Pumps Matter: Knowing the Differences Between Them
Pumps move liquids and gases. Whether it’s in an oil rig, a wastewater treatment system, a car’s heating and cooling system, or a refrigerator, a pump’s purpose is to use mechanical energy to create pressure differences that push and move fluid things.
OK, that’s what they do – but how do you pick out a good one from the crowd?
Steve Sinks, a technical sales rep and in-house pump expert at Orenco Systems, a leading manufacturer of wastewater treatment systems, says a “good pump” – particularly one for the water and wastewater industry – has three definite traits.
“Quality, serviceability, and flexibility are what make a good pump,” he says. “So, quality of materials, like stainless steel or the high-end cord compared to other products, give you a long life cycle. And then, good pumps are serviceable and repairable with spare parts, so you have the flexibility to do what you need to do.”
A quality pump is one that’s made well and made for the job at hand. In the wastewater treatment industry, engineers turn to four different kinds: high-head effluent pumps, low-head effluent pumps, sewage moving pumps, and grinder pumps. Each one has its uses and benefits, Sinks says, “but all these pumps move liquid in some fashion.”
High-head pumps use high pressure from multiple internal impellers to crank up the PSI flow to 100 or more. Ideal for moving effluent and other liquids long distances, high-head pumps are designed to run up to 300 or more times a day because they’re engineered for the well industry, Sinks says.
Low-head pumps and effluent sewage pumps (a.k.a. solids-handling pumps) use a single impeller to move fluids. They’re limited in how many cycles they run per day, but they work well when moving effluent with solids mixed in – pieces up to 2 inches wide in the case of the solids-handling pump.
A grinder pump chops through everything to create a liquid mix of whatever people flush down the toilet.
“a grinder pump works like a garbage disposal,” Sinks says. “The pump has a set of cutting blades in it that turn everything into a slurry, and then it sends it out for final discharge. Those typically are used in commercial applications where there’s no guarantee what may be going down there.”
A good pump for a wastewater treatment system can also be easily serviced and repaired, Sinks says. A high-head version can be completely repaired and refurbished, whereas a low-head version is essentially replaced when its life cycle has passed.
“There are several parts to a high-head pump,” he says. “There’s the motor, there’s the suction connection, there is the liquid end, and there are the internals to the liquid end, and then there also is the cord. Each one of those parts can be replaced individually or as a group.”
“So, if your motor goes out, you can change the motor,” Sinks says. “If the cord gets nicked, you could change the cord. If you need a new liquid end, you could do that. You can even do the internals just to the liquid end.”
Low-head pumps, generally, are not serviceable or maintainable, he continues.
“You can’t replace a cord on a low-head pump because the manufacturers don’t offer that,” Sinks says. “When the life of that pump is over, it basically gets turned into a boat anchor, as we would say in the pump lab. You just take it and you throw it away. The manufacturers don’t even want them back because it’s not cost-effective to try to repair them.”
Besides being made with quality, serviceable parts, a good pump gives you flexibility to do things like develop properties that are difficult to build on, Sinks says.
“Say you had a piece of sloped property,” he says. “And you were going to build a house on the lower part of it, but the only usable part of it where the septic tank could go was away, up the slope,” he says. “A pump would allow you to pump up to a higher elevation to the usable piece of property.”
Similarly, if a homeowner wanted to expand their living space and add a bathroom to the lower level, a pump would allow for the addition, giving them the flexibility they need.
“The bathroom could drain to a basin, and then from that basin it could go to the septic tank at a higher level,” Sinks says. “And then the pumps inside the septic tank could then take the effluent to the final destination.”
Whether you’re an engineer, installer, or maintenance technician, understanding the differences between pumps will help you better create and care for septic systems and sewers.
“Make sure the pump you’re getting fits your design and is going to hydraulically work,” Sinks advises. “And also make sure you have proper power for your pumping system.
“Pump sizing is crucial,” he says. “I can’t emphasize that enough.”
If you’re interested in learning more, listen to the entire “Make It Clear: Why Pumps Matter” episode on your favorite podcast site. You can also visit Orenco.com/resources/podcasts to discover a wealth of resources on wastewater treatment systems.