The Mix

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.

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.   

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).