Posts Tagged: recycling

Biodigester turns campus waste into campus energy

More than a decade ago, Ruihong Zhang, a professor of biological and agricultural engineering at the University of California, Davis, started working on a problem: How to turn as much organic waste as possible into as much renewable energy as possible.

Last week, on Earth Day, the university and Sacramento-based technology partner CleanWorld unveiled the UC Davis Renewable Energy Anaerobic Digester (READ) at the campus' former landfill. Here, the anaerobic digestion technology Zhang invented is being used inside large, white, oxygen-deprived tanks. Bacterial microbes in the tanks feast on campus and community food and yard waste, converting it into clean energy that feeds the campus electrical grid.

“This technology can change the way we manage our solid waste,” Zhang said. “It will allow us to be more economically and environmentally sustainable."

It is the third commercial biodigester CleanWorld has opened using Zhang's technology within the past two years and is the nation's largest anaerobic biodigester on a college campus.

The system is designed to convert 50 tons of organic waste to 12,000 kWh of renewable electricity each day using state-of-the-art generators, diverting 20,000 tons of waste from local landfills each year. It is expected to reduce greenhouse gas emissions by 13,500 tons per year.

The READ BioDigester encompasses several of the university's goals: reducing campus waste in a way that makes both economic and environmental sense, generating renewable energy, and transferring technology developed at UC Davis to the commercial marketplace.

The biodigester will enable the more than 100 million tons of organic waste each year that is currently being landfilled in the U.S. to be converted to clean energy and soil products. The READ BioDigester is a closed loop system, moving from farm to fork to fuel and back to farm. Whatever is not turned into biogas to generate renewable electricity can be used as fertilizer and soil amendments — 4 million gallons of it per year, which could provide natural fertilizers for an estimated 145 acres of farmlands each day.

Nearly half of the organic waste, or feedstock, needed to operate the biodigester to full benefit will come from UC Davis dining halls, animal facilities and grounds. CleanWorld is working with area food processing and distribution centers to supply the remaining amount. Meanwhile, UC Davis will earn 100 percent of the project's green energy and carbon credits and receive all of the electricity generated.

Anaerobic digestion is an age-old process. However, Zhang's patented technology made it more efficient — capable of eating a broader variety and bigger quantity of waste, turning it into clean energy faster and more consistently than other commercial anaerobic biodigesters.

View a video about the UC David biodigester here:

(This blog post is condensed from a UC Davis news release about the biodigester.)

Additional information:

• Read the full press release
• Download biodigester photos
• Vine video: From lunch to lights
• Visit http://www.cleanworld.com/

Master Gardeners recycle Styrofoam

Styrofoam — referring generically to #6 expanded polystyrene foam — is a disposal headache. Extremely bulky, yet lightweight, it takes up space in the waste stream (and in landfills), but its removal doesn’t add much value to what is known as “diversion numbers.”   

In 1989, California Assembly Bill 939, known as the Integrated Waste Management Act, mandated reduction (or diversion) in waste disposal: jurisdictions were required to meet a 50 percent diversion goal by the year 2000. In 2011, Governor Jerry Brown signed AB 341, requiring a 75 percent reduction in disposable waste by 2020.

These goals are based on weight. So, for example, “green wastes” (lawn and garden clippings with a high water content) are targeted for removal from the waste collection system. Styrofoam is ignored because its removal doesn’t add much to diversion goals.   

Many holiday gifts, such as electronics and wine, come packed in #6 Styrofoam. That’s why UC Cooperative Extension Master Gardeners in Tuolumne County host semi-annual Styrofoam awareness events to collect foam from the public. Saturday and Sunday, Jan. 12 and 13, Master Gardeners will unload vehicles and collect Styrofoam from holiday gifts. Once collected, the foam will be compacted, baled and transported for recycling. 

Started in honor of Earth Day 2007, the Master Gardener Save Our Styrofoam (SOS) project has received collaborative support from local waste haulers and county government agencies. Waste Management Inc. (WMI) donates 20-foot roll-off bins to hold the collected Styrofoam. WMI then compacts and bales the foam. Tuolumne County’s Solid Waste Division arranges with the county’s e-waste hauler to pick up and deliver the Styrofoam bales. A Lodi, Calif., division of Dart Container Corporation repurposes the recycled Styrofoam into food containers.

Styrofoam collection events have been held at the California State Fair and by various other recycling groups. Our hope is that, eventually, with California’s focus on recycling, Styrofoam will no longer be a product created from fossil fuels that is then eliminated by being buried in the earth.

UC Davis voted America’s “coolest” school

After just experiencing my first Davis summer, I find it hard to describe anything in Davis as cool. But according to Sierra Magazine, UC Davis is just that. So much so, that the school was recently named the #1 Coolest School in the nation. Granted, they weren’t talking about the weather. Instead, they were referring to UC Davis’ environmental stewardship.

With all that UC Davis does to create and promote environmentally friendly programs and facilities, it’s no wonder the university just received this high honor. The campus is on track to reduce campus greenhouse gas emissions back to 1990 levels by 2020 and reduce campus electrical use by 60 percent by 2015.

UC Davis also provides sustainable forms of transportation to 85 percent of students and 46 percent of employees. As a fairly new Davis resident, I’m still constantly blown away by the number of bikes on campus, especially during the first week of school. Being from Long Beach, I always feel a pang of culture shock watching the Davis police handing out bike traffic violations instead of combating violent gang activity.

In 2011, UC Davis encouraged recycling, composting and reuse efforts that prevented 64 percent of campus waste from entering landfills. Sierra Magazine praised the university for its green purchasing, spending more than 20 percent of its $5.6 million food budget on local and organic products.

UC Davis also received international attention last fall, when it officially opened the doors to UC Davis West Village, the nation’s largest planned zero net energy community.

“At UC Davis, sustainability is one of our core values,” said UC Davis chancellor Linda P.B. Katehi. “I am very proud of the students, faculty and staff who have worked so hard to make this achievement possible and to invest in a more sustainable future for our campus.”

Other California schools that made the top 10 included Stanford University at number 3, and UC Irvine at number 9. California had the highest contingency of schools in the top 10 list.  

Congratulations to UC Davis, for earning the title of Coolest School in the middle of this summer’s heat!

Watch this Sierra Club video highlighting UC Davis’ green achievements to learn more:

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