Brewing operations have been around for a long time. In fact, the oldest proven records of brewing are about 6,000 years old, dating back to the Sumerians who discovered the fermentation process. While the beer-making process isn't novel in itself, Aurora, Colo.-based Merrick Co. has experienced success by capitalizing on the process' waste streams and creating value-added coproducts such as ethanol.

For 12 years, MMI-Etoh Inc., a wholly owned subsidiary of Merrick, has thrived in the volatile ethanol industry by converting brewery residuals such as aged discards, off-spec beer, packaging losses and yeast concentrate into ethanol obtained from Coors Brewing Co.'s brewery in Golden, Colo.

The engineering and construction firm initially built the ethanol facility at a capacity of 1.5 MMgy in 1996, but Merrick doubled the production capacity to 3 MMgy in 2005. The addition of the ethanol facility adjacent to the brewery has proven to be a unique, viable and sustainable operation that has also been profitable and mutually beneficial for Merrick and Coors, according to Steve Wagner, Merrick vice president of energy process systems. "[Coors] brews most of its beer here in one location, producing approximately 20 million barrels per year," Wagner says. "There is a viable market for ethanol as fuel, and it reduces the disposal cost, so it's a resource recovery and waste recycling benefit."



The Merrick/Coors partnership began when Total Petroleum Inc. asked Merrick to construct an ethanol plant at Total Petroleum's refinery in Denver in 1995. According to Wagner, the cost of transporting the waste to the site made it unfeasible. Instead, Merrick leased land from Coors and built the continuous production process plant at the Golden brewery.

"The idea is to minimize the discharge from the brewery from those operations, and that's what the ethanol processing plant does," Wagner says.

Merrick assumed the project development role, secured the financing, provided engineering and design services, procured new equipment and materials, and constructed the facility. Merrick owns and maintains the ethanol recovery operation, while Coors is under contract to operate the facility, and supply the feed stream and utilities for the ethanol plant. Valero Energy Corp., another member of the project team, is responsible for transporting the ethanol and providing long-term purchase agreements, shipping approximately 168 truckloads of ethanol annually.

Merrick's ethanol-making process starts when the plant receives brewing residuals such as spilled or off-spec beer, which is about 6 percent alcohol. Residuals are heated and distilled in a stripper to increase the ethanol content. After the ethanol is further concentrated through a second step of distillation in the rectifier, the remaining water is extracted in a molecular sieve, and wastewater is sent to a treatment plant concurrently throughout the process.

Merrick's ethanol facility helps the brewery to eliminate approximately 70 tons of volatile organic compounds from its emissions annually. In addition, Coors and Merrick have been able to return nearly 20 million gallons of water to Clear Creek in the Front Range region of Colorado during each year of operation, according to Wagner. "[Water management] is something you've got to do no matter what in brewing operations," Wagner says. "We just reduce the cost of doing it by stripping off the ethanol. It significantly reduces the wastewater treating costs."

Merrick's ethanol facility is similar to conventional corn-based ethanol plants with the exception of three major differences: free feedstock supply, carbon dioxide sequestration for brewery use and water discharge quality. Much of the company's success is attributed to taking advantage of Coors' existing transportation infrastructure and the plant's negative feedstock cost, according to Wagner. "The corn costs for fuel ethanol are the single-largest cost associated with the production of ethanol," Wagner says. "The corn cost for a gallon of ethanol today is somewhere around $1.20 per gallon. If you take that corn cost away from your operating expenses, you'll significantly make more money by converting a waste stream instead of corn into ethanol."

Merrick began its ethanol recovery project when the industry was fledgling. Wagner asserts that if current volatile market conditions persist, attaching a waste recovery facility to a brewery could lure more companies to undertake such a venture, depending on how a particular brewery disposes of its waste. "It's just been in the past two or three years that we've seen $70, $80, $90, $100 crude oil and $3 per gallon gasoline prices," Wagner says. "As people look at $3 per gallon gasoline, they begin to think it's going to be here for a while, so these kinds of operations look very attractive in the long term."