Water and Wastewater News - February 2022

Hard freeze

February 1, 2022

One of the advantages of stainless steel as a material for slide gates is that it stands up well to tough conditions -- like when a basin freezes. It's better never to let the water freeze at all, but if there's any chance of it, stainless steel has a decided advantage over cast iron or fiberglass. (Remember: Water expands when it turns into ice. Expanding ice can crack fiberglass, and once cracks develop, the FRP gate itself is going to need repair.) We decided to wait for warmer weather to perform any further inspections on this one.

Temperatures change. Do your blowers change with them?

February 2, 2022

According to historical records, we're just reaching the bitter end of the typical low point for annual temperatures. For most of Nebraska and South Dakota, the average coldest day of the year is between January 16th and January 20th, and for almost all of Iowa, it's between January 21st and January 25th. From this point forward, the days will mostly be growing warmer. Temperature has a big impact on wastewater aeration: Colder air is denser air, and colder water holds more dissolved oxygen than warm water. Thus, the demand for aeration is generally lowest right about now -- and will increase as both air and water grow warmer moving towards the middle of the year. The difference in horsepower required to achieve the same DO levels in treated wastewater can be substantially less in the winter than in the summer, and with thoughtful application and good control systems, engineers can design systems that give operators (and utility owners) significant electrical savings by adjusting to those temperature swings. Every unit of horsepower counts: At 10 cents per kilowatt-hour, dropping aeration demand by just 10 hp for six months out of the year could save well over $3,000. Switching to VFD-controlled high-efficiency centrifugal blowers can have a fast payback period, especially when other financial resources like grants and low-interest loans for energy efficiency are available. Check out our presentation on blower throttling for more details and contact us for more information on free energy audits and technical application assistance.

Floating aeration vs. ice

February 3, 2022

In addition to their ability to make a big difference in lagoons and large tanks with their capacity to provide both aeration and mixing, it's worth noting that floating aerators (and their cousins, submersible aspirators) can be used to control ice buildup. By keeping the water surface agitated, they discourage the formation of ice. If you're looking to install a new mechanical aeration system or retrofit or replace an existing installation, Fluence has options and we will be happy to help you find the right one.

Go big (or go small, whatever works for you)

February 4, 2022

Criss-cross the states of Iowa and Nebraska (our home turf) and you'll see scores of Gorman-Rupp lift stations enclosed in tidy little 6' x 6' packages. They're often affectionately called "doghouse" enclosures, since they're just big enough to pack the pumps, motors, controls, and valves inside -- not large enough to for an operator to get inside. These are cost-efficient and safe lift stations: Nobody has to enter a valve vault or hang out leaning over the side of an open wetwell hatch in order to access the pumps, valves, or other equipment. But don't forget that Gorman-Rupp ReliaSource® lift stations are available in a wide range of configurations, including not only 6x6, but also 7' x 10' designs with a slide-off cover, 8' x 12' stations (still compact, but accommodating for operators to stand inside) and the "Modular" station series, which can handle up to 5,200 gpm and offer wide-open spaces for operations, maintenance, and even storage. Learn more from our brochure or contact us with your parameters to get helpful application assistance.

Quietly blending in for almost 20 years

Don't haul what you can dewater

February 14, 2022

With fuel prices rising and labor shortages breaking out everywhere, it may be time to consider a long-term solution to the costs of hauling away municipal sludge. Payback periods on the initial equipment cost can be very fast, especially with price inflation making it more and more expensive to haul the material away. And since Iowa and Nebraska have some of the lowest electricity costs in the country, those payback periods can be even faster than elsewhere. Learn more in our belt filter press section or contact us anytime for information like sizing, estimates, or cost-benefit analysis reports.

Have you tried unplugging it?

February 15, 2022

If your computer malfunctions, you'll probably be asked if you've tried unplugging it and giving it a reboot. It turns out the same advice can be applied to piping systems inside water and wastewater systems: Have you tried unplugging it? Not by removing power, but by installing bidirectional knife-gate valves in place of plug valves. The Wey knife-gate valve design is an excellent option for flow isolation in applications where the water may contain solids or suspended materials. They are bidirectionally bubble-tight -- which means they can isolate in either direction, without any need to orient the valve in a particular direction. That's a big advantage over plug valves, which must seat with the help of pressure coming from upstream. Wey's knife-gate valves also weigh only a fraction of what comparable plug valves weigh: A 4" Wey Model VM with a handwheel operator weighs only 27 lbs., compared with a typical 4" plug valve that weighs 72 lbs. or more. The difference grows even more dramatic in larger valve sizes. Valves that weigh less are easier to install, easier to operate, and easier to maintain -- plus, they ease pipe strain. Learn more in our knife-gate valve pages, or contact us for estimates, dimensions, pricing, or application assistance.

Standing in the way of the shortest path

February 16, 2022

The shortest path between two points, as everyone knows, is a straight line. And everyone knows that water is, in a sense, lazy -- it follows the path of least resistance as it seeks its own level. This knowledge is highly applicable in the world of pipes and open channels, of course, but it's also enormously important when thinking about flow through tanks and lagoons. Unless we force it to take a different route, water will tend to seek the shortest distance from inlet to outlet. And if a tank or lagoon is being used to apply treatment (like aeration), the result can be a truncated path from inlet to outlet, resulting in two problems: Dead zones where the water sits and stagnates, and water that encountered only the shortest period of treatment before it exited.

Look at how the water quality improves as the water flows from left to right in this lagoon, forced by the three baffle curtains (noted with yellow dots) to take a long, meandering path over lots of aerators. Also note how the algae still grow around the edges of the lagoon (where the water depth is lower) and in corners (which are miniature dead zones). These baffles are making a big difference to the ultimate treatment quality inside this lagoon.

Baffle curtains are a smart, cost-efficient way to ensure the maximum useful treatment within a tank or lagoon. Using durable, lightweight geomembranes suspended either from a frame (in a tank) or floats (in a lagoon), baffle curtains can redirect the flow of water so it crosses the largest number of aerators or has the maximum contact time with chemicals like chlorine. Baffle curtains deserve a first look anytime a system needs to perform better -- learn more in the baffle curtain section of our site or contact us for application assistance.

Vertical-turbine pumps

February 17, 2022

Whether you need to move 50 gpm or 30,000 gpm of water out of a well (or anything in between), we have vertical-turbine and submersible well pumps to do the job.

Past water and wastewater news updates