Case Study – 40 % Drop in Maintenance with Intelligent pH Sensor

Keeping pH measurements operational in pulp and paper processes can be a time-consuming challenge. For a multinational company, changing to a METTLER TOLEDO solution for wastewater monitoring has dramatically cut their maintenance time and costs.

Too much time on sensor maintenance
Based in northern Spain is a major company that develops, produces, markets and sells personal care, tissue and forest products in countries across the globe.

In one of their pulp mills wastewater is closely monitored during processing to ensure only water that meets local regulatory requirements is discharged. During the early stages of treatment, the water has a high level of pulp solids. For the pH sensors they use to monitor reagent dosing, the abrasive material causes mechanical damage, clogs diaphragms and coats the pH-sensitive glass. Further, sulfites in the wastewater enter and poison the sensors’ reference systems. All these issues interfere with the measurement, and maintenance staff at the mill spend a lot of time cleaning, calibrating and replacing sensors in order to maintain measurements.



Tough pH sensor
METTLER TOLEDO approached the mill with solutions to their pH measurement issues that would reduce the workload on their maintenance staff as well as lower pH measurement costs.

The InPro® 4260i pH sensor has a number of features that allow it to tolerate harsh pulp and paper processes:

  • Solid polymer electrolyte – for long sensor lifetime and precise pH measurement
  • Open junction – maintains measurements by eliminating clogging from pulp solids
  • Argenthal reference system – prevents sensor contamination from sulfides

Predictive diagnostics and problem-free startup
The sensor is also one of METTLER TOLEDO’s Intelligent Sensor Management (ISM®) probes. One of the key benefits of ISM is advanced predictive diagnostics that inform operators / maintenance staff when sensor cleaning, calibration or replacement will be required.

Another benefit of ISM is that sensors can be calibrated in any convenient location, such as a maintenance shop, and stored until needed. Thanks to this and ISM’s Plug and Measure feature, exchanging a sensor at a measurement point is fast and problem free, and a measurement point can be operating again within a few minutes.

InTrac® 777 are retractable housings that allow sensors to be inserted and removed from their measurement position without stopping the process. Not only is this highly convenient, it means that a sensor does not need to be exposed to harsh process media when not necessary.

Mill managers were impressed with the METTLER TOLEDO solution and systems comprising the InPro 4260i sensor, InTrac 777 housing along with M400 transmitters were installed at the mill for wastewater monitoring.

Major reduction in maintenance
ISM has transformed maintenance at the facility. The combination of process-tolerant probes, sensor diagnostics, Plug and Measure and retractable housings has reduced pH sensor maintenance by more than 40 % compared with the previous sensor – reducing costs and freeing maintenance staff for more important tasks.

If you work in the pulp and paper industry in Canada and are facing similar challenges with pH measurement, consider using the METTLER TOLEDO InPro 4260i pH sensor for your wastewater monitoring needs.

For more information on our Mettler pH products visit our Mettler Toledo product page or call and speak to one of our representatives at 1-800-912-9262.