Photo Gallery VEOLIA - Christophe Majani d'Inguimbert

When trash cans generate electricity

Posted on 16 March 2016.

Left with the "ultimate" and so unrecyclable waste, Veolia recycles the biogas emanating from the Laogang landfill in Shanghai – right now the largest facility of its kind in China!

In the district of Pudong, the most modern district in Shanghai on the east bank of the Huang Pu river, the Laogang landfill absorbs 5000 metric tons of waste every day. That’s just one third of the garbage produced daily by the 24 million inhabitants of the Chinese megalopolis! Avoiding any contamination of the natural environment, the waste is compacted and covered.

Although landfill is the most usual and most common waste treatment method, it does however generate large quantities of biogas - consisting mainly of methane (from 50 to 70%) and carbon dioxide – which is produced by the fermentation of organic matter in the absence of oxygen.

But what if the biogas given off by this so called ultimate waste - which cannot be recycled and which ends up in the Laogang landfill - could be recycled? This is the idea Veolia put to the city of Shanghai in 2008.

With all its technical expertise, Veolia designed, built and now operates a gas - primarily methane - collection and recycling project under a twenty-five year public-private partnership contract.

This solution, which includes the installation of a biogas collection and pre-processing system and a power generation unit, has two advantages: firstly, it prevents the emission of a particularly potent greenhouse gas (the impact of methane is 28 times greater than CO2) and secondly it improves the energy efficiency of the Laogang site which is now capable of producing electricity for its own use and for sale to the public network in Shanghai.

This double benefit led to the project being listed by the United Nations as a "clean development mechanism" under the Kyoto Protocol which encourages emerging countries to reduce their CO2 emissions. It also fits in perfectly with Veolia's priorities in relation to fighting climate change - namely to increase the capture rate of methane from the landfills it manages worldwide.

Now Laogang has eleven generators with an installed capacity of 15 MW producing approximately 100,000 MWh of green power annually – equivalent to the consumption of 100,000 households! In 2014, 60 million m3 of biogas was recovered and processed, thereby reducing methane emissions by 25,800 metric tonnes (equivalent to 542,000 tons of CO2).