Zhishi Wang

Municipal wastes and their solar transformities: an emergy synthesis for Macao.

The debate over waste management practices has become increasingly important as human activities have begun to overload the biospheres assimilative capacity. An effective waste management policy should be based on the principles of sustainable development, with wastes regarded as a potential resource rather than solely as something to eliminate. This approach requires an integrated waste management plan that makes full use of all available technologies. Macao is a highly populated consumer society that lacks natural resources and must therefore import almost all of its life-supporting goods and raw materials from regions outside the city. During the past 20 years, Macao has experienced an economic boom, accompanied by rapid socioeconomic development. Its discharged wastes have increased steadily during this period. This paper employs emergy analysis to investigate Macaos waste treatment in 1995, 1999, 2003 and 2004. The emergy of gaseous emissions was estimated to be 4.76 x 10(21) sej in 2004. Since 1992, Macaos municipal solid waste (MSW) has been incinerated to reduce its volume. The transformity of the fly ash and slag produced by this treatment in 2004, and the electricity generated by the incinerator, equaled 5.11 x 10(11) sej/g, 6.01 x 10(10) sej/g, and 7.61 x 10(6) sej/J, respectively. A large investment of natural resources and technology is required for the treatment of wastes; the feedback ratio of wastes, which represents the scale of the treatment of inputs, equaled 0.02 for MSW, 0.11 for sewage, and 0.06 for gaseous emissions.

Ecological emergy accounting for a limited system : general principles and a case study of Macao

From the Contents: Emergy Synthesis and Ecological Energy Accounting.- Emergy Synthesis for Eco-economic Systems of Macao.- Emergy analysis for tourism systems: principles and a case study for Macao.- Ecological energy accounting for the gambling sector: a case study in Macao.- Emergy Synthesis of Waste Treatment in Macao.- Per capita Resource Consumption and Resource Carrying Capacity: a Comparison of the Sustainability of 17 Mainstream Countries.

Ecological Energy Accounting for Macao’s Socioeconomic and Ecological Systems

Macao is a tourist city with a dense population, but is short on natural resources. During the past 20 years, Macao’s rapid socioeconomic development has depended heavily on the tourism industry. In this chapter, we employed ecological emergy accounting to characterize the urban evolution and development that occurred in Macao from 1983 to 2004.

Emergy Synthesis and Ecological Energy Accounting

Emergy synthesis offers an obvious advantage compared with traditional ecological or economics methods: it accounts for both human socioeconomic flows and natural flows of materials, energy, information, and money within a single consistent framework.

Measuring the sustainability of tin in China

Tin is a component of many items used in daily activities, including solder in consumer electronics, tin can containing food and beverages, polyvinyl chloride stabilizers in construction products, catalysts in industrial processes, etc. China is the largest producer and consumer of refined tin, and more than 60% of this refined tin is applied in the electronics sector as solder. China is the leader in global economic growth; simultaneously, China is also a major producer and consumer of electrical and electronic equipment (EEE). Thus, future tin supply and demand in China are forecasted, based on the gross domestic product per capita and the average consumption of refined tin in past five years. Current tin reserves and identified resources in China can meet the future two decades of mine production, but import of tin will also be critical for Chinas future tin consumption. However, there will be a lot of uncertainty for import of tin from other countries. At the same time, virgin mining of geological ores is a process of high energy consumption and destruction of the natural environment. Hence recycling tin from Sn-bearing secondary resources like tailings and waste electrical and electronic equipment (WEEE) can not only address the shortage of tin mineral resources, but also save energy and protect the ecological environment.

Emergy Synthesis for Waste Treatment in Macao

Because the production processes that underlie current modes of socioeconomic development are highly wasteful compared with the processes that govern the development of natural systems, waste management becomes a crucial issue for human systems such as cities. An effective waste management policy should therefore be based on the principles of sustainable development, with wastes regarded as a potential resource, and with wastes produced at levels no higher than what the human and natural systems can absorb.