Effective maintenance is critical to reliable water and wastewater treatment. An unplanned breakdown of a critical piece of equipment can lead to a process interruption, a permit violation or a costly unplanned repair.

Three basic maintenance strategies — preventive, predictive and corrective — help facility personnel keep the treatment plant in running condition with optimum performance. Plant maintenance personnel physically inspect all process stages and their critical components. A sound maintenance strategy enables team members to detect trouble and repair or replace devices and parts before breakdowns occur. Here is a look at the basic components of a sound maintenance program.

Corrective maintenance

Corrective maintenance (sometimes called break-fix) refers to making repairs to return a system to a working condition after it has failed. It is considered a reactive strategy. Plant teams can manage corrective maintenance manually or use software solutions that automate different parts of the process.

Manual methods involve significant paperwork and require team members to execute the entire process from receiving complaints to deploying personnel and keeping records. This approach comes with issues that include incomplete records, failure to make repairs in a timely manner and difficulties with replacement parts inventory. It also burdens maintenance personnel with documenting routine activities.

The automated method applies software programs called computerized maintenance management system or enterprise asset management software. These tools help manage treatment plant maintenance by taking control of planning, documentation and resource allocation. CMMS and EAM help streamline corrective maintenance using five approaches:

• Generating tickets (work orders) automatically, notifying the maintenance department and closing the tickets with all the necessary details documented.
• Keeping necessary records and providing easy access to information about assets.
• Deploying maintenance staff based on the scheduling plan.
• Providing a line of communication for maintenance staff.
• Minimizing corrective maintenance by helping staff execute proactive maintenance strategies.

Preventive maintenance

Preventive maintenance is a planned activity performed at regular intervals based on time or equipment usage. Time intervals can depend on the equipment manufacturer guidelines provided, such as changing the oil in the clarifier drive every four weeks. On the other hand, assets can be serviced after a specific use period, such as cleaning the surface of a filtration membrane after a certain number of working hours.

In treatment plants, equipment calibration is an essential part of preventive maintenance. Calibration is the verification of an instrument’s output against a standard reference. Its main purpose is to identify any defective instrument for rectification or replacement. All measuring instruments and gauges should be calibrated at a fixed interval each year.

In today’s world, water and wastewater treatment plants increasingly automate routine processes, helping to optimize production, maintain compliance and maximize operating staff efficiency. CMMS and EAM tools help manage preventive maintenance activities through the following methods:

• Scheduling incoming maintenance work automatically.
• Preparing preventive maintenance checklists.
• Distributing preventive maintenance schedules to relevant departments and personnel.
• Involving relevant departments before planned maintenance work begins so they can execute necessary preparations.
• Updating the records and tracking preventive maintenance treatment plant assets.
• Scheduling calibration tasks and tracking their completion.

Predictive maintenance

Predictive maintenance continuously monitors critical components and water plant sections to detect the likelihood of a fault or breakdown before it occurs. It relies on condition monitoring sensors that feed data into complex predictive algorithms. Data fed into predictive algorithms include vibration analysis, oil analysis and infrared sensing or thermal imaging.  

Vibration analysis, which detects abnormal movement in rotating or moving components. Sensors such as accelerometers detect abnormal vibration levels and then are used to diagnose potential trouble, such as bearing faults, gear faults and unbalancing.

Oil analysis, which is used to study the condition of lubricants. Defects in any component can contaminate oil and change its properties. When an anomaly in the oil is detected, the device can be investigated for any potential fault.

Infrared sensing or thermal imaging, which detects abnormal temperatures in mechanical, electrical, and electronic components. Since abnormal temperatures result from unusual stress or load, the results can be used to investigate the potential for faults.

CMMS and EAM help streamline predictive maintenance using four methods:

• Providing historical asset information and other asset data that can be used to build predictive models.
• Performing data analysis to catch impending failures early, and prevent costly breakdowns.
• Automatically creating work orders based on asset condition and predictive algorithms, or at least notifying the maintenance team about required actions.
• Helping maintenance planners schedule timely maintenance work.

Working in concert

Corrective, preventive and predictive maintenance offer different strategies and tactics. Treatment plant owners and maintenance personnel can benefit greatly when all three are combined. Corrective maintenance is a good choice for assets that are nonrepairable and easy and cheap to replace, such as UV lamps and filter cartridges.

Preventive maintenance is suitable for assets that can cause serious operational problems if they are out of service, and for assets such as valves, sensors and measuring instruments. Predictive maintenance applies mainly to critical assets such as blowers, motors and pumps. Treatment plant managers who combine the three strategies maximize equipment uptime, extend asset life, save money and labor, and avoid permit violations.

Tools for maintenance activities are essential in today’s automated environments. They help plant owners and maintenance personnel concentrate more on the core business of producing clean wastewater effluent or safe drinking water, instead of focusing on routine tasks. However, careful selection of these tools is critical: it leads to optimum efficiency, high return on investment and effective plant performance.

About the author

Eric Whitley is director of smart manufacturing with L2L, a company based in Salt Lake City, that helps businesses accelerate digital transformation. He writes a blog at www.l2l.com/what-is-cmms-software.