Tanks, Structures and Components

Tanks, Structures and Components
Water tower helps meet water need for growing population

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Covered beds eliminate odor issues

Problem: The Northern Moraine Wastewater Reclamation District serves three Illinois communities, a total population of 12,000. The 1.1 mgd plant had stored treated and dried biosolids outside. “The material got wet every time it rained or snowed, causing odor concerns and raising handling costs,” says Todd Sheridan, operations supervisor. The facility needed covered storage space for the drying beds.

Solution: Sheridan purchased two 65- by 70-foot Hercules Truss Arch Buildings from ClearSpan Fabric Structures.

Result: Sheridan is pleased with the buildings: “They were assembled in less than a week. The light that comes through the covers is great.” Both structures now store biosolids, but Sheridan says, “I’m sure we will find more uses for the buildings down the road.” 866/643-1010; www.clearspan.com.

Prestressed concrete tank replaces aging infrastructure

Problem: The Anaheim (California) Public Utilities Department found that a 1935 concrete-lined earthen reservoir had reached its end of life. It did not meet current seismic codes and needed extensive rehabilitation. In addition, the pumping capacities would not meet future demands.

Solution: DN Tanks was engaged to build and prestress an AWWA-D110 circular prestressed concrete tank. Because the tank would likely experience high seismic forces during its life, it was built with a proven seismic design. The corewall was prestressed vertically and circumferentially. Vertical prestressing used threadbars embedded in the wall; circumferential prestressing used a prestressing machine to continuously monitor and provide accurate applied stressing force on the galvanized strand as it was applied to the tank core wall. After prestressing, the strand was encased and protected with shotcrete.

Result: The new 4-million-gallon tank provides safe, reliable water storage to meet current and future capacity requirements, operational needs and seismic performance standards. 800/227-8181; www.dntanks.com.

Water tower helps meet water need for growing population

Problem: In 2012, Midland, Texas, was experiencing its third-worst drought ever. Its reservoirs were running low while the town was growing rapidly. The city decided to tap the aquifer located beneath the T-Bar Well Field. The city needed a large-capacity water tower.

Solution: Along with various treatment infrastructure and 67 miles of pipeline, an elevated water tank was built on site just off of Highway 191. “Throughout the years, the engineer has come to trust Tnemec Company as both a supplier and technical resource for coating needs,” says Lane Salvato, coating consultant with The Barry Group. “We were able to recommend low-maintenance coating systems.” The tank included a concrete pedestal and a steel bowl. Interior and exterior steel was primed with zinc-rich urethane, Series 91-H2O Hydro-Zinc, an NSF/ANSI Standard A 61 certified primer. The tank’s interior steel was then lined with two coats of Series 20 Pota-Pox. After the exterior’s prime coat, an intermediate coat of Series 1075 Endura-Shield II and a finish coat of Series 700 HydroFlon were applied.

Result: The project, recognized with the Tnemec 2014 Tank of the Year award, was completed in less than 12 months. The tank is expected to last 25 years. 800/863-6321; www.tnemec.com.

Wastewater facility selects geomembrane to reline pond

Problem: Built in the early 1970s, the Water Pollution Control Plant Northside Facility in Danville, Virginia, treats up to 24 mgd of domestic and industrial wastewater. In 2009, a 325,000-square-foot treatment pond lined with unsupported PVC had deteriorated beyond repair and needed a new liner system.

Solution: Dewberry Engineers selected XR-3 reinforced geomembrane from Seaman Corporation. Based on XR technology using ethylene interpolymer alloy, it is highly resistant to UV light and harsh climates. The reinforced 30 mil liner provides high strength. To minimize seams, the engineers specified large prefabricated panels, up to 20,000 square feet each.

Result: The liner system continues to hold up well, requiring little maintenance and repair. 800/927-8578; www.xr-technology.com.

Coating helps restore and maintain wastewater containment tanks

Problem: The Englewood (Florida) Wastewater Processing Facility had tank interiors and catwalk lip edges that were deteriorating and exposing reinforcing steel to hydrogen sulfide and other substances. The previous coating and repairs done years ago were failing and had serious spalling conditions.

Solution: Valcon Industries provided a single source supply for cleaning and deodorizing (GELTEKK), surface preparation and profiling (ETCHEX), concrete stabilization and restoration (Restructor and Flexcrete), and final surface sealing and waterproofing (Liquaseal). The products are VOC compliant, safe and permanent, and are easy for contractors or maintenance engineers to use. The line is designed to provide long-term protection in aggressive conditions.

Result: The coatings stabilized and restored the concrete walls, and provide a new surface with long-term protection. 866/311-9737; www.valcon-industries.com.

Dewatering improves solids handling

Problem: The 8 mgd Bluebonnet Water Supply Corp. Water Treatment Plant in Temple, Texas, generated up to 106 million gallons of spent backwash water and clarifier sludge annually, storing it in three concrete lagoons. Solids in the settling lagoon never dried well enough for effective removal. Handling a monthly average of 266,000 pounds and paying a hauler was a major effort and expense.

Solution: Bluebonnet added three modified sludge collection basins with vacuum transport units, two lift stations, and the Poly-Mate polymer system and Sludge-Mate dewatering containers from Flo Trend Systems. Material settles in the bottom to a depth of no more than 1 foot before the sludge is transferred. When the collections system activates, 19,600 pounds of solids flow by gravity to the first lift station, where the material is dewatered to 15 percent solids cake. Filtrate drains to the second lift station and is returned to the headworks.

Result: Damon Boniface, chief of operations, and his staff stay ahead of sludge production and control disposal costs. 713/699-0152; www.flotrend.com.

Product improves total solids destruction in aerobic digester

Problem: Operators in an east-central Missouri city wanted better digester performance in the cold months, when low volatile solids destruction and frozen soils did not allow land application of biosolids. The team wanted better settling, increased decant and more digester space.

Solution: After six months of trials, the operators discovered that BIO ENERGIZER from Probiotic Solutions could accelerate endogenous respiration by improving cell wall permeability, thus increasing biomass metabolism and reducing volume.

Result: The product created nearly 85 percent volatile solids destruction in 27 weeks and improved decants. It led to greater digester capacity, better settleability and better overall digester operation. 800/961-1220; www.probiotic.com.

Building erected to house hydrofluorosilicic acid

Problem: Treatment facilities in Sacramento County, California, disinfect with sodium hydrochloride and fluoridate using hydrofluorosilicic acid. Both hazardous chemicals needed to be confined; hydrofluorosilicic acid and the fumes emitted during the fluoridation process erode surfaces. Since both processes happen at the well site, the equipment needed to be contained separately.

Solution: Sacramento County Water Agency turned to Shelter Works to upgrade 32 old redwood buildings. “It was important that they work with a company that had specific quality-control procedures in place,” says Tracy Switzer, Shelter Works president. “The interior partition wall created an airtight environment that met their needs perfectly.”

Result: Nine shelters were placed at water treatment plants and 23 at well sites throughout the county. Being located in residential neighborhoods, they had to be attractive as well as corrosion-resistant. Shelter Works supplied a series of multi-room fiberglass buildings to contain fumes in one room and allow other equipment to be protected in another room. Airtight partitions separate the equipment and protect each from harmful effects of the other. 800/794-8037; www.shelterworks.com.


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