A Drinking Water Plant Supplies Energy in Chiasso, Switzerland

The drinking water treatment plant in the district of Chiasso in the canton of Tessin in Switzerland not only produces clean water from the Sorgente Rovagina spring, which is located 70m above it, but since November 2009, also environment-friendly electrical energy generated by a turbine. This hydropower emanates from the kinetic energy of the water flow derived both from the difference in altitude between the plant and the spring, and pressure equalisation.

In 2007, WABAG Wasser Technology Ltd. refurbished and enlarged the San Giorgio drinking water treatment plant in the district of Chiasso. Since then 8,640 m3/d of raw water have been conducted to the plant from the Sorgente Rovagina spring along a 1,880 m pipeline and then turned into clean drinking water.

The pressure created during this descent is proportional to the geodetic altitude difference between the spring and the filter plant.  Moreover, as the pressure is several times that required for plant operation, a pressure reduction valve was previously needed to decrease it.  This meant that every hour 50 kW of kinetic energy was transformed into sound. This cannot be used, which meant that considerable energy potential was lost.

The use of renewable energy is funded in Switzerland:
With the introduction, as part of the Power Supply Act from January 1, 2008, of a decree regarding the provision of full cost coverage for the feeding of renewable energy into the grid, the use of such energy potential is being funded by the state. In view of this fact, during the autumn of 2008, the operator of the water treatment plant commissioned WABAG with the planning of a small-scale hydropower plant.

A pump turbine was selected from the three standard types of turbine (Pelton turbine with free outflow, counter-pressure Pelton turbine with closed outflow and reverse running pump turbine) on the basis of the natural and specific, plant-related conditions. This turbine is a modified centrifugal pump, which instead of a motor, is equipped with a generator that converts the kinetic energy of the water flow into electrical energy.  The resultant power is fed into the public grid on the spot and paid for in line with the new Power Supply Act.

Using this technology, the drinking water treatment plant has been expanded to include power generation, which not only represents an intelligent contribution to environmental protection, but also reduces plant operating costs.

The turbine at the Chiasso drinking water plant produces 250,000 kW of energy yearly, which is sufficient to supply some fifty 4-person households. The turbine does not cause any deterioration in water quality as the raw water is both cleaned and treated in the downstream filter system.

Arnold Gmünder, Managing Director of WABAG Water Technology Ltd., is optimistic that in line with the Chiasso model, in the near future numerous water treatment plant operators will start to utilise available energy potential, not just in Switzerland, but also other European countries: “This is because using small-scale power plants, the energy costs relating to water treatment  facilities can be reduced, and as the feeding of electricity into the grid is paid for, the ROI on the overall investment can be quickly shortened by an average of three years.”

Dresser Roots Helps to Meet Urgent Need for Clean Drinking Water in Rural Egyptian Villages

HOUSTON –ROOTS™ blowers, manufactured by Dresser, Inc., a leader in providing highly engineered products for global infrastructure projects, have been specified for a project that is making potable water available to villages in Upper Egypt where it is desperately needed.

The project deploys portable, turnkey water treatment plants to rural villages to purify local water and prevent outbreaks of waterborne illnesses. Typically these plants produce 100 m3 (approximately 26,500 gallons) of clean water per hour.

The Dresser Roots Egyptian distributor, Tartoussieh Engineering of Cairo, supplied 249 of the small ROOTS Universal RAI® blower packages to the three contractors – Veolia, Pharoahs Engineering and Aircraft Factory Helwan – who were selected to provide the water treatment plants. ROOTS blowers were chosen for the project because of their rugged construction and flexible configuration to meet a wide variety of installation specifications.

“ROOTS blowers are very durable and dependable, which makes them ideal for a project when around-the-clock effort is required to supply people with a basic necessity such as clean water,” said Mohyi Tartoussieh, sales manager for Tartoussieh Engineering.

Supplying clean water to its citizenry is a high priority and an ongoing challenge for the Egyptian government. The Nile River provides an estimated 97 percent of the renewable water resources in Egypt. Yet it is subject to pollution by run-off from industrial waste and sewage, the latter because sanitary sewage treatment capacity has not kept pace with the country’s population growth. Conventional water purification processes have sometimes proved inadequate when chlorination treatment has interacted with some of the pollutants and created additional health hazards.

The portable water treatment plants are part of a larger, E£1.3 billion (US $240 million) initiative by the Egyptian government, with support from the Arab Fund for Economic and Social Development and the National Organization for Potable Water & Sanitary Drainage. The goal of this environmental initiative is to provide safe drinking water and expand the capacity of the country’s sanitary sewage treatment infrastructure.