By Mike St. Germain, Customer and Market Insights Lead: Industrial Sector at Watson-Marlow
Water and wastewater treatment plants are facing growing pressure to do more with less. Staffing shortages, rising operating costs and tightening environmental regulations are forcing operators to look beyond simple process performance and focus on operational efficiency.
With fewer personnel on site, reliability has become critical. Operators need equipment that is easy to maintain and provides clear alarms that indicate when intervention is required. Avoiding unplanned downtime, chemical spills and emergency maintenance is becoming just as important as achieving treatment targets.
These changing operational pressures are reshaping how utilities evaluate chemical metering technologies. Historically, chemical dosing performance was evaluated primarily on accuracy. Today, reliability, maintainability and process visibility are increasingly influencing technology selection.
A broader view of dosing performance
Repeatability has become particularly important, with operators needing confidence that a pump calibrated today will deliver the same performance six months or even years later. Consistent, repeatable dosing helps reduce chemical consumption, improve treatment efficiency and minimise the downstream treatment burden.
Safety and high-uptime performance are becoming increasingly crucial selection criteria. Utilities are seeking technologies that minimise operator exposure to chemicals, reduce maintenance interventions and support predictive maintenance strategies. Operators also want to work with pumps that have minimise the risk of chemical spills, particularly polymers, which can be difficult and time-consuming to clean up.
Many operators are looking for complete solution providers that can simplify installation, operation and maintenance across multiple sites. This has driven growing interest in integrated dosing systems, including pre-engineered dosing pods and chem-feed skids.
Meeting the challenges of difficult chemistries
The importance of these broader selection criteria becomes particularly apparent when handling challenging chemicals.
Viscous, abrasive and off-gassing chemistries can present challenges for some chemical dosing technologies, particularly in applications where reliability and process continuity are essential. Diaphragm metering pumps, for example, rely on check valves that can become blocked by viscous products or lose prime, requiring operator intervention to restore performance.
Peristaltic pumps operate differently. By eliminating check valves, they reduce maintenance requirements and can provide more reliable performance in demanding applications. Modern peristaltic dosing technologies can also deliver the accuracy and repeatability required across a wide range of treatment processes involving disinfectants, flocculants, acids, alkalis, polymers, dispersants and defoamers.
At the same time, condition-monitoring capabilities are enabling a shift to more predictive maintenance strategies. By helping operators identify leaks, blockages and changing process conditions before failures occur, these technologies support improved uptime and more efficient asset management. This insight allows maintenance to be planned proactively, reducing the risk of unplanned downtime, chemical spills and emergency interventions.
Case study: improving reliability in odour control and flocculation
A UK-based water company provides a practical example of how changing operational priorities are influencing chemical dosing decisions.
The utility reviewed its dosing strategy after experiencing repeated failures with diaphragm pumps used in odour control applications. Sodium nitrate is dosed during biological wastewater treatment to prevent sulphide gas formation and the resultant unpleasant odours. However, the site’s existing diaphragm pumps proved unreliable, leading to increased maintenance requirements and operational disruption.
The need for reliable continuous operation extended to other dosing applications. Ferric sulphate and ferrous chloride are dosed to support coagulation and flocculation processes, improving solids removal and reducing ammonia levels in treated effluent. These applications place similar demands on the dosing equipment, which must perform consistently around the clock.
Seeking a reliable, low maintenance solution, the water company began replacing diaphragm pumps with our Qdos peristaltic pumps, and today more than 30 are installed across 15 water treatment sites. When existing diaphragm dosing pumps require replacement, the utility now typically replaces them with peristaltic technology.
Since adopting this approach, the company reports that odour complaints associated with the affected sites have been eliminated. The pumps are also supporting compliance with increasingly stringent phosphorus discharge limits by helping maintain reliable and consistent dosing of ferric sulphate and ferrous chloride.
In addition to operational improvements, the utility has seen sustainability gains through reduced maintenance visits and lower transportation requirements for servicing and replacement activities.
Looking ahead
As utilities continue to balance operational efficiency, workforce pressures and increasingly stringent environmental targets, chemical dosing systems are coming under greater scrutiny. The future of chemical dosing is no longer defined by accuracy alone. Reliability, repeatability, maintainability and process visibility are becoming equally important considerations.
Technologies that reduce operational burden while delivering consistent performance will play an increasingly important role in helping utilities build more resilient, efficient and sustainable water and wastewater treatment operations.
