The World's #1 Renewable Energy Network for News, Information, and Companies.
Untitled Document

Paging Little Miss Muffet: Energy from Cheese Waste

Some farmers take recycling to the extreme, to the benefit of both the environment and their bottom lines. They are the often-unheralded pioneers of waste-to-energy technology, sometimes powering entire small towns with their byproducts.

The most common waste-to-energy method is to employ methane-excreting bacteria in anaerobic digesters to turn farm waste like cow manure and rotting vegetables into biogas to heat their property and even sell electricity back to the grid. For dairy farmers making cheese, however, the process can get tricky.

Getting rid of the huge quantities of cheese whey — the byproduct of the cheese-making process — is difficult because the whey matrix is rich in fat and tends to rapidly acidify. That make it unstable in reactors. Some farmers spread the whey on their fields as fertilizer, but depending upon the size of the farm, they quickly run out of field space to distribute the stuff.

“It’s a real problem,” said Elena Comino, an applied ecologist at the engineering department of Politecnico di Torino in Italy.

Now Comino and her colleagues have proposed an easy solution in a recent study: just mix the whey with cow slurry, commonly known as liquid cow manure, to get the right pH balance.

Waste to energy

Outside of nursery rhymes, whey doesn’t come up a lot in most people’s daily lives. But it is a plentiful waste product — there are only 100 dairy farms in the U.S. that produce relatively large volumes of cheese but each one can create millions of pounds of whey in a single year. Figuring out what to do with all of this waste can be a challenge.

To figure out the perfect biogas-producing concoction, the Italian researchers tried mixing different proportions of whey and cow slurry. Through trial and error, they found that a 50-50 mix of slurry and whey yields a methane concentration of about 55 percent in the biogas. This figure compares favorably with the energetic potential associated with digestion of high-energy crops like maize. “We obtained the most convenient mix in order to produce the best biogas in terms of quantity and quality,” Comino said.

Few experiments have examined the biogas potential of co-digestion of slurry or manure with whey mostly because in the past anaerobic digestion was mainly used for wastewater treatment. But the technology is becoming more popular in Europe and North America since it benefits the environment and is an additional source of income for farmers.

“Cheese whey is a waste, but if you put it in a digester you can produce biogas so it becomes something you can reuse,” Comino said.

No more lagoons

In the past, standard practice was to keep agricultural waste like cow manure was kept in an open-air lagoon before spreading it on fields as fertilizer. During this process, methane — a potent green house gas — and other pollutants were released into the air, rainfall could cause the manure to run off and contaminate local waterways. On hot days, the manure smelled awful.

With a digester, rather than being left out in the open, the manure and whey is kept in a closed container, preventing green house gases from entering the atmosphere and further exacerbating global warming. The biogas is instead used as a renewable substitute for natural gas, propane or other fossil fuels. As for the byproduct, it can be used or sold as fertilizer.

Though European farms currently leads the way with aneorobic digesters, subsidies from state a local governments in places like Pennsylvania and Vermont are increasing the affordability for U.S. farmers to install digesters. In the U.S., there are around 160 anaerobic digesters on farms. Digesters number into the hundreds of thousands to a million for the rest of the world, according to the American Biogas Council.

Selling back to the grid

Some U.S. farmers are ahead of the curve. Charley Crave owns Crave Brothers Farm and Farmstead Cheese in Wisconsin and has been recycling cheese whey for years. He estimates that he produces about 20 million pounds (10,000 tons) of whey a year. He loads both cheese whey and manure into the digester, and says he doesn’t have “a scientific recipe” for the proportions he uses. He added that the types of cheese he produces—like fresh mozzarella he sells to Whole Foods—are naturally lower in acidity.

Crave’s says there’s only a handful of dairy farmers in all of North America who use digesters to process whey. Small dairy farms usually don’t have a cheese factory on their farm and so would have to transport the whey back to the farm. Perhaps more significantly, installing a digester can cost hundreds of thousands of dollars.

After the initial installation cost, however, the digester begins to give back. Crave sells the electricity to the power company. He uses the excess heat from the generator to heat the farm. With the digester, Crave said, “There’s probably a $20,000 a year difference between purchasing that heat and utilizing what’s available.”

Crave’s farm values nutrient management and conservation efforts, so the decision to install a digester came naturally. “We feel very fortunate to have one of the higher performing manure digesters right here on our farm,” Crave said.

Rachel Nuwer is a science journalist who writes for venues including the New York Times, ScienceNOW and Audubon Magazine. She lives in Brooklyn, NY. Feel free to contact her via Twitter @RachelNuwer.

This article was originally published on ecomagination and was republished with permission.

Untitled Document

Get All the Renewable Energy World News Delivered to Your Inbox - FREE!

Subscribe to Renewable Energy World Magazine and our award-winning e-Newsletter to stay up to date on current news and industry trends.

 Subscribe Now



DOE Releases Final Programmatic Environmental Impact Statement for Hawaii

Jennifer Delony DOE released a final programmatic environmental impact statement for Hawaii to provide federal, state and county gove...

The 800 Ways Taxpayer Money Supports Fossil Fuel Industries

Reed Landberg, Bloomberg As world leaders converge on New York for a United Nations gathering that’s expected to have a strong emphasis on cli...

Makers of Fuel From Plants Feel Forsaken in Obama’s Climate Push

Mario Parker, Bloomberg Producers of motor fuels from plant waste say they have been left behind in President Barack Obama’s push to fight cl...
clean energy

Report: Vermont Clean Energy Sector Jobs Increased 9.8 Percent Since 2013

Jennifer Delony Vermont saw a 9.8 percent increase in clean energy sector jobs since 2013, and jobs in the sector are expected to gro...

PRESS RELEASES Welcomes Jennifer Delony as Associate Editor

PennWell Corporation is pleased to announce that Jennifer Delony has joined the company...

Customized Energy Solutions Executes Agreement with the Massachusetts Clean Energy Center (“MassCEC”) and the Massachusetts Department of Energy Resources (“DOER”) for Important Energy Storage Study

Customized Energy Solutions (CES) has entered into agreements with Massachusetts Clean ...

CleanTX Releases New White Paper on the Future of Texas Solar in Texas

We love this new White Paper from our clean energy partners CleanTX

Sun Xtender® Launches New Website at

The newly designed website for Sun Xtender solar batteries is now live on the World Wid...


energy efficiency

Beyond the Trend: Maximizing the Impact of Your Energy Efficiency Solution

A revolution is happening in the energy sector. From the new regulations pushed out earlier this summer by the EPA’s ...

Northeast States Create Cap-and-Trade Program for Greenhouse Gas Emissions

Northeast states have worked together for several decades to address air quality issues and, more recently, climate c...

Why the Solar PV Industry Should Love Geothermal Heat Pumps Pt 2

It’s a marriage made in heaven: Solar PV and Geothermal Heat Pumps Part 2 of a 6-Part Series Prevailing Heati...

Park District Goes Solar, Saves Big While Preserving Open Space

Not only do community parks provide green space for recreation and leisure, they also increase property values, attra...



Volume 18, Issue 4


To register for our free
e-Newsletters, subscribe today:


Tweet the Editors! @jennrunyon



Biogas 3: free online trainings on sustainable small-scale biogas f...

The main objective of BIOGAS3 (Sustainable Small-scale biogas production...

International Energy and Sustainability Conference 2015

The fourth International Energy and Sustainability Conference will be he...

2015 AREDAY Summit

The 12th Annual AREDAY Summit, August 8-13th in Snowmass Colorado. Engag...


New coating extends cylinder life 8 times longer than traditional c...

Hydroelectric turbine systems operate in extremely harsh conditions. The...

Clean Energy Patents Maintain High Levels in First Quarter, Solar L...

U.S. patents for Clean Energy technologies from the first quarter of 201...

SAP for Utilities Blog

The Eventful Group produces the annual SAP for Utilites Conference ...


Renewable Energy: Subscribe Now

Solar Energy: Subscribe Now

Wind Energy: Subscribe Now

Geothermal Energy: Subscribe Now

Bioenergy: Subscribe Now