Case Study 4 - East of Scotland Water

variable speed drives on waste water treatment plants

Customer: East of Scotland Water
Application: Pumps
Industry: Water and wastewater treatment


Howden Water Treatment Works near Selkirk is run by Scottish Water. The site also comprises a borehole pumping station. Four pumps at the boreholes serve a common contact tank. Scottish Water wanted to match the rate of filling of the main storage tanks to demand. This would limit the number of stops and starts required and reduce the damaging effects of surging, known as water hammer. Over time, this can result in burst pipes, causing possible injury to operators. Scottish Water asked ABB authorised value provider EDC (Scotland) to develop a solution. Solution: Eight ABB variable speed drives are used on the two applications - four on the pumping station and four at the treatment works. The drives allow demand to be smoothed out, reducing the sudden stops and starts that lead to water hammer.


• Avoids damaging waster hammer
• Matches pump speed to demand, saving energy
• Active harmonic filters limit the distortion to the supply at the point of common coupling