Developers may on occasion wish to develop lands near to an existing or proposed wastewater treatment works. This has the potential to create a problem for potential developers who may have difficulty selling houses in close proximity to a wastewater treatment works. Purchasers generally like to be reassured that there will be no detrimental issues associated with moving into anew dwelling. 

Increasingly, matters related to odour nuisance caused by wastewater treatment works are being highlighted by those who purchase new dwellings in proximity to existing or proposed waste water treatment works. The developer, the purchaser and Northern Ireland Water should be aware of the potential odour nuisance that is possible if a dwelling is built close to a wastewater treatment works. This is known as ‘development encroachment’. As a consequence of the issues relating to odour and odour management and the increasing significance of odour management within the water industry there is a need for a consistent approach, and Northern Ireland Water has developed a policy on Development Encroachment/Odour Assessment that will replace the old cordon sanitaire procedures.

Odour is controlled through two main mechanisms, planning policy and statutory nuisance.

• Proposed new wastewater treatment works or additions to existing treatment works commonly require planning permission prior to proceeding with any development. In granting permission, the Planning Service attaches conditions to the permission. These conditions can require the developer/operator to carry out certain works or to comply with environmental standards that are deemed necessary to protect the local population.
• Where Northern Ireland Water proposes to construct a new wastewater treatment works a general Development Encroachment/Odour Assessment will be undertaken as part of the Appraisal Study and at the expense of Northern Ireland Water.

• Proposed development of lands in proximity to existing or new wastewater treatment works require planning permission prior to proceeding with any development. In granting permission, the Planning Service attaches conditions to the permission, underPPS11. These conditions can require the developer/operator to carry out certain works or to comply with environmental standards that are deemed necessary to protect the local population.
• Where a developer proposes to construct a new development in proximity to a wastewater treatment works a specific Development Encroachment/Odour Assessment will be undertaken at the developer’s expense if an assessment has not previously been completed.
• The Odour Assessment Procedure may recommend the need for the developer to procure an Odour Dispersion Model and Report to Northern Ireland Water specification and requirements. This Odour Dispersion Model and Report will determine the ‘Area of Development Restraint’ and what, if any, mitigation measures it may be possible for the developer to provide
• Once planning permission has been granted and the conditions agreed, the development must be operated in compliance with the planning permission and conditions. If it is not, and the Planning Service can prove that it is not, an Enforcement Notice can be issued by the Planning Service, requiring immediate compliance and where the planning conditions are not met Planning Service can impose a maximum fine for continued non-compliance.
• The Planning Service also has the power to enter the land and take steps to enforce the Enforcement Notice, with costs being recovered from the owner/operator.

Although Northern Ireland Water has no direct statutory duty to provide odour control, beyond the compliance with any planning condition that has been agreed and the avoidance of statutory nuisance, it is accepted that the provision of odour mitigation is considered to be good practice.

Odour Assessment

Northern Ireland Water will work to the design standard and operational practices at works as detailed in the Odour Management Policy, which is summarised below:

• A design standard setting the maximum number of odour units that the first receptor will be exposed to.
• Specify an area adjacent to, and within 400m of a, wastewater treatment works as a consultation zone. The intention to develop within the zone will initiate discussion with Planning Service and Environmental Health.
• Where odour mitigation measures are required the developer will be asked to pay for additional capital costs.
• This policy is designed to reflect the current water industry approach to odour management. Given that best practice can change with time it is recommended that this policy should be periodically reviewed.
• All costs are based on our current Scheme of Charges
• Application form available: DEOA

Should you require any further information or assistance please contact Developer Services:

Developer Services - Servicing Team

Northern Ireland Water

Ballykeel Office

188 Larne Road

Ballykeel

Ballymena

Co Antrim BT42 3HA

Telephone: 03458 770 003

Email: developerservices[AT]niwater[DOT]com

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