Human waste sludge on farms

April 1, 2017

Farmer Dave Blakney and his son, Chris, started growing row crops about 17 years ago on their 300-acre farm in Huron Township, but it was more recently that Blakney said he learned about the availability of "biosolids," as an alternative to traditional fertilizer for some crops. "It's very good. Nitrogen is the main interest. It usually has about 190 pounds of nitrogen per acre, and that's very good. The fertilizing quality is excellent," Blakney said. "It's free. No charge, typically."

Created from the sludge leftover during the treatment of sanitary sewage, the term "biosolids" was coined in 1991 by the wastewater treatment industry. Sewage sludge is formed from the leftover organic and inorganic materials settled out of wastewater after the screening process. However, sludge may undergo additional treatments that allow it to be used recycled and applied to farm fields for crop production as fertilizer, as well as other uses.

Many in the agricultural and wastewater treatment industries say the use of biosolids provides several benefits to cropland while recycling waste materials that would otherwise be disposed of in landfills or incinerated. However, the idea of growing crops in fertilizer derived from human waste is harder for other people to swallow, particularly for those with health and safety concerns about biosolids.

Statewide, about 85,000 tons of biosolids from 175 different wastewater treatment plants was applied to about 18,000 acres of agricultural land in 2016, according to the Michigan Department of Agriculture and Rural Development (MDARD). Of that amount, about 32,163 tons came from the Great Lakes Water Authority wastewater treatment plant in Detroit, with more than 2,000 additional tons of biosolids applied to farmland from wastewater treatment plants in Oakland County, according to the Michigan Department of Environmental Quality (DEQ), which oversees the state's biosolids program. Overall, the state estimates biosolids provided a value of about $14 million to farmers in 2016.

At Blakney Farms – which produces corn, soybeans, wheat, alfalfa, and houses a cow-calf operation with breeding bulls and a handful of horses, hogs and chickens – Dave Blakney said biosolids are applied to about 125 acres of land used for growing corn for livestock feed. 

"We use it just before we plant," Blakney said of the type of biosolids applied to his cropland. "They apply it to the fields, and we plant a few days after. We had used it on about 125 acres this year. Our first usage was about five years ago."

Blakney said he was attending the Michigan Ag Expo when he first learned about the availability of biosolids in his area. He currently receives biosolids from Synagro Technologies, which works with more than 600 wastewater facilities in 34 different states. Most suppliers, he said, apply biosolids at no cost, or charge a small fee for applying the product.

"There is no debris, tissue, or anything that you might find in sewage. It's been centrifuged and tested, probably more than regular fertilizer. What is regular fertilizer? It's typically manure of some sort," Blakney said. "Biosolids get a bad rap, and I don't think it's deserving."

Concerns about biosolids have been raised since the early 1990s when the Environmental Protection Agency (EPA) first created regulations prescribing biosolid use. Those opposing the use of biosolids say the recycled sludge contains thousands of known and unknown substances, including disease-causing pathogens, some of which are resistent to antibiotics; toxic metals; dozens of carcinogens, hormone disrupting chemicals; dioxins; pharmaceuticals; pesticides, PCBs; PAHs; and other contaminants.

"We do have concerns about using biosolids as fertilizer on land," said Gail Philbin, director of the the Sierra Club's Michigan Chapter. "There are too many questions about the safety of the substance for applying it on land right now. The policies that govern it aren't adequate to cover human health, so we do oppose it."

The Sierra Club bases its position statements from scientists in the 1990s and 2000s, who said federal government's regulations regarding land application of biosolids, which were set in place in 1993, need to be updated. Among those who have called for additional research was the National Academy of Sciences' National Research Council, which in 2002 warned that the regulations were based on outdated or nonexistent science.

Current regulations require biosolids to undergo special treatment to kill pathogens and be tested for specific metals. Regulations are also in place to regulate the type of biosolids and amount that may be applied to cropland to ensure potentially harmful contaminants don't over accumulate in soils and uptake into crops. Still, opponents of biosolids say regulations only cover a small fraction of the thousands of contaminants likely to be found in biosolids.

Further, there also are concerns about direct human exposure to biosolids, as reports of illnesses surface from residents living near land application sites who have been exposed to dust and water runoff from fields treated with recycled sludge.

David Lewis, a microbiologist who directs the Georgia-Oklahoma Center for Research on the Environment at the University of Georgia, has called for additional research and restrictions on the public's exposure to biosolids after he investigated illnesses and deaths he said were linked to EPA programs promoting the agricultural use of processed sewage sludge.

"The EPA estimates there are about 60,000 chemicals and toxins in the sludge, and that's just what we know of and have studied. Based on chemicals that there are analytical methods for, there are likely thousands more," said Lewis, also a former research microbiologist for the EPA's Office of Research and Development who serves as Senior Science Advisor to the National Whistleblower Center. "That is only an infinitesimal number of what is produced in the atmosphere. They are like grains of sand in the sea shore. Most of the chemicals that cause cancer and birth defects we have not yet studied. So, sewage sludge is magnified and concentrated in the universe of pollutants – known and unknown – that we worry about the most."

Despite vocal concerns, many in the agricultural and wastewater treatment industries say research has shown biosolids use in crop production is safe, so long as the appropriate protocols and regulations are being followed.

The Water Environment Federation (WEF), a non-profit organization representing wastewater and water quality professionals, said that biosolids provide financial, environmental and social benefits, which support sustainable resource management, create jobs and builds healthy soils.

Patrick Dube, Biosolids Program Manager for the (WEF), said pathogen levels set by the EPA for biosolids ensure that it's safe for human health and the environment.

"It's a matter of employing best management practices to make sure we reach those levels. As long as you're following regulations and procedures, there's nothing to worry about with the land application of biosolids," he said. "There are standard tests being done to make sure they are reaching appropriate levels."

While the EPA's regulations don't account for all of the potential contaminants present in biosolids, Dube said the industry is continually looking at new methods of testing and detection. In terms of emerging contaminants of concern, such as pharmaceutical and personal care products that might be found in biosolids, he said the current consensus among researchers in the field is that those levels in biosolids aren't an issue if all current rules and regulations are being followed.

"A lot of concerns are based on maybe not quite understanding or being aware of the process that biosolids undergo to become safe," Dube said. "Type A biosolids that have no pathogens in them are safe for growing crops, as long as you're following regulations and making sure they are applied at a rate that they don't pose any threat to humans."

Lewis, the former EPA microbiologist now with the University of Georgia, said the spread of heavy metals, pesticides, PCBs and pathogens being spread through dust in the air and water from biosolids should be of greater concern. However, he said there is a lack of data on the threats that biosolids may actually pose. Instead, Lewis said the EPA and the Water Environment Federation, which is the nation's largest trade organization for the wastewater industry, have worked with agricultural colleges to generate research that aims to support the EPA's rules and say there isn't a problem.

"We had numerous tugs of war with Washington before. This was different. The solution Washington had was to slow down scientists, or stop them," Lewis said about the EPA's work on the 40 CFR, Part 503 rules, which were issued by the agency in 1993 and set out regulations on biosolids. "To my knowledge, the EPA scientists just stopped. With biosolids there was no going back and forth with Washington. I think because of the political and economic pressure that was being done."

In 1997, the Cornell (University) Waste Management Institute concluded that regulations governing land application of biosolids don't protect human health, agricultural productivity and the environment.

In 2002, the National Research Council of the National Academy of Sciences (NAS) warned that the scientific underpinning of the EPA's Part 503 rules were based on outdated or nonexistent science. The report included about 60 recommendations for addressing public health concerns, scientific uncertainties and data gaps in the science underlying the sewage sludge standards.

"There is a serious lack of health-related information about populations exposed to treated sewage sludge," Thomas Burke, then chair of the committee that published the report said in releasing its findings. "To ensure public health protection, EPA should investigate allegations of adverse health effects and update the science behind its chemical and pathogen standards."

The committee said it agreed with the EPA's general approach to regulating pathogens, which requires the level of microorganisms to be reduced through treatment and restrictions on land use immediately after biosolids are applied. However, the committee said the EPA should also use new pathogen-detection technology to ensure that treatments are reliable. "Microbial risk assessment should include the possibility of secondary transmission of disease, such as through person-to-person contact or through food, air or water, should also be developed," the report stated.

In response to the NAS report, the EPA in 2003 developed a final action plan that sets out to determine potential risks of select pollutants; measure pollutants of interest; characterize potential volatile chemicals from land application; and understand the effectiveness of water/sludge treatment and risk management practices.

The EPA in July of 2015 updated its plan to include 15 actions that have been undertaken or are ongoing. Those actions include biennial reviews of published data and potential harms; methods for evaluating pollutants; the development of analytical methods for detecting pharmaceuticals and personal care products in sewage sludge; and other measures.

The most recent biennial review issued by the EPA stated that the agency's decision in 2003 that regulation of dioxin and dioxin-like compounds in land-applied biosolids wasn't needed for adequate protection of public health and the environment. However, the EPA said it is in the process of analyzing nine pollutants and molybdenum to determine if additional monitoring or regulation was needed. Those pollutants include barium, beryllium, manganese, silver, 4-chloroaniline, fluoranthene, pyrene, nitrate and nitrite. On a longer term basis, the EPA will continue evaluating another 135 chemicals identified as of possible concern, as well as investigating alternative tools for estimating missing data about environmental properties, human health and ectotoxicity values and acceptable concentration data in sewage sludge.

Jonathan Latham, executive director of the Bioscience Resource Project, a public interest organization that provides independent research and analysis in agriculture-related biosciences, said he too believes more research is needed on biosolids.

"It would really be a good thing to know what the content of food ends up being," he said. "To look at corn that is fed to animals or in crops eaten by people; what is taken up by those crops."

Foods grown with Class A biosolids, or sludges with more advanced treatments, are permitted for human consumption, but there are no special labeling requirements needed, as is the case with genetically modified foods. However, foods that are considered "certified organic" products cannot be grown using biosolids, under the US Department of Agricultural's certification process.

Further, at least one business has taken steps to notify consumers if biosolids are used in food production. In 2014, Whole Foods implemented its "Responsibly Grown" rating system. The system prohibits the use of biosolids on land within three years prior to harvest.

Tracy Yager, a hydrologist with the United States Geological Survey in Denver, said she and other scientists looked at the use of biosolids from 1993 to 2010. The studies, she said, involved biosolids from a specific wastewater treatment plant, and a large tract of farm land that was used by actual farmers. Overall, she said the specific studies didn't show conclusive evidence on how biosolids specifically impacted crops, groundwater or soils.

"There are all these different complicated layers that we really can't say this comes from biosolids for sure. The best we can say is that it may be consistent with use of biosolids, but it could be something else, like cow manure, which can produce the same results, so there are mixed inputs."

The most recent research on the uptake of contaminants by crops was headed by Edward Topp, a research scientist with Agriculture and Agri-Food Canada. The study, "Biosolids applied to agricultural land: Influence on structural and functional endpoints of soil fauna on short- and long-term scale," sampled crops for up to 96 months after biosolids were applied.

"Overall, the present study found only weak evidence for negative long-term impacts of biosolids applied at commercial rates on soil fauna," the study stated. 

When it comes to biosolids, it's important to note that not all are created, treated or used in the same way. And, despite the terms "biosolids" and "sewage sludge" used interchangeably in some contexts, the materials are very different.

Sewage sludge is formed by wastewater treatment plants during the treatment process. Wastewater coming into the facilities goes through a filtering and screening process to remove rocks, grit, plastic and other items. Water then enters clarifying tanks, where the remaining solid materials are separated through settling. While the water is sent to another area to undergo further treatment, the separated solids that fall to the bottom of the form are a sludge consisting of everything that is flushed into a sewer system. The raw matter at the bottom is considered septic sludge, or what as been called "raw primary biosolids," since 1991 by the EPA.

Sludge produced in the primary treatment process can't be used for land application without additional treatment. Likewise, most wastewater treatment facilities employ secondary treatment processes to remove contaminants from water. The most common form of secondary treatment use an activated sludge process, where the bacteria in the sludge is used to break down organic matter left in the water from the primary treatment process. Water is then disinfected, most commonly with a chlorine process, before being returned to the environment. However, advanced treatment processes, such as ultraviolet light, ozone, carbon absorption, distillation or reverse osmosis may be used to further remove pollutants such as pharmaceuticals, metals and other contaminants from wastewater to the point where it may be recycled as drinking water.

Sludge left over from the treatment process must be disposed of, either as sewage sludge or as biosolids that may be used for fertilizer or other applications. Sludge disposal may involve removal to landfills, incineration or surface disposal, where sludge is placed in lagoons, wastepiles or other such impoundments. Surface disposal sites for sludge don't exist in Michigan.

Most sludges undergo additional treatment at the wastewater treatment plant before they are used or disposed of in order to meet regulatory requirements and reduce costs. Only sludge that is treated to meet federal and state requirements for reducing pathogens, certain metals and the attraction of vectors, or disease-carrying organisms like flies, rodents, can be applied to land or used as compost. 

Sludge that is used as biosolid fertilizer is treated through biological, chemical, physical or thermal processes, as well as dewatering or drying. It's these processes that determine the characteristics, quality and use of biosolids produced. The EPA categorizes biosolids as either "Class A" or "Class B" biosolids. Because Class A biosolids undergo additional treatment to remove pathogens, it may be applied to land used for human food consumption. Class B biosolids may contain pathogens that restricts how often it may be applied, and prohibits its use for human food consumption.

Some pathogens found in Class B biosolids could be bacteria such as Bacillus, Legionella, Listeria, Salmonella, Shigella, Staphylococcus, and others; viruses, such as Hepatitis, or Rotaviruses; Protozoa, such as Toxoplasma or Cryptosporidium; and other helminth worms, according to the EPA's Office of Research and Development.

Class B biosolids must meet certain maximum pathogen levels such as average fecal coliform levels that are below two million units of bacteria per gram.

Class A biosolids are considered by the EPA to be safe for immediate and direct contact with humans and animals based on requirements to reduce pathogens below detectable levels. While soils must still be tested in the application of Class A biosolids, there aren't any crop restrictions, meaning that Class A biosolids may be used as most any other fertilizer in the growth of crops for animal or human food consumption.

Federal regulations require Class B biosolids to have pathogens reduced to levels that are "protective of public health and the environment." The EPA states Class B biosolids may have low levels, but not to the level that they may be sold or given away in bags or other forms for land application at public contact sites, lawns or home gardens, nor used directly for crops used for human food consumption. Further, fields that have previously had Class B biosolids applied have specific waiting periods before certain crops for human food consumption may be planted.

Class A biosolids that undergo additional treatment methods, such as composting, heat drying and high-temperature aerobic digestion may meet additional requirements for pathogen reduction and metal reductions, qualifying them as "Exceptional Quality," biosolids, or "EQ." Some municipalities in the country that produce higher quality biosolids opt to bag and market them to the general public. 

While biosolids produced in Michigan aren't available to the general public, the Great Lakes Water Authority wastewater treatment plant in Detroit produces "Michi-green" biosolids through its partnership with the New England Fertilizer Company (NEFCO), which is available to farmers in bulk amounts.

"There are all kinds of different processes that can lead to different end products. We really focus on Class A, particularly with the drying method," said Manuel Irujo, vice president of operations for Massachusetts-based NEFCO. "Class B is more of the liquid that is land applied by injection, but it can also be a stabilized, cake format, which is about 30 percent solids. NEFCO is Class A, and uses a thermal drying process, which covers the time and temperature used."

The Great Lakes Water Authority recently revamped its wastewater treatment facility to produce Class A biosolids, then retained NEFCO to construct and operate a biosolids drying facility. The production of Class A EQ biosolids at the facility started in February of 2016, and is the largest facility of its kind in North America.

"The end product is dried to 97-percent solids, and it's a granulated product, so it's easy to spread," Irujo said. "We only deal with Class A EQ material that comes out to professional quality. That speaks to the pretreatment that the wastewater treatment plant has to eliminate any contaminants."

According to the Michigan DEQ, the Great Lakes Water Authority's facility in Detroit produced about 127,833 dry tons of biosolids in 2016, which includes all forms of biosolids, including that which was applied to land or sent to landfills for disposal. Of that amount, about 32,162 tons were applied to land.

Prior to the implementation of the new biosolids facility, all sludges at the plant were destroyed via on-site incinerators or were processed for Class B application. 

"The decision was made for using biosolids for a couple of reasons," said Majid Kahn, director of wastewater for the Detroit facility. "It can be re-used for fertilizer or a granular product. We had incinerators that needed to be upgraded to the maximum standards. At that point, we asked whether we should upgrade two incinerators where it is destroyed, or go the other direction where we can reuse it for a beneficial purpose."

Suzanne Coffey, Great Lakes Water Authority chief planning officer and interim COO of Wastewater, said the authority retained NEFCO to design and build the drying facility, which will also operate it under a 20-year lease agreement. The facility, at 9125 W. Jefferson in Detroit, is capable of producing 420 tons of finished biosolids each day.

"For us, this idea of sustainability is really important, and is about being a utility of the future," Coffey said. "There are other elements we plan to do in the future. We have plans for a wastewater management plan that includes recovering things like phosphorus. We think that's something that's achievable. Also, the energy we use at the plant, we want to reduce our energy consumption. There are facilities that are providing energy to the grid from wastewater. This is the first step of some very big initiatives."

Much of the pretreatment conditions at the facility help to reduce pathogens and contaminants in biosolids that are produced. Biosolids also undergo a dewatering stage, where a percentage of the liquid is removed. It then undergoes a heated drying process, where it's exposed to air at about 1000 degrees until the biosolids reach about 220 degrees for at least 15 seconds, ensuring the elimination of pathogens. It's then processed into a pellet form and stored in large silos at the site, or shipped to locations for land application.

Biosolids produced at the Detroit facility are applied by NEFCO throughout much of southern Michigan, portions of Ohio, and Windsor, Ontario, where biosolid regulations are more restrictive.

Prior to NEFCO's partnership in Detroit, the majority, if not all, biosolids applied in Michigan were Class B biosolids. 

"Detroit has skewed the amount of Class A biosolids used," said Mike Person, state biosolids coordinator with the DEQ. "In the state, there are some 30,000 dry tons of Class A, EQ, and probably 75,000 tons of Class B. Detroit is responsible for skewing that for Class A. There are only a handful of Class A facilities in Michigan, but more and more are looking at this as they are beginning to make updates. They are transitioning from Class B to a more dewatered Class A, EQ, and that's a good thing."

Jared Buzo, operations engineer with the Oakland County Water Resources Commissioner's Office (WRC), said the office has plans to upgrade the Pontiac Wastewater Treatment Plant so that it will generate Class A biosolids. Currently, the wastewater treatment plant uses an aerobic digestion method to produce Class B biosolids. 

"We always call all of it biosolids," Buzo said about the sludge and the fertilizer at the wastewater treatment plants. "In Pontiac, it goes to a digester. That heats it up and some of the biosolids will react and create a gas and reduce the amount of solids."

The gas generated by the breakdown of biosolids is used to power two boilers and an air pump at the plant to further treat the biosolids. The boilers heat up the biosolids to about 100 degrees, which many of the pathogens in the sludge. From there, the biosolids are sent to a dewatering process and are then ready for land application.

Buzo said upgrades planned at the Pontiac wastewater treatment plant in the future will heat biosolids to about 300 degrees to eliminate all additional pathogens. 

Of the some 3,633 tons of biosolids produced at the Pontiac wastewater treatment plant in 2016, about 1,302 tons were digested as biosolid fertilizer, and about 410 tons of that being applied to farm fields or pastures. The remaining biosolids and raw sludge was disposed at landfills.

"We digest as much as we can, but we have limited capacity," Buzo said. 

Still, the process saves the plant money in disposal fees. Current landfill disposal costs at the plat are $54.35 per dry ton, while the application of biosolids cost the plant $31.83 per ton. Buzo said the plant contracts with Bio Tech Agronomics of Beulah, Michigan, to handle the application of biosolids. In 2016, the company applied Class B biosolids from the Pontiac facility to fields in Genesee and Livingston counties.

Other wastewater treatment plants in Oakland County that produced biosolids fertilizer in 2016 include: Wixom, which produced and applied 564 tons of biosolids; the Walled Lake-Novi facility, which produced 337 tons of biosolids and applied 254 tons; the Holly wastewater treatment plant, which produced and applied about 299 tons of biosolids; the South Lyon wastewater treatment plant, which produced and applied 168 tons of biosolids; the Milford wastewater treatment plant, which produced and applied about 149 tons of biosolids; and the Lyon Township wastewater treatment plant, which generated and applied about 66 tons of biosolids.

Lenawee County Commissioner Bob Knoblauch, who stopped farming in about 2003, said he has received phone calls from residents who are concerned about the use of biosolids in the county, particularly the Class A EQ type coming from the Detroit wastewater treatment plant.

"When they were doing spreading when it was cold and there was snow on the ground, nearby residents – particularly when it's windy – ended up having materials in their yards, on their decks and in their water. They have dust on their window sills inside," he said. "Nobody was absolutely opposed to having the material being spread, but in those cases, they thought there should be more guidelines as far as how they had to stay away from residential property.

Knoblauch said the drifting dust from the finer quality EQ being produced has also caused some farmers to take action to stop the spread of biosolids into the watershed and nearby waterways.

"We are in the River Raisin Basin, and that goes into Lake Erie. They have put in tile structures and filter strips next to ditches," he said. "With the tiles, they can cut off water from going into a drainage system, so they put them on if they made a fertilizer application and get a heavy rain, then they can stop the water from discharging into waterways."

The runoff into the river basin, and eventually Lake Erie, is of particular concern, as it is a location that has experienced harmful alga blooms and phosphorus loading in the past.

"Because (Lake Erie) is a non-attainment area, a lot of that work is being done by farmers in the area. The farmers aren't doing the spreading; it's a contractor that does the spreading," Knoblauch said. "But on windy days when the ground is frozen, some of the material was ending up in the waterway, and they didn't feel that was a good practice to be doing it that way because some are trying to help the situation and it looked like others were creating problems."

Both the Michigan Farm Bureau and the Oakland County Farm Bureau said they weren't aware of any Oakland County farmers using biosolids on their lands. The DEQ, which maintain records of all biosolids applied in Michigan, said it's possible some farmers in the county are using biosolids, but the current tracking system makes listing application by county difficult.

Laura Campbell, agricultural ecologist with the Michigan Farm Bureau, said biosolids are a valuable resource for the agricultural industry, and a win for both farmers and the wastewater treatment plants. However, she said there are potential issues, as with other fertilizers.

"The thing that makes them particularly different is that when you deal with biosolids, it's not just human waste, it's everything that homes and businesses put down the drain, so it has to go through a process that is pretty heavily controlled by the state of Michigan," she said.

Other contaminants that are regulated by federal rules include nine heavy metals that the EPA says are commonly found in biosolids, including arsenic, cadmium, copper, lead, mercury, molybednum, nickel, selenium and zinc.

"They have to go through a treatment process to make sure we aren't contaminating farmland when it's put on, and then there are agronomic rates on where and how much they can spread it, so how much they can apply without creating runoff problems," Campbell said. 

Wastewater treatment plants that produce and apply biosolids work with third-party contractors for the actual application of biosolids to land. State and federal regulations require the applicators to conduct certain actions when applying, such as testing biosolids for some contamination and minerals before they are applied, testing soils to ensure agronomic rates of nutrients and minerals aren't being exceeded, and keeping records of tests and the exact location of the land applications. 

Biosolids that exceed certain limits can't be applied to land, or must be restricted. Limits include ceiling concentration limits, which is the maximum concentration of each pollutant allowed in biosolids for land application. The EPA also regulates pollutant concentration limits, along with pathogen level and requirements to stabilize organic matter set standards for EQ type biosolids. Those biosolids with metal concentrations below a certain level can be land applied without obtaining a permit. Those with higher levels above the pollutant concentration limits require a permit for each site and rate applied based on agronomic levels, or the nitrogen need of a crop. The cumulative amounts must be tracked. Cumulative pollutant loading rates must also be tracked, which is the maximum amount of a pollutant that can be applied to a site over its lifetime by all biosolid applications. Finally, annual pollutant loading rates determine the maximum amount each pollutant can be applied in a 365-day period.

Mike Person, with the DEQ's Biosolids Program, said the state's regulations go beyond that of federal Part 503 rules. Those rules include additional soil testing, including phosphorus limits, along with notification requirements to county health departments where biosolids are being applied.

"The permit approval process is far beyond the EPA requirements," he said. "Each facility beforehand has to have a residuals management program plan, which is their way of saying how they will comply with Michigan's Part 24 rules. From operation to vector attraction and pathogens, how it will be tested and analyzed and how it goes through the process of monitoring agronomic rates, as well as how its transported and applied to land."

Person said each facility that produces biosolids is permitted by the DEQ. He said virtually all wastewater treatment facilities then work with other companies to apply the biosolids to land. In order to meet the state and federal requirements, the contractors will execute an agreement on behalf of the treatment facility with the landowner where the biosolids are being applied. The agreements include the type of biosolids that will be applied, the rates and any restrictions on the type of crop that will be grown. The agreement and other information, including soil testing results, are provided to the treatment facilities. The facilities must provide that information to the DEQ on an annual basis.

In terms of enforcement, he said the DEQ does track it, but he can't recall any serious violations. He did confirm an incident in the early 2000s, however, in which a shipment of pickles were seized, after a farmer in the Alma area grew pickles on land that was treated with Type B biosolids. In that case, Person said a neighbor alerted the DEQ about the mix up after learning about the biosolids rules on the DEQ's website.

In 2003, a Michigan Auditor General report on the DEQ's Water Division Program, which oversees the biosolids program, found the division didn't effectively operate the program.

The Water Division did not inspect some biosolid generators or sites where they applied biosolids to verify that parties that applied biosolids to land provided or maintained current soil analysis documentation or maintain current soil analysis documentation. Of 13 wastewater treatment plants the auditors inspected in 2000 and 2001, eight didn't have complete inspections. The audit also found a backlog of residual management plans.

Person, who said he wasn't previously aware of the audit's findings, said the program has five equivalent full-time employees that cover the entire program for the state. However, he said each facility is typically inspected every year.

"We set (inspection) priorities based on the size of the facility," he said. "It's the goal to get to every one (inspected). There are some some smaller ones we don't always get to."

In terms of conducting on-site inspections where biosolids are being applied to land, Person said it's also the goal to conduct them each year, however, those actually done are "hit and miss."

"We have a goal to get out to every plant while they are land applying," he said, "but it's not always easy to do."

Professor emeritus and retired Michigan State University Extension specialist Lee Jacobs worked on research with biosolids from about 1973 to 2009 at MSU's Department of Crop and Soil Sciences. Jacobs also worked on regional research committees to help establish the EPA's Part 503 rules, and Michigan's Part 24 rules, addressing land application of biosolids in the state.

"When I came to Michigan State University, we had some pretty bad sludges that were being generated in municipalities, particularly those in conjunction with metals in the auto industry," Jacobs said. "The sludge that generated a lot of high concentrations of metals we didn't want going to agricultural land."

It wasn't until stricter water quality laws came into effect, some years after they were enacted in the 1970s, that metal concentrations in sludges started to drop, and biosolids use in agriculture was considered favorable. Jacobs said early metal samples of sludges, in some cases, were higher than some ores being mined in the state.

"To give some perspective, it takes about 10,000 parts-per-million to be a one-percent consistency. We found one sludge that had about 27,000 parts-per-million of copper, so basically, we would say there's 2.7 percent on a dry weight basis of solid materials that were essentially copper," he said. "When Michigan had a White Pine copper mine operating, they were basically mining an ore that had a one percent concentration for extracting copper ore. So, that sludge was basically a mineable resource, and something we didn't want to see go out on agricultural land."

Since that time, he said the quality has greatly improved. Further he said land application rates, which are required to be monitored in all types of biosolids, were developed by looking at many different pathways of exposures. Those pathway exposure models, he said, require solid scientific inputs to ensure safety.

"A lot of people have some unscientific views of biosolids application to land, and some just flat out don't like the process and try to make a case against it, and it's not necessarily scientifically-based rational. Lewis is among those," Jacobs said. "While he had issues with it, most issues he had didn't have a good scientific basis for it. You're always going to have people look and find something that they think isn't appropriate because they don't like the kind of material being used. 

"It's not just biosolids, but a lot of scientific issues that people don't like. I'm not saying they don't have valid fears, but a lot of those negative things are based on they just don't like it and are trying to get it stopped."

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