For some area residents, biosolids mean fertilizers with foul odors that carry questionable health concerns.

For people who make biosolids, they see them as heavily-regulated fertilizers and the only type of farm fertilizer that comes with limitations and requirements.

Farmers see it as a free source of fertilizer that helps produce ample crops.

Making biosolids is also a form of recycling, and the only alternative aside from using it as fertilizer is to dump it in landfills.

“We do it safely, and it’s recycling,” said Ron Adams, superintendent at Mechanicsburg’s wastewater treatment plant. “We’re all regulated. The alternative is to put it in a landfill, and that’s not good.”

Eric Laur, soil scientist at the Department of Environmental Protection, said the state has regulated biosolids since 1977 and biosolids have been created since the establishment of wastewater treatment plants a century ago.

Considering how long the process has been around, Laur said biosolids have “been proven to — if done right — be a safe practice.”

Still, officials know area residents have concerns, proven this past month in Dickinson Township where neighbors complained about biosolids’ application at a township farm. Laur said the issues develop in Central Pennsylvania because the region is an agricultural region.

“It’s more frequently in our area because we are in an agricultural region,” he said. “There are thousands (of sites) in the state, and there are about 60 to 70 percent in our region.”

Jeff Heimbaugh, sludge coordinator at Carlisle’s wastewater treatment plant, said education and explaining how the system works can help ease the health concerns about biosolids.

“Some people think that it’s a toxic product, that it’s unsafe, unregulated and untested,” he said. “They’re just not sure about it and are very, very suspicious. If you don’t know what it is, then it makes sense.”

Still, those like Bev Polk in Newville are not convinced or at least push for all biosolids to be produced at a Class A level.

“(Some biosolids) run right up to the property,” she said. “It may be 300 feet from the building, but it’s right up to the grass, where children are playing. I just don’t think it’s healthy.”

The process

Biosolids start as waste at municipal wastewater treatment plants. Heimbaugh said the organic waste comes from basically anywhere that is connected to the municipal sewage system.

The biosolids, however, don’t leave in that same form.

There is no specific method wastewater treatment plants must follow to kill the bacteria and microorganisms in biosolids. It’s the end result that must follow requirements from the DEP.

“Biosolids are sewage sludge from wastewater treatment plants,” Laur said. “They are treated to meet requirements to land apply. We have extensive regulations on treatment.”

All municipal biosolids must meet a number of requirements and wastewater treatment plants must fulfill three criteria to be granted a General Permit from the DEP — pathogen reduction, vector attraction reduction and pollutant concentrations.

The DEP said pathogen reduction is the reduction of disease-causing organisms while vector attraction reduction involves minimizing the characteristics of the biosolids that makes it attractive to vectors, such as flies, mosquitoes and rodents.

The pollutants involve the nine metals that DEP tests to make sure biosolids are fit for land application. The DEP tests for arsenic, cadmium, copper, lead, mercury, molybdenum, nickel, selenium and zinc. The DEP will also test for Polychlorinated biphenyls (PCBs), a group of manmade chemicals. These 10 pollutants were identified to be the ones with detrimental effects on human health and the environment.

Treatment plants also complete a hazardous waste determination involving an analysis of the biosolids for several hazardous materials.

Each treatment plant will have a different method to complete this process, partially because treatment plants are designed differently and may be built for a certain method — just as the water treatment part of the plants will be different among municipalities.

Adams said they use an anaerobic process at Mechanicsburg to kill off the microorganisms.

“We use a process called anaerobic digestion where they’re broken down by microorganisms in an environment that has no oxygen,” he said.

Carlisle adds lime to its process, which Heimbaugh explained helps them meet the criteria and additionally helps farmers who receive the biosolids.

“We mix lime with water and add it into the sludge to help it maintain a pH of 12,” Heimbaugh said, noting a pH level that high will ensure the bacteria is killed. “With the added lime to the product, it helps the soil maintain a good pH for crop production.”


Once the biosolids pass the tests, they’re ready for land application.

Treatment plants can either send out crews themselves to land-apply biosolids or they can contract with businesses, like Merrell Bros., which is based out of Kokomo, Ind., but also has a location in Lancaster.

Ryan Zeck, chief operating officer at Merrell Bros., said the company contracts with the city of Lancaster to take its biosolids and coordinate with area farmers to land-apply the material. Some of that material makes its way into Cumberland County, and the company recently land-applied the material to a Dickinson Township farm. That started a series of complaints by neighbors filed with the Dickinson Township supervisors. Similar complaints have been filed in West Pennsboro and North Middleton townships.

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Merrell Bros. has been around since 1987, but it has only had an office in Central Pennsylvania for the past two years.

“It’s a good organic fertilizer source,” Zeck said, adding that biosolids are “organic-based and have a slower release of nitrogen. (Plants) contract with us, and we haul the material according to EPA and DEP regulations.”

Just as plants need permits to treat the biosolids, haulers need a DEP permit to land-apply.

Carlisle’s wastewater treatment plant does both the treating and land-application of biosolids.

“Our plant has a staff of three men that run everything,” Heimbaugh said. “They haul it to places (and spread the biosolids) — we do it all in-house.”

Heimbaugh explained his staff land-applies biosolids within a 20-mile radius of the borough. Most of the 24 sites they deal with are located in Dickinson, North Middleton, Upper Frankford, Lower Frankford and West Pennsboro townships.

Farmers who receive the biosolids don’t have to pay for it.

In a DEP presentation on the Pennsylvania biosolids program, the department said it’s an added bonus for farmers who need fertilizer to grow crops.

Agricultural use is one of four uses for biosolids, and the DEP said biosolids used as fertilizer on crops has been found to show significant improvements in crop growth and yield. Because biosolids are rich in nutrients — since they come from organic material — they also help replenish nutrients that are depleted over time with use of the field, the DEP said.

According to Biosolids.com, a website advocating the use of biosolids, there are federal and state restrictions about the use of crops after biosolids are applied. The site said animals cannot be grazed on land until at least 30 days after application, food crops that are above the land’s surface cannot be harvested until at least 14 months after land application and food crops below the land’s surface cannot be harvested until 20 to 38 months following land application, which depends on how long the biosolids have been sitting on the field.

The DEP said biosolids are usually used on crops that will go to animal feed, but studies from the U.S. Department of Agriculture have indicated there are no health concerns for humans or animals to eat the crops.

The DEP also makes sure a notice is sent or hand-delivered to adjacent property owners near a farm that uses biosolids at least 30 days before land-application.

In addition to agricultural use, the DEP said biosolids can also be used at mine reclamation sites to promote vegetation, promote rapid timber growth in forestry, and exceptional-quality biosolids can be sold for home gardening and landscaping.


The last of those uses involves the highest quality of the three types of biosolids.

There are three categories of biosolids in the state, the DEP said. Those categories include exceptional quality (or Class A), biosolids/farm grade (or Class B) and residential septage.

Exceptional quality biosolids are the highest quality biosolids and once treated, can be used with few restrictions.

“Exceptional-quality biosolids are sold and given away to the public,” Laur said. “People can buy it and basically use it without restrictions. There are some guidelines, and we do require an instruction sheet on the product. It’s treated to a higher extent, and can be used basically restriction-free.”

Adams said Mechanicsburg is currently in the process of changing its process to create Class A biosolids.

“We’re right in the middle of going through treatment plant upgrades, where we’ll go to Class A with biosolids,” he said. “It’s the next step up and is suitable for residential use.”

The second- and third-class materials have similar land-use restrictions, and while they are treated, they don’t have to meet the same requirements as the exceptional-quality biosolids.

Carlisle fits into this area. Heimbaugh said Carlisle has considered upgrading its process to create Class A biosolids but the transition would be costly for the plant and plans have not been approved.


Though Class A biosolids can be used with little restriction, there are limitations to where Class B biosolids can be land-applied.

Laur explained Pennsylvania’s restrictions are based on restrictions from the federal Environmental Protection Agency.

“All our regulations are based on federal regulations,” he said. “Pennsylvania adopted EPA’s regulations back in the mid ’90s. This applies across the country — it’s not unique to our region. Should pollutants get into the water, then it’s a Clean Streams Law violation.”

Laur said the requirements include set-back requirements of 100 feet from a perennial stream, 33 feet from an intermittent stream, 300 feet from a home and 300 feet from a well — unless the owner of the home or well signs a waiver, which Laur said does happen. Land application is also not permitted within specific distances from sinkholes.

There are also limitations for the agronomic loading rate — or the amount of biosolids that can be put on a field in relation to what crop production would actually need. The DEP said this restriction is in place to make sure biosolids are not over-applied, which would take care of concerns about any effect on groundwater or run-off.

Because of the process and the restrictions, the DEP and treatment plant operators consider biosolids to be good sources for fertilizer.

“There are no restrictions on chemical fertilizer or farm-generated manure, but yet with municipal biosolids, you have to match crops’ nutrient needs for the growing season,” Adams said, noting there are no set-back limitations on the other kinds of fertilizer, which means those kinds are the most likely to get washed into the streams.

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