Author: Lisa Sheppard

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Study tracks emerging contaminants from landfill to treatment plant to application

Aerial photo of a wastewater treatment plant.
Photo credit: Amine KM/Pexels

Treatment plants can effectively remove microplastics and per- and polyfluoroalkyl substances (PFAS) from wastewater before they’re discharged to lakes and rivers, but large amounts of contaminants end up in solid waste, called biosolids, often used on agricultural fields as soil nutrients. By land applying this material, these contaminants then are re-released back into the environment.  

In a recent study published in an Illinois Sustainable Technology Center report, John Scott, analytical chemist at ISTC in the University of Illinois, studied the fate of microplastics and PFAS as they moved from landfill leachate, or water that filters though the mound of trash, to wastewater treatment plants and beyond. As health concerns about PFAS in water continue to grow, Scott predicts that state and federal regulatory agencies will set rules limiting these contaminants in water.

“I expect regulations concerning PFAS will be coming soon, but the big question is that nobody knows where to set the limits because the toxicity of PFAS hasn’t been established yet,” Scott said.   

To date, wastewater treatment plants are not required to monitor for PFAS and microplastics, so studies on these contaminants provide a better understanding of their major sources and how they can end up in the environment.

Eighty percent of plastics are destined for landfills. Among the castaways are food packaging, furniture, clothing, and other textiles that shed microplastics and PFAS contaminants. Scott noted that while all samples contained both microplastics and PFAS, PFAS concentrations in landfill leachate were found to be much greater than in wastewater influent.  

After wastewater treatment, the highest levels of microplastics and PFAS were in the biosolids, of which 50% are applied back to the land. If farmers stop using biosolids in fields due to regulatory and liability issues, the only option is to send them to landfills where the cycle from landfill to wastewater treatment plant will continue.

“Once in landfills, the stuff moves into the leachate, which is headed back to the wastewater treatment plant,” Scott said. “We’re just moving them from one environmental compartment to the next without addressing the problem. We never get rid of them; we’re just shifting them back and forth.”

To manage this problem, which is increasing over time because plastics and PFAS take so long to break down, consumers have some responsibility, he said.

“People have the perception that when you throw something away and it goes to a landfill, then it’s gone forever, when it’s not,” Scott said. “A landfill is just a holding place, and actually, the contaminants will end up fugitive in our environment.”

If the use of PFAS is regulated, PFAS in raw sewage will decrease, but contamination in landfill leachate will continue to rise, Scott said. Similarly, as plastics are added to landfills, they breakdown to smaller sizes, increasing contamination levels in leachate. Over time, landfills will become an even more significant sources of these contaminants, as well as many others. 

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Media Contact: John Scott, 217-333-8407, zhewang@illinois.edu

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TAP helps Chicagoland organizations tackle food waste

In an ISTC pilot project, several small organizations in Chicago learned that there are better, feasible options for handling wasted food than throwing it away. Composting, for one, works well for businesses that have access to compost hauling services.

The ISTC Technical Assistance Program (TAP) helps businesses and industry find solutions to reduce waste and use sustainable technologies. For this project, TAP staff hoped to make a difference working with owners of small businesses in disadvantaged communities that lack resources and are often overlooked for funding, according to Zach Samaras, ISTC technical assistance engineer and project director. The project is part of the University of Illinois Extension program, Building a Culture of Composting in Greater Chicagoland.

The five businesses in the case study included the Abiding Love Food Pantry in Zion, IL; Casa Central, a Latino social services agency with a full kitchen on site, located in Humboldt Park; Food He.ro, a Latino-led culinary school and grocery store in the Little Village; Khepri Café, a café and kitchen in Albany Park; and Tom’s Place, a full-service breakfast and lunch restaurant in the Back of the Yards community.

After touring the businesses, Samaras and staff collected, sorted, and weighed two days-worth of waste and recycling to determine how much could be composted. Results showed that more than 60 percent of all material sorted could be handled this way. The waste audit illustrated the amount of waste each day that these businesses produce.

“Most business owners probably think that they don’t waste that much so showing them the data was really eye-opening for them,” Samaras said. “It helped people put into perspective that the amounts get pretty big, pretty fast. It also helped them to get on board, to understand the issue and what they can do about it.”

TAP provided funding for compost hauling services and staff gave individualized recommendations and helped set up compost bins and coordinated services. Some of the challenges to initiate composting and reduce waste by other means were physical space issues in tight kitchens and the importance of staff on different shifts communicating about prioritizing foods for future shifts so less food is wasted.

Samaras did find, though, that kitchen staff were receptive to suggestions. Besides composting, other waste-reduction measures were suggested, such as preventing food waste by highlighting food soon to expire, donating food, and recycling food scraps.

“It tends to be the case that people who work with food are conscious of food waste and want to do a better job, but they are busy folks,” Samaras said. “They don’t have time to be looking up storage techniques.”

One of the five businesses was unable to initiate a composting program because they are located outside of Chicago where there are few compost haulers to service the area. The other four businesses were interested and committed to continuing their program after the funding ends.

For more information, read the case study, Food Waste Technical Assistance for Small Businesses. The project was funded by an NTAE Extension Foundation Expansion Grant. ISTC’s TAP program helps to make companies and communities in Illinois more competitive and resilient.

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Media contact: Zach Samaras, 217-265-6723, zsamaras@illinois.edu.

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New law fosters farmers’ fresh produce donations to Illinois food banks

With Governor JB Pritzker’s signature on House Bill 2879, the Farm to Food Bank Program has been established in Illinois. The program helps farmers donate their surplus produce to local food banks and assists more than 1 million Illinoisans facing food insecurity. An ongoing three-year Illinois Sustainable Technology Center (ISTC) effort, which includes a feasibility study and pilot projects, has proven that the program can be successful in Illinois.

“This new law recognizes that we have a lot of residents facing hunger and a lot of surplus food on farms,” said Zach Samaras, ISTC technical assistance engineer and project director. “This program will support farmers with a secondary market, provide local, nutritious food to those in need, and reduce wasted food and wasted resources at the farm.”

The ISTC feasibility study began in 2020 when Feeding Illinois, the association of Feeding America food banks serving the state, commissioned ISTC to discover if the Farm to Food Bank Program is needed, wanted, and achievable in Illinois. ISTC staff visited eight food banks to learn about any existing relationships with local farmers and interviewed organization personnel that manage similar programs in 14 other states. In partnership with the Illinois Farm Bureau and the Illinois Specialty Growers Association, they also surveyed and conducted focus groups with Illinois farmers.

Over 60 percent of farmers surveyed were interested in finding new markets for some or all their commodities. The barriers to donating or selling food to food banks were primarily packing and labor expenses, storage, and transportation. 

In 2022, ISTC coordinated six pilot projects that resulted in donations of nearly 2.5 million pounds of produce that would have otherwise gone to waste, yielding nearly 990,000 meals. Feeding Illinois received a grant from the U.S. Department of Agriculture that provided $611,000 to reimburse farmers for some of their expenses incurred in donating produce. 

“We learned from our focus groups that farmers want to donate their surplus food, but that it should not be a burden on them financially to pick produce, package it, and deliver it to food banks,” Samaras said. “This program provides a safety net for farmers so they can grow a few extra acres for their primary markets, knowing that if they don’t sell everything, there is a program that can help them recoup some costs and make sure that the food is going to end up on someone’s plate.”

The newly signed law will invest $2 million to support already strained food banks and the farmers who donate food. The law also provides grants for capital improvements to transport and store food for underserved communities, which often lack the resources for residents to obtain fresh fruits and vegetables.

Links for more information about the feasibility study, Farm to Food Bank survey results, pilot projects, and a 2022 summary report are available on the ISTC Technical Assistance Program website. ISTC is a unit of the Prairie Research Institute at the University of Illinois Urbana-Champaign.

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Media contacts: Zach Samaras, 217-265-6723, zsamaras@illinois.edu; Joy Scrogum, 217-333-8948, jscrogum@illinois.edu.

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Scientists study how a diabetes drug affects soils

The transport of pharmaceuticals released from sewage treatment plants into farmland soils, with the potential to load into drinking water sources, is one that researchers at the Illinois Sustainable Technology Center (ISTC) study carefully. Even at low concentrations, medications can affect water ecosystems and soil health.

“Applying sewage waste to crop fields is a win-win practice because it provides nutrients and organic matter to the soil and prevents waste sludge from ending up in landfills,” said Wei Zheng, ISTC environmental chemist. “The issue is that wastewater treatment plants cannot remove emerging contaminants and pharmaceuticals. We cannot ignore the potential risks from this practice.”

Biosolids, which are treated sewage sludge, are a product of the wastewater treatment process. Biosolids can be used on farmland to improve soil fertility, Zheng said.

In a recent study, Zheng and colleagues investigated the adsorption of sitagliptin in soils treated with sewage wastewater. Sitagliptin is commonly used to treat diabetes and is frequently detected in sewage effluent and the environment because it does not fully degrade during the wastewater treatment process. Lagoon-based sewage treatment systems in rural areas also remove fewer contaminants than typical municipal wastewater treatment facilities, so contaminant concentrations in sewage are higher.

Sitagliptin concentrations in the environment are unregulated in the United States. The drug is considered an emerging contaminant for its potential risk to the public. 

Study findings showed that biosolids, which have a large amount of organic matter, bonded with the medication in soils and reduced its adsorption. Results also showed that increasing the amount of sewage effluent used for soil amendment reduces the adsorption of sitagliptin in soils.

Metformin is often prescribed, sometimes with sitagliptin, to treat diabetes. As part of this study, the researchers examined how this medication affects the uptake of sitagliptin in soils. Metformin is more water soluble, more degradable, and has less adsorption in soils than sitagliptin. 

They found that increasing metformin concentrations in sewage effluent reduced the interaction of sitagliptin with the soil surface. This means that multiple pharmaceuticals and personal care products (PPCPs) in sewage can compete in soils, reducing the adsorption capacities of individual products.

“Some states have regulations for contaminants, such as per- and polyfluoroalkyl substances (PFAS), which are considered ‘forever chemicals’, in biosolids and sewage effluent, so over certain levels, biosolids cannot be used for soil amendments,” Zheng said. “In Illinois, there are no regulations, so it’s highly possible that organic chemical contaminants released from biosolids will leach to drinking water supplies, especially in rural areas. It is important to study and explore ways to minimize the leaching and runoff of PPCPs.”

The results of this study can be used to predict how other PPCPs are transported and adsorbed on agricultural soils and develop management strategies to reduce the risks of using sewage wastes in rural areas.

The U.S. Department of Agriculture funded the project. An article, “Influence of Biosolids and Sewage Effluent Application on Sitagliptin Soil Sorption,” was published in the journal Science of the Total Environment. Zheng is also working on a project supported by the U.S. Environmental Protection Agency to monitor PPCPs in sewage effluent and develop mitigation strategies to protect the environment and drinking water quality.

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Media contact: Wei Zheng, 217-333-7276, weizheng@illinois.edu

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ISTC scientist is set to develop technology addressing water contaminated with PFAS

Man-made per- and polyfluorinated substances (PFAS), known as “forever chemicals,” withstand many treatment options and bioaccumulate in the environment, posing serious environmental and health concerns. With a three-year, nearly $1 million grant from the U.S. Department of Defense (DOD) Strategic Environmental Research and Development Program (SERDP), Illinois Sustainable Technology Center (ISTC) scientists are developing a new technology to remove and destroy PFAS from contaminated water using a designer biochar produced from woody biomass or agricultural residues such as corn stalks and cobs.

PFAS are a widely used class of chemicals found in many different consumer, commercial, and industrial products, including non-stick coatings and textiles. Since the 1970s, PFAS have also been used in firefighting foam, which is why the DOD is interested in finding new solutions to clean up contaminated sites where firefighters have trained, according to Wei Zheng, principal investigator of the project at ISTC, a unit of the Prairie Research Institute at the University of Illinois Urbana-Champaign.

Activated carbon, as a most common adsorbent, is typically used to treat PFAS-containing water. Once the activated carbon is saturated with the contaminants, the spent adsorbent is incinerated. However, incineration, even done at sufficiently high temperatures, cannot completely destruct PFAS and will create some hazardous and toxic byproducts. In 2022, the Office of the Assistant Secretary for Defense placed a temporary ban on incineration of materials containing PFAS until safe guidance for disposal of PFAS is issued.

“If incineration is not an option, the spent adsorbent ends up in the landfill where PFAS can leach to water sources and evaporate to air because they won’t degrade,” Zheng said. “So, PFAS will go back to the environment. In this way we just solve one issue but generate a new problem.”

In addition, wastewater treatment plants can’t solve the PFAS issue because these contaminants are never destroyed by conventional treatment techniques. That is why they are called forever chemicals.

In the new project, Zheng will develop a hydrothermal technology, likened to pressure cooking, that will destroy PFAS absorbed on low-cost designer biochar created at ISTC, and at the same time reactivate the biochar that has reached its sorption capacity for reuse. Thus, the designer biochar will act a double role as an adsorbent to remove PFAS from contaminated water and as a catalyst to destroy these compounds under a hydrothermal system. 

“The most important and innovative aspect of the project will be the complete destruction of PFAS once they are removed from the water,” Zheng said. “PFAS are widely detected in the environment and in the atmosphere. Our project is designed to mitigate human exposure to PFAS, helping to find ways to indeed solve this problem.”

ISTC is collaborating with researchers at the U.S. Army Corps of Engineers Construction Engineering Research Laboratory on this project.

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Media contact: Wei Zheng, 217-333-7276, weizheng@illinois.edu
news@prairie.illinois.edu

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Technology to absorb CO₂ at power plants is promising

ISTC engineer Paul Nielsen stands beside the biphasic solvent system at the Abbott Power Plant.
ISTC engineer Paul Nielsen stands beside the biphasic solvent system at the Abbott Power Plant.

Illinois Sustainable Technology Center (ISTC) researchers have given the thumbs up to an innovative biphasic solvent system for its efficiency and effectiveness in absorbing CO₂ from flue gas in a coal-fired power plant at the University of Illinois (U of I).

With $3.4 million from the U.S. Department of Energy (DOE) National Energy Technology Laboratory, an ISTC team sought to validate the various advantages of a biphasic CO₂ absorption process (BiCAP) at a 40-kilowatt electric small pilot scale at the Abbott Power Plant on the U of I campus. The system was designed based on the testing results at the laboratory scale under a previous DOE cooperative agreement.

Previous laboratory testing has proved the biphasic solvent-based process concept and has shown that the technique can achieve greater than 90 percent capture efficiency and greater than 95 percent CO₂ purity and has the potential to significantly increase energy efficiency and reduce  CO₂ capture cost.

From the recent field testing, the team verified that their technology could achieve 95 percent efficiency in CO₂ capture, compared with 90 percent in conventional methods, with a 40 percent higher energy efficiency. The cost advantages have not yet been determined, but previous laboratory testing showed a 26 percent cost reduction. The system has also been shown to run continuously for two weeks, verifying that it can operate under Midwest winter weather conditions.

“The conventional CO₂ capture process has several disadvantages, and our goal was to reduce the carbon footprint and costs and increase the energy efficiency,” said Yongqi Lu, principal investigator. “These energy-efficiency advantages of the BiCAP system, coupled with reduced equipment sizes when scaled up for commercial systems, will lead to reductions in both capital and operating expenses.”

The BiCAP method uses biphasic solvent blends that can form and develop dual-liquid phases during CO₂ absorption. The solvents, which were tested and selected in previous DOE-funded studies, are highly resistant to degrading from either high temperatures or oxidative atmospheres. Also, less solvent is required for this process.

Although the focus of the study was on CO₂ capture from flue gas at coal-fired power plants, the BiCAP technology can be used in natural gas combined cycle (NGCC) plants as well, incorporating flue gas from natural gas, biomass, plastics, and other renewable materials.

“The exciting feature of this capture technology is its robust nature and ability to be used on a variety of flue gas sources. We are now ready for commercial partners to assist in moving this technology to the marketplace,” said Kevin OBrien, co-principal investigator for the project and director of ISTC.

Preliminary tests with synthetic NGCC flue gas made of air and bottled CO2 gas have been performed on the small pilot unit recently. Results revealed that a 95 percent CO2 removal rate could be achieved, and the energy use only slightly increased compared with that for the coal flue gas that contains more concentrated CO2.

The concept of biphasic solvents was developed as part of a dissertation research project in 2013–2015. From 2015 through 2018, screening of biphasic solvents and studies of proof of the BiCAP process concept were conducted at the laboratory scale with funding from DOE. After that, the small pilot system was designed, constructed, and tested at the Abbott Power Plant with continued DOE support.

The main research team for this project was transferred from the Illinois State Geological Survey (ISGS) to ISTC in January 2022. Now that the team has collected the data, the next steps are to complete a techno-economic analysis, then scale-up the technology for commercial use.

Media contact: Yongqi Lu, 217-244-4985, yongqilu@illinois.edu or
news@prairie.illinois.edu

This story first appeared on the Prairie Research Institute News Blog. Read the original story.

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Microplastics on the move: Research projects detect microplastics in water and on land

Microplastics

The mind-boggling amount of microplastics in the environment is becoming a greater concern as early studies suggest serious health effects from human exposure to the plastic particles. Taking these effects seriously, the United Nations recently endorsed a historic resolution to end global plastic pollution, including microplastics.

At the Illinois Sustainable Technology Center (ISTC), researcher John Scott is studying microplastics in landfills, rural streams, and city drinking water to further understand where they are coming from and how they move in the environment.

Illinois landfills and microplastics

Since about 80 percent of all plastic waste is destined for landfills, they are a logical place to look for microplastics. Landfills that use plastic liners underneath the waste piles routinely pump out leachate, the waste “soup” that has drained into the liners. The leachate is sent to wastewater treatment plants, which are not designed to handle plastic waste.

As a result, plastic entering water treatment plants can end up either in the treated wastewater, where it is ultimately discharged to rivers or lakes, or in the sludge, called biosolids. Scott’s team has found that 99 percent of microplastics are in the biosolids, which are typically applied to agricultural lands as fertilizer. This means that microplastics taken from landfills are released back into the environment.

In this project, the researchers hypothesized that landfill leachate is the most significant source of microplastics taken to wastewater treatment plants. They compared the contribution of microplastics in leachate with other potential sources.

Although the study is still ongoing, the significance of this finding is that, although it is not feasible to treat the enormous amount of wastewater that comes into a treatment plant every day, treating the smaller amount of leachate may be an option.

“If our hypothesis is correct, then addressing plastic pollution in landfill leachate may be a more efficient and cost-effective way to reduce its environmental loading,” Scott said. “It’s better to treat the waste further upstream.”

The project has been funded by the Illinois Hazardous Research Fund.

Rural Iowa streams

ISTC is partnering with the University of Iowa and the U.S. Geological Survey in the first statewide assessment of microplastics and co-contaminants in rural Iowa streams. Most research studies to date have focused on microplastics in ocean habitats. In contrast, the research team sampled stream water, fish tissues, and rural sediments for this study. They also examined the samples for other contaminants, such as herbicides and insecticides, pharmaceuticals, and per- and polyfluoroalkyl substances (PFAS).

Some of the sediment samples have the highest concentrations of microplastics that they’ve ever seen, said Scott. With the methodology they designed in 2020, they can detect microplastics as small as 20 micrometers, while other researchers are limited to 100-micrometer sizes.

More microplastics appeared in the soil sediments than in the streams and fish tissues.

“Some of the concentrations of microplastics we found in samples were astronomical,” Scott said. “If concentrations for other contaminants approached that percentage level in the soil, it would raise an alarm. Microplastics may not be as toxic as other contaminants, but when there is this much stuff loading into out sediments, the concentrations will get worse over time.”

These findings support the theory that most of the microplastics that go to the wastewater treatment plants end up in biosolids and are released into soils in agricultural areas.

One objective of the study is to investigate the relationship of microplastics to sediments and other contaminants, such as PFAS. Microplastics can harbor exotic bacteria that are much different from that in the surrounding environment. Previous studies have shown that contaminants concentrate on these materials at hundreds of times the background levels.

In addition, studies have shown that microplastics as small as 20 micrometers can be taken up by plants.

“We don’t know if microplastics affect agricultural land, but if we load enough into our soils, it’s going to have some adverse effects, like trying to grow plants in plastic,” Scott said.

St. Louis city and county drinking water  

In a new three-year project, ISTC researchers’ role will be to investigate micro- and nano-plastics and other contaminants in surface waters, water treatment plants, and in tap water samples from residential households in St. Louis. Nanoplastics are particles that are even smaller than microplastics and are not visible to the naked eye or even under a simple optical microscope.

It is known that surface waters contain microplastics, but less is known about water distribution systems in the home and from water treatment facilities. Scott plans to trace microplastics found at water supply plants back to water distribution systems to determine if water softeners, dishwashers, and household plumbing can also be sources of microplastics.

Scott said he doesn’t expect to find microplastics originating from these sources, implying that in terms of microplastics, tap water is safer than bottled water, which contains large amounts of the plastic specks.

These efforts will be part of a larger project to determine an impact baseline for those contaminants in St. Louis city and county water systems, to survey community members to obtain their perceptions of drinking water quality, and to provide hot-spot mapping and policy recommendations for clean water investments and regulations.

Findings from the project will be provided to local water utility companies to begin to address micro- and nanoplastics in city water systems. Project partners also hope to promote equitable investments in clean water infrastructure.

The project is funded by the Missouri Foundation for Health. ISTC’s partners are Mixte Communications, Waterkeeper Alliance, and LH Consulting.

Because roadways are suspected to be another major contributor to microplastics pollution, Scott will soon begin another project, this one focused on microplastics in Michigan lakes that are highly affected by road salt.

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Media contact: John Scott, 217-333-8407, zhewang@illinois.edu
news@prairie.illinois.edu

This story originally appeared on the Prairie Research Institute News Blog. Read the original story.

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Divert and convert: Campus project takes plastic from waste stream for fuel production

Plastic straws

A new Illinois Sustainable Technology Center (ISTC) pilot project is gearing up to remove 200 pounds of non-recyclable plastics from University of Illinois campus trash daily and convert it to 140 pounds of crude oil to power university vehicles. The project will demonstrate its benefits to the environment and campus and present unique learning opportunities for students.

Behind food waste, plastics are the second largest component of trash that ends up in landfills. From the U. of I. waste stream, an estimated 1.39 tons of non-recyclable plastics head to a landfill each day. In this two-year project, scientists are using continuous catalytic pyrolysis technology capable of producing 80 percent fuels from plastics #4–#6.

“We will be demonstrating the technology for distributed production of the most desirable fuel for use in university trucks and generating data to make a business case for a commercial-scale system capable of using all plastic waste produced on campus,” said ISTC research engineer Sriraam Chandrasekaran, project principal investigator.

The project is funded by the University’s Student Sustainability Committee, which is a group of students committed to building a more sustainable campus. By converting waste to fuel, the project will decrease the amount of trash in landfills and reduce the University’s greenhouse gas emissions and reliance on fossil fuels, as well as the campus’ carbon footprint.

A critical element of the project is to involve graduate and undergraduate students in all aspects of the study, particularly those in chemical, mechanical, and environmental engineering. This project is ideal for independent study as part of a senior undergraduate program, Chandrasekaran said.

Students will learn about the technology, identify the parameters of the pyrolysis process for producing high fuel yields, and study the effect of continuous operation on various catalysts. Other tasks will include recording data on system operation and collecting and analyzing liquid samples. The research will also focus on different kinds of contaminants in plastics.

Outreach to the community is particularly important for the project. Chandrasekaran plans to have an open house to showcase the technology’s capabilities.

“The main idea is to show the community how the process works and why plastic recycling is so important,” Chandrasekaran said. “We will emphasize how much we can reduce carbon footprint through this technology, leading to a more sustainable campus. Once the process is underway, non-cyclable plastics can be considered and reclassified as zero waste.”

For more information about waste plastics and other projects, visit the ISTC website.

Media contact: Sriraam Chandrasekaran, 217-300-1477, schandr@illinois.edu
news@prairie.illinois.edu

This story originally appeared on the Prairie Research Institute News blog. Read the original article.

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Scientists study ways to reduce PPCPs transferred from soils to food plants

Plant growing in soil

The debate continues: how much risk to human health is the transfer of pharmaceuticals and personal care products (PPCPs) through soils to food plants when biosolids, sewage effluents, and animal wastes are applied to fields? As scientists speculate and study the factors that affect risk, researchers at the Illinois Sustainable Technology Center (ISTC) are finding innovative solutions to remove PPCPs before they contaminate the vegetables and fruits we consume.

PPCPs are the chemicals that make up fragrances, cosmetics, over-the-counter drugs, and veterinary medicines. These chemical residues in the environments are considered emerging contaminants because they are not yet regulated by state and federal agencies.

Organic wastes like biosolids, sewage effluent, and animal waste contain PPCP residues. When these are applied to farm fields, some of the chemicals may degrade, while others may transfer from soils to roots of vegetables and fruits, and then possibly accumulate in edible plant tissues.

Field studies have shown that pharmaceutical concentrations in soils were lower than predicted because PPCPs may degrade in soils, latch on to soil particles, or run off/leach into surface and groundwater. Yet continued and long-term application of PPCP-containing biosolids, animal wastes, and wastewater effluents may increase their concentration levels in plants, according to Wei Zheng, ISTC scientist.

“There has been much argument and debate if PPCPs derived from organic waste application in crop fields can cause risks on public health,” Zheng said. “This issue will become even more at the forefront as the use of biosolids and sewage effluents in crop production systems increases. More studies are necessary because PPCPs vary in their toxicity and physicochemical properties in the environment. In particular, the compounds that are highly persistent and toxic will be a concern.”

Zheng reviewed the literature, summarized the research findings, and made recommendations for future research in a recent article published in Current Pollution Reports.

Factors affecting PPCP transfer

In his review, Zheng reiterated that the factors that have the greatest effect on PPCP transfer are the properties of the PPCPs and soils as well as plant species. Plants grown in sandy soils have higher levels of PPCPs than those grown in high organic matter and clay soils. For certain PPCPs that are destroyed in soils, the process breaks down the original compound into metabolites that may be more toxic and mobile. Metabolites with lower molecular weights could be taken up by plant roots more readily.

Studies have also found that leafy vegetables, such as lettuce and cabbage, tend to have a higher potential to take in PPCPs than root vegetables. Furthermore, certain chemicals accumulate in the roots and have little effect on human health, while others can be transferred to leaves. Further research is needed to develop thresholds for accumulations of PPCPs in food crops when biosolids, effluents, and animal manure are used on fields.

Mitigation efforts

At ISTC, Wei and colleagues are studying several technologies to remove PPCPs, either before they reach the soils or after sewage waste application. The study is being supported by a project funded by the U.S. Department of Agriculture (USDA).

In the project, Wei is studying the feasibility of using inexpensive oils to capture hydrophobic PPCPs from wastewater effluents. The treatment, which would be used at water treatment plants, is especially low cost when applying used cooking oils, such as those from restaurants.

One advantage of this process is that oils remove PPCPs from rural sewage water while leaving behind the nutrients that fertilize crops. After capturing PPCPs, the spent oils can be used as fuel for diesel engines. The process can eliminate the captured contaminants.

Carbon-rich biochar produced from forest and agricultural residues can be used as a filter to absorb PPCPs from sewage water.  Biochar can also be directly applied to soils.

Studies found that the average PPCP concentrations in lettuce leaves decreased by 23 to 55 percent when biochar was used in the soil compared with the soils without biochar. Biochar can also be composted with solid waste to immobilize PPCPs and reduce their transfer in soil-plant systems.

In the USDA project, scientists will conduct laboratory, field, and numerical modeling studies to better understand the transfer of PPCPs to crops when rural sewage effluents are applied to agricultural lands. The results will help federal and state agencies and farmers evaluate their current nutrient management and nontraditional water-use practices, inform science-based regulatory programs, and suggest best management strategies to minimize risks and promote the safe and beneficial use of nontraditional water in agriculture.

Media contact: Wei Zheng, 217-333-7276, weizheng@illinois.edu
news@prairie.illinois.edu

This story originally appeared on the PRI News Blog. Read the original story.

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New project uses flue gas and wastewater to make algae

Aerial image of an algae cultivation system from Global Algae Innovations
Aerial image of an algae cultivation system from Global Algae Innovations

A three-year, $2.5 million Illinois Sustainable Technology Center (ISTC) engineering-scale project will be one of the first and largest to combine carbon dioxide (CO2) from a coal-fired power plant with nutrients from wastewater treatment plants to cultivate algae for animal feeds. The project will demonstrate that producing algae for commodity animal products can be cost-effective and has added environmental benefits.

Algae has been used for decades in the niche markets of health and beauty. A more recent focus is its ability to use CO2 from coal-fired power plants to make biofuels and protein-rich food products.

Algae is fast-growing compared with traditional terrestrial feed crops, so it’s an attractive alternative for use in taking up CO2 from power plants because it requires less land, according to ISTC principal investigator Lance Schideman. Researchers will use the algae species Spirulina because it is already FDA approved for use as a food ingredient and has a high protein content, which commands higher prices.

The algae cultivation system will be integrated with the City Water, Light and Power plant in Springfield, Illinois. Schideman is collaborating with University of Illinois researchers Joshua McCann and Carl Parsons, who will conduct the animal feed studies. Global Algae Innovations will provide the algae biomass production system to be demonstrated at field scale for this project. The project is co-funded by the U.S. Department of Energy National Energy Technology Laboratory.

In the past, ISTC scientists have researched wastewater algae systems that are now used at 10 full-scale operating wastewater plants. They’ve also been a leader in recycling the byproducts of hydrothermal biofuel production to enhance algal biomass productivity. Global Algae Innovations is a leading designer and equipment supplier in the algae industry that has developed and demonstrated cost-effective, large-scale algae production systems.

“We’re putting all the pieces together in a coordinated fashion and lowering the net costs of growing algae using industrial and municipal by-products as inputs to improve the economic environmental sustainability of algal carbon capture,” Schideman said.

This approach reduces pollution and replaces the costly CO2 and nutrient inputs used in most algae cultivation systems. In the current commercial technology, managers buy liquid CO2 and various commercial fertilizers for the nutrient supply.

The wastewater, which is full of organic nutrients that support algae growth, will come from a local wastewater treatment plant.

“Using wastewater is a cost savings in the production process and it helps to solve problems that wastewater treatment plants are experiencing in trying to minimize nutrient discharges in the environment,” Schideman said. “In Illinois, the treatment plants are under increasing scrutiny, and regulations that are now voluntary are expected to become more stringent and potentially mandatory within the next decade.”

Ultimately, the system will produce feed especially for cattle and chickens. The product will be dry, which helps reduce spoilage, and will have a high nutritional value compared with some other feeds.

The typical price range for most bulk animal feed ingredients is $150–350 per ton, and certain high-value products can have a market value of $1,000–$2,000 per ton. Algae has the potential to command prices near the top of the range since some species contain highly nutritional components such as antioxidants and poly-unsaturated fatty acids. However, algal animal feeds are not yet established in the market, and the value of these products must be demonstrated through research studies like this one.

Schideman notes that the size of the animal feeds market is quite large and is a good match with the amount of CO2 produced by power plants around the country. Thus, using CO2 from flue gas in algae production has the potential to significantly reduce greenhouse gasses.

Media contact: Lance Schideman, 217-390-7070, schidema@illinois.edu
news@prairie.illinois.edu