Let us be absolutely clear: it was a high B.O.D. (biological oxygen demand)
sewage discharge from Severn Trent Water's Strongford works at Barlaston that caused the fish kill. Not Cyanide which can occur in nature and at much higher concentrations (try marzipan to learn the taste).
http://www.guardian.co.uk/uk/2009/oc...-investigation
Quote:
...the fish kill had affected 20 miles of the river. Anglers had first spotted fish gasping for air "like canaries in a mine" on Monday, he said.
The levels of cyanide were less than one part per million but "aquatic life is very sensitive to poison," he said.
The cyanide had killed the bacteria used at the treatment works, and a combination of ammonia, from the sewage, and cyanide had killed the fish.
"Teams of people are working in Stoke-on-Trent to try to identify where the cyanide came into the sewerage system and why it happed. We hope to gather enough evidence to bring a case to court."
It was likely to have emanated from a metal-type industry.
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The Chromium and Nickel plating industry use Cupricin a greeny cream powdered
insoluble form of Copper Cyanide CuCN. Other industries would use different CN compounds.
They would all have killed the anaerobic bacteria in the deep 'activated' sludge that treats the sewage.
Anything more than 50 ppm should not have been discharged. Entirely preventable with proper monitoring; however carelessnes seems to have set in there.
The same works was fined for an earlier pollution incident earlier this year - not that AT (Fish Legal) or ACA involved themselves.
http://www.thisisstaffordshire.co.uk...l/article.html
Quote:
SEVERN Trent Water has been ordered to pay almost £10,000 for polluting the River Trent.
It admitted causing sewage pollution to enter the river.
Stafford Magistrates Court was told Strongford Sewage Treatment Works, Barlaston, has an average of 150 million litres of water flow through it each day, with the final, treated water pumped into the Trent.
Amy Jacobs, for the Environment Agency (EA), said it treats sewage and trade effluent from across the area.
But on January 12, the EA noticed the effluent coming from the plant was brown and had a sulphurous smell.
Severn Trent took immediate action, stopping overflows on the afternoon of the incident.
The firm was fined £6,700 and ordered to pay £2,777 costs and a £15 victim surcharge.
A Severn Trent spokesman said the utility "deeply regrets" the incident.
He said: "This incident followed an unfortunate and unusual series of events, where sludge deposits were dislodged during an operation to reduce ammonia levels in the effluent. "We have introduced processes to reduce the risk of pollution in future, and are spending £46 million upgrading the plant."
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metalworks,blame for trent ??
A track record for pollution?
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