Earth Day began on April 22, 1970. The biosolids beneficial use program in Fort Wayne, Indiana, goes back almost that far.

The city’s Biosolids Handling Facility, established in the 1970s, converts solids from the Fort Wayne Water Pollution Control Plant and the city’s Three Rivers Water Filtration Plant into products farmers and city residents can use to enhance their soils.

“Our motto is ‘every day is Earth Day,’” says Brian Robinson, biosolids facility superintendent. “Our public information officer, Frank Suarez, came up with that — he just said it on a news program one day. We try to live by that. We reuse as much as we possibly can. That’s pretty much how we operate out here.”

The facility, in a partnership with Fox Contractors that goes back 17 years, converts biosolids and combined sewer overflow solids into a compost sold in bulk to farmers and landscapers and given at no charge to homeowners. Dewatered lime from the water plant is sold to farmers for soil pH adjustment. 

It doesn’t end there: Facility staff members collaborate with the city Street Department on leaf pickup twice a year. The leaves, along with yard waste and brush brought by residents and other city departments, are ground up, composted, and used in producing the city’s Class A biosolids product. For its efforts, the city received a 2017 Residuals & Resource Recovery Award for Excellence in Operating from the Indiana Water Environment Association.

Serving three facilities

The biosolids program serves the three facilities that protect Fort Wayne’s water resources and deliver clean water to homes and businesses. The water plant, capacity 72 mgd, was built in 1933 and has seen several upgrades, most recently to add UV disinfection in 2014.

The water pollution control plant (60 mgd design, 47 mgd average, 100 mgd peak) was built in 1939 and also extensively upgraded, notably with a new headworks building and new primary clarifiers in the early 2000s and an upgrade of the aeration system with coarse- and fine-bubble diffusers (Sanitaire - a Xylem Brand) in 1998.

The plant’s activated sludge process uses nine secondary treatment trains, each with its own aeration basin and final clarifier. Methane from the six 1.7 million-gallon anaerobic digesters fuels boilers and a pair of Guascor engines driving 400 kW generators that produce about one-third of the plant’s electricity.

The city’s CSO facility consists of two side-by-side, 30-acre ponds 11.5 to 12 feet deep. A pump station with 500 mgd capacity delivers storm flows to the ponds from the city’s extensive combined sewer system. The ponds drain into an interceptor sewer that feeds the water to the treatment plant after storm events end and the treatment process catches up.

All told, the Biosolids Handling Facility encompasses 582 acres, of which lagoons occupy 382 acres, providing 1.75 million cubic yards of capacity. In 2017, the site yielded 24,319 dry tons of biosolids product and 23,233 dry tons of the lime product.

Handling biosolids

The biosolids process starts with sludge pumped from four primary clarifiers along with waste activated sludge from the secondary clarifiers. Rotary drum thickeners (Andritz Separation) deliver the material to the digesters at 4 to 6 percent solids. “The digested material is pumped through an underground pipeline about 2 miles to the biosolids facility,” Robinson says. “There it is placed in 7-acre lined dewatering lagoons for natural drying.” Besides material from its own water pollution control plant, the city takes anaerobically digested and nondigested sludges from other sources.

After two to three years drying in the lagoons, the material is windrowed to enable more dewatering to occur in a second year. The biosolids are then turned about every two weeks. “All water including storm runoff from the site is sent to the water pollution control plant,” notes Travis Medina, operations manager and Fox Contractors employee.

The dried material is tested by way of mixed core samples taken from the windrows. A sample of the mixed material is then analyzed for heavy metals, PCBs, volatile solids, vector attraction reduction and pathogen reduction. Testing validates whether the material complies with Process to Further Reduce Pathogens requirements and heavy metal concentration limits. Any material that does not meet the requirements is reblended.

The final biosolids material contains 68 to 70 percent solids. It is mixed with compost made on the site from yard waste and wood chips. “We have a three-bin mixing plant,” Medina says. “The biosolids are in one bin, and the compost is in another. It’s an electronically fed process. We can adjust the feed rates according to how we want each batch to be mixed.”

The 9-by-12-foot top-opening bins load material onto three 42-inch-wide feeder belts that in turn dump the material onto a troughed 48-inch-wide collecting belt. The material then flows onto a 42-inch-wide inclined belt that carries it to the screening unit. 

Robinson adds, “The feeder belts are controlled by variable-frequency drives. Each belt’s speed can be set by way of the operator interface, so we can tweak the amounts coming out of each bin. If we want more biosolids or more compost, Travis can make those adjustments.” Typically, the mixture contains about 60 percent biosolids and 40 percent compost.

The third bin in the plant is used to fill requests for custom batches, which require a minimum order of 2,000 tons. In the past, custom blends have included additives such as sand and horticultural perlite. The process is seasonal and weather-dependent; the basic aim is to maintain a 30-day supply. Before distribution, the material is screened to remove oversized material. Final testing is also done to ensure regulatory compliance.

Lime and CSO solids

Lime is used at the Three Rivers Water Filtration Plant as a water softening and coagulation agent. Material removed from the treatment process is pumped via force main to the biosolids facility for dewatering in 23 lagoons. The dried product is tested for heavy metals before being sold to farmers.

Periodically, undigested sludge and grit from the CSO ponds and the collections system clean-out are treated and processed at the biosolids facility. The settled solids in the ponds are dredged and pumped into large biofilter bags for dewatering and thickening; the decant water flows back to the ponds. Composite samples of the CSO waste are analyzed for pollutants.

The dewatered solids are trucked to the biosolids facility and placed in a 7-acre system of clay-lined lagoons. Soon afterward, the material is hauled to a 6-acre compost pad, blended with yard waste and wood mulch, and composted at a minimum of 131 degrees F for at least 15 days while being turned at least five times with a self-propelled windrow turner.

When the compost begins to cool, it is placed in a curing pile to await screening. At that point, another composite sample is analyzed for pollutants. The finished material is also analyzed for E. coli, enteric viruses, helminth ova, Salmonella and vector attraction reduction. 

All the processed materials find a willing market. Homeowners take the material, usually in smaller containers like 5-gallon buckets, but sometimes in pickup trucks. The compost materials sell in bulk for $12.20 per ton and the lime for $10.50 per ton. “For farmers who purchase large volumes, Fox Contractors works with them on the pricing,” Robinson says. “We also take in brush and grind it into mulch, which we sell for $5 a ton. People can bring their trimmings for a drop-off fee of $20 per ton, prorated.”

A team success story

Making it all happen requires teamwork between the city and Fox Contractors. Besides Robinson, city team members are Chris Gach, assistant superintendent of the water pollution control plant and biosolids; Chris Hart, equipment operator crew leader; and Tim Gallaway, Renee Hodgkin, Kim Schinbeckler, and Johnathan Stantz, equipment operators. Fox Contractors personnel on site are Tim Bruce, scale house manager, and equipment operators Kevin Ort, Randall Davis, and Cameron Douglas.

Also essential is a good relationship with state regulators at the Indiana Department of Environmental Management. “They are there to help,” Medina says. “They do a great job of providing guidance and answering any questions we have.”

Robinson adds, “The other big thing is getting publicity out there about the product so that people understand it’s safe and a beneficial option for use on their flower beds, gardens and trees.” It’s a formula that has worked for more than 40 years, and all signs indicate it will continue to work, through many more Earth Days to come.

Residents on board

Any biosolids beneficial use program depends on public accept- ance and support. The Fort Wayne, Indiana, program is so well accepted that the demand for product consistently exceeds supply.

“One thing we do is open up our treatment plants to the public,” says Brian Robinson, superintendent of the city’s Biosolids Handling Facility. “We have three open houses set up this year, and we advertise them. Our Parks Department issues a calendar of things to do on the weekends, and we are listed on that.

“We have had requests to hold tours of the Biosolids Handling Facility, and we’re trying to work out a way to do that. Because it’s such a large facility, that would involve either a lot of walking or some type of transportation.”

To help with promotion, Robinson created a four-page handout to give to people at public events, such as rain garden workshops, which typically attract about 75 people. Another public resource is an information sheet developed by a Purdue University agronomist describing how to use biosolids as a soil amendment, as mulch, as a potting medium, and as a lawn fertilizer. Earlier this year, Robinson hosted a TV program on biosolids for the city’s public access cable channel.

Meanwhile, the city has taken steps to make the biosolids facility attractive. “The entrance is designed so as to help retain property value for the surrounding homes,” Robinson says. “It includes a new driveway and hilled landscaping on the north side of the property. City representatives attended several neighborhood association meetings to discuss the design. When it was completed, we received a thank-you card signed by several neighbors.”

In addition, the city offers biosolids and mulch delivery for community gardens and provides biosolids at no cost to properties being restored to help transform vacant lots into green space.

There is also outreach to the water industry. In March, the Indiana Water Environment Association held its statewide residuals conference in Fort Wayne. “We had seminars in the morning, and then we did bus tours of our facility in the afternoon,” Robinson says. “The state gave continuing education credit to licensed operators who attended.”