Current Status of Global Wte

This paper is based on data compiled in the course of developing, for InterAmerican Development Bank (IDB), a WTE Guidebook for managers and policymakers in the Latin America and Caribbean region. As part of this work, a list was compiled of nearly all plants in the world that thermally treat nearly 200 million tons of municipal solid wastes (MSW) and produce electricity and heat. An estimated 200 WTE facilities were built, during the first decade of the 21st century, mostly in Europe and Asia. The great majority of these plants use the grate combustion of as-received MSW and produce electricity. The dominance of the grate combustion technology is apparently due to simplicity of operation, high plant availability (>90%), and facility for training personnel at existing plants. Novel gasification processes have been implemented mostly in Japan but a compilation of all Japanese WTE facilities showed that 84% of Japan's MSW is treated in grate combustion plants. Several small-scale WTE plants (<5 tons/hour) are operating in Europe and Japan and are based both on grate combustion and gasification technologies. Lists of several European plants are presented that co-combust medical wastes (average of 1.8% of the total feedstock) and wastewater plant residue (average of 2% of the feedstock). INTRODUCTION In 2010-2011, the Earth Engineering Center of Columbia University was engaged by InterAmerican Development Bank (IDB) to prepare a WTE Guidebook for use in the Latin America and Caribbean region (1). Many private sector firms visit governmental authorities in the IDB borrowing member countries and offer various novel technologies for the thermal treatment of municipal solid wastes (MSW). Government officials may not be well informed about the fundamentals of thermal conversion, the commercially available technological options, their environmental impacts, and the associated capital and operating costs. Therefore, the WTE Guidebook is intended to provide technical guidance in assessing the feasibility and in implementing WTE projects. This paper is based on the sections of the WTE Guidebook that discuss the current use of WTE technology around the world. Since the beginning of history, humans have generated solid wastes and disposed them in makeshift waste dumps or set them on fire. After the industrial revolution, near the end of the 18 th century, the amount of goods used and then discarded by people increased so much that it was necessary for cities to provide landfills and incinerators for disposing wastes. The management of urban, or municipal, solid wastes (MSW) became problematic since the middle of the 20 th century when the consumption of goods, and the corresponding generation of MSW, increased by an order of magnitude. In response, the most advanced countries developed various means and technologies for dealing with solid wastes. These range from reducing wastes by designing products and packaging, to recycling of usable materials, composting of green wastes, combustion with energy recovery, commonly called waste-toenergy (WTE), and sanitary landfills that prevent aqueous and gaseous emissions to the environment. It has been estimated that the recorded disposal of post-recycling MSW amounts to over 1.2 billion tons per year, of which one billion are landfilled and 0.2 billion are treated by various waste-to-energy technologies (2,3). Also, only 20% of the landfilled MSW is disposed in sanitary landfills that reduce aqueous and gaseous emissions to the environment. 2. THERMAL TREATMENT TECHNOLOGIES The only proven alternative to landfilling for post-recycling MSW is combustion or gasification to recover electricity, heat, syngas and metals. Worldwide, there are over 800 thermal treatment plants, most of them in E.U., Japan, the U.S., and Proceedings of the 20th Annual North American Waste-to-Energy Conference NAWTEC20 April 23-25, 2012, Portland, Maine, USA