Ceramic membrane system solves disinfection byproduct challenge

Problem

In 2010, a pine beetle infestation at the Basin Creek Reservoir in Butte, Montana, killed most of the surrounding trees, many of which fell into the water, increasing the organic matter level. The Butte-Silver Bow Water Utility received a violation notice from the state Department of Environmental Quality for exceeding its maximum contaminant limit for a certain type of disinfection byproduct. To maintain the use of the reservoir, filtration had to be added.

Solution

The utility procured Aqua MultiBore C-Series ceramic membrane system from Aqua-Aerobic Systems. It consists of four trains, each with 100 modules arranged in ten 10-module rows. The backwash water is settled and treated with a backwash recovery train of two six-module rows. For both systems, each row has a complete set of valves and operates independently. Backwashes and cleanings are performed on one row at a time while the others remain in service. Jim Keenan, chief operator, says, “It saved a lot of infrastructure cost and a lot of pumping cost — that was a big advantage of this design.”

Result

At the 7 mgd design flow, the plant wastes less than 14,000 gallons, close to zero liquid discharge. “We’ve been really pleased with how well the system works and how efficient it is,” Keenan says. 815-654-2501; www.aqua-aerobic.com

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Carbon provides PFAS solution for Air Force base 

Problem

Eielson Air Force Base southeast of Fairbanks, Alaska, had perfluorooctanoic acid and perfluorooctane sulfonate (also called PFOA and PFOS) in drinking water that were above the U.S. Environmental Protection Agency health advisory. 

Solution

After considering options, the base leaders chose treatment with bituminous reagglomerated activated carbon. Testing determined that Calgon Carbon’s FILTRASORB 400 and Model 10 GAC adsorption systems could supply contaminant-free drinking water cost-effectively.

Result

After two systems showed great success, the base added two more systems. Since then, per- and polyfluoroalkyl substances (PFAS) have been undetectable. 800-422-7266; www.calgoncarbon.com

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Membrane system allows fish farm to treat and reuse wastewater

Problem

The owner of a large Midwest fish farm needed to treat and reuse wastewater from its processing plant to prevent high-strength wastewater surcharges. Feedwater for the application test consisted of wastewater from a fish processing waste stream with 3,300 ppm COD.

Solution

Cerahelix installed a single-stage system using five 1-meter, 19-channel membranes. Its picofiltration process — filtration with molecular weight as low as 400 Daltons — provides filtration at the molecular level and opens the door to new applications of ceramic membrane technology, while minimizing lifetime costs. The process uses a DNA template to form the pores that filter the water, controlling the pore size to extend the range of treatment applications for ceramic membranes from nanofiltration to high-purity picofiltration.

Result

Results of the test, with no pre- or post-treatment, showed a reduction in COD over 99.9%. 800-604-0697; www.cerahelix.com

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Extended aeration package plant specified for power plant wastewater 

Problem

A coal-fired power plant in northern Indiana needed a new wastewater treatment system. The plant is a zero-liquid-discharge facility; all wastewater streams are returned to a 3,000-acre cooling pond.

Solution

Delta Treatment Systems provided a turnkey extended aeration package plant installed below grade at a design flow rate of 40,000 gpd. The system treats domestic wastewater less than 25 mg/L CBOD, 30 mg/L TSS and 125 cfu/100 mL fecal coliform. A lift station pumps the wastewater to the treatment system. A heavy-duty grinder at the receiving end reduces solids particle size. The design includes a flow equalization chamber to maintain consistent flow rates to the secondary treatment chamber during peak hours via time-dosed duplex nonclog submersible pumps. Duplex blowers are in fiberglass housings, and a control panel communicates with the operations room on site.

Result

Delta Treatment Systems supplied all equipment necessary for proper operation. Water levels are continuously monitored with a VEGAPULS liquid level radar system. The system operates consistently and meets effluent requirements. 800-219-9183; www.deltatreatment.com

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Injection process enables iron removal from groundwater 

Problem

In 2008 the City of San Angelo, Texas, was dealing with significant radium and iron in the water from the Hickory Aquifer wellfield. Ion exchange technology was chosen to remove the radium, but first the iron had to be removed to avoid fouling of the ion-exchange resin. This meant oxygenating the raw water while removing undissolved gas bubbles — all without breaking pressure. 

Solution

The GDT sidestream injection process and pipeline flash reactor from Mazzei Injector were selected to aerate, oxygenate and remove remaining gas bubbles in the wellfield’s pressurized pipeline. The highly oxygenated effluent exiting the system is blended back into the wellfield’s pipeline at a minimal pressure loss of less than 0.30 psi. The Hickory Aquifer Groundwater Treatment Facility typically had a flow rate of 2 to 8 mgd and pressure of 80 to 100 psi.

Result

After aeration, the pipeline flow passes into pressurized detention tanks for 15 minutes to provide time for the insoluble ferrous iron to be oxidized to its insoluble ferric state. Media filtration then removes the oxidized iron, enabling the mainline flow to pass through the ion exchange beds for radium removal with no fouling issues. 661-363-6500; www.mazzei.net

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Combined gravity settler and continuous media filtration systems used at pollution control facility

Problem

The Cherokee County Water and Sewer Authority needed to achieve an effluent total phosphorus level of less than 0.14 mg/L at the Fitzgerald Creek Water Pollution Control Facility in Woodstock, Georgia. The plant treats municipal and poultry processing plant wastewater with an average daily flow of 5.0 mgd.

Solution

After extensive on-site pilot testing, the authority chose an integrated design with Parkson Corp.’s Lamella gravity settler and DynaSand continuous backwash media filter. The gravity settler in a plate pack configuration includes Parkson Corp.’s EcoFlow technology, enabling 100% plate surface area utilization. Clarified water essentially free of TSS is then directed by gravity to the DynaSand filter modules for polishing. The single-stage, deep-bed filter system can achieve limits well below 0.14 mg/L total phosphorus.

Result   

The system continually delivers water quality of less than 0.1 mg/L ammonia, less than 0.07 mg/L phosphorus and less than 0.5 NTU. The plant consistently goes well below its NPDES permit requirements. 888-727-5766; www.parkson.com

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Aeration tank odor eliminated using pure oxygen injection

Problem

A Midwest meat-processing plant’s wastewater pretreatment facility produced an odor linked to insufficient dissolved oxygen in the first of three aeration tanks. Hydrogen peroxide had been used to control odor, but it was costly and of suspect effectiveness. The addition of new aeration equipment was constrained by the aeration tank’s structural cover.  

Solution

Praxair demonstrated that odor could be eliminated through restoration of aerobic conditions in the first aeration tank. The shortfall in oxygen transfer could be corrected through injection of pure oxygen into the recirculating waterline of the jet aeration system of that tank. A demonstration showed that DO above 0.5 mg/L could be maintained for about half of the day, eliminating the sulfide odor.

Result

The cost of adding pure oxygen was less than the previous approach. The plant expected savings of 74%. 800-772-9247; www.praxair.com

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Facility installs MBRs for increased capacity and water reuse 

Problem

The Santa Ynez Band of Chumash Indians operates a hotel and casino in California. Wastewater used to be treated by a sequencing batch reactor and sand filtration. As the hotel and its vicinity grew, the SBR capacity was exceeded, requiring an upgrade. Because the area is subject to drought, hotel expansion required water reuse.

Solution

The band evaluated expansion of the SBR and abandoning the SBR in favor of a membrane bioreactor. An engineering study showed an MBR construction cost of $3.3 million versus $5.3 million for the SBR. Econity MBRs from Schwing Bioset were selected, and the system was built using two containers to minimize disruptions to current plant operations and to fit in the available space.

Result

The facility’s capacity has increased significantly. Effluent turbidity (0.05-0.2 NTU) exceeds California Title 22 requirements for reuse water. 715-247-3433; www.schwingbioset.com

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Disc filter system allows facility to maintain capacity

Problem

The 6 mgd activated sludge wastewater treatment plant in Camas, Washington, sought to replace its cloth media disc filters, as its pile cloth fabric experienced excessive fouling over time. The cloth was difficult to clean and maintain. The site needed a low-maintenance solution that would fit the existing filters’ footprint and hydraulic profile.

Solution

Gray & Osborne designed the filter upgrade based on Veolia Water Technologies’ Hydrotech Discfilter system. The compact footprint and low headloss fit the available space and allowed for easy cleaning and maintenance. The filters include an automatic cleaning system. The control system automatically regulates the supplemental chemical cleaning process to remove foulants, enabling the filter media plant to maintain optimal capacity.

Result

The system has run effectively since commissioning in 2013. The staff can easily maintain and operate the system. The filters meet effluent performance requirements and maintain the required flow-through capacity. 919-677-8310; www.veoliawatertech.com