Rebuilding C&D Waste Recycling Efforts in India

In India nearly 50% of Construction & Demolition waste is being re-used and recycled, while the remainder is mostly landfilled. Professor Sadhan Ghosh explains why the management of this material is becoming a major concern for town planners, and challenges of increasing awareness about recycling. In India it's common practice for large Construction and Demolition (C&D) projects to pile waste in the road, resulting in traffic congestion. C&D waste from individual households finds its way into nearby municipal bins and waste storage depots making the municipal waste heavy, and degrading its quality for treatments such as composting or energy recovery. The Indian construction industry is highly labour intensive and has accounted for approximately 50% of the country's capital outlay in successive Five Year Plans, and projected investment continues to show a growing trend. Out of 48 million tonnes of solid waste generated in India, C&D waste makes up 25% annually. Rapid economic growth leading to urbanisation and industrialisation is generating waste, which is adversely effecting the environment. The percentage of India's population living in cities and urban areas increased from 14% at the time of independence to 27.8%. Projections for building material requirement by the housing sector indicate a shortage of aggregates to the extent of about 55,000 million m3. An additional 750 million m3 of aggregates would be required to achieve the targets of the road sector. There is also a huge demand for aggregates in the housing and road sectors, but there is a significant gap in demand and supply. Estimated waste generation during construction is 40 kg per m2 to 60 kg per m2. Similarly, waste generation during renovation and repair work is estimated to be 40 kg per m2 to 50 kg per m2. The highest contribution to waste generation comes from the demolition of buildings. Demolition of pucca (permanent) and semi-pucca buildings, on average generates between 300kg per m2 and 500 kg per m2 of waste, respectively. The presence of C&D waste and other inert matters makes up almost one third of the total MSW on an average, but so far no notable development has taken place for using this in an organised manner. At present, private contractors remove this waste to privately owned, low-lying land for a price, or more commonly, dump it in an unauthorised manner along roads or other public land. Taking action The fine dust like material (fines) from C&D waste is not currently being used and is thus wasted. In more than 95% cases wastes such as bricks, metal, wood, plastics and glass have some market value and there are contractors who focus solely on dealing in C&D wastes. The use of these materials requires them to be sorted and separated, and is dependent on their condition, although the majority of this material is durable and therefore has a high potential for reuse. It would, however, be desirable to have quality standards for the recycled materials. An investigation revealed that total waste from India's construction industry could reach 12-14 mt per year In view of the significant role of recycled construction material in the development of urban infrastructure, the Technology Information, Forecasting & Assessment Council (TIFAC) has conducted a techno-market survey on 'Utilisation of Waste from Construction Industry', targeting the house building and road construction industries. The total quantum of waste from the construction industry is estimated to be between 12 million to 14.7 million tonnes per annum, out of which seven to eight million tonnes are concrete and brick waste. According to the survery's findings 70% of the respondents said they were "not aware of the recycling techniques" as the reason for not recycling C&D waste, while the remaining 30% have indicated that they are not even aware of recycling possibilities. Furthermore, the Bureau of Indian Standards (BIS) and other codal provisions do not provide specifications for the use of recycled products in construction activities. In July this year, in West Bengal, a consultative committee comprising top level municipal management and experts from the Centre for Quality Management System and Mechanical Engineering of Jadavpur University and government departments was formed to address solid waste management issues, including C&D Wastes. Construction waste in Delhi Gurgaon Municipal Corporation near Delhi is planning a C&D waste recycling plant on five acres of land. There is considerable construction activity taking place in Gurgaon, but no place to dump the C&D wastes. The fast pace of the construction and renovation work will continue for at least the next five years. Hence, there is need for a C&D waste processor. With the three existing landfill sites having exhausted their capacity some time ago, the Municipal Corporation of Delhi (MCD) has given the go-ahead for the establishment of a sanitary landfill facility at Narela-Bawana in northwest Delhi. The Rs 700 million ($15.5 million) integrated solid waste management facility is being developed to meet Delhi's garbage disposal needs for the next 20 years. The site is being developed as the first engineered landfill site in the city and is spread over 150 acres. Approximately 50 acres will be kept aside for disposing of C&D wastes. The landfill site will take care of refuse from Rohini and Civil Lines zones, and has an initial capacity to handle 1000 tonnes per day, and is planned to expand to handle 4000 tonnes per day. Around 6500 tonnes per day of MSW is generated in Delhi. The Narela-Bawana landfill site has been notified under Master Plan 2021. In addition, the MCD has also carried out a feasibility study on use of C&D waste in road and embankment construction. Recycled roads in Kolkata As in many other countries, in Kolkata the recycling of bituminous material is carried out using hot or cold mixing techniques either on site, or at a central asphalt mixing plant. It offers benefits including reduced use of asphalt, energy savings and a reduction in aggregate requirements. Cold in-situ recycling is done by pulverising chunks of road material to a certain depth, mixing in cement, bitumen emulsion or foamed bitumen and compacting. This recycling process is best suited to roads with light traffic. For hot in-situ recycling, the upper layer of the road is pre-heated and the asphalt is loosened by milling devices. It is mixed together with a recycling agent and the mixture is spread along the road and compacted. Both practices are widespread in Kolkata. Legislation In India there has yet to be a concerted effort to enact legislation governing C&D waste management. There are however some initiatives in different states to address the issue in isolation, or in tandem with the existing Municipal Solid Waste (Management and Handling) Rules, 2000. One example of this is the state of Maharashtraa, which has taken a pioneering step to include a separate collection and disposal of debris and bulk waste in its Action Plan. Under the plan each city is required to have a mechanism for the collection and disposal of waste and construction debris from bulk producers. The Municipal Corporation of Greater Mumbai has enacted the "Construction, Demolition and De-silting Waste (Management and Disposal) Rules". Waste recycling plans should be developed for construction and demolition projects, prior to beginning construction activity. The plans should identify the wastes that will be generated and designate handling, recycling and disposal methods. A minimum of 4% of the total site area should be allocated for storage and pre-treatment of the waste. This storage area should be covered and the pollutants from the waste should not affect the surrounding. Demolition contractors specialise in planned deconstruction that enables the recovery of good material for re-use to be maximised. Recovery rates vary from 25% in old buildings to as high as 75% in new buildings. The demolition of old buildings usually generates wastes such as brick, wood and steel. In India most of the old buildings are mainly made up of good quality bricks. The foundation of the old buildings is of load bearing type where a huge number of bricks were used. When an old building is demolished, almost all the materials are sold at reasonable price. Table 1 shows the quantity and make up of C&D waste per annum in India. Analysis shows that reuse of construction waste can reduce the cost of low budget houses by approximately 30% to 35% without compromising the durability of the structure. Conclusion Legislation needs to specifically address C&D waste management. In addition, the awareness level and availability of technology for C&D waste re-use and recycling needs to be improved to make a sustainable change in India. Quality standards for the recycled or re-used products need to be developed and monitored by Bureau of Indian Standards. Not much effort has been made in this sector and data on generation and characteristics is scarcely available. There should be a proper institutional mechanism to take care of the collection, transportation, intermediate storage (if necessary), utilisation and disposal of C&D wastes. Appropriate rules should be framed and implemented. Separation of C&D waste should be promoted at source and private enterprise can be gainfully employed for the collection and transportation of the waste. Public-Private-Partnership schemes may be a possible mechanism of implementation of C&D waste management in India. Sadhan Ghosh is president of the International Society of Waste Management, Air and Water (ISWMAW), India and professor of Mechanical Engineering at Jadavpur University, Kolkata. e-mail: [email protected] Co-authors include Sannidhya Ghosh, a day scholar at the university and Asit Aich, executive engineer, department of municipal affairs, Government of West Bengal, Kharagpur. More Waste Management World Articles Waste Management World Issue Archives Free MagazineSubscription Free Email Newsletter