What Makes a Sewage Pump Special?

Different pumps are needed for different situations. It’s possible to optimize a pump’s design to work in rugged conditions, work under a fluid (submersible pump), to operate precisely (a parastaltic pump), and even to resist clogging in heavy-duty usage. The latter is the type of design that makes a sewer pump special.

A Special Kind of Fluid

Sewer systems need to process more than just liquid. It turns out sewage is actually made of a lot of solid material that can clog a pump or pipeline. Human waste won’t just break up, it can often remain solid and become an obstacle to a smooth flowing system. This problem is very analogus to flushing golf balls. Eventually one of them will get stuck somewhere, and then others will get stuck, and things like toilet paper will block up the whole pipe.

In some cases, clogs like this can be defeated with pressure. If you can exert enough force on something, such as with a plunger, you can break up the blockage and force the material to keep flowing. The only problem is that you need to keep fixing the problem over and over again. And sooner or later, a clog will develop that either burns up the pump or that can’t be fixed without taking apart pipes and being more direct about the problem.

This unique waste composition of solids and liquids is a massive issue for sewer systems. It’s not feasible to stop and fix every little problem that develops. It’s going to ruin the efficiency of the system and lead to raw sewage discharges when the clog is dealt with and a whole surge of material floods into the system all at once.

A Pump For Solids

The issue of solid-filled waste was solved back in the 1950s by Christian Ølgaard. He invented the chopper pump, intending it for use in fields to distribute manure to the soil. The same issues were faced then as now with sewage: the waste was mostly solid, more of a suspension than a solution. With manure, the issue was mainly dirt, straw, and other plant matter clogging up normal pumps. Plant fibers in particular were a challenge, able to get wrapped around tight spaces and bind up equipment.

The solution was to reduce the size of the solids, a pump that could grind up whatever was sucked into it. This is an idea not disimilar from a garbage disposal in your sink. The intake end of the pump is equipped with blades that are mounted to the drive shaft so they spin when the pump is engaged. Any solid matter that approaches the pump is turned into a slurry before it enters the pump.

The slurry of material is essentially clog proof. In the area near the pump, it’s too liquified to do anything but flow through the pipes. Elsewhere in the system, some solids may reform, but its a smaller. Once the material has been chopped up, if a clump does form, it can be handled by a booster pump with the chopper attached or it may be small enough that the pressure alone prevents a clog from forming again.

A Pump For Many Applications

These chopper pumps are incredibly popular in the industrial-sewer world, but that’s not the only area this design has proven beneficial. Blockages can form anywhere a mixed-medium liquid needs to be pumped. Consider for example, a paper mill, where plant fibers could easily form into clogs. With a chopper pump, that issue is averted entirely. The same can occur in food processing, pharmaceuticals, chemical production, and still more fields.

Chopper pumps may have some incredibly gross origins, but they’re essential to keeping our modern world function quickly, smoothly, and efficiently.

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