Hybrid system used to alleviate odor concerns

Problem

A wastewater treatment plant outside of Charleston, South Carolina, was expanding and the existing headworks facility was being relocated. During construction, odor from the influent pump station was a major concern.  

Solution

Anua delivered a multistage prepackaged odor control system. The 3,700 cfm AiraHybrid system uses a two-stage process. The first stage, a biotrickling filter using engineered AiraGlass media made from recycled glass bottles, treats hydrogen sulfide. The second stage uses activated carbon media.

RESULT:

The system was completely shop-assembled, prewired, preplumbed, skid-mounted and shop-tested before shipping. It has performed as expected, mitigating odors. 346-225-8033; www.anuainternational.com

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Natural flocculent dewaters sludge and reduces polymer usage

Problem

The wastewater treatment plant in Lovington, New Mexico, had settling problems in the sequencing batch reactor tanks. They were overloaded with solids but were wasting mostly water. The 2.5 mgd (design) plant has an average flow of 1.3 mgd. There are two SBR tanks, two aerobic digesters and a screw press (HUBER Technology) for biosolids dewatering.

Solution

BICI Chemicals supplied AT-318 and Aqua Aide treatments. AT-318 is a natural flocculent and settling aid. The two products reduced phosphorus, controlled filamentous bacteria bulking and helped dewater sludge. To start the process, BICI Chemicals applied a shock load of both products. The plant staff then started daily dosing, and within a couple of days, the solids were settling. The waste flow to the digesters increased from 0.5% to 2% solids.

RESULT:

FOG and filamentous bacteria have become almost nonexistent, solids settle well in the SBRs, and polymer usage in the screw press decreased by 25%. “AT-318 and Aqua Aide keep working after being activated,” says Miguel De La Crus, plant superintendent. “We had to reduce the daily dosing to only four days a week. The solids in our digester were thickening so much that our screw press was having trouble pumping them for dewatering.” 918-720-2066; www.bicichemicals.com

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Aerators enable BOD removal in wastewater lagoon

Problem

Kansas Dairy Ingredients was faced with fines exceeding $65,000 per month from the City of Hugoton for excess BOD and FOG, low pH and high TSS. To address these and future issues, the city constructed a 2-acre poly-lined lagoon that’s 12 feet deep to treat the waste stream. BOD discharge was more than 8,000 pounds per day, FOG was higher than 95 ppm, pH was 3.1 to 4.2, TSS was higher than 2,900 ppm and odor was extreme.

Solution

DO2E Wastewater Treatment supplied a 4 hp Little John Digester with four tubes of advanced oxidation processing in a lift station between the Kansas Dairy Ingredients plant and lagoon. Each tube of ozone produces 0.5 grams of ozone per hour, delivered to the waste stream through the digester. Each aerator delivered 650 scfm, transferred 18.9 mgd and produced 2.85 pounds of oxygen/hp/hour.

RESULT:

The pH stabilized at 7.65, and critical testing began. The first goal was to condition the effluent to hold its highest levels of dissolved oxygen. DO quickly increased from 0.65 ppm to 2.85 ppm, and over the next six months, it steadily climbed to 4.6 ppm, where it remained. 850-698-6805; www.do2e.com

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System solves waste treatment challenges for rural town

Problem

The rural Alabama town of Section (population of 770) sought an effective and relatively maintenance-free wastewater treatment solution.

Solution

The town installed a two-phase, 30,000 gpd ECOPOD-D system from Delta Treatment Systems that is designed for expansion. The first phase treats 30,000 gpd at 300 mg/L of both BOD and TSS and handles an average daily flow fluctuation of 50% to 100%. The units were installed in poured-in-place concrete tanks with aluminum hatches. A 14,208-gallon flow equalization tank stores wastewater and doses it to the treatment system. The equalization tank includes duplex pumps to prevent flow surges. A 19,190-gallon primary tank precedes the equalization tank. Effluent is UV disinfected. A drip disposal system, also from Delta, includes an effluent pump chamber, headworks, tubing, controls and all valves and fittings. A concrete building on site houses electrical controls and equipment. 

RESULT:

The system is automated and requires minimal operator attention. It meets effluent requirements and has served as a training site. 800-219-9183; www.deltatreatment.com

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Encapsulated enzyme reduces sludge in wastewater lagoon

Problem

The wastewater treatment lagoons in Hennessey, Oklahoma, had trouble with suspended solids, excessive sludge, high COD, odor, stagnant/flat water and black mold. Their average daily flow was 160,000 gpd, and the six-lagoon system discharged through land application.

Solution

IMR Lagoon Systems supplied a turnkey lagoon maintenance and restoration program. A drip meter was installed at a lift station where the chemicals are delivered every 30 minutes. The encapsulated enzyme does not cannibalize itself and only works when introduced to bacteria. IMR Lagoon Systems staff visits the lagoons every other month to refill the chemicals, take COD, DO and pH readings, and make sure all is working properly.

RESULT:

After one year, the water was a healthy emerald green, no odor was present and TSS was eradicated. “Within the first three months, we began to see a noticeable change in the clarity of our water,” says Curtis Turner, Public Works director. “Since the rise of our DO, we were able to reduce the time we run our aerators. That has saved on electricity cost.” 918-720-2066; www.imrlagoonsystems.com

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Mixing system defeats biogas digester crust

Problem

A thick crust was hampering biogas operation at a Danish hog producer after problems with propeller stirrers.

Solution

Landia first lent a 30-kW digester mixing system as a temporary solution. In a short time, the facility staff saw improvement. The retrofit was simple, and slowly but surely the half-meter-thick floating layer was gone.

RESULT:

The digester has trouble-free circulation, and the staff can save energy by switching off the Landia equipment during the daytime. The facility is seeing 15% to 20% faster turnover. 919-466-0603; www.landiainc.com

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Venturi technology used to alleviate taste and odor issues

Problem

The North Texas Municipal Water District needed to add ozone at the Wylie Water Treatment Plant to satisfy regulatory requirements to control disinfection byproducts and remediate taste and odor problems caused by seasonal algae blooms at Lake Lavon.

Solution

Venturi sidestream injection technology from Mazzei Injector was chosen to minimize the size and maintenance of the 11 ozone contact basins that would treat a future maximum 890 mgd. To ensure the ozonated effluent was well-mixed into the raw water, basin inlet channels were constructed to allow confined-space gas mixing of all incoming water with a single basin nozzle manifold. To provide turndown, each manifold can operate with either a single or dual injection system. 

RESULT:

Each contact basin has single-nozzle manifold with two duty and one standby injector. The final design operates at an energy cost of 0.99 kW/kg of applied ozone at the peak ozone design dosage of 3.5 mg/L. Plant operators can fine-tune ozone dosage in response to algae blooms. 661-363-6500; www.mazzei.net

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Food production facility meets discharge limits with compact system

Problem

Hempler’s Foods in Ferndale, Washington, needed to treat meat processing wastewater with high BOD and TKN to meet discharge limits.

Solution

Nijhuis Industries provided a compact solution for production line and smokehouse wastewater. The system consists of a static curved screen, primary dissolved air flotation, flow equalization and smokehouse storage tanks, continuous aerobic biological treatment, dissolved air flotation for sludge thickening, and a chemical dosing system.

RESULT:

The system discharges effluent with BOD and TKN well below the discharge limits, resulting in minimal impact to the local wastewater treatment plant. The system is designed for expansion. The system can reduce BOD by up to 95% and TKN by up to 90%. 312-300-4101; www.nijhuisindustries.com

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City successfully tames disinfectant residual variability in distribution network

Problem

Southlake (Texas) Water Utilities services a growing community of more than 30,000 and purchases chloramine-disinfected water from Fort Worth. With no treatment plant, it has a limited ability to control disinfectant residuals in the distribution network. Operations personnel examined techniques to improve disinfectant residuals throughout the system. They focused first on the seven water storage tanks. 

Solution

Kyle Flanagan, water supervisor, thought a two-step process might be ideal; adding tank mixers first would provide systemwide improvement, and he could then more precisely determine which tanks and pressure zones would benefit from more active disinfectant residual control. Southlake installed seven PAX Water Technologies tank mixers in the four elevated storage tanks and three ground storage tanks. Immediately, the system reached equilibrium with a more stable systemwide disinfectant residual.

RESULT:

Southlake staff now can more precisely determine the location and quantity of the disinfectant residual boosting stations. By installing the mixers first, Southlake was able to install two boosting locations instead of the originally anticipated seven. “The mixers immediately improved the uniformity of our water and allowed us to more thoughtfully add more active water quality improvement measures,” Flanagan says. 866-729-6493; www.paxwater.com

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Mixer reduces grease buildup and high solid slug loading to treatment plant

Problem

The Random Farms Wastewater Treatment Facility in Chappaqua, New York, faced issues related to pump station grease buildup, solids settling and pump clogging.

Solution

C3ND Environmental Consulting installed PHi-Constant Air from Pulsed Hydraulics within 2 inches of the bottom of the pump station to provide a full mix of the wet well, eliminate sedimentation buildup and remove residual grease at the surface and that accumulated on floats.

RESULT:

The residual grease at the surface was removed, and the complete mix enabled transfer of sedimentation through the station to the wastewater treatment plant. Within one week, residual grease accumulation on the pump floats and appurtenances was removed, enabling consistent pump operation. The installation eliminated the task of grease and debris removal every two to three months. The system paid for itself within six months. The pump station also has less odor and less maintenance related to ragging of the pump impellers. 800-641-1726; www.phiwater.com

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System designed to reduce struvite buildup

Problem

The 30 mgd Tres Rios Water Reclamation Facility in Pima County, Arizona, experienced severe struvite buildup in pipelines and equipment after anaerobic digestion. A combination of ferric chloride addition and dilution water in centrate return lines was used to slow the buildup. The facility sought a more efficient method.

Solution

The county selected the integrated phosphorus management system from Schwing Bioset/NuReSys to convert orthophosphate into struvite and eliminate the need for dilution water and ferric while reducing return phosphorus loads to the facility. The two-stage process controls pH in the first stage and precipitates struvite in the second stage, allowing precise process control. 

RESULT:

Orthophosphate levels are reduced from 150 mg/L to 40 mg/L, preventing struvite scaling. The phosphorus return load has been greatly reduced and so has polymer consumption for biosolids dewatering. Struvite sequestered in biosolids increases phosphorus availability and so enhances the fertilizer value. The system has flexibility to convert to hybrid operations in the future, enabling the processing of dewatering centrate and high harvest rates of the produced struvite. 715-247-3433; www.schwingbioset.com

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Plant adds oxidation ditch to meet nutrient removal requirements

Problem

The wastewater treatment plant in Lawrence, Kansas, did not include the capacity for removing nitrogen and phosphorous to meet new permit limits. The city also needed capacity for future population growth.

Solution

Consulting engineers selected a WesTech Engineering OxyStream oxidation ditch with biological nutrient removal. The ditches use an anaerobic area to increase phosphorous uptake. They also include a pre-anoxic zone that uses the system’s nitrate-recycle stream to remove nitrogen as a gas and a post-anoxic zone that uses internal respiration to remove remaining nitrate.

RESULT:

The plant (average flow 3.6 mgd) delivers efficient aeration and mixing while removing phosphorus to levels below 0.5 mg/L. 801-265-1000; www.westech-inc.com