There are many design factors for operators and engineers to consider when specifying mixers for water storage tanks – ranging from tank size and geometry to obstructing tank internals like columns and baffles. Below are the three of the most common questions we’ve received regarding mixing and storage tank design.  Feel free to add your own tank design challenge to the list by leaving a comment below.

In the water distribution system, cold weather can create risks that are hidden from plain sight: ice accumulation inside water storage tanks. Often, when operators realize they have a problem with ice buildup in their tanks, the tank’s interior is already damaged or the wall is punctured. Additionally, traditional methods for reducing ice formation inside water tanks have been expensive, difficult and often only partially effective.

Six years ago, PAX Water Technologies entered the water industry with a novel approach for improving water quality in storage tanks – biomimicry. By examining how fluids move in the natural world, PAX Water Technologies Founder Jay Harman, developed a small yet powerful impeller that mimics the spiral flow patterns found in whirlpools and tornados. This 6-inch “Lily” impeller is not only organic in shape (it resembles a Calla Lily), it can mix a 10 million gallon storage tank using the same energy footprint as three 100-watt light bulbs.

Record-setting heat waves are sweeping the country this summer, placing higher-than-usual demand on water utilities. High water use by consumers typically translates into high turnover in water storage tanks, giving water less time to age and stagnate within the tank. However, areas with large capacity tanks or low summer demand can suffer from thermal stratification inside water storage tanks and serious water quality problems.

PAX Water Technologies had a great time in Dallas at ACE12 last week – our new THM Removal System (TRS) was featured at the New Product Technology Showcase and we fielded many great questions from ACE12 attendees at our booth. We always appreciate the opportunity to hear directly from operators and engineers about their water quality challenges.   

The Stage 2 DBP rule is here and presenting tough choices for water system operators. Upgrades to the treatment plant are expensive and constrained by existing infrastructure. Changing disinfectants can also be expensive and difficult to sell to a wary board and community.

Charles Fishman (author of The Big Thirst) wrote a piece for the Washington Post last month on “Five Myths About Water.” Number two on Charles’ myth list is “bottled water is better than tap water,” where he unveils that tap water is actually MORE closely monitored than bottled water and that in blind taste tests “people can’t reliably pick bottled from tap.” At PAX Water, Charles’ article got us thinking about some of the myths we’re trying to bust in the drinking water industry. Here are our top five:

Just as electronic technologies have improved with time, technologies in the water distribution system have evolved from large and expensive pieces of equipment into smaller and more efficient solutions. Developed in the ‘80s, passive mixing systems use bulky nozzles with one-way valves to squirt water in different directions during the fill cycle. Because these mixers rely on the momentum of influent water, passive systems do not mix water once the tank is full or during the drain cycle and tanks re-stratify once the infill has stopped. A common workaround is forcing tank operators into a minimum turnover rate (which is both energy-intensive and expensive).

The AWWA Distribution System Water Quality Committee is embarking on revisions to their M56: Fundamentals and Control of Nitrification in Chloraminated Drinking Water Distribution Systems.  The M56 manual is a complete guide to managing nitrification and is intended to be a principal technical resource for water system operators throughout the US.

PAX Water Technologies presented a technical talk at the 25th annual Association of State Drinking Water Administrators meeting last week in Pittsburgh, PA entitled Stabilization and Improvement of Distribution System Water Quality in Reservoirs and Tanks – a Key to Stage 2 Compliance.