Waste stream refers to the complete flow of waste from residential, commercial and/or industrial sectors to its final disposal. It is important to optimise waste streams to avoid wasting valuable waste resource, which is waste with the potential to be re-used and to re-enter the economy, and to also reduce the volume of waste sent to the landfill.
However, maximising the full value of a waste stream involves making changes from its source or starting point and across different phases of its lifecycle, including usage, collection, resource recovery, recycling, disposal and end of life.
Why Should Waste Stream be Maximised?
Maximising waste stream can generate two key advantageous results: reduce the volume of waste flowing into landfills; and maximise the usability and profitability of waste in all its forms and throughout its lifecycle.
A large percentage of waste only ends up in landfills where their potential for reuse is lost. For example, since plastic has been invented, around 91% of it was never recycled – 12% were incinerated and 79% is either accumulating in landfills or polluting the environment.
This means the potential of plastic to be recycled and recovered to manufacture new products, along with its economic and environmental benefits, are ultimately lost, leaving only the detrimental effects of plastic waste.
Different waste streams and different uses
Solid waste, such as glass, metal, paper, textile and plastic, contains resources that can recovered and reused and/or recycled to make brand new products, and in some cases, recycled several times.
Glass can be recycled over and over again and still retain its quality and purity.
Metal, like glass, can be recycled repeatedly without losing its natural properties. Steel and aluminium are the most commonly recycled metals as these are highly demanded for construction and manufacturing.
Paper recycling uses 70% less energy and generates 73% less air pollution compared with making paper from raw materials. Plus, using recycled paper to manufacture new products avoids cutting down trees, thus conserving nature.
Rubber can take between 50 to 80 years to decompose, as it is a very strong and sturdy material. Although that is a good thing for manufacturing, it is not beneficial for the environment. Recycled rubber can be used for making asphalt for roads, as cushion for play areas, and as a material for shoes, among many other uses.
Plastic takes up to 500 years before decomposing, but it’s still widely used worldwide. In fact, one million plastic bags are used every minute but only 1% of these are recycled. Plastic recycling helps prevent plastic pollution, especially in our oceans, where plastic bags kill over one million sea creatures every year. Recycled plastic can be made into T-shirts, shoes, bags and other reusable plastic goods.
Organic waste includes kitchen scraps, leftover food, animal food, and animal and human waste. Using specialised technology, organic waste can be converted into green energy to power communities and businesses in an environmentally friendly way.
Wastewater can be recycled and treated to serve numerous uses, including for agriculture, irrigation, landscape, public parks, toilet flushing, concrete mixing, artificial lakes, and as cooling water for power plants and oil refineries.
By recycling water, we can help reduce the need to use the Earth’s limited freshwater supply, which is only about 3%, and the rest is ocean water.
How to Maximise the Full Value of Different Waste Streams?
The process starts with proper waste segregation (i.e., paper waste items are grouped together, plastics go together, metals go together, and so on). Sorting waste into the right groups prevents contamination and damage to recyclable materials, ensuring all waste streams will be recycled effectively and not just dumped in landfills.
Waste streams then go to a materials recovery facility (MRF) for further classification, where waste items that pass quality control are selected and prepared for resource recovery and recycling. During recycling, waste streams undergo specific conversion processes that transform them into new materials, ready to enter the market once again.
By repeating this process cyclically, we can ensure that waste resources are fully harnessed, waste items going to the landfill are minimised, and our natural resources are conserved for the future generation.