Injection system helps clear odor issues from pump station
Problem: Hydrogen sulfide at 1,000 ppm at the Forest Hills Pump Station in Pikeville, Kentucky, was creating a nuisance odor, corrosion issues and a possible health risk. The station was at a major intersection across the street from the high school and football stadium. The city had tried chemicals and other odor controls, none of which worked.
Solution: The Mountain Water District chose a Phantom Odor Control System from Anue Water Technologies. The system continuously injects ozone and oxygen into the well to break up FOG and reduce hydrogen sulfide.
Result: The hydrogen sulfide level dropped to 9 ppm after the first day and to zero the second day. The system also broke up the FOG, eliminated odors and resolved the corrosion issues. Chemical treatment costs were eliminated. 760/727-2683; www.anuewater.com.
Cloth media filter helps reduce power consumption
Problem: In December 2015, Talladega, Alabama, underwent an upgrade to its tertiary filtration to comply with an effluent TSS limit. The existing microscreen filters were no longer serviceable due to plugging and leaking of solids.
Solution: The city replaced the microscreens (12 mgd capacity) with two eight-disk Aqua MegaDisk Filters using an OptiFiber PES-14 Pile Cloth Media from Aqua-Aerobic Systems. The filters were easily retrofitted into existing tankage and hydraulic profile.
Result: The filters increased capacity by 4 mgd in a smaller footprint, reducing power consumption. Better turbidity and TSS removal improved disinfection. The filters will accommodate growth of the city and will meet tighter permit requirements. 815/654-2501; www.aqua-aerobic.com.
Efficient blowers provide air injection into aeration tanks
Problem: The Schlammersdorf-Vorbach sewage treatment plant processes household wastewater for 2,900 residents in two communities in Germany. In summer 2015, the plant’s two blowers failed.
Solution: The plant installed two Tyr blowers supplied by Busch Vacuum Pumps and Systems. The blowers deliver intermittent overpressure at 0.5 bar with constant volume flow. As the maximum pumping speed is required only in cases of extreme contaminant load, the control system is programmed to operate both blowers at two speeds without frequency converters. This means the total pumping speed may be set to four levels, saving energy. The control system runs the blowers for up to 12 hours a day. Control of dissolved oxygen is automated.
Result: Personnel costs have been reduced by the automation and the participation of the Grafenwoehr utility company, which receives plant alarm messages. After a year, the utility company expressed complete satisfaction. 757/463-7800; www.buschusa.com.
Efficient mixing system helps community receive Green Project Reserve funding
Problem: The Mount Pleasant (South Carolina) Waterworks Center Street Wastewater Treatment Plant was upgraded to improve treatment and increase capacity. The upgrade included replacing inefficient positive displacement blowers and coarse-bubble aerated mixing in the flow equalization basin.
Solution: BioMix Compressed Gas Mixing technology from EnviroMix was installed to provide anoxic mixing in two biological nutrient removal selector basins.
Result: The project was funded through South Carolina’s State Revolving Fund program, and the work related to the design and installation qualified for Green Project Reserve (GPR) funding with a 1 percent interest rate loan versus the standard 1.8 percent. The solution reduced power demand by 70 percent. 843/573-7510; www.enviro-mix.com.
Lagoon system helps clean up discharge
Problem: The old three-cell 0.302 mgd aerated lagoon in Miner, Missouri, had high suspended solids and ammonia and nitrogen concentrations above targets. The discharge needed to be cleaned up to comply with state and U.S. EPA regulations.
Solution: Environmental Dynamics International proposed an Intermittently Decanted Extended Aeration Lagoon (IDEAL) to provide full nitrification while removing a majority of total nitrogen through denitrification. The process uses two ponds, the IDEAL for advanced treatment followed by a partial mix basin with a settling zone for sludge storage and solids separation, shrinking the plant while improving efficiency and effectiveness.
Result: Ammonia has averaged 27 mg/L in influent and drops to less than 0.05 mg/L by discharge. No sample has come in above the method detection limit, even when the temperature in the unit dropped below 37 degrees F. BOD dropped from 230 to 4.5 mg/L and TSS from 104 to 5.3 mg/L. Total nitrogen dropped 66 percent from 32 to 11 mg/L. 573/474-9456; www.environmentaldynamics.com.
Automation helps treatment facility save costs
Problem: In 2015, a 30 mgd water pollution control facility in New England completed upgrades to meet the anticipated NPDES permit for nutrients. The new permit included discharge standards for nitrogen and phosphorus that were more stringent than the design basis for the upgraded biological nutrient removal system.
Solution: The facility retained EOSi to study denitrification with MicroC 2000A, a glycerin-based supplemental carbon, in one of the four treatment trains. EOSi provided inline analyzers, a chemical storage tank and pumping equipment for the evaluation study, as well as an automatic feeding system using a Nitrack Controller to optimize the supplemental carbon usage. The company’s technical staff continuously monitored key process parameters, optimized setpoints, and modified the process control strategy.
Result: The selected treatment train consistently achieved effluent total nitrogen concentrations lower than the permit requirement. Automation ensures that internal COD in the primary effluent is used for denitrification when available, minimizing supplemental carbon costs. The facility staff expanded the supplemental carbon program to all four biological treatment trains. 866/642-7621; www.microc.com.
Cloth media filters increase operational efficiency
Problem: A wastewater treatment plant outside New Bern, North Carolina, had failing packaged sand filters, requiring extensive maintenance on the mechanisms. The plant had recently upgraded from chlorination to UV disinfection, but effluent showed inconsistent TSS and fluctuating turbidity.
Solution: The operating company, with local regulators and engineers, installed Fluidyne Fixed Plate (FFP) cloth media packaged filters. The system uses simple open-close pneumatic valves along with gravity to control filtering and backwash. No pumps are needed to create backwash flow, allowing media panels to remain in place at all times instead of being rotated past a stationary spray or suction manifold. This eliminates moving parts and wear items and allows the elements to be square or rectangular (versus circular), easing manufacture, installation, removal and maintenance, while maximizing treatment area. Media elements can be independently isolated and removed without discontinuing flow to the entire filter or diverting flow during routine maintenance or inspections.
Result: Plant personnel were satisfied with the treatment system for its ease of use and maintenance and low cost to purchase and operate. 319/266-9967; www.fluidynecorp.com.
Combined processes provide reliable biosolids receiving
Problem: In 2010, Emerald Coast Utilities Authority (ECUA) in Pensacola, Florida, finished a rebuild after Hurricane Ivan and no longer had a biosolids receiving facility. This presented a problem in light of the authority’s grease trap ordinance and the need to provide a site for off-loading of biosolids.
Solution: ECUA selected Huber Technology to provide a complete solution using the RoFAS center-feed drum combined with rock trap, screenings wash press and grit trap as one integral unit.
Result: The solution performed reliably, handling anything brought into the system. The large-capacity automated facility enabled haulers to quickly and efficiently off-load. Plant staff was pleased to provide an environmentally safe receiving station. 704/949-1010; www.huberforum.net.
Deammonification system helps city meet nitrogen limits
Problem: The South Durham (North Carolina) Water Reclamation Facility needed to meet a total nitrogen limit of 3 mg/L at design flow to comply with the total maximum daily load in the Jordan Lake Watershed. The facility uses anaerobic digesters followed by belt filter press dewatering. The liquid from dewatering accounted for about 20 percent of the nitrogen load in the plant’s BNR process.
Solution: The city determined that ANITA Mox sidestream deammonification technology from Kruger USA would cost three times less per pound of nitrogen removed in capital and operating costs. It uses about 60 percent less oxygen, requires no external carbon source, produces less biosolids and is based on the moving bed biofilm reactor platform. The system consists of engineered polyethylene carriers (AnoxKaldnes K5 media) to provide protected surface for biofilm growth.
Result: The system was started up in 12 weeks. Now operating full scale, it achieves more than 80 percent ammonia removal and 70 percent total inorganic nitrogen removal, helping meet strict nitrogen limits. 919/677-8310; www.veoliawatertech.com.
Hydrolysis process helps city produce marketable fertilizer
Problem: With a capacity of 7.2 mgd, the Water Pollution Control Plant in St. Thomas, Ontario, discharges to the local waterway under strict Ministry of Environment requirements. City leaders were concerned with the general health and shape of the digesters, and wanted a more sustainable, year-round management solution.
Solution: City staff chose the Lystek International Thermal Hydrolysis Process. The technology uses a physical/chemical process to produce a fully marketable, federally registered, Class A biofertilizer called LysteGro. This system can also be used to create LysteCarb, an alternative source of carbon for use in BNR systems. “The technical criteria were proven through a peer review of existing installations,” says Justin Lawrence, director of environmental services and city engineer. “The environmental and social benefits are primarily the reuse of bionutrients and a greatly improved odor control system.”
Result: “The lower life cycle capital and operating costs create a significant savings, and we can also improve our capacity in the biosolids system,” says Lawrence. The $10 million project enables the city to divert biosolids from landfill. 888/501-6508; www.lystek.com.
Injection system helps city meet effluent DO goal
Problem: The Hagerstown (Maryland) Wastewater Treatment Plant used ozone produced by an oxygen-fed ozone generator for disinfection. Effluent discharged to a creek contained dissolved oxygen levels that met regulatory standards. Once the plant converted to UV disinfection, the regulatory agency was concerned about the impact of discharging effluent with a lower level of DO.
Solution: Since the compressors and oxygen concentrators that were used in the old system still worked, the plant team used that equipment to feed oxygen to reach the effluent DO goal (as high as 8 mg/L during certain seasons). A pure oxygen injection system using gas-contacting equipment from Mazzei Injector Company was purchased to meet the DO requirement. A fraction of the mainline flow is taken off the effluent pipeline and directed through a booster pump, and then through a 4-inch Mazzei stainless steel injector to aspirate pure oxygen. The oxygenated sidestream is mixed back into the 36-inch effluent pipeline through an inline Pipeline Flash Reactor, eliminating an additional tank/basin and reducing energy consumption and footprint.
Result: Since startup, mainline flows have varied from 3.5 to 30 mgd (average 6.5 mgd). The system has increased the effluent DO levels, exceeding the discharge requirements under all conditions with minimal maintenance and low operator involvement. 661/363-6500; www.mazzei.net.
Self-cleaning water filter helps reduce plant downtime
Problem: A county utility in eastern Washington operates a micro-hydroelectric plant that delivers power generated by a local river. The plant was seeing excessive downtime; efficiency was affected by the high TSS in the water source, which is subject to seasonal turbidity. The plant relied on 200-micron bags to filter the cooling water for the plant’s two turbines. The bags filled to capacity at times, depending on river conditions, requiring employees to manually clean or replace them. Because clogged filters and bag replacement require plant shutdown, the plant had to keep employees on call 24 hours a day.
Solution: The plant installed a 50-micron SWT Filter from Spiral Water Technologies inline before the mechanical seal water delivery. The SWT is an automatic, self-cleaning water filter for ultrahigh and variable TSS of up to 25,000 ppm. With helical action, the system can filter up to 100 times dirtier water and provide continuous 10- to 100-micron filtration with 90 percent less energy than traditional filtration systems. It automatically collects, condenses and purges solids, eliminating filter bags.
Result: After operating the system through the river’s most variable seasonal conditions, the plant facilities manager declared it a successful upgrade that significantly improved plant efficiency. 844/277-4725; www.spiralwater.com.
Submicron filtration system reduces maintenance costs, chemical use and pump wear for a paper manufacturer
Problem: Paper manufacturer Kimberly-Clark uses a nearby well as a source of process water. The filtration system had difficulty filtering water high in solids, iron, calcium and manganese. This put the filtering system under stress. Routine maintenance, product failures, increased downtime and rising chemical costs required a full review of the filtration system.
Solution: The company installed a Vortisand submicron filtration system from Neptune Benson, eliminating solids that were adversely affecting the manufacturing process. The system included a delivery system capable of dispensing 1,000 gpm in a custom design to fit a restricted floor plan.
Result: The maintenance-free system with submicron filtration eliminated fouling, reduced chemical expenses, and eliminated filter bags and the attendant manual maintenance. Pump wear was significantly reduced, eliminating the need to send manifolds for remanufacturing every three months. Less maintenance led to less downtime and $8,000 savings in its first two weeks of operation. 888/876-9655; www.vortisand.com.
Membranes enable plant to meet drinking water standards
Problem: As water use triples during the summer months in Cottage Grove, Oregon, city officials needed to identify a treatment method to meet drinking water standards and meet peak demand at the Row River Water Treatment Plant.
Solution: The plant installed an Aria FLEX membrane system from Pall Corporation that uses advanced pressurized filtration membranes. The system can provide excess capacity in addition to meeting drinking water standards and flow rate demands.
Result: The flexible membrane unit enabled the plant to expand its capacity from 2 to 4 mgd; it will produce 8 mgd at full build-out. The operator-friendly system enables operators to manage, monitor and adjust water levels as needed. In the last eight years, the system has seen no fiber breakage. The system also removes Giardia, Cryptosporidium and bacteria. It enables clean-in-place to occur every 60 days versus 30 days. Efficiency has led to annual $5,500 savings and reductions in use of chlorine and other chemicals. 607/758-1774; www.pall.com/water.
Packing company solves waste screening problem
Problem: Wastewater officials in Toronto, Ontario, requested more efficient removal of gut trimmings, paunch waste, grease, solids and manure from wastes at a meat packing company. Waste included 1.4-inch fat particles, plus a large percentage of fat in manure.
Solution: The company installed three 48-inch-diameter SWECO Stainless Steel Vibrating Screen Separators. The units use 80-mesh, 0.007-inch openings, plus two 8- by 8-inch table discharge spouts and one 8- by 8-inch frame discharge spout. Additional screen cloths of 40-mesh, 0.015-inch openings and 94-mesh, 0.0071-inch openings are available when needed in the screening room. Waste from the killing floor is received by a surge tank.
Result: Using the 80-mesh screen cloth, the company screens a flow rate from 840 to 1,080 gpm. Removal of undesirable solids has satisfied system requirements. The solids are delivered from the separators to a drag conveyor and then to railway pickup for fertilizer. 800/807-9326; www.sweco.com.
UV system protects hospital patients from chlorine-resistant pathogens
Problem: To protect patients from Legionella infection, a U.S. Veterans Administration medical center in Tallahassee, Florida, needed a point-of-entry UV disinfection system for additional treatment of a municipal water source.
Solution: The hospital installed 12 UV Pure Upstream systems to treat all incoming water and protect more than 15,000 visitors per year from Legionella and other waterborne pathogens. The systems are connected by a compact stainless steel multiplex manifold for a total treatment capacity of 336 gpm. Each system uses Crossfire technology, a dual-lamp, reflective design that reuses lamp energy to provide 2.4 times the UV dose of conventional systems and enables the system to achieve the required UV dose even when UV transmittance is as low as 75 percent.
Result: The systems can easily be taken offline for maintenance while the others remain in operation. Dual-smart UV sensors continually monitor parameters such as UV dose, UV lamp intensity and UV net transmittance. If any parameters are not within specifications, the affected system goes into alarm, shuts down and notifies the operator. A robust, automatic cleaning system prevents fouling of the quartz sleeves and ensures maximum UV dose. 888/407-9997; www.uvpure.com.
City replaces lagoon surface aeration, saving energy
Problem: The city of Yerington, Nevada, was frustrated by the poor treatment, high energy costs and unreliability in its lagoon system’s surface aerators. The system has a 15-foot-deep treatment cell followed by a partially aerated polishing pond.
Solution: Yerington upgraded to MARS aerators from Triplepoint Water Technologies. The units combine coarse-bubble mixing and fine-bubble oxygen transfer in a single, portable unit. Because they are powered by an onshore blower, there are no moving parts in the water, ensuring reliability and saving on operation and maintenance costs. The team retrofitted the system to an unused train and then discontinued flow to the existing train. Twelve aerators were installed in the primary cell to meet the daily oxygen demand of 495 pounds. Four units were installed in the polishing cell. Air is supplied by an onshore blower with a variable frequency drive.
Result: Savings on energy and maintenance are expected to exceed $400,000 over 10 years, and the facility upgrade is expected to pay for itself in less than three years. 800/654-9307; www.tpenv.com.
Process filter allows plant to reuse water
Problem: To operate more efficiently in drought-ravaged conditions, the Douglas (Arizona) Wastewater Treatment Plant sought to use internal secondary water. However, plant personnel had concerns about using the water for pump seals and other equipment, such as conveyor system nozzles.
Solution: VAF Filtration Systems, manufacturer of automatic self-cleaning filters, provided a V-500 filter with flexibility to interchange screens with varying degrees of capability to meet the changing needs of the plant. Its Bi-Directional Hydrodynamic Drive (BHD) allows the cleaning scanner to move bi-directionally during each flushing cycle, allowing the filter to keep up with unexpected high TSS during system upsets.
Result: The technology increases cleaning efficiency and simplifies the self-cleaning process so that pistons, electric motors, gears, limit switches and PLC controls are not required. The self-cleaning process produces flush waste that is less than 1 percent of flow. 303/425-4242; www.vafusa.com.
Aerator slashes costs and saves jobs
Problem: In 2012, the city of Evart, Michigan, needed to replace several aerators in its 300,000 gpd wastewater facility of two aerated lagoons, a storage/polishing lagoon, and a four-cell rapid infiltration basin. The aerated lagoons are 1.1 surface acres each and are about 10 feet deep. The storage/polishing pond is nearly 20 acres with a 12-foot depth. The city was faced with the possible need to eliminate two employees due to budget shortfalls.
Solution: The city purchased six air turbine aerators from VaraCorp, with a provision that 13 more units could be acquired if the original six met expectations. Precession creates a low-pressure zone in the midst of a cavity within the turbine. This zone is sated with air, which flows from surface holes above the waterline through a hollow, rotating airshaft. Atmospheric pressure pushes air down to the turbine’s cavity, at which point it is slung outward at high speed due to centrifugal force. The result is a cloud of dissolved oxygen that saturates the water.
Result: Although the air turbines were powered by motors that were only one-seventh the size of the prop aerators being replaced (3 hp vs. 20 hp), the dissolved oxygen content of the water began to rise to new levels. Once all 19 air turbine aerators were in operation, the DO level rose from 4 to 5 ppm to 5 to 7 ppm. Patrick Muczynski, lead operator, reported that the electrical costs are barely 25 percent of the costs for the old aerators. The aerators have required virtually no maintenance. The low capital cost of the aerators and the lower electricity costs enabled the city to keep the two employees. 800/801-6685; www.varacorp.com.