People who visit Joe Van Groll’s ethanol plant in Stratford, Wis., typically look around and say, “This is it? You don’t have much here.” To which he replies, “Exactly, that’s why I can [make ethanol] so cheap.” Van Groll has experimented with a whey-to-ethanol process part time for more than a decade and full time for the past four years. He believes he can produce ethanol for less than $1 per gallon. The feedstock he uses is whey permeate, the waste product of cheese manufacturing. Although it may sound more complicated than producing ethanol from corn, Van Groll’s philosophy is to avoid waste and keep things simple. The energy integration he is targeting, however, is anything but simple. Besides turning the whey permeate into ethanol, he separates and dries the yeast coproduct for feed; utilizes the waste heat from fermentation and distillation for biodiesel production; and is now demonstrating that the waste heat, water and carbon dioxide can be used to raise oil-bearing algae for biodiesel. He can also incorporate an anaerobic digester that turns wastes into methane to power the process.

While the integration appears complex, the machinery is rather basic. The plant relies upon the same kind of tanks and liquid transfer systems utilized in cheese plants, Van Groll says. “The receiving tanks for the whey permeate are milk silos, which become the fermenters,” he says. “We make a couple of pumps do a lot of work for us.” The major difference is the distillation system for the ethanol process.

Van Groll’s whey-to-ethanol process solves a waste disposal problem for the cheese industry, and at the same time sidesteps some of the criticisms regarding corn ethanol. Whey permeate is the liquid that remains after cheese makers extract the protein from whey. Large cheese makers dry the whey permeate and sell it as a feed supplement. Smaller cheese plants often can’t justify the capital investment required to purchase dryers; furthermore rising energy costs are pushing drying costs higher. Each year the United States produces 10 billion pounds of cheese, which results in 86 billion pounds of whey permeate. Wisconsin alone produces about 18 billion pounds of whey annually. Because the whey permeate has a high biological oxygen demand that requires pretreatment before it can be disposed of in municipal water treatment facilities, much of that permeate is spread onto farmers’ fields, with the cheese plant paying the cost. There is a limit, however, as to how much can be dumped on a given field and environmental regulators are beginning to restrict the practice, Van Groll says. “My process takes a cost center and turns it into a profit center,” he says.

With 15 years in the cheese industry, Van Groll knows the issues cheese makers are facing. During that time, he was often charged with making arrangements for disposing of the whey permeate. That might have been just the impetus he needed to look for new uses for the cheese byproduct.

Van Groll and a friend began to experiment by making ethanol from the liquid waste starting with batches in 5 gallon pails in Van Groll’s garage. Four years ago, he purchased the closed Grand Meadow Co-op cheese plant at Stratford, Wis., to scale his project up to the next level. He formed Grand Meadow Energy LLC to hold the intellectual property, and DuBay Ingredients LLC owns the plant.

Van Groll developed the whey-to-ethanol process with help from Clay Boeger, his sole employee who contributed his skills as a stainless steel fabricator to make modifications as the two developed the processes. In their work, they established that every 100 gallons of whey permeate at 16 percent solids will produce 8 gallons of ethanol, 8 pounds of dry yeast, 60 pounds of carbon dioxide and 16 gallons of water. The energy spent to produce 1 gallon of ethanol is 30,000 British thermal units, according to Van Groll, which is a favorable energy balance compared with ethanol’s 84,000 Btus per gallon.

Greener than Corn
One of the criticisms directed at the corn ethanol industry is that it takes about 3 gallons of water to make 1 gallon of ethanol. Water isn’t an issue when it comes to Van Groll’s process. “Cheese whey permeate is 85 percent water to start with,” he explains. No water is added, and the water leftover from the process is recycled and used for tank washing.

Energy savings can also be achieved, particularly when the permeate arrives from the cheese plant at 90 degrees Fahrenheit. Sometimes the cheese plants chill the permeate to 40 degrees for holding, in that case Van Groll says to keep energy costs low the waste heat from the distillation process should be recycled to heat the chilled permeate before fermentation.

The expense and equipment required to carry out the saccharification process in a corn-based ethanol plant aren’t required in Van Groll’s process because whey permeate is primarily water and lactose—the form of sugar found in milk. While it’s considered a difficult sugar to ferment, through trial and error Van Groll discovered the right combination of yeasts, nutrients and conditions to make it work. “The existing Carberry process is a 30-year-old patent using a simple yeast strain, but it could only use 10 percent solids with lactose. I can use up to 20 percent solids and get a greater content of alcohol in a shorter period of time,” he says.

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