Ramboll has in cooperation with the Municipality of Vefsn in northern Norway developed a master plan for water supply, and has e.g. undertaken the associated risk and vulnerability analysis. This work resulted in the identification of improvements required to ensure a stable and reliable water supply for the municipality.
Robust measures to ensure safe drinking water
The waterwork's average water consumption of is 60 – 70 l/s with a maximum capacity of 180 l/s. Whilst the plant's primary function is to supply the municipality, it has also been designed to be able to service Elkem Aluminum, a nearby aluminium smelter, in certain situations.
The water treatment process will consist of filtering in pressurised automatic filters, and disinfection through a UV-system. A standby system for chlorination will provide backup for disinfection. These installations will together form a very robust barrier against microbes, viruses and parasites in the drinking water.
Cost and energy savings
To increase the security of water supply, an elevated basin will be constructed adjacent to the water treatment plant with a capacity of 5,000 m3 of water. The water source, Langvatnet, is located at an elevation of 330 meters above sea level (masl). Since the elevated basin is located at 180 masl, pressure reduction is required. The energy created in this process would be wasted using conventional pressure reduction valves. However, a new type of technology has been selected for this scheme that generates electricity while reducing the pressure. The resulting energy saving amounts to 725,000 kWh, which represents an annual cost saving of EUR 66,000 for the customer.
Ramboll has assisted the customer during all phases of the project, including project management related to all engineering disciplines.