'WASTE TO ENERGY' IN CHINA

   

Due to its skyrocketing economic growth, China is also facing a major challenge in terms of waste. China, the world’s second-largest economy, is also the number-one waste producer. Some 430,000 tonnes of waste are generated every day in the country. The need for intelligent waste management has led to the concept of the ‘hierarchy of waste management’ that places the various means for dealing with MSW in order of environmental preference.  Waste to energy is proving to be an unstoppable technology, as its growth in China shows us.

Despite the relatively high capital cost of WTE, the central government of China has been very proactive with regard to increasing WTE capacity. One of the measures brought in provided a credit of about $30 per MWh of electricity generated by means of WTE rather than by using fossil fuels. 

‘Harmless treatment’ of MSW in China

The term ‘harmless treatment’ in China means the disposal of MSW by recycling, composting, WTE and sanitary landfilling. The ‘harmless treatment’ rate is defined as the percentage of the weight of total MSW treated with these methods. The generation of MSW, and also the ‘harmless treatment’ fraction have been increasing over the past 30 

years in China.

Most WTE plants are located in eastern China, especially in the districts of the Changjiang and Pearl River Deltas. As of 2007, three provinces in these two districts, Guangdong, Zhejiang and Jiangsu had fifteen, fourteen and nine WTE plants, respectively. These plants constitute 64 % of the existing WTE capacity in China. This is explained by the relatively high economic development in these provinces.

                                                                                                   

WTE technologies used in China

Stoker grate incinerator and circulated fluidized bed (CFB) incinerator are the main types of technology used in WTE plants in China. According to a preliminary survey of 100 WTE plants in operation or under construction, most of the MSW incinerators are of the grate combustion type (‘mass burn’), and are based either on imported or domestic technologies. The CFB incinerators co-fire MSW with coal (up to 15 % coal by weight) and have been developed by Chinese academic research centers, such as Zhejiang University, Chinese Academy of Sciences (CAS), and Tsinghua University. Most of the new plants are based on the stoker grate design.

Since the beginning of the 21st century, China has increased its WTE capacity from 2 to 14 million tons of municipal solid wastes. This makes China the fourth largest user of waste-to-energy (WTE), after the EU, Japan, and the US. There were 66 WTE plants in China by 2007 this is projected to increase to one hundred by 2012. Two thirds of these plants employ either imported or domestic versions of combustion on a moving grate; and the other third various forms of a home-developed technology, the circulating fluid bed reactor.

The generation of billions of tonnes of solid waste by humanity presents both a challenge and an opportunity to developing nations. The information presented in this article shows that China, more than any other developing nation, is taking major steps to increase its WTE capacity.