Submersible Sewage Pump Applications
Sewage pumps are specifically designed for the most demanding tasks among the three types mentioned in this article. They are primarily used for handling blackwater applications. These pumps typically feature semi-open non-clog or vortex impellers. With their robust capabilities, they can effectively manage solids of up to 1-1/2″ in residential and smaller commercial systems. For larger applications typically seen in plans and specifications, they can handle solids of 2″ or greater.
A common question I often encounter is where to use a sewage pump designed to handle 3″ and 4″ solids versus one designed for 2″ solids. This question perplexed me as well. How could 4″ solids be flushed down a toilet? Drawing from personal experiences with my children and now my grandchildren attempting to force a 4″ solid down the toilet, it simply does not work!
To shed light on this inquiry, I reached out to the product line manager at Bell & Gossett, who provided their expertise. Although there may be instances of coagulation in larger systems, that is not the determining factor. The pump is not engineered to handle 4″ solids; instead, it is designed to deliver a high flow rate with a non-clog impeller. Subsequently, it undergoes testing to determine the maximum solid sphere size it can effectively pass. When designing plumbing systems in buildings, there’s no need to be concerned with any size larger than 2″.
It’s worth noting that a submersible sewage pump can be utilized in all blackwater, graywater, and rainwater applications. In situations where lighter duty applications require a larger pump, this may be your only viable option.
These pumps offer a wide range of seal and impeller options. To discern the distinctions between good, better, and best pumps, visit the R. L. Deppmann sump and sewage product webpages.
Effluent Pump Applications
Keep in mind that this article revolves around drainage in buildings. In a waste treatment plant, the term “effluent” holds a specific meaning. However, within buildings, it refers to a lighter duty wastewater pump. An effluent pump may or may not feature a non-clog impeller. It can handle smaller solids, usually in the ½” or ¾” size range. In smaller graywater applications where the drainage water is separated, this pump would be the suitable choice.
In our context, I view an effluent pump as a larger version of a sump pump. These pumps typically boast superior seals and impellers compared to the smaller residential sump pumps. They can be used in graywater and sump pump applications. However, it’s important to note that effluent pumps should not be utilized in toilet blackwater applications.
Sump Pump Applications
Sump pumps find their usage in draining clearer drain tile and rainwater runoff. These pumps are usually compact in size. Price often plays a determining role in this market. If a higher-quality pump construction is desired, consider opting for an effluent style pump.
In general, sump pumps are designed to handle minimal to no solids. They are limited to handling solids ranging from 3/8″ to ½”. Therefore, these pumps are not suitable for the aforementioned wastewater applications.
I intentionally omitted discussing grinder pumps. These pumps are specifically engineered for wastewater applications involving a municipal forced main. They serve a distinct purpose and should not be employed in traditional drainage systems.
Grinder pumps have significantly higher heads. Misapplying them will lead to curve runout and over-pumping with short cycles. Additionally, these pumps are equipped with cutting teeth, resulting in higher maintenance costs for your clients.
Stay tuned for next week’s R. L. Deppmann Monday Morning Minutes, where we will delve into the comparison between vortex and non-clog impellers.