Hornsey zebra mussels to bite the eco bullet

The molluscs clog up the pipes, costing Thames Water bosses hundreds of thousands of pounds a year

�Costly infestations of zebra mussels in Hornsey Water Works are to be stamped out by an eco-friendly ‘biobullet’.

Huge infestations of the molluscs have been clogging up the pipes at the treatment works, costing Thames Water bosses hundreds of thousands of pounds a year trying to flush them out.

The mussels originate in the Black and Caspian Seas and are thought to hitch rides with ships heading to Britain from Eastern Europe before decamping from the docked vessels and settling in raw water pipes at water treatment plants.

Adult zebra mussels can grow up to 4cm long and females can release more than 30,000 eggs per year. The free-swimming larvae quickly attach to surfaces where they live for up to five years.They are no good to eat and, with no known predators in Britain, their numbers are out of control.

But experts have now created mussel-killing pellets which they hope will eradicate the problem.

The biobullets are covered in a fat-coated blob irresistible to zebra mussels and containing an inner centre that is toxic to mussels but harmless to humans and other creatures living in the water.

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The chemical is fully approved for use in drinking water treatment.

Dr Piers Clark, commercial director for Thames Water, said: “Zebra mussels were prevalent in the middle of the 20th century but have recently become a problem again with an influx in trade from Eastern Europe since the 1990s.

“They eat by filtering small particles out of the water, so in the right place they are potentially beneficial to us as they feed on algae in the reservoirs, but in the wrong place, they block up parts of the water treatment process, like fat furring arteries.

“We believe biobullets will save hundreds of thousands of pounds in operational costs in a way that has no adverse impact on the environment.”

Barrie Holden, water innovation manager at Anglian Water, said: “Zebra mussels are a growing problem for us. They narrow the pipes, forcing us to pump water through at higher pressure and at much higher cost.”