The Chennai Corporation collects 1,143 tonnes of construction and demolition (C&D) waste a day and charges Rs. 532 a tonne for its removal from the site. With the rapidly expanding construction industry generating tonnes of waste, what are we doing to manage it?
The Centre for Science and Environment (CSE) estimated that India generated around 530 million tonnes (MT) of C&D waste in 2013. Avikal Somvanshi, Senior Research Associate, CSE, says, “Currently, at the national level, there are no official estimates about the quantity of waste generated. In 2014, responding to a question in Parliament, the Ministry of Urban Development said it had no records.” Arun Kumar, managing director, Casa Grande, says in a year, of 48 MT of solid waste generated in India, C&D waste is 25 per cent. “Not even half the waste is recycled. Apart from environment degradation, this will lead to an increase in transportation and disposal costs, and a drastic shortage in dumping sites.”
C&D waste has multiple issues. From the environment perspective, it’s a double murder of our rivers and natural resources, says Avikal. “Our rivers are first destroyed by extensive sand mining, which mostly goes into making concrete and mortar. This material is wasted and dumped back into these denuded rivers and wet-lands, further degrading them,” he says. In India, minimising on-site waste is not a priority and hence leads to enormous quantities generated. Analysis shows that reuse of waste in low-budget houses can reduce costs by 30 to 35 per cent without compromising on the durability of the structure, says A. Shankar, national director, JLL.
Construction and demolition waste is classified into two components — major components including cement concrete, bricks, cement plaster, steel from RCC, doors and windows, roofing support systems, rubble, stones, and timber; and minor components including conduits, GI pipes/ iron pipes/ plastic pipes, electrical fixtures, panels and glass. “Materials and components from demolished buildings are being reused for new construction as well as renovation projects, especially by low-income communities in developing countries,” adds Shankar.
Recycling will cut costs of producing new raw materials and reduce the use of landfills. So how can the waste be recycled? Dr. Kumar, Managing Director, Navin Housing and Properties, says C&D waste falls under three categories — scrap, rework and demolition. “Scrap such as gunny bags, paint boxes and steel scrap are being reused. Demolition waste such as concrete, timber, tiles and marble are used for curing and also for low-cost projects,” he says. Adds Shankar, “Plastic, rubble can be used for levelling, and larger pieces can fill low-lying areas. Fine material such as sand can be used as cover over a landfill.”
In India, we have not built two-thirds of the buildings that we will have by 2030, and we need to adopt some earlier strategies of the West. “Thirty per cent of the concrete used in the London Olympic stadium was made using recycled aggregates. Although as per the National Building Code, any builder can use recycled waste in construction, there are issues on legality. Once clarified, the onus will be on municipalities and builders,” says Avikal of CSE.
Shripal Munshi, principal architect, Shripal and Venkat Architects, says we need a C&D waste management strategy, as in other countries. Singapore reuses 98 per cent of its C&D waste, South Korea almost 45 per cent, Hong Kong more than 70 per cent and in 2000, Japan used 95 per cent of its concrete waste in roadbeds. “Most material is designed for multiple uses, but is underutilised. Contracts must make it mandatory for developers and vendors to reuse material and also provide them with incentives,” he says.
Clearly, the onus is on developers, contractors and development authorities to implement and promote sustainable construction methods that reduce and reuse waste.
Best Practices United Kingdom: 28 per cent of the total C&D waste is recycled New York: Developers mandated to segregate waste at site; to dismantle and not demolish Denmark and the Netherlands: Aggressive strategy to reuse C&D waste Japan: 98 per cent of asphalt and concrete, and 35 per cent of sludge recycled Hong Kong: Construction waste levy imposed on developers, tax concessions for reuse Singapore: 98 per cent of C&D waste is reused South Korea: Waste management part of its low carbon green growth strategy (Extracted from CSE report) |
