Urban mining

News: In late April, the Municipal Corporation of Gurugram angrily ordered its officials to find out who dumped “malba” — the Hindi word for Construction and Demolition Waste (C&DW) on either side of the Gurugram-Faridabad road.

Frameworks to tackle C&DW already exist. Implementation needs to be improved.

What are the causes behind C&DW?

C&DW is generated from

a) construction,

b) renovation,

c) repair, and

d) demolition of houses, large building structures, roads, bridges, piers, and dams.

What is the utility of C&DW?

C&DW comprises wood, steel, concrete, gypsum, masonry, plaster, metal, and asphalt. The C&DW comprising cement mortar, stone, red bricks and concrete blocks undergoes screening, crushing and washing.

– It can then be processed to produce usable building materials such as fine aggregate, coarse aggregate, bricks/blocks, tiles, paver blocks, kerbstones and prefab slabs.

Aggregates made from this type of waste can substitute natural aggregates in a number of applications like road construction, landscaping and concrete production. This helps save natural resources and minimize the waste sent to landfills.

Effective management of C&DW helps in curbing excessive consumption of natural resources and contributes to sustainable development.

– For example, the demand for sand more than doubled between 2010 and 2020. In India, river sand is primarily used for construction. Increasing demand, constrained availability and limited government oversight have given rise to a thriving illegal trade in sand. Manufactured sand from C&DW provides an environmentally sustainable alternative.

Since almost 60% of the stock of buildings projected to be there in 2030 is yet to be built, effective management of C&DW, and therefore “greener construction” assumes even greater significance.

What are the associated challenges?

Insufficent recycling capacity: India generates an estimated 170 million tonnes of C&DW every year, according to the Building Material Promotion Council. But the official recycling capacity is a meagre 6,500 tonnes per day — just about 1%.

– The processing and recycling of C&DW in India is limited to only four operational plants — three in Delhi and one in Ahmedabad.

Rules not implemented: Construction & Demolition Waste Management Rules were notified in 2016 and apply to all involved with C&DW.

– For example, the rules require state government and local authorities to procure and utilize 10-20% of material made from construction and demolition waste in municipal and government contracts. This is not implemented at all, as is evident from anecdotal evidence.

What steps need to be taken?

To address appropriate C&DW utilisation, elements of the existing policy framework need to be revisited.

The concrete and cement industry should start embedding circularity within their operations i.e. using recycled C&DW by reducing its dependence on natural aggregates and raw materials.

But in order to increase higher utilisation of C&DW in concrete and cement, a fresh set of norms are needed.

– The Bureau of Indian Standards (BIS) needs to review many of the current specifications it mandates for C&DW usage in cement and concrete.

– In public works programmes too, usage can be allowed to increase from 20 per cent to higher levels of 30-50 per cent.

What is the regulatory framework to tackle municipal waste?

In 2016, the Ministry of Environment, Forests and Climate Change has provided a regulatory framework for the management of municipal solid waste generated in urban areas of the country. These rules attempt to:

– Improve the collection, regeneration, recycling, treatment and disposal of C&DW in an environmentally sound manner.-

– Emphasise the roles and accountability of waste generators and various stakeholders.

In March, 2017, the Central Pollution Control Board followed this up with detailed procedural guidelines on Environmental Management of C&DW.

Way forward

It is not the lack of official frameworks for managing C&DW. The challenge lies in removing the laxity in their implementation at operating levels. This is now the big change required.

Source: This post is based on the article “Urban mining” published in the Business Standard on 7th June 22.