An important oxygenation trial on the Inner Clyde Estuary – from the tidal weir at Glasgow Green to about 0.6 miles downstream of the Erskine Bridge – has started and will continue until autumn.
The pilot trial is being undertaken by Scottish Water in conjunction with the Scottish Government, SEPA, Glasgow City Council and Clydeport.
Low Dissolved Oxygen (DO) levels in the Inner Clyde Estuary have a major impact on the water quality classification and compromise achievement of the Water Framework Directive (WFD) objective of “Good Ecological Potential”.
Kenny Boag, SEPA, said: “DO is critical to the survival of aquatic life and low DO levels threaten aquatic life and negatively impact on other aspects of water quality, such as appearance and odour.”
To perform the oxygenation, two oxygen injection units are being suspended from an unpowered barge moored off the river bank at Scottish Water’s Shieldhall waste water treatment works (WWTW). These units will draw in river water, oxygenate it and discharge it back into the river.
Normally an estuary would naturally oxygenate as part of the tidal cycle. However changes to the shape of the Inner Clyde Estuary made over the past two hundred years mean that this is no longer the case.
Improving the water quality in the Clyde is not solely Scottish Water’s responsibility, but they are taking a lead in tackling the issue because of the potential benefits to the environment and customers.
Kieran Downey, Special Projects Manager, Scottish Water, said: “It is hoped that this oxygenation trial – which involves the injection of oxygen into the water – will confirm that the introduction of oxygen and mixing of the water column will help the Inner Clyde Estuary achieve Good Ecological Potential.
“The field trial will enable the performances and risks associated with an oxygen injection system to be identified, monitored and better understood. This is all part of the development of our long term waste water asset strategy for the Clyde catchment.
“This wider strategy is to achieve reduction of flood risk, water quality improvement in watercourses and support of economic development objectives.
“Outputs from the trial will allow the Scottish Government to make an informed decision on how to achieve any future improvements to water quality.”
The trial is being undertaken this summer when the DO levels in the Inner Clyde Estuary can become stressed.
After the trial the impact the injection of oxygenated water into the river has had on the Inner Clyde Estuary. Recommendations based on the results of the trial will allow an informed decision to be made about future improvements to water quality in the River Clyde.
If the trial shows that oxygenation works it will mean that Scottish Water’s Outline Wastewater Strategy – our strategy for wastewater treatment which involves investment at the four main WWTWs in the Glasgow area – will enable the achievement of “Good Ecological Potential” classification of the Inner Clyde Estuary under the Water Framework Directive.
For more information, visit www.scottishwater.co.uk or www.scottishwatersolutions.co.uk