Wastewater management
Wastewater management policy
To collect and treat wastewater from our domestic and industrial customers, to treat and reuse sludge generated from the treatment process while minimising the operational impact on the natural environment (air, land and water) and local community.
In considering our operational impacts, we will cover the whole life cycle of our activities, including the direct, indirect and cumulative impacts of the design, construction, operation, maintenance and disposal of our assets. Our operational activities will also be used to support, and where possible enhance, the local community where we operate.
The company is committed to protecting the water environment through the collection and treatment of sewage and other effluent. When releasing treated water back into the environment, our policy is to undertake sampling and monitoring to ensure that we operate within our consents to protect the water environment.
Wastewater management action plan
• Plan and invest to ensure our wastewater assets and people meet the current and future needs of the business and community which we serve.
• To optimise the physical performance of our network.
• Maximise the potential to manage odours.
• Continue to examine the performance of our sewerage assets and deliver operational change to improve performance.
• Minimise the impact to customers through investment and management of sewer flooding.
• Minimise the impact to the environment by reducing the number of pollution incidents.
Wastewater management KPIs
• Invest £380 million in the wastewater network in the five year period ending 2010.
• 95% of all sewage sludge produced in 2007/08 to go to beneficial re-use outlets.
• To have received no odour abatement notices due to our operational activities in 2007/08.
• Ensure that 99.5% of the population in our operating area are served by a sewage treatment works operating within consents.
• Continue to reduce pollution incidents by investment and operational improvements, reducing category one incidents to zero, category 2 incidents to less than six and category three incidents to less than 110.*
• Continue to reduce prosecutions, brought by the Environment Agency, in 2007/08 through investment and operational improvements to less than six*.
• To reduce the amount of bathing waters failing to meet EA mandatory standards to zero.
*We work to prevent all pollution incidents, and resultant prosecutions. However due to the nature of incidents being subject to the natural environment many are out of our control and/or are caused by the activities of third parties.
Wastewater management case study
Conversion of sludge into green energy
We are continuously working to develop beneficial disposal routes for the sludge remaining after sewage treatment and our latest scheme will convert green energy into power which will supply our treatment works at Bran Sands.
It will be the biggest single plant of its kind in the UK, using the emerging new technology of ‘thermal hydrolysis advanced digestion’ and will put us at the forefront of the industry.
Sludge will be squeezed to further reduce water content before being loaded into giant steam pressure cookers and then cooled before being fed into tanks for bacteria to digest. The methane given off by the bugs eating the waste will then be collected in biogas storage bags before being used to fuel engines to create enough renewable electricity to power about half of the entire treatment works site. Heat and steam generated will also be captured and used efficiently elsewhere in the process.
The digested sludge cake remaining after the process will be a safe and low odour product containing no detectable levels of pathogens, such as E-coli, and will be used as a valuable agricultural fertiliser.
The new process will improve efficiency and reduce our carbon footprint. It will reduce more than 500,000 tonnes of sludge – from the treatment of domestic sewage and industrial effluent from a population equivalent of 1,900,000 people – to about 60,000 tonnes and will generate five megawatts of green electricity.
Operations Director, Graham Neave, said: “This is another leading development at our Bran Sands works which has already won international awards for innovation. Development of this sustainable process to re-use and recover valuable resources from sludge and create renewable energy puts Bran Sands once again in the national spotlight as a centre of environmental excellence”.