Construction waste involves construction, roadwork, and demolition materials, as well as complex waste such as plastics, metal, ceramic, and cardboard. Construction materials including wood, shingles, asphalt, concrete, and gypsum make up more than half of the construction waste produced annually.
‘Reduce, reuse and recycle’ policies are required to regulate the amount of building waste, but inadequate funding, lack of standardisation, thin profit margins, political apathy and lack of awareness on the issues prevent this from occurring. The Asia-Pacific region is projected to produce a majority of building waste in the coming year, followed by North America.
Construction and demolition materials consist of debris created during construction, home renovation contractors, and demolition of infrastructure such as buildings, roads, and bridges. Heavy and bulky materials like the following are some examples of construction and demolition materials. The construction sector is struggling to find suitable building materials for the booming cities in Asia and businesses are now vying for toxic waste to replace some of the resources they use, experts claim.
Land reclamation in Lantau
The artificial reclamation scheme for the island of Lantau in Hong Kong does not rely on imported sand but rather will use local building waste. The scheme involves the development of 1,700 hectares of artificial islands off the island of Lantau in west Hong Kong, through sea reclaim.
Construction waste will be a major component and will shape a significant percentage of fill rather than sand. Each year Hong Kong generates 15 million tons of building waste, enough to restore 60 hectares of land, he added. Building waste was also used for the reclamation of the third runway at the Hong Kong International Airport.
Illegal dumping in China
The Shenzhen landslide that collapsed nearly 40 buildings highlights the difficulties that China faces as it digs and constructs subway networks and underground facilities to handle construction waste.
The tragedy was blamed for the illegal dumping of building soil that locals say has gone on behind the Hengtaiyu industrial park in the city for two years. Chinese media reports have highlighted that since 2008, when the city started constructing a network of subway lines, finding places to dump constructing waste soil in coastal Shenzhen was a problem.
Although the problem for Shenzhen, which has small land in comparison with Beijing or Shanghai, is more severe, construction waste is a problem for all China. The situation is worsened by the rush of Chinese cities to create subway lines, which contain more soil waste than normal buildings. At least 38 cities are expected to have one subway line by 2020.
Underground dumping grounds
Cities even tend to go underground as land gets scarce. Hubei’s Wuhan has started constructing the largest underground city in China, announced yesterday by a Chinese state news agency.
According to one state media study, in northern Jinan, less than half of waste dumps have enough capacity to take in construction waste. Since the cost of operating a proper dump was high, it said that illegal ones flourished. After the tragedy Shenzhen stepped up assessment of other dump sites.
Processing waste into construction materials
The Ministry of the Environment and Water Resources (MEWR) in Singapore will soon begin a field trial to evaluate the real-life performance of potential NEWSand materials derived from bottom ash incineration (IBA), the thicker and heavier portion of incinerated ash and that derived from slag, the by-product of solid waste gasification.
The initiative was born out of the push of Singapore to solve constraints and create a valuable waste resource. Since two-thirds of Singapore are designated water catchment areas, the agency said the environmental requirements for NEWSand must be sufficiently strict to ensure that the material can be used at any location in Singapore without compromising the water supplies and environment of the country.
NEWSand implementation comes at a time when Singapore is seeking to reduce the amount of waste that is sent to Semakau. At the time, about 2,100 tons of waste were transported daily to the landfill.
