How cities are using technology to solve their trash problems – CNN

As urban populations continue to grow, some cities are struggling to cope. Many are turning to new technologies for cost-effective solutions to clean up waste.

Cities that address waste problems immediately have the best chance to avoid severe long-term consequences, says Ricardo Cepeda-Mrquez, solid waste director for C40 Cities, a global network of cities committed to tackling climate change.

Waste that goes uncollected can lead to blocked drains, flooding and the spread of waterborne diseases. Organic matter dumped in landfills where it lacks the air to decompose quickly generates methane gas, accelerating climate change.

Generating energy from waste

The plant, which burns waste instead of fossil fuels, is capable of converting 450,000 tons of trash into energy annually, delivering electricity to 30,000 households and heating to 72,000.

Though it still produces CO2 emissions from burning, the city plans to install a system to capture the carbon released by the incineration process, and then store the carbon or find a commercial use for it. By tapping an otherwise unused resource, it will also help the city move away from its dependence on fossil fuels.

"Instead of placing waste outside in a big landfill, we use the waste to produce energy for heating and electricity in the most efficient way currently available," the Lord Mayor of Copenhagen Frank Jensen told CNN Business in an email.

"Efficient waste incineration supplies district heating for 99% of the buildings in Copenhagen, so we will eliminate the pollution from coal, oil and petroleum," he adds, helping the capital meet its goal to become the world's first carbon-neutral city by 2025.

But Cepeda-Mrquez warns that this technology has its limits. A city needs solid infrastructure and a strong waste collection system already in place before it can reap the benefits of one of these plants.

"Many global south cities, with badly managed waste management systems, expect that with the ideal incinerator or waste-to-energy facility all of their problems will go away," he says. "But if you have a broken system, there is no technology that is going to fix it."

Smarter systems

Other cities are starting on a street level, using artificial intelligence and automation to sort recyclables, or sensors to reduce the amount thrown away.

For instance, Singapore and Seoul, South Korea, have installed smart, solar-powered trash cans on their streets. Each is equipped with a compactor, enabling it to hold more trash. Once the bin is full, its sensors alert the waste collectors.

Typically, cities send out different trucks to collect different types of waste - one truck collecting plastic for recycling, another collecting food waste, for example. But that requires a lot of trucks, which means added costs and more traffic.

"In many cities in Europe, the streets are very narrow, and there isn't a lot of open space for multiple waste collection trucks to be doing the rounds," says Cepeda-Mrquez.

Norway's capital Oslo has designed a clever model to avoid this. Since 2012, city residents have been required to use different colored bags for different types of waste, and instead of collecting them separately, trucks gather all the bags at once and take them to an optical sorting plant.

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How cities are using technology to solve their trash problems - CNN