Sacramento is the first city in the country to succeed in implementing a holistic approach to diverting organic waste from the landfill.
Dubbed ‘closing the loop,’ Sacramento’s organic waste diversion is part of a complete process in which a population grows its own food, feeds its people, converts food waste into energy (e.g., electricity, renewable natural gas), and uses that energy to power buildings or vehicles. Material not converted to energy becomes potent compost and makes its way back to area farms.
Sacramento Mayor Kevin Johnson is calling this process “farm-to-fork-to-fuel,” and is promoting Sacramento as a national leader in energy security.
“A resilient community is able to bounce back from disasters while maintaining a good quality of life,” says Mayor Johnson. “If the Sacramento area can feed ourselves and produce our own energy, we are better prepared for uncertainties and able to adapt to changing conditions.”
Positioned smack dab in the middle of a rich agricultural region—surrounded by fields of rice, almond trees and tomato farms—the Sacramento area champions its easy access to fresh food and owns its farm-to-fork way of life as a means of agricultural tourism.
“Diverting waste from landfills reduces greenhouse gas emissions, which is good for the environment while creating jobs at the same time,” says Sarah Leddy, project manager with Greenwise Joint Venture, an area nonprofit that partners with Johnson on growing the number of green jobs in the capital region. “When we close the loop in Sacramento we are creating an energy secure community by diverting waste from our landfills.”
Dr. Ruihong Zhang, a professor of Biological and Agricultural Engineering with the University of California, Davis and partner with Sacramento-based company CleanWorld, leveraged the region’s rich agricultural landscape and developed an improved process that converts organic waste into energy in the form of electricity or fuel. Her innovations to create a high-solids, low water type of anaerobic bio-digestion, controls the breakdown of organic matter without air to release energy. Anaerobic bio-digester facilities are built and planned in the Sacramento region to provide renewable natural gas (RNG) to commercial facilities, and to fuel vehicles that would normally run on diesel.
“The only thing slowing us down is keeping the anaerobic bio-digester full,” says Andrea Stephenson, sustainability director with local waste hauler Atlas Disposal. “We are connecting to grassroots organizations to provide education and model zero waste operations in businesses, particularly those that generate food wastes like restaurants, grocery stores and food manufacturers. When a company goes zero waste they separate organic materials into bins, like how we already separate recyclables. Organic waste feeds the bio-digester and reduces landfill costs. It’s a win-win.”
Over the past two years, Sacramento went from producing zero gallons of biogas to making 450 gallons each day.
The public sector is now poised to incentivize the demand of biogas through purchasing and policy. The city of Sacramento is developing a pilot waste diversion program that sends all organic waste from one residential neighborhood to an anaerobic bio-digester. City fleet vehicles will be fueled by the bio-digester’s recycled food beginning in October 2013—making Sacramento the first municipality to contract for RNG from organic waste.
Greenwise Joint Venture is working on public-private projects to increase the consumption of RNG, and looks to models like the Zero Waste Zone in Atlanta for inspiration.
“Zero waste zones in other cities stop within the boundaries of one neighborhood—we see Sacramento expanding that idea to larger areas like a major commercial or entertainment district,” says Leddy. “Through leadership with the city, the private sector and grassroots advocates, we envision that our downtown core will eventually use food waste to power the electric grid and vehicles.
“Sacramento is a resilient city and we are uniquely positioned to sustain ourselves from farm to fork, to fuel.”
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