An innovative approach to managing demolition waste via GIS (geographic information system): a case study in Shenzhen city, China

Highlights

• One method to quantify the demolition waste with spatial and temporal distribution was developed.

• The recycling potentials of demolition waste and associated demand of landfills were evaluated.

• GIS is a promising approach to quantify and manage the demolition waste.

• GIS-approach could be applied to manage the demolition waste at both regional and national-level.

Abstract

A large amount of demolition waste was generated due to the rapid urbanization. Prior to designing corresponding management measures, it is imperative to understand the amount, composition, and flows of the generated waste. This study proposes a novel approach to quantifying the demolition waste from generation to final disposal and, consequently, formulates corresponding strategies to managing the demolition waste, by using spatial and temporal dimensions in the Geographic information system. Specifically, a GIS-based model is proposed and consequently applied to a case study. Results show that over 135 million tons of demolition waste will be generated in the Nan Shan District between 2015 and 2060, and the recycling potential is valued at $ 6072 million under the optimistic scenario. By contrast, under the worst-case scenario, over 54 million m3 of land area which equals to approximate $ 218 billion could be needed for landfill. Compared to the worst-case scenario, the optimum scenario would reduce the amount of waste to be disposed in landfills by 80% and increase the value of recycling by 65%. The results revealed that, as a rapidly developing city, Shenzhen would likely experience the peak in the generation of demolition waste. Therefore, it is imperative to improve the recycling rate as it helps to raise the potential economic benefits and to reduce the landfill demand. This research is innovative in terms of the systemization, visual representation and analysis of quantifying the demolition waste flows via a novel method. The findings about the generation trends, economic values and environmental effects provide valuable information for the future waste management exercises of various stakeholders such as government, industry and academy.

Introduction

The urbanization rate of China has increased more than 30% over the past three decades, from 19% in 1980 to 54% in 2013 (NBSC, 2014). Rapid urbanization has not only contributed to an increasing use of non-renewable resources, but has also led to the generation of significant amount of construction and demolition (C&D) waste and its associated environmental concerns (Tam, 2009, Yuan, 2013, Passarini et al., 2014, Wang et al., 2015). Meanwhile, this rapid growth has resulted in enormous pressure on the ecosystem due to a large amount of energy required. To achieve sustainable development, China has to consider promoting energy efficiency whereas reducing environmental impacts to meet the demand of the rapid economic growth in China (Wang et al., 2012a, Wang et al., 2012b). Thus, it is imperative to identify a new economic growth mode to replace the traditional mode which is featured with high energy-consuming and high-polluting. The low carbon and high recycling economy have been widely recognized as the most dramatic change since the Industry Revolution (Wang et al., 2012a, Wang et al., 2012b, Wang et al., 2015, Wang and Yang, 2015).

Recently in China, however, only less than 10% of C&D waste was recycled while the majority of waste remain to be simply landfilled or just to be dumped. This does not fulfill the related requirements specified in policies of resource recycling (Wang et al., 2008, Lu et al., 2011, Li et al., 2013). To reduce the waste of recyclable materials and the volume of C&D waste dumped, C&D waste could be used as a raw material in the manufacture of construction materials and for the compliance with its own recycling targets (Rodrigues et al., 2013). One potential use of C&D waste is in the reinforced concrete as a replacement of natural aggregates (Poon et al., 2004a, Poon et al., 2004b, Rodrigues et al., 2013, Richardson et al., 2011, Beltrán et al., 2014). Similarly, previous studies have been undertaken to investigate the suitability of recycled C&D waste materials (e.g. crushed brick, recycled concrete aggregate and reclaimed ceramic) as a pipe back filling material (Rahman et al., 2014), as road bases (Xuan et al., 2015) and used for making cement (Puertas et al., 2008) or as a substitute of cement for mortar production and as an addition to mortar (Naceri and Hamina, 2009, Silva et al., 2009).

Higher grade uses of recycled C&D waste, which are at least as good as the products from which the waste derives, have been cited as an important factor for the closed construction cycles (Coelho and de Brito, 2013). From an environmental point of view, the recycling of C&D waste has the following advantages: i) it minimizes the sand mining from rivers and seashores, which is causing serious environmental problems in many parts of the world; ii) it minimizes energy consumption and CO₂ emissions generated from crushing quarry rocks for sand production, mitigating the global warming and iii) it prevents illegal deposits and landfill of the fine fraction of C&D waste (Ledesma et al., 2015). However, the main barriers for recycling C&D waste are: lack of information related to the sources of waste generation, poor planning of waste treatment facilities, and lack of incentives, which have reduced the demand for recycle rates and the interest in developing business from the recycling sector (Dahlbo et al., 2015).

Prior to constructing management measures, it is necessary to understand the amount, composition, and flows of the generated waste as precisely as possible within a given geographic area (Gallardo et al., 2014). For example, treatment plant and landfill planning are guided by the data of demolition waste generation and flows - particularly its spatial-temporal heterogeneity (Ragazzi and Rada, 2008, Ionescu et al., 2013, Economopoulos, 2012). However, in many cities of China, including Shenzhen, there is lack of regular statistics on the quantities of demolition waste, which presents a major barrier to the development of effective management measures (Yuan, 2013).

C&D waste have become a growing public concern due to their significant impact on environment, economy and society. As a result, significant efforts have been made to the management of C&D waste over the last two decades (Faniran and Caban, 1998, Yuan and Shen, 2011). A number of management measures have been recommended, which cover a wide range of aspects such as on-site sorting, construction material handling and storage, waste transportation, waste recycling, and final disposal (Wang et al., 2010, Yuan and Wang, 2014). Similarly, a number of studies have been conducted to investigate the generation of C&D waste. These studies revealed that reliable information on the waste generation is required to formulate successful waste management strategies (Wu et al., 2014). However, very few studies have placed focuses on the generation of demolition waste. Demolition waste is significantly different from construction waste, e.g. larger quantities, more complex composition, higher recycling potential and the need for more land for landfills (Kourmpanis et al., 2008). Moreover, a very limited number of studies attempted to quantify the generation via computer techniques (Cheng and Ma, 2013).

The aim of this paper is to develop an innovative approach for managing demolition waste using a GIS-embedded method. This will make it possible to obtain a spatial distribution of demolition waste within a specific geographic area, taking into account its generation, composition and variations over a year's cycle. In addition, the projection of waste generation and flows can be used to assess the demand for landfills and to plan waste recycling facilities. Specifically, this method provides the data needed to create an accurate map of the spatial distribution of demolition waste. Such a map would be useful in the management of demolition waste, such as selecting waste collection firms, transportation management, and the planning of waste recycling facilities and landfills.