ballynacor wastewater treatment works environmental...
TRANSCRIPT
Ballynacor Wastewater Treatment Works
Environmental Improvement Project
Improving our environment for future
generations
November 2012
Welcome
Jeff Bishop
Glen Water
Housekeeping
• Emergency exits
• No planned fire alarms
• WC’s
• Tea and biscuits at rear of room
Meeting Agenda
Introduction & Welcome: Jeff Bishop (Jeff Bishop)
Setting the Scene: Ciaran Crozier (Northern Ireland Water)
What are we doing? Paul Foster (Glen Water) &
Dr Chris Piddington (Vertase)
Questions for the Panel: Dr Ray Flynn (Independent Chair &
Queens University Belfast)
Setting the Scene
Ciaran Crozier
Northern Ireland Water
Ballynacor WwTW lagoons
• Wastewater treatment produces two products – liquid
effluent and sludge mass - both require safe disposal
• UK sewage sludges were historically disposed of at sea or
spread to land as fertiliser
• EU/UK Legislation and Policy has evolved to limit such
disposal routes
• In 2000, Water Service committed to a policy of incineration
for sewage sludges
In 2007 two significant events occurred:
1. Formation of NI Water Ltd (GoCo)
• DRD transferred all assets and liability of the Lagoons
• The Pollution Prevention Control (NI) Regulations demanded
the lagoons needed remediated
• DRD agreed to fund the liability
2. Project Omega Contract Award
• 25 year project to develop and operate WWTW
• Ballynacor WWTW included
• PPC Permit would be held by Contractor
• Negotiated a Value For Money solution
Partner Relationships
What is being done?
Paul Foster (Glen Water)
Introduction to Ballynacor WwTW & the
remediation options
Ballynacor’s on site
lagoons are being
restored back to
grassland.
This will prevent the
contents of the
lagoons potentially
polluting the
environment in the
future.
Work starts in
January 2013 and is
expected to take 18
months.
Why restore the lagoons back to land?
• Environmental assessment shows no evidence of environmental
damage.
• The lagoons do contain a number of contaminants
• Environmental experts and engineers have been working on a
plan to restore the area.
• Our approach is acknowledged as the best environmental
solution.
Remediation Process Regulatory Approval
• Eighteen months of Groundwater monitoring
1. To establish if any environmental damage is occurring
2. To establish a base-line for future monitoring
• Propose a solution that is deliverable and meets all the regulatory
requirements
• Prove that the process will achieve the aims
• Conduct trials that satisfies the NIEA
• Conduct leachability trials of final product
• Exact remediation process to be approved in detail
“Stabilisation”
• Seals the contaminated soils and wastes in a solid structure
• Achieved by adding specific ‘binding’ materials to the sludge
• A chemical bond ensures contaminants become more insoluble
and more stable compounds
• The resulting mixture forms an impermeable stable block
• Prevents the release of contaminants into the environment
The Selected Process
• Safe
• Cost effective
• Sustainable & environmentally sound
• Approved by NIEA and NIW as the best available option
• Minimises local disruption
What is being done – the detail
Dr Chris Piddington (Vertase)
The Stabilisation Process
How the lagoon is being restored – Step One
• Sludge from the lagoons is pumped to an on-site treatment plant where it
is cleaned
• Clean water is discharged from the site and eventually ends up in Lough
Neagh
• This follows that standard process that exists on-site today
How is the lagoon being restored – Step Two
• The sediment from the lagoons is dried and mixed with safe stabilising
materials
• These materials are no more than ash & cement which bind to the
sediment making it safe to leave in the ground
• This is done on-site to remove the need for transporting large
quantities of materials by lorry which would cause disruption
Environmental Controls & Monitoring
• Strict environmental controls and monitoring will be undertaken
throughout the duration of the works and beyond, as required by the
regulators, including:
• Noise Control
• Dust
• Groundwater quality
• Surface water quality
• Odour
How is the lagoon being restored – Step Three
• Odour emissions are controlled by keeping the treatment process
covered
• A layer of water is maintained on the lagoon to keep the sediment
away from the air
• Equipment will be installed around the site that sprays a neutralising mist to remove odours from the air.
Odour Suppression
• Odour suppression equipment will be installed on site to ensure any odours that are created by the cleaning process are mitigated
How the is lagoon being restored – Step Four
Once the material from the lagoons has been treated, the stabilised
material is returned to the empty lagoon, covered with a layer of soil and restored to native grassland.
Leaving behind a restored native grassland.
Questions for the Panel
Chaired by Dr Ray Flynn
Want to learn more?
Visit our website at http://www.niwater.com/ballynacor.asp
Want to be added to our e-mail updates?
Email us at [email protected]
Do you have any more questions?
Email us at [email protected]
Thank you