures and solutions, thus indirectly introduces students to the concept of cost-benefit assessments/decisions. In the game, the students find a map (layout) of a water production and distribution system and are faced with eight management decisions to ensure the supply of water and the treatment of wastewater. In each decision they will have to discuss the cost, energy requirements and water demand to try to solve the challenges whilst keeping the highest level of points under each category. The game thus involves discussions and decision making and needs coordination and teamwork. It encourages the audience towards using different kinds of thinking skills. Other issues that are tackled through this game are saltwater intrusion in aquifers, reverse osmosis treatments and the use and benefits of green roofs.
A borehole is a deep narrow circular hole, usually about 15 – 30 cm wide which are drilled from the surface to a few metres below the freshwater level within the porous rock formations. Long narrow pumps called submersible pumps are typically lowered into these boreholes from the surface to a few metres below the water level and are used to lift the water through a pipe from the porous rock surrounding the borehole which continuously fills the borehole. The Water Services Corporation operates around 100 of such boreholes.
Wastewater Treatment Plant (and Water Reclamation plants)
Water which was previously utilised in our homes, businesses and factories is collected in sewer pipes and is directed to one of four wastewater treatment plants around the Maltese Islands. A wastewater treatment plant is used to clean the previously used water, which is still mostly made up of water but will now have contaminants which were introduced into this water as it was used. This treatment process is important to make the water suitable to be discharged into the sea or utilised for irrigation of agricultural areas around Malta and Gozo. A wastewater treatment plant cleans previously used water in a number of treatment steps, starting with the removal of large solids using screens. Bacteria and other small organisms are used to consume chemicals which we wish to remove from the water by giving these organisms oxygen which is bubbled into large tanks. The water is then separated from these organisms by allowing them to settle to the bottom of these large tanks. In Malta the water is then passed through a series of fine filters which further purify the water before it can be reused for irrigation.
Reverse Osmosis Plant
Because Malta’s groundwater is not enough to meet the demands of households, businesses and agriculture, the Water Services Corporation also has to convert salty seawater into freshwater by a desalination process known as reverse osmosis. Water is extracted from the sea through wells drilled at the coastline through which seawater is filtered by Malta’s porous rock. This water is then pumped through a membrane which has very small pores which allows water to pass through while retaining salt. Water produced from these seawater desalination plants are transferred to large reservoirs where the water is blended with groundwater from pumping stations and boreholes.
The Water Services Corporation has three reverse osmosis plants located in Pembroke, Cirkewwa and Ghar Lapsi and will soon have a fourth plant operating at Hondoq ir-Rummien in Gozo.