Marine

Why Ought to I Set up a Water Storage Tank Mixer? | Kasco Weblog


Written by Thom Tackman, Kasco Marine Licensed Water Operator (aka the man with the hat!)

As a water therapy plant operator, with expertise working in Arizona, Illinois, and most lately in Missouri, my duty was to effectively function the floor water therapy plant(s) and to ensure they met all regulatory necessities. Over the previous 45 years, I’ve accomplished hours of routine water high quality testing, verifying that the water leaving the plant met regulatory necessities. And I don’t ever keep in mind a single constructive coliform pattern leaving the water therapy facility. All through my expertise, I’ve tried numerous methods to make sure my consuming water was of top quality. By far, one of the best, most effective and efficient method I’ve discovered is by utilizing an energetic water storage tank mixer.

Discovering Inconsistency in Saved Water High quality

In Arizona, my water high quality group members accomplished routine sampling in our distribution system for chlorine and coliform micro organism. Sometimes, we’d get a constructive pattern within the distribution system with a measurable free chlorine residual. Instantly, we’d resample once more, and more often than not, the test pattern would point out no coliform micro organism. And we might additionally maintain weekly water style checks and usually the water tasted okay, however then there have been instances when the water tasted earthly or musty. Sometimes, we’d even odor chlorine and hydrogen sulfide (i.e. a rotten egg odor).

Water high quality and buyer complaints are necessary. All metropolis councils I labored with took each very critically. It was a high precedence for us to make sure that the water exiting the floor water therapy and our groundwater wells had been good high quality. So, we elected to look nearer at our distribution and water storage tanks to see if we may enhance the consistency in our water high quality on the buyer faucet.

Difficulties in Testing for Consistency

TANK DESIGN
Our first discovery was that water storage tanks will not be designed for sampling. In an effort to pattern the water storage tanks, we needed to first practice our group on methods to safely climb a water tank. As soon as we realized methods to correctly climb a tank, we needed to discover a strategy to pattern the tank. The place potential, we put in tubing and siphoned water from the tanks to acquire a consultant pattern. The place we couldn’t set up a siphon, we used small sump pumps and pumped water, sampling from numerous ranges contained in the tank. In Arizona, we at all times tried to do the sampling as early as potential within the day as a result of the tank tops would warmth up by noon the place it was nearly inconceivable to work safely.

CHEMICAL STRATIFICATION
We discovered inconsistency within the saved water high quality. We observed that the chlorine ranges could be good on the backside of the tanks however would lower to undetectable ranges in direction of the highest of the tank. In an effort to improve the chlorine residual, we’d add chlorine. First with chlorine tablets after which later with bleach.

We calculated the quantity of the tank(s) then added the quantity of chlorine to succeed in the specified residual. We might retest, hoping that the chlorine residual would attain the specified stage. It by no means occurred to us that the chlorine compounds merely couldn’t disperse inside the tank with out further mixing motion to interrupt up the stratified water. We thought that the water stream into the tank would supply ample mixing motion.

MANUALLY MIXING
Throughout my time in Arizona, we didn’t have energetic tank mixers put in—and attempting to manually combine a 0.5 MG or bigger tank by way of a tank hatch simply was not possible. We tried to switch the inlet and outlet of the storage tanks in order that the water would come into the highest of the tank and exit by way of the underside. It appeared like a good suggestion, however among the tanks solely stuffed for an hour or two per day, and poor water high quality remained.

RECIRCULATION PUMPS
Lastly, we then added giant exterior recirculation pumps to combine the storage tanks. That too got here with restricted success in enhancing water high quality. In a single 10.0 MG tank, we put in baffle partitions on the advice of our consulting engineer and that elevated the quantity of floor space for biofilm to develop and made tank cleansing almost inconceivable. To say the least, we tried many, many various choices to repair the poor water high quality of those tanks with out a lot success.

Ultimately, my story exhibits an countless cycle of testing and attempting new strategies to repair the issues that often happen in water tanks nationally.

Thermal Stratification Defined

Rising up within the midwest we swam in lakes the place the water was at all times heat on the floor and chilly at our toes so it appeared regular for saved consuming water to be heat on the highest and colder beneath.

We by no means considered thermal stratification as a water high quality drawback till sooner or later a diver was despatched right into a tank to wash it. He complained concerning the chlorine odor within the headspace and the way sizzling the water was close to the floor of the tank. As I recall, he referred to as that phenomenon thermal stratification and mentioned most all tanks have the identical water temperature variation regardless in the event that they’re above the bottom or constructed within the floor.

Kasco’s CertiSafe™ Mixer working in an elevated tank.

Thermal stratification is what happens in a physique of water the place two distinct temperature layers develop. In the summertime, the nice and cozy water or epilimnion layer is on high and chilly water or hypolimnion layer is beneath. Through the winter; nonetheless, ice varieties on the floor, and the hotter water is situated beneath the ice.

Thermal stratification is well-known within the naval warfare area. There’s a barrier of water in our ocean that may display out trendy sonar gear making it troublesome for subsurface boats to detect ships on the floor and vice versa. The stratification in water storage tanks can also be on account of a variation in water temperature. The solar warms the tank exterior transmitting that warmth to the water. Hotter water molecules are lighter and fewer dense so they continue to be on high of the cooler and denser water.

Research have concluded that thermal stratification happens in as little as 4 hours. And, a level or much less of temperature distinction will create the barrier talked about, separating the cooler water from the hotter water; subsequently, creating a rise in water age and chlorine decay fee on the water within the higher portion of the storage tank.

Passive vs. Energetic Tank Mixing

Over the previous few years, a number of tank mixers have turn out to be obtainable available on the market to assist break up thermal stratification in water storage tanks and to enhance water high quality. There are two varieties of tank mixers obtainable:

  • Passive mixers solely perform when water is flowing into the tank, and these mixers require equipped water strain to function.
  • Energetic mixers are designed to function repeatedly for twenty-four hours a day and-7 days per week.

When evaluating passive and energetic mixers, first take a look at your utility and decide the fill cycle of your tank. The blending cycle ought to be shorter in period than the fill cycle. For instance, in case you have a 1.0 MG tank and add 0.1 MG of water each 4 hours, then the mixer ought to be sized to finish the contents of the tank in lower than 4 hours.

Along with evaluating the acquisition value, take a look at the guarantee, discover out if the unit may be rebuilt and the associated fee to rebuild it, annual energy prices to function it, and design/ease of set up.

Try the motor bearing life. Mixers designed for lengthy life will likely be equipped with bearings with an L-10 score of 200,000 hours that are constructed to final for not less than 20 years. Lastly, ask for and take a look at references. Ask the references about guarantee claims and general satisfaction with the unit buy, set up, and most significantly, operation. Is the mixer working for these operators as meant?

Water High quality Administration and The Kasco CertiSafe™ Tank Mixer

Kasco started constructing high quality mixers in 1968 primarily for the marine trade to maintain ice from forming round and damaging docks. Among the mixers additionally had been used primarily within the northern states in water storage tanks to maintain ice from build up and damaging the water storage tank.

In 2016, Kasco, on the request and recommendation of water storage tank house owners, obtained NSF 61/372 certification for his or her mixers and floor aerators. NSF rankings may be both NSF compliant or NSF licensed. The Kasco CertiSafe™ Mixer is NSF 61 licensed. Just be sure you are evaluating NSF {qualifications} when choosing a mixer.

NSF certified logo

Kasco builds over 15,000 mixers yearly for numerous functions. Most of the mixers in operation as we speak are within the marine trade for de-icing and had been put in over 15 to twenty years in the past. These high quality mixers are inbuilt Prescott, Wisconsin, and constructed to final. The key to greater than 50 years of success is that Kasco takes nice delight of their merchandise. We attempt to supply one of the best mixers obtainable which can be held to the very best high quality requirements, are rebuildable, and backed by a terrific guarantee – all at aggressive pricing.

Ground storage water tank
Concerning the Writer

Thom Tackman has over 40 years of trade expertise in upkeep operations, water/wastewater course of management, water and distribution operations, and wastewater assortment system operation. He has hung out each as an authorized operator within the discipline, but in addition as a college-level teacher and educator specializing in water and wastewater operator certification evaluation, disinfection, and regulatory necessities.


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