Introduction

As the world adopts greater sustainability standards to tackle the challenge of climate change, the issue of construction and demolition waste becomes an important topic in the real estate sector. The socio-economic and environmental impacts of construction waste can have significant considerations for human health, safety, and quality of life. Despite having precise calculations for project costs and an estimated quantity of materials required, construction material is always left behind and construction waste is produced. Increased urban infrastructure developments can become a source of degradation of the environment and biological ecosystems, and the construction and demolition waste generated due to these developments require a considerable amount of money for recycling, reusing, and disposal.  Most of the landfills in Pakistan are filled with solid waste generated from the construction sector. Therefore, it is important that this material be reused and recycled in a sustainable manner to protect the surrounding environment.

This swift research article by the Iqbal Institute of Policy Studies discusses the impact of construction waste on the environment and how a sustainable model can be achieved for its recycling and reuse.

Understanding Construction Waste

Waste production is a natural outcome of material consumption. However, poor handling of materials, inadequate storage and protection, over-ordering of materials, poor site control, lack of training, bad stock control, and damage to materials during delivery are some of the main causes that lead to excessive waste generation and inefficiency in construction projects. Moreover, reasons and sources of waste are also found in faulty design, poor material handling, lack of planning, inappropriate procurement, mishandling, and other processes. Labour attitude and behaviour is another important aspect that can influence the amount of construction material that is wasted during use and application. A study has found that lack of experience and inadequate planning mistakes in the design along with frequent design changes as major reasons for the generation of construction waste. Likewise, multiple stakeholders such as vendors developers’, architects, owners, designers, and contractors also influence waste generation in their own capacities.

No matter how well planned a construction project is, there is bound to be a wastage of construction materials during development. There are multiple ways to categorize construction waste; however, it can be divided into three main categories namely, inert, non-inert, and hazardous. The first category includes soil, sand, rocks, concrete, aggregates, plaster, bricks, masonry blocks, glass, and tiles. The second category includes items like wood, paper, drywall, gypsum, metals, plastic, cardboard, and packaging, whereas the last category includes flammable materials like paints and corrosive materials like acids, bases, and explosives. A study conducted on 30 construction sites revealed that concrete (12.32%), metal (9.62%), brick (6.54%), plastic (0.43%), wood (69.10%) and others (2%) are some of the major categories of waste generated during construction (Iqbal & Baig, 2016). In another study, concrete was estimated to be the largest part of construction waste (Park et al., 2020).

How much construction waste is produced in Pakistan?

The quantity and composition of construction waste keep on changing due to the dynamic nature of construction activities. This makes the exact measurement of varying construction waste products a difficult task. However, various efforts to determine the amount of waste generated during different construction projects and phases of construction have generated insights into how much construction waste is generated in Pakistan. Considering global standards, construction waste accounts for a substantial share of 25 to 30 percent of the total solid waste generated worldwide, and it makes 10 to 30 percent of all waste in landfill sites. Construction processes in the European Union contribute to 33 percent of total waste generation, while approximately 136 million tonnes of construction waste are generated in the US each year. In the UK, 70 million tonnes of construction waste are generated each year, with China having a staggering 40 percent share of construction waste in total solid waste generation. Other studies have also shown that in countries like Hong Kong, Australia, and Germany, the share of construction waste in proportion to total solid waste generated is around 25 to 30 percent. In Pakistan, as much as 30 percent of the total solid waste generated comprises of construction and demolition waste, whereas construction materials wastage accounted for 9.8 percent at construction sites in Punjab (Iqbal & Baig, 2016). Therefore, considering that Pakistan generates 48.5 million tonnes of solid waste every year, which is also increasing by 2 percent per annum, construction waste stands at around 14 million tonnes per annum (ITA, 2019). The Government of Pakistan (GOP) estimates that 87,000 tons of solid waste is generated per day all over Pakistan, mostly from major metropolitan areas. Karachi, Pakistan’s largest city, generates more than 13,500 tons of municipal waste daily.

Source: Mr Saadat Ali, USCS Pakistan contact from Project Procurement International, Pakistan, (website; http://projectpi.pk/)

Impact of Construction Waste on the Environment

From mining processes used to extract raw materials to the waste produced during a construction project and how it is disposed of, there are many significant impacts on the environment. It is important to understand these impacts and take initiatives that will reduce the effect of construction processes on the environment. The construction sector is responsible for the demolition of many buildings, as well as the establishment of new infrastructure. And while most of the waste generated during the construction process is recyclable and reusable, it usually ends up in landfill sites. While it is easier for construction companies to dump their waste in landfill sites, the practice can have significant negative impacts on the environment. Landfill sites emit methane which pollutes the air and exacerbates the greenhouse effect. Dumping of flammable and toxic materials such as paint, varnishes, and other chemicals into landfills can also lead to seepage of harmful materials into the soil. The seepage can also travel to groundwater reserves and pollute waterways, destroying the ecosystems connected to freshwater supplies.

Demolition of buildings can also introduce a variety of pollutants to the environment. Wind often carries loose dust and debris hundreds of miles away, and depending on what the dust is composed of, it can have many adverse effects on public health. While emissions generated from transport, burning of crops, and power generation plants are blamed for air pollution and damaging of the environment, there seems to be considerably less focus on the environmental impacts of construction waste. According to many studies conducted around construction sites, the development and demolition of buildings generate huge amounts of coarse pollutants that are strongly linked to heart disease. Construction sites also produce hazardous waste such as mercury, lead, aerosol cans, and other toxic substances. The environmental impacts caused by landfilling of construction and demolition waste is estimated to increase by 20.2% by 2025. However, if a 50% rate of recycling and reuse can be achieved by 2025, the environmental impact will reduce by 33.2% (Maha & Fujiwaraa, 2018).

Bibliography

Iqbal, K., & Baig, M. A. (2016). Quantitative and Qualitative Estimation of Construction Waste Material in Punjab Province of Pakistan . IDOSI Publications.

ITA. (2019). Pakistan – Country Commercial Guide. Retrieved from International Trade Administration: https://www.trade.gov/country-commercial-guides/pakistan-waste-management

Maha, C. M., & Fujiwaraa, T. (2018). Environmental Impacts of Construction and Demolition Waste Management Alternatives. The Italian Association. Retrieved from https://www.aidic.it/cet/18/63/058.pdf

Nagapan, S., & Rahman, I. A. (2012). CONSTRUCTION WASTE MANAGEMENT: Malaysian Perspective. International Conference on Civil and Environmental Engineering for Sustainability. Retrieved from https://www.researchgate.net/profile/Sasitharan-Nagapan/publication/258224407_CONSTRUCTION_WASTE_MANAGEMENT_Malaysian_Perspective/links/00b7d5277239cb5842000000/CONSTRUCTION-WASTE-MANAGEMENT-Malaysian-Perspective.pdf

Park, W.-J., Kim, R., Roh, S., & Ban, H. (2020). Identifying the Major Construction Wastes in the Building Construction Phase Based on Life Cycle Assessments. Department of Architectural Engineering, Kangwon National University. Retrieved from https://www.mdpi.com/2071-1050/12/19/8096/pdf