BBC World News Horizons explores sustainable ways of dealing with global waste

Plastic is a petroleum product, bitumen is a petroleum product. Plastic definitely improves the performance of the road and the longevity of the road."K.Ahmed Khan, Managing Director, K.K. Plastic Waste Management
Date: 11.10.2012     Last updated: 18.03.2014 at 18.16
Category: BBC World News
The amount of solid waste mankind generates in urban areas on a yearly basis has almost doubled over the last decade and as urban populations continue to grow, it is estimated that by 2025 we will produce nearly one billion more tonnes each year.

The amount of solid waste mankind generates in urban areas on a yearly basis has almost doubled over the last decade and as urban populations continue to grow, it is estimated that by 2025 we will produce nearly one billion more tonnes each year. In the thirteenth episode of the Horizons series, presenters Adam Shaw and Saima Mohsin visit California, USA and Bangalore and Mumbai, India to learn how cities are dealing with the growing amount of waste being generated.

Saima begins in California’s capital city of Sacramento, where biotech start-up Micromidas is researching new ways in which it can recycle sewage sludge into useful biodegradable plastics. Micromidas uses microbes to feed on sewage sludge. Once consumed, the bacteria produce linear polyesters called polyhydroxylalkanoate (PHA) in order to store carbon and energy. These plastics are biodegradable and the company has already raised millions of dollars in investment funding to build a bio-refinery where it can start pilot testing this process.

Peter Matlock, Vice President, Business and Corporate Development, Micromidas, explained: “We can make a broad variety of plastics that are available today [using PHA]… and when you are done with it, you throw it away and it completely biodegrades. We have identified literally millions of metric tonnes of waste material that are eligible for the process.”

Saima then travels to India’s southern city of Bangalore to visit K.K Plastic Waste Management, a company that transforms thousands of tonnes of waste plastic into roads. Plastic is collected, shredded and mixed with asphalt to form a compound called polymerized bitumen. Since plastic is water-resistant, this combination means roads survive monsoons, have fewer potholes and need to be repaired less frequently than traditional pavements.

K.Ahmed Khan, Managing Director, K.K. Plastic Waste Management said: “Plastic is a petroleum product, bitumen is a petroleum product. Plastic definitely improves the performance of the road and the longevity of the road.”

Saima also travels to Mumbai, India’s most populous city, which is turning to local waste management to cope with the 8,000 metric tonnes of waste it generates daily. Housing districts like Chembur have started to deal with their waste directly at the source. A women’s collective gathers Chembur’s rubbish and biodegradable wet material, which makes up to 60 percent of the district’s household waste – is composted on-site and used for gardening, while dry material is recycled. Similar schemes are now running at 40 locations around Mumbai.

Jessica Culshaw - Jessica.Culshaw@bbc.co.uk | +44 20 843 33340