Tank prestressed to withstand seismic forces

Problem

Padre Dam Municipal Water District in Santee, Calif., needed to supplement its 27 water storage tanks, replace an aging 1.5-million-gallon storage tank, and build a new pump station.

 

Solution

The project team specified a circular concrete tank from Ward-Henshaw Construction to replace the old one. Seismic design was important, as the site had a high probability of experiencing an earthquake. Due to hydrostatic, hydrodynamic, differential temperature and differential moisture wall loads, DN Tanks prestressed the tank wall vertically and circumferentially.

Result: The upgrade created a safe and reliable water distribution system capable of providing emergency water storage. 800/227-8181; www.dntanks.com.

 

Mixer thwarts ice buildup

 

Problem

During winter, ice up to 2 feet thick on reservoirs supplying water to the City of Rochester, Minn., caused extra maintenance and expense for water operations manager Cary Johnson and his staff.

Solution

The utility installed a GridBee GS-12 submersible electric mixer from Medora Corp. in the 2.25-million-gallon Bandel Reservoir. The mixer, seated on the bottom of the lake, created a constant flow by drawing water off the lake bed and mixing it throughout the water column. It also helped minimize thermal stratification and prevented short-circuiting and stagnant water conditions.

 

Result: “Since the installation, we’ve had no ice in the Bandel Reservoir,” said Johnson. “For comparison, we checked and found ice in another large reservoir.” 866/437-8076; www.medoraco.com.

 

New coating needed on reservoir

Problem

Tucson, Ariz.’s Martin Reservoir, an underground potable water storage facility, required a new coating and lining system after 47 years of service. The reservoir would be out of service three months while rehabilitation teams drained the tank, stripped its deteriorating butyl rubber liner, and prepared and recoated the concrete surface. Time was of the essence.

 

Solution

Tucson Water needed a durable, flexible lining with fast cure time and low solvents paired with on-site training for rehabilitation staff. To avoid future water leaks, a monolithic and pinhole-free surface was essential. Tucson chose Sherwin-Williams’ 100 percent solids SherFlex elastomeric polyurethane coating system and the NSF 61 certified primer Dura-Plate 235 PW. SherFlex’s single-coat application system can be applied at thicknesses of 30-250 mils in multiple passes during a single application with a plural component spray system, and dramatically reduces cure time, even at lower underground temperatures.

Result: Martin Reservoir was returned to service one week early, before the summer peak when the need for water would be at its highest. 800/524-5979; www.sherwin-williams.com/protective.

New treatment system stops corrosion and oxidation

 

Problem

The Dyersburg Water Treatment Plant in Tennessee discovered that their water treatment system needed to be replaced. Twenty years ago, these systems were made out of steel, and after two decades, the system was exhibiting corrosion and oxidation.

Solution

MFG Water Treatment Products won the project. The company designed, fabricated and shipped large high-strength replacement troughs and weirs made of fiber-reinforced plastic. The products are low-maintenance, corrosion-free, high-strength and lightweight.

 

Result: A complete fiberglass water management system was installed that will not corrode or oxidate, and meets new government regulations. 877/826-2509; www.mfgwtp.com.