Responsible management of waste is an essential aspect of sustainable building. Waste management is a key area of concern within the construction industry today. With dumping sites currently overflowing everywhere in Africa, it is time to take salvage/reclamation opportunities, recycling or reusing materials, source reduction and waste disposal more seriously. The following are tips for sustainable waste management in construction:
Some building-related waste can be minimized. For example, construction products can be selected on the basis of its being designed and manufactured to be shipped with minimal packaging. Also consider that selection and use of recyclable materials and products offers potential to minimize waste.
Segregate waste efficiently
How waste is separated and stored is essential for effective construction waste costs management. This can be done by:
- Introducing a secure on-site waste storage area that features clearly labelled and colour-coded skips, bulk bags or wheelie bins for different types of waste
- If applicable, deploying a mini crusher and screener for leftover bricks, blocks and hardcore
- Training employees in basic segregation procedures, using incentives and rewards to ensure they follow them
- Bringing on board a team to exclusively monitor and manage materials and waste either on a full- or part-time basis (depending on your budget).
Some materials can be reused. For example, doors and windows in good, resalable condition might substitute for new products, or be donated and or sold for use on another project; a form of beneficial reuse.
Materials and products which cannot efficiently and effectively be eliminated, minimized or reused ultimately are collected, and unless managed, will probably be disposed at the lowest cost. In many areas of the country, disposal fees at solid waste landfills are substantially higher than the cost of separation and recovery, including the disposal cost for residues.
Some waste generated in the process of construction can be eliminated. For example, durable modular metal form systems for use in concrete construction may be selected on the basis of being readily demountable and reusable on other projects, thus eliminating wood waste associated with formwork fabricated of plywood and dimensional lumber. Elimination of waste can be beneficial to reduce impacts on human health and the environment.
Demolition and deconstruction
Building demolition results in heavy pollution and waste generation, so deconstruction needs to be the focus instead.
Deconstruction allows for extensive recovery of usable material at every level, right from systems and assemblies to entire structures and foundations. In addition to preserving resources and minimizing landfill waste, it also boosts the economy by creating new employment opportunities.
Here are some aspects to consider while designing/removing buildings:
- Complete deconstruction is not always possible, but most buildings can be partially deconstructed by combining demolition and deconstruction methods.
- Buildings that are wood-framed are highly deconstructable, especially if they have been constructed with heavy timber or versatile, old growth wood.
- Paving or construction projects using high-quality brick covered with low-quality mortar are easier to deconstruct, clean and reuse in new buildings.
- Structurally sound buildings that are constructed with durable materials are the easiest to deconstruct, with the maximum salvage/recovery potential.