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“垃圾围城”出路在何方 | 央企品牌打造中国环保新名片

随着城镇化的不断推进,高速发展中的中国城市正在遭受“垃圾围城”之痛。传统的垃圾填埋并非最科学的处理方式,为环境带来诸多隐患。而垃圾焚烧发电不仅解决了环境污染问题,同时带来巨大的经济效益。

垃圾焚烧发电厂内部结构如何?垃圾究竟如何发电?又能带来哪些环境和经济效益呢?《北京周报》记者邓亚卿带您一一解答。

Hangzhou Jiufeng waste-to-energy plant stands in Jiufeng Village, Yuhang District, Hangzhou (COURTESY PHOTO)

Along the overlapping green mountains of the Hangzhou city suburbs lies a secluded, garden-like patch of land, where strips of limpid water converge into a spectacular sapphire fountain filled with koi carp swimming below lotus leaves. If the protruding cooling tower didn't betray its true identity, one would think it was a holiday village or scenic resort. In fact, it is the site of a waste-to-energy plant.

"Every day, roughly 3,000 tons of domestic garbage is transported by trucks to the factory for treatment, accounting for one third of the total volume generated in Hangzhou," said Xiong Jianping, General Manager of the Hangzhou Jiufeng waste-to-energy project run by Everbright International. After some mental math, he calculated that if no treatment measures had been taken, garbage generated by the capital of east China's Zhejiang Province would have filled the city's West Lake in a mere five years.

"In fact, the fountain water in the park is produced from waste leachate, and all the electricity and water needed by the power generation equipment are self-produced," Xiong said, adding that the factory generates 390 million kWh of green electricity every year.

Four years ago when the local government first announced the location of the waste incineration project and contracted it to a local company without fully informing residents, the setting was a stark contrast to the picturesque scene of today. Thousands of villagers gathered around the site to protest and attempted to obstruct its construction by smashing vehicles and attacking enforcement officers.

To break the impasse, Everbright International, headquartered in Hong Kong and the largest waste-to-energy investor and operator in Asia, was chosen to replace the original contractor and tasked with carrying out the project with the local government. From August to October 2014, more than 5,000 villagers were invited to visit similar Everbright projects in the cities of Changzhou, Suzhou, Nanjing and Jinan and related compensation measures were unveiled.

"Local residents' understanding and support is a must for smooth construction and operation," said Xiong.

When the project was completed and set to begin running last September, about 80 representatives from nearby villages were invited to a meeting in the factory to make the final decisions. After consensus was reached, the waste incinerators were finally ignited.

This March, during the annual session of the 13th National Committee of the Chinese People's Political Consultative Conference (CPPCC), Li Xiaopeng, Chairman of China Everbright Group and member of the 13th CPPCC National Committee, submitted a proposal calling for the popularization of a rural-urban waste-to-energy system, designed to reduce pollution from random crop burning in rural areas and collect rural and urban household waste in an integrated way for power generation.

China Everbright Group Chairman Li Xiaopeng (center) inspects a waste-to-energy plant in Sanya, south China’s Hainan Province, on May 22 (COURTESY PHOTO)

Domestic garbage is mainly comprised of solid waste generated by people's daily lives and everyday needs. As urbanization continues in China, the urban population also continues to grow. By the end of 2017, the country had an urban population of 813.47 million, an increase of 20.49 million from a year earlier, representing an urbanization rate of 58.52 percent, according to statistics from the National Bureau of Statistics.

More urban residents mean greater pressures on living environments, especially for the disposal of household garbage. In China, an urban resident generates around one kilogram of household waste on average every day, totaling nearly 400 million tons of household waste a year across the country.

There are three principal methods to carry out the treatment of household waste: the sanitary landfill, incineration and compost. In 2016, a total of 196.74 million tons of urban household waste underwent treatment, according to a report on the prospect of and investment in household waste treatment released by the Industry Research Institute of Qianzhan, a Beijing-based industry consulting service provider. Landfill, incineration and compost treatment made up 60 percent, 35 percent and 5 percent, respectively.

Since domestic garbage contains plenty of organic matter, it is a hot bed for various pathogenic bacteria and easily decomposes and produces a malodorous smell. According to public statistics, there are more than 200 cities at risk of being surrounded by waste landfill, while half of them are out of control and not under management.

"If it is not properly handled in a timely fashion, household waste may cause air and water pollution, incubate fire hazards, do harm to animal nests and result in excessive land occupation," said Xiong.

In order to propel garbage classification, reduction and treatment, the National Development and Reform Commission recently published a guideline on innovating and improving the pricing mechanism of green development, which requires establishing an all-round pricing system for domestic waste disposal by 2020.

Scientist Shao Zheru (third right) leads his team in the devlopment of waste-to-energy equipment (COURTESY PHOTO)

Where there is human activity, there is garbage. The green management of household waste is a major challenge on the path to building a well-off society, and garbage incineration power generation is an important solution, said Jia Feng, Director of the Center for Environmental Education and Communications of the Ministry of Ecology and Environment.

Currently, when a garbage truck enters the factory, its weight is checked by a wagon balance at the gate. After being unloaded into a vast treatment pond, the garbage is left to ferment for a week. The atmospheric pressure in the pond is lower than that outside, thus keeping the smell of rotting garbage locked within and sparing the neighborhood the stink. Once fermentation has significantly lowered the water content of the garbage, it is fed to incinerators, where generated heat is transformed into electricity through steam turbine generators.

Since 2010, waste incinerators have been sprouting up in China, and simultaneously, extensive public attention has been aroused by the prospering industry, said Liu Jinghao, a senior researcher with the Ministry of Housing and Rural-Urban Development. He also noted that waste incineration technology is more advanced in China than elsewhere.

Take Everbright International for example. It first turned to the environmental protection industry in 2003. At that time, China was heavily dependent on the import of overseas waste incineration power equipment.

Yet, due to higher water content, Chinese household waste couldn't be effectively treated and had to be burned by expensive foreign-made equipment tailored more to the garbage generated in Western countries. The company decided to develop more efficient and economical technology and equipment to meet the needs of Chinese incinerators.

"Over the course of equipment research and development, pioneering scientists encountered numerous obstacles and difficulties," said Shao Zheru, chief scientist at Everbright International, who led his team from scratch in 2004 in a dilapidated shed.

The company has now developed a grate furnace which can process 750 to 850 tons of waste per day and is expecting to leap up to 1,000 tons per day by 2023. This will make it the largest and most advanced system in the world. In addition, special leachate treatment technology has been developed to deal with the high moisture content of Chinese household garbage.

"As long as the temperature is kept higher than 850 degrees Celsius and the flue gas stays in the combustion chamber for longer than two seconds, the generated dioxin can be decomposed. Moreover, gas purification systems can neutralize and filter generated fly ash, acid gas and heavy metal," said Shao, noting that all emission indicators are up to the Euro 2010 Standards.

At the beginning of this year, China Everbright Group's Chairman Li highlighted the goal of further cementing the company's core competitiveness and market standing by shoring up comprehensive development and leveraging green industry funds.

In expanding green business along Belt and Road routes, Li insisted that an equal emphasis should be laid on scale, quality and economic benefit.

"Remarkable breakthroughs have been made in areas such as waste-to-energy, water treatment, biomass utilization and equipment manufacturing," said Li, who noted that these endeavors are targeted at building Everbright International into a global frontrunner in the eco-environmental industry.

So far, Everbright has signed over 80 waste incineration power projects scattered throughout 13 provinces, with roughly 50 projects in operation and treatment capacity totaling 45,000 tons per day. In addition, its overseas business footprint has also been expanded to Germany, Poland and Viet Nam.

A better knowledge of waste incineration can help remove the widespread attitude of "not in my backyard." A full consideration of local environmental capacity, the scientific collection of public opinion, an improved sense of gain from green development and information transparency are also quite necessary, Jia noted.

"Residents across the country can check all the real-time emissions data of our projects on Everbright International's website at any time. Keeping the public fully informed will help them feel more secure," said Xiong.

责任编辑:周晓燕

设计排版:卢一凡

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