Buildings apart from requirement of water, energy and material also generate waste. Construction and demolition (C&D) waste is generated in the construction, maintenance and disposal phases of a building. This includes demolished structures debris, renovations in buildings and construction and repair of road projects, flyovers, bridges, etc.
World Bank report 2012 says that about 1.3 billion tonne of solid waste per year is generated by cities globally and this volume is expected to increase to 2.2 billion tonne by 2025. About half the solid waste generated worldwide and materials used are building materials
C&D waste can become an invaluable source of building material. There is a need to recycle, reuse and substitute naturally sourced building materials such as sand due to recent controversy over sand mining in India.
Types of Construction And Demolition waste
Global best practices
It has very stringent controls over C&D waste and imposes a construction waste charge on developers due to serious land constraints to afford landfills. This system has lowered the quantity of C&D waste needing disposal at landfills by 60 per cent.
The waste is charged at HKD $27 per tonne. If more than 50% of waste needs to be dumped in landfill, disposal is charged at HKD $125 per tonne. This has incentivised on site recycling and reuse. C&D waste recycling centres are maintained and subsidised by the revenue generated and also tax concessions are offered.
Structures are dismantled systematically instead of demolishing. Debris generation is further minimised by its reuse and very efficient construction practices
It recycles 98 per cent of its C&D waste and is a land constrained country
Law on Acceleration of C&D Waste Reuse/Recycling 2005 provides for step-by-step demolition, and utilisation of recycled aggregates. Separate building codes has been adopted for recycled asphalt concrete aggregates, recycled concrete aggregates, and road pavements.
Increased use of recycled C&D material is recommended by the Architectural Institute of Korea’s Standard Building Construction. Target of increasing effective recycling rate which is 36 per cent to 45 per cent by 2016 in Korea
Aggregates should be from natural, recycled, and manufactured material according to European Standards for Aggregates 2004. They do not discriminate between resources and focus on fitness of use. C&D waste is extensively used in non-structural frameworks but not in structural and foundation frames in the EU.
The Quality Protocol for the Production of Aggregates from Inert Waste was published in 2004 by Northern Ireland Environment Agency. Almost 280 MT of aggregates which is 28 per cent of total C&D waste are used every year
New York has limited space for disposal as it is land locked and has stringent measures for C&D waste which are more efficient than the rest of the US. The developers should segregate waste at site, dismantle and not demolish, in addition to other measures.
Denmark and the Netherlands
Aggressive strategy to reuse C&D waste. Bricks and concrete forms 80% of its C&D waste that can be recycled to minimise pressure on land.
C&D waste generation in India
The construction industry in India is burgeoning. It has been growing annually at the rate of 10 per cent over the last 10 years as against the world average of 5.5 per cent and is already at 10% of the GDP. The built-up area is expected to surge almost five times from 21 billion sq. ft in 2005 to approximately 104 billion sq. ft by 2030. The Union ministry of forests and environment (MoEF) has acknowledged that there is no systematic database on C&D waste. However, we can infer from same data from Technology Information, Forecasting and Assessment Council and Centre for Science and Environment. Just for year 2013:
- India has constructed 5.75 billion sq. m of new additional floor space from 2005 with almost one billion sq. m.
- Approximately 50 kg per sq. m of waste is generated during construction. India must have generated 50 million tonnes (MT) of C&D waste.
- 300-500 kg per sq. m of waste is produced due to demolition. About 288 MT more C&D waste would have been generated due to demolition and rebuilding of 5% existing building stock annually.
- 40-50 kg per sq. m of waste is generated due to building repair. About 193 MT of C&D waste would have been generated due to repair or renovation of 1/3rd of existing building stock
A total of about 530 MT of C&D waste was generated in India from buildings in 2013 alone. This was 44 times higher than the official estimate. This waste is being used illegally to fill up water bodies and wetlands around urban centres for real estate development and rest is just being dumped into rivers and open spaces.
No reuse in India
Indian laws permit the use of only naturally sourced building material according to CPWD. Concrete can be made only with naturally accessed materials and this rule stipulated in IS: 323-1970 by BIS is specified to avoid using recycled C&D waste. In the Municipal Solid Waste (Management and Handling) (MSWM) Rules, 2000 separate collection of C&D waste is mentioned. Some basic guidelines on handling of C&D waste is provided which are not binding in Municipal Solid Waste Management Manual of MoUD 2000.
MoEF, in 2010, constituted the Working Group on Solid Waste . It is suggested by Sub-Group to generate data on C&D waste. It also recommended waste segregation at source, development of waste collection institutional mechanisms, reuse and reprocessing, charges to be imposed on C&D waste generators, standards formulation, and MSWM Rules, 2000 amendments for ensuring collection, utilisation and safe disposal of C&D waste. The recommendations were not included in the draft Municipal Solid Waste Management Rules of 2013 by the MoEF.
Lack of standardisation, not listing the construction techniques and cost-effective recycled building material in the Indian Standard Codes and/or the Schedule of Rates (SOR), poor policy push and lack of awareness are the key barriers.
The Bureau permits use of aggregates other than natural aggregates in plain concrete under IS: 456-2000 and BIS does not forbid the use of any new material and initiative can be taken by any authority to permit the use of recycled material according to Sunil Soni, director general of BIS.
Using Performance Appraisal Certification Scheme (PACS) by Building Material and Technology Promotion Council (BMTPC), new products manufactured by using recycled waste in fact, any new product, system or technique not covered so far by the BIS can be certified under this scheme after evaluation and has been used to certify new construction material such as bamboo.
Crisis of building material and environment
Extensive damage has been caused to the environment; rivers injured, made many areas susceptible to floods, and destroyed the crucial recharge zones due to haphazard mining of sand and other minor minerals
To regulate mining of minor minerals and ensure environmental management; State Governments have been told to amend the rules by Supreme Court in 2012. The National Green Tribunal (NGT) declared sand mining without environmental clearance illegal on august 5th 2013.
The shortage is so severe that several civic projects in India are facing delays. This is affecting the construction of roads, bridges, canals and the housing crisis.
Case study of Delhi
Delhi produces 3000 to 4000 tons per day (TPD) of C&D waste. It is the responsibility of Municipal Corporation of Delhi to transport and dispose of unclaimed waste. The quantity of C&D waste generated in the city is more than the total quantity collected and disposed by MCD.
Large amount of C&D waste is dumped illegally in barren areas like the Delhi Ridge and Yamuna flood plains. Waste is disposed without any processing and there is no scientific method followed at disposal site. Lack of space for storage and landfill are also issues of concern.
IL&FS Environmental Infrastructure & Services Ltd (IEISL) in collaboration with MCD developed a pilot project to demonstrate a scientifically managed process of C&D waste collection and recycling in Delhi. It is the first project of organized management of C&D waste in the country, which can be replicated by other cities in India.
This project predicts a collection mechanism for C&D waste, transportation to the designated processing site for processing of waste and reclaiming of land by filling up, levelling and compaction. It has been set up on a PPP model at Burari for a period of 10 years on seven acres of land provided by MCD. This model is successful as it saves landfill space and also develops a market for C&D waste recyclables
IEISL collects 500 tonne per day (TPD) of C&D waste from three designated zones of the Delhi: Karolbagh, Sadar Paharganj and City. At the waste management facility this waste is being recycled into aggregates. This is converted to Ready Mix Concrete (RMC), pavement blocks, kerb stones and concrete bricks. The products have been tested in various laboratories and found to be suitable for the specific purposes. These products are actually being sold in the market.
IEISL had to constantly ameliorate the production process as well as the technology adopted for recycling due to diverse nature of C&D waste generated. The products manufactured by the recycling plant are not selling well though. This is due to the lack of information and confusion over the Indian Standards. This has as well led to IEISL facing an economic sustenance crisis
Case study of Bangalore
A unit is developed to crush and process 50 lorry‐loads of debris every day at Mallasandra on Hessarghatta road, by BBMP with direction of KSPCB
- For sustenance & viability combination of technologies for MSW processing has been attempted.
- Recyclables and inert rejects are going to the scientific landfill.
- Attempt is being made to utilize all the recyclables.
- In the construction of pavement roads small quantity of plastic is being used.
- About 8% of Poly blend is mixed in the asphalt
- There is an exposure of converting the plastics into diesel by following de‐polymerisation technology, which is yet to be implemented in large scale.
- GPS/GPRS Based Tracking system is implemented for accountability of distance travelled by vehicle.
- To view the vehicles reached at the sites CCTV cameras have been installed at various points.
- Ticketing system using Hand Held Device which collects the data and sends it to the central server for monitoring and analysis is in place
- Through GPRS truck numbers and operation schedule is automatically downloaded to the Hand Held device.
Future changes and recommendations
- BIS code on recycled material should be formed
- Promote alternative material in buildings
- Products made out of recycled C&D waste should be included in CPWD SOR
- Rules and Bye-laws should include waste collection, disposal and reuse provisions.
- To minimise waste stimulate efficient construction practices
- Promote use of alternative material in other infrastructure
- Introduce tax policies to minimise waste generation and prevent unsafe disposal
Member of NOSPlan
- Construction and Demolition Waste by CSE
- URDPFI Guidelines