By Tom Lendrem, Solutions Architect, Badger Meter
As we enter AMP8, the national rollout of Continuous Water Quality Monitoring (CWQM) is underway.
While well-intentioned, the programme faces well-documented challenges including maintaining power to remote systems and land access issues. Add to this that CSO (Combined Sewer Overflow) discharges are, by nature, transient. Due to their dilution with rainwater, their long-term impact on river health – particularly on water quality parameters like biochemical oxygen demand (BOD) – is questionable. As CWQM data emerges toward the end of AMP8, the spotlight will probably shift toward a more meaningful indicator of environmental impact: Continuous Final Effluent (FE) Monitoring.
Many UK utilities already conduct online FE monitoring – tracking parameters like ammonia, turbidity, iron, pH, phosphate and more. This data helps identify process issues before they result in potential compliance failures. However, to better understand long-term impacts on river health, particularly dissolved oxygen levels, the industry will need to embrace the likes of real-time online BOD monitoring.
Historically, in the UK, uptake of such ‘surrogate measurements’ has been slow, in part due to reliance on outdated surrogates like turbidity. Badger Meter, a leader in flow measurement, water quality, pressure monitoring and software helped one utility discover that their turbidity measurements bore little correlation to BOD, leaving them exposed to potential BOD compliance risks. Recognising this, they trialled three types of online BOD sensors – two based on absorbance and one on fluorescence. The s::can sensor from Badger Meter, which utilises UV-Vis absorbance spectroscopy, proved the most effective not just in accuracy but also in ease of deployment. The well conducted trial period demonstrated that all the sensors could be used for online BOD measurement.
The key differentiator? Calibration. A BOD sensor that requires extensive, or even worse, frequent adjustment to align with manometric compliance samples is impractical. Utilities need reliable tools that give sensible results “out of the box,” with minimal maintenance and immediate value. Based on their findings, the utility has chosen to deploy the s::can sensors from Badger Meter as part of its AMP8 strategy, primarily because the calibration work required was far less than any of the other sensors on trial, even when the other sensors were using the same fundamental technology.
Looking ahead to AMP9, the case for broader adoption of FE monitoring tools grows stronger. Online data can fill the gaps between traditional compliance samples, offering regulators richer insights and enabling utilities to proactively manage their processes. With validated sensors in place, we may even see a shift away from frequent spot sampling in favour of continuous, evidence-backed monitoring.
UV-Vis spectroscopy for the likes of online COD and BOD isn’t new. As the regulatory focus evolves from CSO discharges to final effluent quality, now is the time for utilities to validate and invest in these solutions. Doing so not only ensures compliance but also demonstrates a genuine commitment to safeguarding our rivers.
For more information visit –
www.badgermeter.com/AMP8
