Case Study

Zero-Maintenance Chlorine Monitoring for Uisce Éireann (Irish Water)

Zero Reagents. Zero Maintenance. How Cully Upgraded Chlorine Monitoring for Uisce Éireann with the Halogen MP5-A.

Background

Reagent deliveries. Membrane replacements. Electrode cleaning. Fouling-related drift. For water utility operations teams across Ireland, the true cost of running a conventional chlorine analyser in the field is far higher than the purchase price, and the maintenance burden falls squarely on already-stretched ICA technicians.

When Uisce Éireann needed to upgrade chlorine monitoring at a service reservoir in Co. Kildare, the brief went beyond better readings. It demanded a step-change: continuous, reliable chlorine residual data with the maintenance overhead engineered out entirely.

Cully’s solution was the Halogen Systems MP5-A: a self-cleaning, reagent-free, membrane-free multiparameter analyser, now deployed in-reservoir and streaming real-time water quality data into the ICONICS cloud SCADA platform, accessed by UE’s regional operations team.

The Challenge

The site’s existing chlorine monitoring arrangement had three compounding problems, none of them unusual for Irish water utilities managing ageing field instrumentation.

No remote visibility

Chlorine residual readings were local-only. There was no feed into the regional SCADA platform, no remote alerting, and no historical data, meaning the only way to check current values was a physical visit to the reservoir.

High and recurring maintenance costs

Traditional colorimetric (DPD reagent-based) chlorine analysers require scheduled reagent replenishment, membrane replacement, and periodic deep cleaning to manage electrode fouling, particularly in outdoor field environments. These costs routinely reach thousands of euros per year, per instrument, when labour and consumables are combined. At remote and unmanned sites, the logistics of reagent delivery alone represent a significant operational overhead.

Probe fouling — the field engineer’s constant battle

Biofouling, scaling, and organic adsorption on electrode surfaces are a chronic problem for water utilities. A fouled probe drifts out of calibration, generates unreliable readings, and triggers unnecessary alarm responses. For operations teams, this means unplanned site call-outs, lost confidence in the data, and ultimately a reluctance to rely on online analysers at all — defeating the purpose of continuous monitoring.

Why the Halogen MP5-A?

Following a review of the site requirements, the Halogen Systems MP5-A was selected as the monitoring solution. The MP5-A is an amperometric chlorine sensor that measures free chlorine alongside four additional water quality parameters simultaneously without requiring membranes or reagents.

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Why MP5-A is the right fit for this site?

Key Selection Criteria

  • Reagent-free and membrane-free design — eliminates the consumable chemical costs and scheduled reagent replenishment associated with colorimetric DPD-based systems. Traditional reagent-based systems can cost thousands of euros annually in materials and maintenance; the MP5-A offers essentially zero ongoing consumable costs.
  • Five parameters in a single instrument — free chlorine, pH, conductivity, temperature, and ORP measured simultaneously from one installation point, replacing the need for multiple instruments.
  • Flexible mounting options — the MP5-A supports dip/immersion mounting, wet tap installation, and flow cell configurations, making it adaptable to the physical constraints of different site types.
  • Digital communications — Modbus RTU (RS-485) serial communication from the Halogen transmitter enables structured data transfer to PLCs and SCADA systems, in addition to standard 4–20 mA analogue outputs.
  • Proven suitability for drinking water infrastructure — designed for continuous, unattended operation in water treatment and distribution environments.

Scope Delivered

Instrument Supply & Integration

Monitoring

Cully supplied and installed the Halogen MP5-A at the Kildare service reservoir using a dip-mounted (immersion) arrangement; the sensor assembly lowered directly into the reservoir for continuous, unattended in-situ measurement. A new local display and controller unit was installed in the site control room, giving operators immediate on-site readings without needing to access the instrument directly. The local display also supports calibration of up to five MP5-A units from a single interface, useful for future multi-point expansion.

PLC & SCADA Connectivity

Integration

The core engineering scope was end-to-end signal integration into UE’s existing telemetry and operational infrastructure:

 

  • The MP5-A transmitter was hardwired to the on-site ABB telemetry marshalling PLC, delivering all five measured parameters as structured signals into the site’s automation layer.
  • From the ABB PLC, data was pushed to the Cully-managed ICONICS cloud SCADA platform, giving UE’s regional operations team remote, real-time visibility of chlorine residuals and water quality parameters.
  • Continuous timestamped data logging was enabled through ICONICS, creating a full historical record for operational trend analysis and EPA regulatory audit.

Outcome & Benefits

Zero reagent & consumable cost – Ongoing reagent, membrane, and electrolyte spend eliminated entirely. No chemical deliveries, no disposal obligations, no reagent-related downtime at a remote site.

Self-cleaning; no fouling call-outs – SensiCLĒNE™ continuous electrode cleaning eliminates biofouling and scaling-related drift, the leading cause of unplanned site visits and recalibration events for conventional field probes.

24/7 remote chlorine visibility – Real-time readings from all five parameters accessible through ICONICS cloud SCADA — no physical site visit required to check chlorine residuals.

Full historical data & audit trail – Continuous timestamped logging via ICONICS supports trend analysis, alarm investigation, and EPA/regulatory audit requirements.

Five parameters, one instrument – Free chlorine, pH, temperature, conductivity, and ORP from a single dip-mounted installation — replacing multiple legacy instruments.

No waste stream required – NSF/ANSI 61 certified. Installed directly in the reservoir with no drain connection or chemical disposal infrastructure.

Seamless SCADA integration – Hardwired via ABB marshalling PLC to ICONICS, no additional comms hardware. Compatible with standard PLC and SCADA platforms across the Irish water sector.

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Technical Notes for Specifiers

 

For engineering teams considering the Halogen MP5-A on similar projects, the following notes reflect the experience from this deployment:

 

  • Mounting flexibility: The MP5-A supports multiple installation configurations — dip/immersion mounting (as used at this site), wet tap, and flow cell arrangements — making it adaptable to different reservoir and pump station environments.
  • Communication options: In addition to hardwired 4–20 mA analogue outputs, Modbus RTU serial communication from the Halogen transmitter is available. This supports structured digital data transfer to PLCs and SCADA systems where analogue signals are not preferred.
  • SCADA platform compatibility: The integration approach used here, hardwired to an ABB marshalling PLC, then to ICONICS cloud SCADA, is representative of typical utility telemetry architectures. The MP5-A’s standard output options make it compatible with the majority of PLC and SCADA platforms used in the Irish water sector.
  • Installation time: The full scope, including instrument installation, electrical terminations, PLC integration, and SCADA commissioning, was completed efficiently with no disruption to normal site operations.