This is the highest fine handed out to South West Water for a case brought by the Environment Agency.
The treatment plant at Camels Head serves a population of over 40,000 people and discharges into the sensitive Tamar Estuary near the Devonport Naval Dockyard.
The court heard that between March and September 2013, South West Water failed to operate and maintain the works in accordance with good operational practice and to treat effluent so as to minimise the risk of pollution.
It also heard that on 12 June 2013, a statutory sample taken breached the limits for Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) under the Urban Waste Water Treatment Regulations.
The court took into consideration three further permit breaches in 2015 and previous convictions in 2012 and 2013 relating to this site.
South West Water admitted breaching the permit conditions.
Judge Lawrie told the court that South West Water were clearly “tiptoeing through a minefield of operational problems at this site and a pollution event beyond failure of minimum discharge standards was not only a risk but likely”. He added: “there was a complete failure to anticipate and take measures to counter some of the problems.”
The judge said that it is clear that the polluted material coming from the site was easily in excess of the minimum standards for discharge, and the fact that this happened on a number of occasions over an extended period of time should have prompted greater efforts by South West Water to reduce that significant risk.
The judge concluded there seemed to be a “lack of urgency in addressing the assorted problems”.
South West Water was fined £214,000 with costs of £27,750.
Mike Ingman, for the Environment Agency, said: “Compliance at South West Water sewage works is generally good. But in this case South West Water failed to operate the site in a way that minimised the risk to the environment. As a result, the site breached its permit on a number of occasions and risked serious pollution of the River Tamar.
“It is encouraging that South West Water has now set about extensive improvements on the site which are due to be completed next summer. These will help secure compliance for the future.”
This story originally appeared on WWTonline.co.uk