Compost may be key to climate

Four-year-old "Pearl" and her handler at Recology's facility in San Francisco. The company uses hawks to deter gulls from flocking to the gathered trash to rummage for food. LIA ZHU / CHINA DAILY

For greenhouse gas emissions, soil degradation, food waste and other common issues China and the US face today, composting may provide a solution, said industry insiders.

San Francisco is known for promoting recycling and aims to reach zero waste by 2020. To achieve that goal, the city's waste management company Recology figured out the answer long ago: compost.

In the city, the major component of waste is food, which is also an important part of the trash, said Michael Sangiacomo, president and CEO of Recology.

San Francisco is among the first cities in the US to introduce an urban compost collection program. In 2009, the city, with the help of Recology, passed a mandatory recycling and composting ordinance, which requires residents to pre-sort waste into three bins: a blue bin for recyclables, a green bin for organic material and a black bin for the rest.

Composting food scraps not only helps prevent them from ending up in landfills, but also serves as fertilizer in farming, thus offsetting some greenhouse emissions.

"Our modern farming techniques are extremely harmful to the soil and to the environment. Tilling soil puts carbon into the air, and destroys the ecosystem that exists in the soil," said Sangiacomo.

By pulling carbon dioxide from the air, compost stores it in the ground. "The most effective farming technique is organic — by putting organic matter back on top of the land, like nature always does, you can get much better crop results and plant life," Sangiacomo explained.

Recology's composting program processes about 650 tons of food scraps and yard trimmings per day. Currently, as much as 50 percent of trash could be diverted for composting.

In many top-tier Chinese cities, between 60 and 75 percent of municipal waste comes from disposed food.

According to China Association of Urban Environmental Sanitation, municipal cities produce more than 150 million tons of solid waste a year, and the number is increasing by 8 to 10 percent annually. As a result, the annual loss of resources is valued at 25 billion yuan to 30 billion yuan (about $3.6 billion to $4.4 billion).

Landfill is the ultimate fate of solid wastes in China, which brings problems such as water pollution and reduced land resources, especially to densely populated cities.

More attention has been given to composting in recent years and some compost facilities have been built in China. However, experts said the major challenge those facilities face is high cost from the complex separating process.

Recology has recently received a lot of interest from China, especially in their compost program, according to Minna Tao, general manager of Recology's Golden Gate operation.

They have hosted Chinese delegations of officials, industry businessmen and academics. "Everybody realizes the climate challenges (in China)," she said.

The Chinese government has recently announced measures requiring offices, restaurants and businesses in 46 major cities to sort and separate all household trash, including food scraps and recyclables, by 2020.

The biggest issue is getting people to sort.

"The education process is one of the challenges we continually face," said Mark Arsenault, general manager of Recology. San Francisco is unique in that the three primary materials — recycling, compost and landfill — are ubiquitous, in every building, business and apartment complex, he added.

The company has an education center that hosts tours for more than 5,000 people every year, mostly 3rd to 5th grade students. "Waste Zero specialists" are also sent out in the field all over the city, making sure residents know where to put the materials.

"One of the biggest changes we are making currently is shrinking the trash services and upsizing the blue bin for recycling," said Arsenault. "We are promoting recycling as the primary means of discarding materials and then educating the customers to use it."

"It's yucky — a lot of people don't want to do that," Sangiacomo admitted. "You need to have the environmental mindset."

China introduced measures to encourage the sorting and separation of waste 16 years ago, but progress has been slow.

Sangiacomo said China is now ready for urban composting program.

"A lot of it happens with the middle class. Poor people don't have the time, or the effort or energy. Rich people often just don't care," he said. "Twenty years ago, China didn't have a big enough middle class to do this. Now they do."

liazhu@chinadailyusa.com