Inject Reliability in Water, Wastewater Pumps
Michelle Segrest | August 10, 2016
Address the most common problems and follow best maintenance practices to keep critical water movers running around the clock.
One faulty $5,000 pump in a wastewater-treatment facility can shut down an entire operation and end up costing the company or municipality $500,000/day, according to Jim Elsey, vice president and general manager of Summit Pump Inc., Green Bay, WI. Why do pumps fail? The 44-year veteran of the pump repair and maintenance business has five very specific reasons and they all trace back to the people who are charged with making those pumps perform and those who provide (or don’t) the resources needed to purchase, install, and service the devices that form the backbone of every water-handling system.
From a management perspective, Elsey offers these five factors:
The required maintenance is not completed because:
• there is no money in the budget
• there is not enough manpower
• the maintenance crew does not have knowledge and/or the training to do the work
• the maintenance is not scheduled at the right time or with enough time to conduct it
• maintenance cannot be scheduled because the company cannot get the equipment out of service
• management does not know what type of maintenance is required or when
• equipment performance is not monitored
• a lack of record keeping (with a dependence on human memory)
• communication is lacking between workers and management (both directions).
The required maintenance is not completed correctly because:
• operators did not reference the installation and operations manual (IOM)
• there is no IOM
• there is no support from the manufacturer or the manufacturer was not asked for support
• there is no effort from management or workers to ask for help or clarification in general
• maintenance personnel are not properly trained or trained at all
• communication is lacking between workers and management (both directions).
Equipment performance is not measured because:
• there are no gages or gages are broken (pressure transmitters)
• vibration analysis is not conducted
• temperatures are not measured or recorded
• equipment-performance records are not kept
• there is a misunderstanding of allowable parameters
• there is no analysis for short- or long-term trends.
Technology is not used/maximized because:
• management and/or workers do not perceive a need for any technology
• the perception of technology payback (ROI) is that it does not exist or is very minimal
• if technology is used, there is a wide gap from reams of data to succinct and useful information
• technology and how to use it is misunderstood at the plant. Someone buys a portable vibration instrument or an infrared camera, but no one knows how to use them properly and/or interpret the data.
Perceptions and tribal rules become roadblocks because:
• management views maintenance as a liability rather than an asset
• operators are not allowed to do maintenance, and vice versa
• there is no cross training between trades (mill wright to electrician to pipe fitter)
• “fire fighters” (people who thrive in an emergency) are rewarded but fire preventers are not. Maintenance that must always require emergencies and high drama is never efficient or effective…or safe.
Now that some of the common problems have been described, Elsey offers expert advice on how to solve them. He stated that, in his experience managing maintenance crews, the team generally conducts a critique after each job.
Critical questions are asked and answered. How could we have done this job better, faster, safer, more efficiently, with less pain, less drama, and less cost? What tools or assets would improve the job?
“At first, the workers can be apprehensive until we have a few good ideas surface,” Elsey explained. “I assure them that no one is going to get in trouble or lose their jobs because of any improvements or changes. In one instance, a particular project initially took 14 days with 15 people and it cost us x amount of dollars. Fast forward five years later, and we were doing this same project in seven days with seven people at 50% less cost. All the workers were cross trained to do all the other jobs, albeit some better than others, but all had an understanding of each other’s job requirements.”
Unplanned or emergency maintenance is typically unsafe, Elsey said. “When there is an emergency breakdown, this is when people get in a rush or bypass rules and procedures. This is the time to be more vigilant around safety.
Set priorities for decision making because the manager cannot always be everywhere all the time. Empower your people to make decisions and to prioritize them. Never punish an employee for making decisions based on these priorities in the proper order.”
Elsey’s priorities are:
Elsey also advises to never skimp on proper tools and special tools and to make them accessible where they are used. It’s also important to get corporate buy-in on any hardware or consumables that would be required.
Elsey emphasized the importance of managing from the plant floor to see first-hand how things are operating.
“Know your staff’s core competencies so that these professionals can work in their competent areas,” he said. “Hire someone else to do the other stuff. I hate seeing millwrights mowing the grass or electricians painting the parking lot lines. Invest in training.”
Nuts and bolts
Tom Bennett is a regional service and aftermarket specialist for Flygt, a Xylem brand, Rye Brook, NY. A pump mechanic and maintenance supervisor since 1980, he is affectionately called “The Pump Whisperer” by his colleagues.
Bennett described what he considers to be the Top 5 most common maintenance tips that involve water and wastewater pumping systems:
• Keep the level control devices (floats, transducers, ultra sound, probe) clean and working properly.
• Keep the control panel clean and working.
• Keep the wet well as clean as
• Maintain a record of the maintenance on the equipment (amp draws, flow rates, run times).
• Maintain the equipment so that it can run it until dies. Follow manufacturer guidelines.
To address some of these issues, Bennett said, use mix flush valves that will either stir the bottom of the wet well pointing down or break up the grease cake on the top pointing up.
“Controllers can be programmed to do a variety of different things from pulling the level down, to ‘snoring’ to clean the top off, to staggered start levels,” he said. “This stops grease wrath from building up at one level.”
A real-world example
In Charleston, SC, Flygt has a storm-water station with six pumps. Four large propeller pumps operate at the 30-ft. down level, and two pumps operate 140 ft. down in the well.
“To remove these pumps, we would have to pump it all the way down. This would take a day and a half,” Bennett explained. “The repairman would have to go down in a man basket to hook up the pumps for removal. Once the unit was hooked up it would take about two to three hours to get it out of the well.” Obviously, this presents significant problems.
“We have a tool that is a deep-lift mechanism that goes down the guide rails and positively locks on to the pump,” Bennett said. “But this is for our large pumps, and these are not large pumps. During a standard rebuild of the units, I measured and designed a bail arrangement for the deep lift to match up to it. We now do not have to pump the well all the way down or go down in a man basket to hook the pump. Since installing lifting bails, we can remove a pump, inspect it, and have it back in the well in about three hours.”
To secure the best-possible reliability in water and wastewater pumping applications, Bennett recommends diligence in doing the planned maintenance. SCADA systems can provide daily reports with parameters that will alert operators to normal wear of the impellers or pumps that have been running for long periods of time.
Four Tips for Wastewater-Pump Reliability
Juan E. Bustamante, Technical Support, KSB Inc., Richmond, VA, Waste & Water Division, offers the following four maintenance tips for efficient and effective wastewater-pump reliability.
• At least weekly, record the electrical-motor parameters. Record the flow and pressure whenever possible.
• Follow the preventive maintenance written in the operating and maintenance manual.
• During the first year of pump operation, regularly inspect the impeller and casing wear rings to prevent wear, clogging, and cavitation.
• Measure pump vibration on a regular basis.