Engineers study biochar to fertilize crops, manage manure odors, reduce greenhouse gases

Scientists Chumki Banik, left, and Santanu Bakshi show how biochar can be used to extract nutrients from livestock manure. Bakshi is pouring a simulated manure sample into a column of biochar, demonstrating how a biochar-based bioreactor system would separate, capture and process phosphorus for use in slow-release fertilizer pellets. Photo by Christopher Gannon.

Heat up stalks, stems, leaves or wood in a reactor with little or no oxygen (in a process called pyrolysis) and you get bio-oil for fuel and biochar for fertilizer.

There’s always a market and a value for the liquid energy.

But efforts to study, develop and market the black powder as a fertilizer weren’t adding a lot of value to biochar – at least until there’s a carbon market that will pay a premium for the charcoal’s ability to store carbon.

Robert C. Brown

Iowa State University’s Robert C. Brown and his collaborators thought there might be some new ideas and applications that could make biochar a more valuable and useful product, thus enhancing the economics of biorenewables.

So, a few years ago – with nearly $1.5 million from the Biomass Research and Development Initiative, a joint program of the U.S. Departments of Agriculture and Energy – they began using biochar to capture phosphorus from livestock manure and create a slow-release crop fertilizer.

A new, three-year, $1 million, competitive grant from the Agriculture and Food Research Initiative of the USDA’s National Institute of Food and Agriculture will allow them to build on that biochar project.

The researchers say their latest project could one day provide “ecosystem services” such as reductions in manure odors, greenhouse gas emissions and fertilizer runoff to waterways.

“This new grant gives us opportunities to specifically study animal agriculture for ways to valorize biochar even further,” said Brown, an Iowa State Anson Marston Distinguished Professor in Engineering, the Gary and Donna Hoover Chair in Mechanical Engineering, the director of Iowa State’s Bioeconomy Institute and the leader of the latest biochar research project.

Biochar as a manure manager

Santanu Bakshi, an environmental research scientist at the Bioeconomy Institute, has spent about a dozen years studying biochar, everything from doctoral student efforts at the University of Florida to remove copper from the soils of citrus groves to Iowa State efforts to make phosphorus stick – adsorb – to the surface of biochar.

There’s a trick to the latter: Santanu found that pretreating biomass with iron sulfate, an inexpensive byproduct of steel production, modifies the surface of biochar, which has a mostly negative-charged surface, to adsorb, rather than repel, negatively charged molecules such as phosphorus. That biochar-phosphorus combination ended up creating a slow-release fertilizer.

“When we found biochar was useful to trap phosphorus, we thought it would be useful for recycling nutrients from animal manure,” Bakshi said.

The new project will continue to develop biochar technology for capturing phosphorus. It will also develop technology that uses a naturally occurring mineral called zeolite (which attracts positively charged molecules) to capture nitrogen. The two nutrients would then be processed into solid, slow-release fertilizer pellets.

The research team (see sidebar for the full team) will start in the laboratory. Next year, with the help of an industrial-scale pyrolyzer now under construction just west of Des Moines, they’ll have enough biochar for laboratory, farm and field studies.

Bakshi said the goal is to develop an automated bioreactor system. Manure would move through a series of biochar and zeolite chambers that separate, capture and process the nutrients. The resulting biochar and zeolite would then be made into pellets and applied to fields rather than raw manure with its potential for odor, transportation, runoff and greenhouse gas emission problems.

That switch could have big environmental impacts.

“The United States Environmental Protection Agency estimates that 15% of the greenhouse gas emissions are associated with animal manure management in the United States agricultural sector,” the researchers wrote in a project summary. “Hence, it is critical to develop enhanced nutrient management strategies to boost nutrient use efficiency in crop production, improve water quality, and reduce odorous and greenhouse gas emissions.”

Advanced manufacturing for biorenewables

The new project will start with biochar supplied by Iowa State’s existing pyrolysis pilot plant at the BioCentury Research Farm west of Ames.

Iowa State’s pilot plant – developed, in part, as part of RAPID, the country’s 10th Manufacturing USA Institute, supported by the U.S. Department of Energy and led by the American Institute of Chemical Engineers – tests the autothermal pyrolysis process developed at Iowa State.

The autothermal process adds a small amount of air to normally oxygen-free pyrolysis. That partially burns some of the biomass being processed and creates some heat for the reactor, dramatically increasing the rate that biomass can be converted to bio-oil and biochar.

One of the RAPID project’s industry partners, Stine Seed Co. of Adel, is working with Frontline BioEnergy of Nevada to build an industrial autothermal pyrolyzer plant based on Iowa State’s technology. It would also test the idea that small, efficient biorefineries could process local biomass, saving the cost and trouble of transporting large amounts of biomass to big biorefineries.

The Stine plant in Redfield will process 50 tons of biomass per day and create 10 tons of biochar per day; Iowa State’s pilot plant can process about a half ton of biomass per day.

“We’re looking forward to scaling up our technology in the Stine pyrolyzer,” Brown said. “That’s important because so much of our work has been done at the lab scale and with small pilot plant studies.”

But those studies have led to big ideas for the bioeconomy such as finding ways to provide ecosystem services in addition to biorenewable products. As a summary of the Bioeconomy Institute’s work says, “Biorenewable feedstocks are produced from an ecosystem that needs to be conserved and renewed in order to ensure future production capacity.”

The original story appeared at Iowa State University News. Read the original story.

Phoenixville’s wastewater treatment plant to get a first-of-its-kind upgrade

Read the full story from WHYY.

Phoenixville has announced plans to build what it claims will be the first hydrothermal carbonization plant at a municipally-owned wastewater treatment center not only in Chester County, but in all of North America.

Making green hydrogen and biochar from digestate

Read the full story at Biocycle.

Hitachi Zosen Inova USA (HZIU) announced it has entered into an agreement with the Canadian technology company CHAR Technologies Ltd. to develop a test project to produce green hydrogen and biochar at HZIU’s San Luis Obispo, California biogas plant.

Student’s Pig and Pines Project aims to find waste solutions

Read the full story from North Carolina State University.

A believer in fresh perspectives and sustainable biological solutions, Victoria Augoustides has been the lead researcher on a project to add value and remediate waste products of pine and swine production in North Carolina.

California high school student wins 2020 US Stockholm Junior Water Prize

Read the full story at Water World.

Eshani Jha is the winner of the 2020 U.S. Stockholm Junior Water Prize for her method to use modified biochar for the removal of toxic contaminants from water.

Evaluating the Effects of Biochar with Farmyard Manure under Optimal Mineral Fertilizing on Tomato Growth, Soil Organic C and Biochemical Quality in a Low Fertility Soil

Rehman I, Riaz M, Ali S, Arif MS, Ali S, Alyemeni MN, Alsahli AA. (2021). “Evaluating the Effects of Biochar with Farmyard Manure under Optimal Mineral Fertilizing on Tomato Growth, Soil Organic C and Biochemical Quality in a Low Fertility Soil.” Sustainability. 13(5):2652.

Abstract: Biochar amendments are widely recognized to improve crop productivity and soil biogeochemical quality, however, their effects on vegetable crops are less studied. This pot study investigated the effects of cotton stick, corncob and rice straw biochars alone and with farmyard manure (FYM) on tomato growth, soil physico–chemical and biological characteristics, soil organic carbon (SOC) content and amount of soil nutrients under recommended mineral fertilizer conditions in a nutrient-depleted alkaline soil. Biochars were applied at 0, 1.5 and 3% (w/w, basis) rates and FYM was added at 0 and 30 t ha−1 rates. Biochars were developed at 450 °C pyrolysis temperature and varied in total organic C, nitrogen (N), phosphorus (P) and potassium (K) contents. The results showed that biochars, their amounts and FYM significantly improved tomato growth which varied strongly among the biochar types, amounts and FYM. With FYM, the addition of 3% corncob biochar resulted in the highest total chlorophyll contents (9.55 ug g−1), shoot (76.1 cm) and root lengths (44.7 cm), and biomass production. Biochars with and without FYM significantly increased soil pH, electrical conductivity (EC) and cation exchange capacity (CEC). The soil basal respiration increased with biochar for all biochars but not consistently after FYM addition. The water-extractable organic C (WEOC) and soil organic C (SOC) contents increased significantly with biochar amount and FYM, with the highest SOC found in the soil that received 3% corncob biochar with FYM. Microbial biomass C (MBC), N (MBN) and P (MBP) were the highest in corncob biochar treated soils followed by cotton stick and rice straw biochars. The addition of 3% biochars along with FYM also showed significant positive effects on soil mineral N, P and K contents. The addition of 3% corncob biochar with and without FYM always resulted in higher soil N, P and K contents at the 3% rate. The results further revealed that the positive effects of biochars on above-ground plant responses were primarily due to the improvements in below-ground soil properties, nutrients’ availability and SOC; however, these effects varied strongly between biochar types. Our study concludes that various biochars can enhance tomato production, soil biochemical quality and SOC in nutrient poor soil under greenhouse conditions. However, we emphasize that these findings need further investigations using long-term studies before adopting biochar for sustainable vegetable production systems.

How These Scrap Wood Startups Could Help Colorado Fight Wildfires

Read the full story from CPR News.

If there’s a piece of wood out there, James Gaspard will probably take it. 

The 17 acres his company owns in Berthoud, Colo., is stacked with rejected trees from across the state. The beetle-kill branches and fire-scarred trunks wait to be fed into 100 massive kilns, which look like a fleet of rusty UFOs landing in the farmland below Longs Peak. 

His company, Biochar Now, uses the contraptions to convert wood into biochar, a carbon-rich charcoal that can help soil retain water and nutrients.

Gaspard said the cannabis industry has been an early and loyal customer, but he sees vast possibilities beyond agriculture. In his office, he showed off newer product ideas: cat litter, animal feed, water filters, plastic, soap — all made from wood usually treated as trash. 

“We’re making a market for stuff that had no market,” Gaspard said. 

As Colorado recovers from its worst wildfire season in recorded history, many foresters see entrepreneurs like Gaspard as essential. Products like biochar could provide the financial motivation for fire mitigation products, which reduce fuels but also creates massive piles of unwanted timber. 

EPA Awards Nearly $1 Million to University of Illinois to Research How to Control and Prevent Harmful Algal Blooms

The U.S. Environmental Protection Agency (EPA) has announced $999,377 in funding to the University of Illinois to research how to control and prevent harmful algal blooms (HABs). Specifically, the research will address subsurface drainage systems that can deliver large quantities of nutrients from agricultural fields to receiving watersheds, potentially leading to HABs.

“Harmful algal blooms are a serious and persistent problem across all 50 states that can have severe impacts on human health, the environment, and the economy,” said EPA Administrator Andrew Wheeler. “By expanding our knowledge of how to control and prevent the occurrence of these blooms, we can better protect our watersheds—especially our drinking water sources and recreational waters.”

“EPA proudly supports the efforts of the University of Illinois to develop innovative approaches to combat excess nutrient runoff,” said Regional Administrator Kurt Thiede. “This work is vital in improving our ability to control harmful algal blooms and protect water resources for all residents.”  

The project, “Development of a Novel Bioreactor and Biochar-Sorption-Channel (B2) Treatment System to Capture and Recover Nutrients from Tile Drainage,” will produce and scale up an innovative treatment system to effectively capture excess nutrients from subsurface drainage in agricultural fields, recycle the nutrient-captured biochar as a slow-release fertilizer, and keep nutrients in the closed agricultural loop. The project is expected to offer an innovative, feasible, and cost-effective practice to mitigate the loading of excess nutrients into watersheds from agricultural fields, improve water quality, and thereby diminish the occurrence of HABs.

“This process has the potential to be a win-win for agriculture, not only by reducing the nutrient run-off that leads to harmful algal blooms but also by capturing those nutrients and routing them back into fields, leading to increased yields,” said Illinois Sustainable Technology Center director Kevin C OBrien. “It’s our goal to put cost-effective, feasible tools for sustainability in farmers’ hands.”

Seven grants totaling over $6 million were awarded to institutions to address the environmental challenges posed by HABs. Through the development of new technologies and the optimization of existing technologies and best management practices, these projects will assist in reducing excess nutrients that enter the Nation’s waterways and support EPA’s goal to reduce the occurrence of HABs across the United States.   

Preventing and mitigating excess nutrients in our waters, and the HABs that they can create is one of EPA’s highest water quality priorities. In 2020 alone, EPA has awarded Small Business Innovation Research funding to companies developing technologies to better detect HABs, released draft nutrient criteria for lakes and reservoirs, and announced an award of more than $2 million in funding to help states implement plans to that reduce excess nutrients and improve water quality in the Mississippi River/Atchafalaya River Basin. Today’s award marks the largest research grant to date to support a nation-wide effort to prevent and control HABs.


HABs are overgrowths of algae in water that have the potential to harm human health and aquatic ecosystems. There are several factors that can cause HABs to develop, including excess nitrogen and phosphorous in waterways.

Two-part series on growing bedding plants with biochar and vermicompost

BioCycle has a two-part series on growing bedding plants with biochar and vermicompost. The articles include:

New project uses biochar to absorb excess nutrients from tile drainage

by Lisa Sheppard, Prairie Research Institute

In a new $1 million three-year project, Illinois Sustainable Technology Center (ISTC) researchers will develop a bioreactor and biochar-sorption-channel treatment system to remove excess nitrogen and phosphorus from tile drainage water, which will reduce nutrient loss from crop fields to local waterways.

Excess nutrients in surface water contribute to harmful algal blooms that produce toxins and threaten the health of water ecosystems. A variety of treatment techniques have been studied to reduce nutrient losses.

Woodchip bioreactors, which are buried trenches, have proven to be a cost-effective and sustainable solution to reduce nitrate-nitrogen loss from tile-drained crop fields. However, concentrations of ammonium-nitrogen are often elevated after water has flowed through a bioreactor. Also, woodchip bioreactors do not have a significant effect on phosphorus removal.

Principal investigator Wei Zheng and colleagues plan to develop an innovative treatment system by integrating woodchip bioreactor and designer biochar treatment techniques to reduce the losses of both nitrogen and phosphorus nutrients from tile drainage.

Designer biochars are applied in biochar-sorption-channels to capture dissolved phosphorus and ammonium-nitrogen simultaneously. Researchers will seek to produce the most efficient designer biochars by pyrolysis of biomass pretreated with lime sludge.

The U.S. Environmental Protection Agency-funded project will evaluate the new system by conducting a scale-up field study at a commercial corn production farm.

Researchers will also apply the nutrient-captured biochars as a soil amendment and a slow-release fertilizer in fields to improve soil fertility.

The results from this project will help federal and state agencies and farmers evaluate their current nutrient management practices, inform science-based regulatory programs, and offer an innovative, feasible, and cost-effective practice to mitigate the excess nutrient loads to watersheds, prevent and control algal blooms, and improve agricultural sustainability.

Media contact: Wei Zheng, 217-333-7276,

This post originally appeared on the ISTC blog.