Background
A planning application for two new dwellings at Belle-Monte, Sturminster Newton received an objection from Wessex Water Developer Services. Their concern related to the site’s position within the development restraint zone of the Sturminster Newton Wastewater Treatment Works (WWTW) and the potential for odour nuisance affecting future residents.
Anderson Acoustics was appointed by Neil Northover to prepare an Odour Assessment addressing the objection and demonstrating that the site lay safely beyond any significant odour influence zone.
What We Did
Evidence Review
An existing validated AERMOD dispersion model from the adjacent Wyatt Homes development (Ref 2/2019/1801/FUL) was reviewed. That model identified the C₉₈, 1-hour 1.5 ouE/m³ contour – the standard significance threshold under CIWEM (2012) guidance. Analysis confirmed that the Belle-Monte site lay entirely outside this contour, even under conservative “worst-case” operational assumptions.
Verification and Context
- Distance: ≈ 230 m from the nearest WWTW process units;
- Wind Climate: Prevailing south-westerlies carry emissions away from the development;
- Screening: Existing hedgerows and topography provide further dispersion;
- Precedent: Nearby approved schemes (Wyatt Homes and Willow Tree Barn) are both closer to the WWTW yet required no odour mitigation.
Consultation and Reporting
A concise technical report and odour-risk summary were issued to Wessex Water and Dorset Council. Findings showed that odour concentrations at Belle-Monte are well below perception thresholds, satisfying the requirements of Wessex Water Policy WWDS-DEV 062G and CIWEM (2012) guidance.
Project Progress
Wessex Water agreed with our assessment confirming that the site presents a low risk of odour nuisance to the proposed development and as such removed their objection to the planning application.
Why It Matters
Odour constraints often stall small residential developments near wastewater sites. By applying proportionate, evidence-based analysis and referencing existing validated modelling, we provided the clear technical justification needed to overturn the objection. This project demonstrates how targeted odour risk assessment can streamline planning, build regulator confidence, and enable sustainable growth without unnecessary delay or cost.
