Treatment plant expands biogas cogeneration system
Problem
The outdated wastewater treatment plant of Oneida, New York, needed an overhaul. In 2019, the city began a multiyear project of designing and implementing energy efficiency improvements.
Solution
Plant operators turned to Capstone Green Energy distributor RSP Systems. They initially installed a five-bay microturbine cogeneration system with three bays in operation. And since the enclosure can expand to accommodate larger loads in the same footprint, an upgrade added two more 200 kW microturbines, expanding capacity from 600 to 1,000 kW. Minimally processed biogas fuels the microturbines to produce electricity and thermal energy for digester heating.
Result:
The system gave the city more control over its energy use and improved plant energy efficiency, energy and water security, and carbon emissions. 800-422-7786; www.capstonegreenenergy.com
Centrifuge helps municipality make consistent cake solids
Problem
The Wastewater Treatment Division in Middletown, Ohio, operates a 26 mgd water reclamation facility. In 2018, the utility removed an under-performing belt press that was difficult to operate and produced no better than 15-18% solids. A centrifuge produced 30% solids.
Solution
In 2018, the facility installed a Flottweg Xelletor centrifuge, reducing production time from five days a week to three days a week (8-10 hours per day). The older centrifuge was kept as a backup. The city saved money by installing the machine in-house. The facility cut the use of ferric chloride in half and also cut polymer usage significantly.
Result:
The city realized cost savings and consistently produced cake at 28-30% solids. “We had to ask ourselves if we really needed the 32% solids,” says Gerry Burris, wastewater manager. “We are now averaging between 28 to 30% solids on a consistent basis. For the extra 1.5% solids we couldn’t justify the extra expense in chemicals. Flottweg was very responsive to our needs. They will send a tech out whenever we need one, and they stay until they get it right.” 859-448-2331; www.flottweg.com
Pioneering farmer shows the benefits of renewables
Problem
Pig farmer Tom Butler wanted to reduce impact on the environment and increase biogas production at Butler Farms in North Carolina. The farm takes 20,000 hogs per year from their arrival weight of 40 pounds up to about 290 pounds. Manure at up to 10,000 gpd is fed to an anaerobic digester (60 by 180 by 18 feet deep).
Solution
Butler replaced his old small mixers with two Landia chopper pumps. Landia also helped optimize the system, which due to unsuitable pressure ratios and varying diameters of pipework put a strain on the biogas-fueled engine.
Result:
The upgrade from 10 hp to 60 hp means a million gallons of manure slurry can be moved whenever required. The setup uses the chopper pumps the start of the process; one is enough to keep everything moving. With two nozzles per pump, everything is mixed properly, increasing in methane production by 10%. 919-466-0603; www.landiainc.com
Coast Guard deploys a rainwater collection and treatment system
Problem
The U.S. Coast Guard needed a new sector headquarters at Ellington Field in Houston, Texas. The 117,000-square-foot facility was required to achieve LEED Silver status. ParkUSA assisted with the design.
Solution
A RainTrooper Rainwater Collection and Treatment System from Park USA includes a pretreatment filter, 50,000-gallon cistern, cistern pumps, rainwater treatment system, dye and chlorine dosing, a 900-gallon day tank, and re-pressurization booster pumps. A Rainwater Management Panel with a digital touchscreen display monitors cistern and day tank levels, filter system water pressure, building water pressure, and usage of city water and rainwater from the cistern. The panel displays a visual alarm when tank water levels fall below preset levels.
Result:
The system has performed as expected, helping the facility to achieve LEED Silver status. 888-611-7275; www.parkusa.com
Project uses BAE and existing infrastructure to stabilize food waste and increase biogas production
Problem
A 6 mgd wastewater treatment facility located in a region with multiple food processors needed to stabilize food wastes coming into its receiving station before sending it to the digesters. The facility also could also benefit from the addition of Biological Activity Enhancer (Prodex) to increase gas production and revenue.
Solution
Prodex assistance and the use of existing infrastructure negated a $3 million to 5 million investment to construct a farm digester from the ground up. The project helped demonstrate that food waste, manure and municipal waste can efficiently mixed to create biogas for a co-generation unit.
Result:
The addition of BAE stabilized the materials being treated, increasing biogas output by 37%. The now generates $150,000 per year in revenue and growing. The plant receives and process effortlessly due to increased buffering capacity and throughput. 856-234-4540; www.prodexproducts.com
