The UK company Panton McLeod cleared some 12 tons of empty freshwater mussel shells from the intake channels during a routine drain-down cleaning of Severn Trent Water’s Church Wilne Water Treatment Works in Derby, England.
According to Jim Panton, who has more than 40 years experience in the water industry, “It was really bizarre and I have never seen anything quite like it. Nobody had any idea why they should have collected there in quite such large numbers. The shells were all empty. Basically this treatment works abstracts from the Trent and the intake is just a sluice gate away from the river itself. The chances are they have simply washed in and collected over the years.”
The mussel shells posed no threat to the water treatment process, he added. Specialist suction equipment was used to remove the shells to a tanker.
Church Wilne is a modern dissolved air flotation plant and from the intake it has five channels leading to the aeration chambers. Panton McLeod’s six-member team spent seven days cleaning the aeration areas, in addition to everything else back to the intake, including the flocculation paddles.
Panton McLeod operates from offices in Nottingham and the Scottish Borders and specializes in the cleaning of drinking water structures. Traditional drain-down cleaning requires treatment works to be shut down and drained, but new underwater cleaning machines are now used to clean reservoirs, tanks and slow sand filters while they remain full and in supply.
