Life Cycle Assessment of the Environmental Impacts of Typical Industrial Hazardous Waste Incineration in Eastern China

The environmental impacts of rotary kiln incineration, which is widely used in China for treating industrial hazardous waste (IHW), is evaluated in this work through life cycle assessment (LCA).

by Wenjuan Li, Qunxing Huang*, Shengyong Lu, Hailong Wu, Xiaodong Li, Jianhua Yan

Emissions data of key pollutants, along with energy and material inputs and outputs of rotary kiln incineration, were collected from a commercial-scale operating IHW incineration plant located in Hangzhou city in eastern China, and the corresponding environmental impacts were analyzed based on the LCA model. It is concluded that the IHW incineration process has the greatest impact on human toxicity, followed by global warming. Heavy metals, especially Pb and As, are the main contributors to human toxicity, while CO 2 is the main cause of global warming. PCDD/Fs have a relatively small contribution to human toxicity and overall environmental safety. This study has two improvement suggestions based on the assessment results: An energy recovery system and a DeNO x system should be added to the IHW incineration process, since the former would reduce the contribution of IHW incineration to global warming, while the latter would enable incineration plants to minimize the emissions of NO x; Fly ash and bottom ash should be stabilized and further treated to mitigate the problems caused by heavy metals.

Introduction

The industrial waste which meets hazardous waste identification criteria for toxicity test, corrosivity test, ignitability test and some special character test, like radioactivity test is defined as industrial hazardous waste (IHW) (Ministry of Environmental Protection of China, 2008; U.S. Environmental Protection Agency, 2009). Resulting from fast economic development, the generation of IHW in China has increased dramatically in the past few years from 8.3 million tonnes in 2000 (National Bureau of Statistics of China, 2001) to 34.31 million tonnes in 2011 (National Bureau of Statistics of China, 2012). Because of the contained toxic and dangerous components, all IHW must be treated environmental friendly to avoid secondary pollution to environment and human health. Compared with traditional landfill, incineration can reduce the volume of IHW by more than 70%, convert all residues into inert materials and recover heat (Dorn et al., 2012). Due to the high flexibility to different forms of waste, rotary kiln incinerator is recommended for IHW mass bu rning according to the technology specifications for HW incineration facility construction (HJ/T176-2005). However, waste incineration also generates many pollutant species, including dusts, acid gases, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), waste water, etc. For example, solid waste incineration facilities in China have emitted 8,500 tons of SO2, 11,200 tons of dusts, 14,100 tons of NO x in 2010 (Ministry of Environmental Protection of China, 2010) and 610.47 g I- TEQ of dioxins in 2007 (China National Implementation Plan, 2007). These pollutants may impose serious impacts on surrounding environment and such impacts should be quantitatively examined to assess the influence on human health. In this paper, such examination will be presented through life cycle assessment (LCA).

LCA is a promising method to evaluate the environmental footprint of a product, an industrial process or activity throughout its life cycle or lifetime. It can identify and quantify all steps involving energy and materials consumption, as well as pollutant emission, to evaluate the environmental impact and to find the chance of improving negative impacts (SETAC, 1997). During the early stage of the development, LCA was mostly applied to products manufactures (Burgess and Brennan, 2001). In the last few years, it has been employed to characterize municipal solid waste management process (Blengini et al., 2012) and also been extended to help developing sustainable integrated waste management systems. Unfortunately, only a few LCA researches have been carried out on IHW. Saft compared the pyrolysis and gasification treatment of hazardous paint packaging waste with rotary kiln incinerators in Netherlands (Saft, 2007). Vermeulen et al. (2012) compared the rotary kiln incineration and cement kiln co-incineration of automotive shredder residue and meat and bone meal. However, previous LCA researches are mainly focused on the influence of single hazardous waste instead of the incineration system. So the present study evaluated the whole incineration systems which is fed with mixed IHW and uses rotary kiln as primary incinerator.

In 1997, International Organization for Standardization (ISO) enacted the ISO14040 standard (Environmental management-LCA-principles and framework) as the LCA technology framework and principle (International Organization for Standardization, 1997). Currently, the LCA procedure is divided into four steps: goal and scope definition, inventory analysis, impact assessment and interpretation. This paper implements the ISO14040 standard and builds the assessment model and inventory, based on the typical IHW incineration plant in China. The model and inventory are also used for analyzing environmental impact.

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published: Aerosol and Air Research, 1|2015
Keywords: Hazardous Waste, China

Ph.D, Professor, Qunxing Huang
Global Wtert Council, College of Energy engineering