Case Studies - February 2022

Case Studies - February 2022

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No more manual raking for pump station operators

Problem

The Louisiana Pump Station in Tampa, Florida, moves up to 35 mgd. It needs high-quality equipment keep debris from getting to the river Hillsborough River and to perform in hurricanes and heavy rains than can cause storm surges and flooding. The facility’s manual bar screen with 2.5-inch spacing allowed smaller debris to pass. Operators had to clean the screen manually as often as three times a day. 

Solution

The city chose an Aqualitec Heavy Duty Screentec vertical bar screen. With its 90-degree angle installation, it fits almost all headworks, pump stations, lift stations, wet wells and manholes. Due to constraints of the site, there was no way to build a new well, but the screen installed seamlessly in the existing 30-foot-deep wet well.

Result:

The screen only solved the clog issues and eliminated potential safety hazards for operators. 310-703-2174; www.aqualitec.com


Biosolids and odor challenges mitigated at plant

Problem

The 1.0 mgd wastewater treatment plant in Weyburn, Saskatchewan (population of 10,000) had biosolids piles above the waterline in its main settling pond and continuous biosolids problems in its multiple storage lagoons. This created severe odor problems and chronic resident complaints. Frequent flushing of mainlines for heavy FOG and fatberg buildup was also burdensome.

Solution

Vital Utilities set up an EBS-Di unit from Enbiorganic Technologies in one lift stations. The unit uses a customized active-state soil microbiology tailored to the city’s wastewater. The formulation is autonomously delivered to the collection system in a process that generates and activates the microbiology.

Result:

The facultative anaerobic and highly adaptable organisms immediately went to work. Within 30 days after installation city staff saw evidence of 20% biosolids removal, nearly 100% odor eradication and a significant reduction in FOG and fatbergs. Within 60 days, the frequently mainline flushing was eliminated, the biosolids piles disappeared and build-up in the corners of the main lift station was gone. Lab analysis reported other changes that translate to reduced retention time and lower cost per volume treated. 888-356-8333; www.enbiorganic.com


Facility makes dewatering upgrade with rotary press

Problem

The City of Pittsfield, Massachusetts, had to reduce effluent phosphorus discharges to the Housatonic River. The addition of tertiary treatment was projected to generate 20% more sludge; a dewatering upgrade was crucial.

Solution

Fournier led a tour of several rotary press installations in New England. “The first thing we liked of the Fournier Rotary Press was that it’s totally enclosed, clean and contains odors,” noted Carl Shaw, superintendent. “Operators did not need to babysit the equipment. We appreciated that the units were built of several chambers, providing redundancy.” The city installed four rotary presses, each with six modular watering chambers, in 2020.

Result:

The presses run six to seven hours, five days per week, processing an average of 59,000 gpd. Five to seven dry tons of cake leave each day at 18-23% solids. With the major process upgrades going on in our plant, we’ve been working with a whole lot of vendors,” says Shaw. “We’ve been very pleased with Fournier’s service and responsiveness.” 418-423-4241; www.fournierdewatering.com


Dewatering unit solves problem caused by municipality’s COVID-delayed centrifuge rebuild

Problem

A Midwest U.S. city’s wastewater treatment plant had delayed a rebuild of its only centrifuge because parts were unavailable during the COVID pandemic. The city needed to remove biosolids that were accumulating each day.

Solution

City staff contacted a contractor with a mobile dewatering unit from In the Round Dewatering. The dewatering drum was unloaded from the roll-off truck and set on the concrete pad with a center drain for sending water back to the headworks. Within a few minutes, the 3-inch hose was connected to the drum, polymer had been injected, and the biosolids were rapidly floccing. Once the drum was full, the hose was unhooked and the drum rotated until the next morning at about one turn per hour. The drum uses a 1/4 hp motor, making it efficient to operate.

Result:

In the morning the liquid-free biosolids were unloaded in a roll-off box for landfilling. This process was repeated until the centrifuge was back in operation. On average, 18,000 to 25,000 gallons per run were dewatered, generating 9 to 11 tons of material hauled off each day. 317-563-2072; www.itrdewatering.com


Treatment plant gains flexible biosolids thickening system

Problem

The Brockville (Ontario) Wastewater Treatment Plant faced stricter effluent limits, resulting in biosolids volumes that overwhelmed digester capacity. The city had a choice to build another digester for $2.9 million or add two rotary drum thickeners for less than $1 million.

Solution

JWC Environmental installed two Monster Drum Thickeners for their low maintenance, easily removable wedgewire or mesh panels, and adaptive controls to compensate for variable flow and solids content. The plant team estimated a daily additional 20 to 30 cubic meters of primary sludge (3-4% solids), along with 200 to 250 cubic meters more waste activates sludge (0.5% solids). The thickeners converted the waste activated sludge into 20 cubic meters at 5% solids, meaning less water sent to the digesters. The digesters now handle a total of 40 to 50 cubic meters more per day, within their capacity.

Result:

The plant met its effluent limits without building a new digester, avoiding more than $2 million in cost. 800-331-2277; www.jwce.com


Screw press a fit for pressure sensitive waste

Problem

A tofu manufacturing facility in the northeast U.S. to dewater a 50-50 blend of waste activated sludge and primary tofu waste, a highly pressure-sensitive sludge.

Solution

A Model MWP-240 Multi~Wave Screw Press from Komline-Sanderson was commissioned, with feed solids 3-5%. The press dewaters pressure-sensitive sludges such as waste activated and oily sludges without blinding or poor capture rates. Instead of a cylindrical screen, alternating fixed and moving rings are stacked to form a cylinder in which the screw is inserted. As the screw rotates, the rings rise and fall as they ride on the screw, creating a continuous self-cleaning action. The cylinder is set at an incline to speed liquid evacuation; and the solids are progressively stabilized as they move toward the discharge end. 

Result:

The equipment achieved an average 650 dry lbs/hr throughput and cake 25% solids. Previously liquid sludge was hauled out in tanker trucks; dewatered material is now hauled in dump trucks at a significant savings. 800-225-5457; www.komline.com


Decanter centrifuges remove flume solids from water used to convey beets to sugar factory

Problem

A sugar factory in Bay City, Michigan, needed to remove flume solids from water used to convey beets to a sugar factory. Near the end of processing campaigns, when beets deteriorate and lime salts increase, the facility struggled with the purification process.

Solution

Three Mammoth Decanters from Pieralisi North America now remove beet residual solids from the flume water at an average of 80 dry tons per day. Flume water typically contains 2.5-3.5% solids. The factory settles those solids out through a flume clarifier and a series of settling ponds that need to be cleaned out annually. Residual solids are mixed with water down to a 20% concentration, pumped into tanker trucks, transported to fields and injected into the soil. Decanter centrifuges separate much of the flume solids from the water before it reaches the settling ponds, minimizing pond cleaning.

Result:

The high centrifugal force induced by a high-speed drum enables efficient sedimentation or separation of the liquid and solids. This material has a moisture content of less than 50% and is being sold as a co-product. 513-707-2946; www.pieralisinorthamerica.com


Rotary fan press leads to simplicity in city’s dewatering

Problem

When the Cambridge, Ohio wastewater treatment plant needed to move from drying beds to a more efficient and effective dewatering process, they did their homework. 

Solution

They decided the Prime Solution Rotary Fan Press was the simplest and most effective solution for their dewatering needs. Chris Jamiel, Site Superintendent, says the selection of the Rotary Fan Press was made not only on price, but also on simplicity of use and simplicity of maintenance. “It is pretty simple and compact to work on if you need to, but you really do not need to, as maintenance is at a minimum,” he says. “There are some things that may wear over time, especially when you run the amount of sludge we do and how abrasive our sludge is, but major repair-wise there has been nothing and we have had it for eight years.”

Result:

After installation they went from 10% to over 21% solids, equating to, in their words, “a lot of savings.” When they decided to upgrade their capacity this year, a second rotary fan press was an easy decision. 269-694-6666; www.psirotary.com


Products helps improve solids handling treatment at plant

Problem

The team at a 60 mgd wastewater treatment plant in northern New Jersey wanted to improve cost structure in the solids treatment section due to rising chemical treatment and landfill costs.

Solution

Adding BAE from Prodex to the digested solids at the plant’s gravity belt thickeners produced higher cake solids, a cleaner return stream, and lower disposal costs.

Result:

The product achieved annual savings of $353,000 on re-treatment costs; less polymer was required for dewatering. A reduction of 2.28 tons per day of sludge cake significantly reduced tipping fees. 856-234-4540; www.prodexproducts.com


Dryer helps reduce biosolids hauling risks

Problem

The City and Bureau of Juneau (CBJ) produces 7,000 wet tons of dewatered biosolids each year, hauled 1,300 miles by truck, barge and train to the Columbia Ridge landfill in Arlington, Oregon. This was costly, and CBJ faced uncertainty over environmental regulations.

Solution

Veolia’s BioCon medium-temperature belt dryer met CBJ’s four guiding principles for selection. The Class A EQ biosolids process provides pathogen reduction and expands the range of uses to include landfill cover material, fertilizer for community sites and parks, erosion control and topsoil replacement. These options offer potential for a significantly lower end-to-end cost.

Result:

The dryer is designed for 36 wet tons per day and will produce 5.5 tons of dried product, an 85% reduction in volume and weight. This means less truck traffic, lower emissions, less noise and lower costs. 919-677-8310; www.veoliawatertech.com   



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