Hangzhou makes efforts to turn trash to gold
Hangzhou, one of China's most popular tourist cities, is famed for the beauty of its mountains, willow trees, lotus blossoms and ancient stone-arch bridges. These days, a new sight is attracting attention: the local landfill.
Earlier this month, Hangzhou's local residents were invited to join a special tour run by the Hangzhou Environmental Group, which is responsible for the city's waste management. This tour didn't feature any scenic routes; instead, tourists were transported to an eco-park, Tian-zi-ling (天子岭), a de facto landfill site located on the northern outskirts of the city operated by the Hangzhou Environmental Group. Sun Xuankan from the company served as the tour guide.
"It may be unimaginable that some one and half meters underneath the lush green park where we stand is a mountain of trash generated by the city's residents more than a decade ago. More than 9,000,000 tons of domestic waste were permanently buried here to form a hundred-meter-tall hill. Next to the site is the second landfill site in operation which is 3 times larger than the first one. But the question is, how long can this landfill be used to collect the municipal trash? With more than 4,000 tons of trash arriving at Tian-zi-ling (天子岭) to be buried every day, this new landfill is expected to reach its storage limit in only 5 years."
Sun Xuankan says the second landfill in operation was actually planned to have a lifespan of 24 years. But now, the new mountain of trash is almost as tall as the first one. A record high of 5,300 tons of trash was received at the landfill site during the last holiday, making the situation even worse. Here is Sun Xuankan again.
"The city's fast growth has seriously shortened the projected life of the landfill life. Our company has been searching for different ways to handle more trash while occupying less space. After spending a tremendous amount of time on experimenting efforts, we arrived at the idea of building this circular economy industrial park where we can generate value from the solid waste in a sustainable way."
With the development of the Chinese economy, further urbanization and changes in lifestyle, waste output is continuing to rise, leading to serious environment pollution. Many cities are being faced with garbage disposal problems.
Currently, waste in China is processed via landfills, incinerators and composting facilities. Landfill currently accounts for 85 percent of the refuse, while incineration accounts for 17 percent.
China now generates the highest amount of waste output in the world with more than 7 billion tons of untreated municipal solid waste that occupies over 3 billion square meters of land. Out of the 668 cities in China, two-thirds are surrounded by garbage. In a quarter of the cities, garbage has to be transported to nearby rural areas, leading to secondary pollution such as underground water contamination and stench.
By 2030, the World Bank predicts China will produce 480 million tons of solid waste each year. These numbers don't even include the 8 million tons of electronic waste that is smuggled into China each year and causes carcinogenic pollutants to seep into the soil and groundwater. According to China Business News, the final destination of around 70 percent of the world's annual 500 million tons of e-waste is China.
And, there are many other types of waste in addition to the solid waste, including sewage sludge, agricultural waste, emissions, marine waste, liquid waste, heat waste and more.
The gravity of the problem has drawn the attention of the country's decision makers. The Twelfth Five Year Plan of the Construction of Municipal Solid Waste Treatment Facilities issued by the Chinese government stipulated that by 2015, the disposal rate of harmless garbage in Chinese cities must reach 90%, whilst that in rural areas should be 70%.
The capacity of urban waste incineration facilities is expected to account for 35% of total harmless treatment capacity, of which the eastern region will exceed 48%. To achieve this goal, the Chinese government has launched a series of policies to encourage waste incineration for power generation projects. At the same time, a national campaign has been rolled out to urge cities to reduce their waste as well as to find ways to create value from it.
These incentives have encouraged waste treatment companies, such as the Hangzhou Environmental Group, to develop more creative ideas. The company is now transforming its business from simply burying trash to becoming a one-stop solution provider that taps into every possible way of re-using waste.
At the landfill site, a special landfill leachates filtration system is operating under close monitoring. Bai Long from the Hangzhou Environmental Group tells us how waste water, is being re-used through this treatment facility.
"The filtration system helps separate the rainwater from the liquids in the waste. The rainwater is then collected, while the wastewater receives secondary treatment. This filtration system can deliver 25 liters of pure water that is safe for drinking. And the rest of the water permeating from the system can be used for irrigation, washing cars, or even as aquarium water."
Landfill leachate is generated from liquids existing in the waste as it enters a landfill or from rainwater that passes through the waste within the facility. The biggest source of leachate in most places is rainwater. When rain hits collected trash, it tends to pool up. If this runoff is not properly managed it is at risk for mixing with the groundwater near the site; thus leading to possibility of contaminating the drinking water of the local communities and impacting the ecosystems of rivers, streams, and oceans.
So, landfill sites are required to be equipped to collect, store, and treat leachate. In most cases this means that dumps have impermeable layers on the sides and bottoms made of hard plastic or other non-corrosive materials.
While the leachate treatment system is an only small part of the bigger plan to generate value from trash in a sustainable way for the Hangzhou Environmental Group. The company is already leading China's move to deal with methane, a climate-harming byproduct of decaying trash, by turning it into clean energy. Now it aims to speed up the methane production cycle from years to a matter of days at the same time as cutting the need for more land to bury garbage.
Zhang Haihua, vice president of the Group, tells us how 200 tons of kitchen waste is converted into electricity power every day in his plant.
"We use the kitchen waste to produce methane which is then burned to generate electricity. The plant, built next to the landfill, stretches tentacles composed of hundreds of pipelines that are woven through the layers of trash. It catches the bubbling landfill gas and shoots it into highly sophisticated machinery to clean it. Then the processed gas is burned to generate electricity."
Everyday, the decaying trash releases a cocktail of large quantities of harmful gases. Methane, which warms the planet 20 times faster than carbon dioxide, accounts for more than half of landfill gas. At the same time, methane has a tendency to explode; and untreated landfill gas emissions will lead to important environmental, hygiene and also security problems. So, the technology that inhales the dangerous gas and exhales clean energy must spread across China soon.
While such eco-friendly moves help extend local energy supplies, they can't help another problem. Collecting sufficient amounts of kitchen waste remains a hard task, despite the fact that half of all urban waste is produced in the kitchen.
The city of Hangzhou is estimated to generate nearly 3,000 tons of kitchen waste per day, but less than 200 tons of that goes to the designated trash bin. The rest is mixture containing various types of non-degradable materials the majority of citizens do not bother to separate it properly.
Although Hangzhou started a pilot scheme for garbage classification 4 years ago, the additional roadside receptacles are now seen by many citizens as nothing more than extra trash bins. Here is Zhang Haihua again.
"The results are not satisfactory although we have pushed forward garbage classification among the residents for years. The kitchen waste we received still has a lot of non-degradable materials."
Efforts to educate the public to produce less trash, separate waste properly and recycle more are intensifying. Though it may take some time to change people's behavior on a wide scale, environmental entities, including the Hangzhou Environmental Group, are still trying to develop alternatives, to keep their communities clean.
In an exhibition center that forms part of the company's "trash tour," visitors are now playing a new video game. They must drop trash correctly into different bins in order to win.