Terrific trash

Prosperous Beijing is famous for its ancient buildings with red walls and golden tiles, green jade moats and fine courtyards and alleys.

However, like many other modern cities, garbage is a big concern for Beijing authorities and residents alike.

With its strong economy and increasing population, Beijing generated about 4.3 million tons of waste in 2007, 11,900 tons a day on average. And China generates an estimated 280 million tons of trash annually.

There are 23 garbage-processing plants in the capital city, including six transfer stations, four integrated processing plants and 13 landfill sites. Over 97 percent of the city's garbage has undergone waste disposal treatment to render it harmless.

As a major force in waste treatment in Beijing since the 1990s, the southern Beijing Waste Disposal System has been processing mountains of garbage and improving the quality of life in the city.

Before 1996, garbage in southern Beijing was transported directly to landfills without any special treatment.

The Southern Beijing Disposal System was built during 1994-1998 as a cooperative effort by China and Germany for 480 million yuan.

The total investment includes about 20 million euros from the German government, plus a 290 million yuan fund from the Chinese government.

The German government also provided 840,000 euros for professional training.

Liu Jing of the Beijing Municipal Administration Commission, says Germany also introduced a treatment system for garbage disposal.

"(Germany) has contributed a lot to Beijing's environment and sanitation," he says.

The system consists of Majialou and Xiaowuji transfer stations, the Nangong compost plant, Anding and Beishenshu landfill sites, and the Dongcun compost plant and one incineration plant.

It serves four districts in southern Beijing, primarily Chongwen and Fengtai districts, with a population of about 2.5 million.

The system has a daily capacity of 2,000 tons of garbage. Domestic waste is separated into four categories: less than 15mm, 15 to 60mm, more than 60mm and magnetic materials.

Depending on its size and composition, the assorted trash is transported either to the landfills, the compost plant or incineration plant. For example, garbage in the less than 15 mm category goes to the Anding and Beishenshu landfills.

The 46-hectare Beishenshu landfill looks like a park, not a garbage dump. In the center of the site is a 20-meter high hill covered with green grass and blooming flowers making it hard for people to connect the hill with 2 million tons of garbage.

He Liang, director of the Beishenshu landfill site, says it takes years to convert a huge amount of waste into a garden or park.

Hundreds of tons of leachate (liquid that drains or leaches from a landfill) oozes daily from Beishenshu and presents an environmental threat to the groundwater and soil.

But a treatment system has been installed that filters and decontaminates the leachate and allows it to be used for landscaping at the landfill.

Methane is another landfill byproduct and a potentially hazardous one that could cause an explosion. But it's been put to good use with a methane-powered 500 kW generator that satisfies all the landfills power demands.

He says the Beishenshu landfill site has a maximum capacity of about 5 million tons of garbage and after it is full it will become a park for Beijing residents.

Garbage that is 15 to 60 mm is sent to the Dongcun and Nangong compost plants.

With a daily capacity of 600 tons of waste, fertilizer produced from trash at the Nangong plant is safe and effective in improving soil quality.

Experts say making fertilizer from garbage is an important and ecological way to maintain sustainable development.

Over 45 percent of the waste processed through the Southern Beijing Waste Disposal System is composed of trash over 60mm. It's mainly waste paper and plastic bags and the best disposal choice is incineration.

For that, Beijing's first garbage-powered plant, the Gao Antun plant, was fired up in July with an annual capacity of 533,000 tons of waste, generating 220 million kilowatt-hours of electricity a year.

According to statistics, there are more than 500 garbage and kitchen refuse treatment facilities installed in residential areas across Beijing. And about 4,800 waste reclamation venues have been built and more than 50 garbage transfer vehicles are working in the streets.

By 2010, Beijing will have 44 urban waste treatment plants with a total daily capacity of 18,000 tons of waste.

(China Daily 09/22/2008 page5)