Turning trash into treasure isn't easy, but a number of companies are successfully making a business out of converting food waste into renewable energy and other products.

Part of the opportunity in food recycling comes from laws that are adding food waste to the list of mandatory recyclables. Connecticut, Massachusetts and New York already have laws requiring certain businesses to separate food waste from regular trash, and states such as Vermont have similar plans to require food recycling by 2020, The Wall Street Journal reports.

Here are three businesses that are finding opportunities in food recycling:

  • Turning Earth. The Pennsylvania-based recycling company produces electricity and natural gas from food waste using a biological process called anaerobic digestion. Most anaerobic digesters in the U.S. compost sewage and manure, but not food. Turning Earth is partnering with public energy corporation Covanta on a $20 million project to build two anaerobic digesters for food waste in Connecticut.
  • Quest Recycling Services. The Frisco, Texas-based waste-management business provides food recycling services that help companies reduce waste-disposal costs. Quest recycles fruits, vegetables, dairy, deli and bakery foods for conversion to bio-diesel, alternative fuels and animal feeds. The company recycled more than 850 million pounds of food waste in 2012. 
  • Missouri Organic. Through its Food Residuals Environmental Diversion (FRED) program, the Kansas City-based company manufactures compost made from recycled food and yard waste. FRED kept 16,000 tons of food waste out of landfills in 2013 and expects to increase the amount to 20,000 tons in 2014. The company charges $130 per month to collect roughly 1,100 gallons of food waste.

While a number of states in the U.S. would like to recycle food waste on a larger scale, the infrastructure required to do so is not ready yet. Still, businesses that generate substantial amounts of food waste should plan to devise a food recycling strategy before one is imposed on them.