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Construction and demolition waste (C&DW) management is gaining attention from policy makers in India. Recently, the government of India directed every urban area in India to install a construction and demolition waste processing plant to save natural resources and improve resource efficiency of cities. This thesis aims to fulfill three objectives.
First, it estimates the construction and demolition waste generation from urban, rural, and infrastructure sectors in India by using a top-down up material flow analysis approach using the historical consumption of cement as the governing material for the flows of all materials within the construction sector. The entire construction industry was divided into urban, rural, and infrastructural sector. The impacts of uncertainties in the results were also explored using Monte-Carlo simulations for year 2019. Second, the study compares environmental life cycle implications of two construction and demolition waste management alternatives (inert landfilling and integrated wet-recycling), on many impact categories under several scenarios. The study uses SimaPro tool, customizes the ecoinvent database for Indian scenario using mix of primary and secondary data, and deploys ReCiPe method for the impact assessment. Third, this study analyzes the attitude of builders towards construction and demolition waste recycling in India. A conceptual framework is proposed using theory of planned behavior (perceived benefits, perceived costs, attitude, subjective norms and perceived behavioral control), institutional pressures (regulatory, normative and mimetic) and environmental consciousness on behavioral intention of builders towards construction and demolition waste recycling. Empirical data with 260 responses from different builders of construction sector in two large Indian cities are analyzed through partial least squares based structural equation modelling in Smart-PLS tool.
The results indicate that Indian generated between 112 Mt to 281 Mt of C&DW per year in the recent past. Urban areas generated between 57-145 Mt of waste with a mean amount of 89 Mt, a little over 50% of the total waste in India. The amount from rural areas varied from 46 Mt to 119 Mt with an average quantity of 74 Mt. The contribution from construction and demolition waste, respectively, ranged between 25 to 32% and 68 to 75% of the total waste in both urban as well as rural areas. The waste from of infrastructure sector was small (5-7%).
The environmental life cycle profile of managing 1 t of C&DW showed that recycling was more environmentally beneficial than landfilling on nearly every impact category under most parametric combinations. Scenarios were developed to capture uncertainties in plant operational efficiencies, the share of carbon neutral electricity in overall generation mix, and avoided transport of natural materials. Higher share of cleaner electricity lowered carbon emissions, but increased mineral scarcity and eutrophication among other impact categories, indicating environmental tradeoffs associated with energy intensive recycling process. Integrated recycling promises to lower environmental footprint of urban India while lowering requirement of virgin natural materials.
The findings of the last objective indicated that behavioral intention towards C&DW recycling appears to be mainly driven by personal motivations (perceived benefits, perceived costs, attitude, and perceived behavioral control), regulatory pressures and environmental consciousness. Social norms (from Theory of Planned Behavior) and normative and mimetic pressures (from Institutional Theory) had no statistically significant role.
These findings will help the government and regulators plan for recycling infrastructure according to the amount of waste generated and recovery maximum secondary resources while also lowering environmental impacts associated with C&DW recycling. Furthermore, the insights from this study can also help the construction sector understand the significance of various drivers of C&DW recycling behavior. The study concludes with presenting different ways of extending the research in future.
Keywords: Construction and demolition waste, Material flow analysis, Life cycle assessment, Structural equation modeling, Urban India.
