Construction waste is a very self-explanatory term. This waste is generated as an aftermath of any construction activity on residential, commercial or even infrastructure projects. Raw materials such as steel, concrete, rubble, wood, stone etc. are the most common types of construction wastes that are generated.
With construction activity at an all-time high in India, this sector currently generates a whopping 10–12 mn t of waste every year. While retrievable materials such as bricks, wood, metal, titles are recycled by domestic developers, concrete and masonry waste that account for more than 50 percent of the waste from construction and demolition activities are not. With pollution control targets and care for environment looming large on the priority list of developers, more and more professionals and firms alike are waking up to the importance of efficient construction waste management.
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An outstanding example of this is the recent initiative undertaken by the Municipal Corporation of Delhi (MCD), which used to generate 2,500 TPD construction waste, up until some time ago. To address this, a new landfill site was set up at Narela-Bawana in North Delhi, with a waste-handling capacity of 1,000 t per day. The site, which was made operational recently, can expand its capacity to handle up to 4,000 t of waste on a daily basis.
Strata Geosystems India Pvt. Ltd completed a major project to improve a landfill access road in Assam; Ramky Enviro Infrastructure Ltd chose Strata’s Geocell product to construct an approach road for a landfill site. Strata engineers determined the appropriate amount of Geocell needed, supplied installation details, and provided the necessary training to the local crew, in order to ensure a professional result. In the process, this has also generated huge cost savings. The access road for the Guwahati Solid Waste Landfill site at West Boragaon, Guwahati (Assam, India), under Guwahati Municipal Corporation was purely filled-up with soil and subject to heavy settlement, because of the surrounding high water table. This was hampering the movement of garbage dumping trucks, which were increasingly dumping garbage, much before the demarcated area, thus triggering total mismanagement. Moreover, in the monsoons, it was increasingly difficult to maintain the serviceability condition of the approach road. Thus, Geocell—a cellular confinement system from Strata Geosystems—was chosen for the job. Geocell is a proven component of slope stabilisation, load support, earth retention and channel applications. This expandable, honeycomb-like cellular structure can be collapsed and easily transported. In this case, regular construction methods would have called for at least 500–800 mm moorum infill to stabilise the soil and to run the heavy vehicular traffic. The use of Geocells has helped the company to save natural resources and reduce its carbon footprint. Geocell, being a fast and all-weather installation, ensured that no time was wasted because of the ongoing rainy season.This has resulted in savings in terms of time, money and natural resources.
The government body was earlier under constant scrutiny due to its inability to manage waste, with the existing overflowing landfill sites also receiving construction and hazardous wastes, leading to contamination of soil and groundwater. The Narela-Bawana facility seeks to address the area’s waste management woes by demarcating approximately 50 acres specifically for the disposal of construction and demolition wastes.
Here, we investigate the efforts that are being made in order to manage construction wastes effectively at present, innovative methods of reusing materials and common challenges that are faced during this process.
Same Materials, Different Story
Most contractors and architects agree that there is no specific technology or machinery used to recycle the various types of construction wastes. However, they also agree that most of these materials—if not completely damaged—can be reused in innovative ways, and that this should be made a practice.
“Building materials waste can be reduced by trimming materials to fit exactly, taking into account the labour cost for installation. Although there are no actual numbers available, about one-third of construction wastes essentially arise from design decisions. Results also indicate that a number of constraints such as lack of interest from clients, attitudes towards waste minimisation and training act as disincentives to the proactive and sustainable implementation of waste reduction strategy during the design process itself,” says Madhur Khaitan – CEO, Arcmesh. He believes that this problem can be mitigated at the source—the planning stage—which will result in a substantial amount of construction material being saved.
In most developed nations, construction waste is taken to facilities to be formally treated. For example, the best solution to convert asphalt roof-shingles into usable material again, is to use them to pave a road. Another example is the recycle of flooring or wall materials. Carpets can be treated and reused to make components such as composite lumber, carpet cushion or even automotive parts. Even tiles and crushed concrete can be reused as gravel, or as dry aggregate for new concrete. The same is the case for dirt, rock and sand—these can easily be reused in landfills for cover.
Architect Hafeez Contractor points out that old materials are usually reused during a redevelopment project. In his practice, the company makes sure that materials are used differently at different sites. “We use materials at various places, but in myriad ways. Take for example our DLF project—a lot of construction material was used for centring purposes, and we found that it had lost its value. So, we cut it and used the best parts to make a complete railing for the golf course,” he informs.
|The Legal Take on Waste
Scotland: The government has been working on developing specifications and code of practice for waste management for the past few years. Attempts are being made to establish links with the planning system, computerise the transfer note system to facilitate data analysis and facilitate dialogue between agencies for the adoption of secondary aggregates by contractors.
Denmark: According to Danish Environmental Protection Agencies (DEPA), in 2003, 37 percent of the total waste generated was Construction and Demolition (C&D) waste. Around 70–75 percent waste was generated from demolition activity, 20–25 percent was from renovation, and the remaining 5–10 percent was from new building developments. Because of constraints pertaining to landfill sites, recycling is a key issue for the country. A statutory order, action plan and voluntary agreement was carried out, for example, for the reuse of asphalt and sorting of C&D waste (1995).
Netherlands: More than 40 percent C&D waste is generated, of which 40 percent is brick and concrete. Initiatives such as the prevention of waste stimulate recycling, and the promotion of building material that have a longer life, products that can be easily disassembled, separation at source and prohibition of C&D waste and landfills have been undertaken.
USA: C&D waste accounts for about 22 percent of the total waste generated in the US. Reuse and recycle of C&D waste is one component of a larger holistic practice called sustainable and green building practice. Promotion of deconstruction-or planned breaking of a building with reuse being the main motive-is on the rise, as opposed to demolition.
Source: White paper on Management of C&D Waste in India by the Delhi government
The crux of the situation is that developers need to plan more efficiently so that resources are not wasted. More often than not, it is possible to use waste management techniques that are well within their means, rather than opting for exorbitant stop-gap arrangements. “Also, the situation is not justifiable if some material has been used at one place efficiently, but a lot of wastage has happened elsewhere. This factor has to be looked at from a broader perspective,” Mr Contractor adds.
Speaking about recycling raw materials on construction sites, Sherman Stave – Principal Architect at Sitetectonix for Lodha’s New Cuffe Parade project in Wadala, Mumbai points out, “Since the Lodha project is striving for sustainable construction, we are going to make a conscious effort to reuse and recycle raw materials as much as possible. In this regard, we are going to use as many native materials as possible—that is one way of recycling and minimising waste. In terms of efficient waste management, if there is a lot of cut-stone waste generated for example, these small pieces of stone can be crushed and used as gravel. Even in the case of timber, whatever timber is damaged is recycled and used as part of compositing material. In instances such as these, materials can be efficiently used, but I am not too sure if a developed programme is available right now. This is something we will have to work out with the contractor over time.”
Cutting through the Waste Mound
Construction waste management is not without its own share of problems. Mukul Gupta – Managing Director, Chemtreat India explains, “There should be an increase in use of RMC and designated landfill areas near the site. Also, in the initial stage itself, non-reusable construction materials should be replaced with their recyclable counterparts. This process of recycling can be repeated several times during construction, thus resulting in the reduction of costs and wastage. If this factor is taken care of, instances like the Mithi River in Mumbai will reduce.”
Mr Khaitan brings to perspective that currently, when an existing structure is modified or even when a new one is built, a lot of the waste and rubble is not easy to dispose of, and builders end up incurring additional expenses to get rid of this waste. “One way to combat this problem is the use of meshed steel. Meshes act as a plug-and-play raw material and help to reduce building cost. Given their light weight and flexible design, meshes produce significantly less waste than most traditional building materials. Most important of all, they can be reused by simply rolling back and preserving them, or selling them for an equivalent amount of stainless steel,” he explains.
Stainless steel architectural mesh systems reduce the need for electric light and unwanted heat gain. The basic ingredients for building products—whether for concrete walls or roofing membranes—are obtained by mining or harvesting natural resources. The extraction of raw materials, whether from renewable or finite sources, is in itself a source of severe ecological damage and also leads to wastage. In new construction projects, mesh solar shading can lower the initial cost and also decrease the necessary size of HVAC systems.
Mr Gupta highlights that materials used in processes such as shuttering are rendered as unusable waste. These materials cannot even be used as land refill and are finally burnt. However, commonly-used wastes such as cement, concrete and other construction debris are generally used as land refill or recycled as part of the construction material.
“Landfills in India are located far away from the construction site, causing major infrastructure problems. The cost of transporting them to the area is expensive; thus, a make-shift landfill nearby is used to dump the waste. An increase in the usage of RMC in designated landfill areas near the site will drastically help waste reduction and management. Also, new technologies and recyclable materials should be used to replace construction materials,” he suggests.
The Legal View on Wastage
There is a common sentiment among most builders and contractors that there should be a proper institutional mechanism to take care of the collection, transportation, intermediate storage, utilisation and disposal of construction and demolition waste.
According to the Solid Waste Management Manual released by the Ministry of Urban Development, Government of India, a number of municipalities and the sanitary department or the health department is responsible for municipal garbage, whereas the engineering or planning department is responsible for construction and demolition waste. Under such circumstances, it is extremely important that either the Solid Waste Management Department is made responsible for collection of construction and demolition waste, or that these departments work in close coordination. It is essential that proper accountability is fixed, and official information is readily available regarding the day-to-day situation.
The Government of India has made a few initiatives towards waste management in India. There are as follows:
Bio-medical Waste Handling Rules, 1998
Municipal Solid Waste Management Rules, 2000
Reforms Agenda (Fiscal, Institutional, Legal)
Technical Manual on Municipal Solid Waste Management
Technology Advisory Group on Municipal Solid Waste Management
Inter-ministerial Task Force on Integrated Plant Nutrient Management from compost
Tax Free Bonds by ULBs permitted by Government of India
Income tax relief to waste management agencies
PPP in Solid Waste Management (SWM)
Urban Reforms Incentive Fund
Introduction of Commercial Accounting System in Urban Local Bodies (ULBs) and other sector reforms
Model municipal bye-laws framed/circulated for the benefit of ULBs for adoption
Financial Assistance by Government of India – 12th Finance Commission Grants
Mr Gupta points out that the laws in India are present, but not enforced or made stringent. There is a lack of designated landfill areas. In other regions such as Europe and America, such laws are extremely stringent and heavy penalties are levied if they are not followed.