The City of São Paulo produces, on a daily basis, 15,000 tons of waste, which is delivered to one of two solid waste landfill sites on the outskirts of town. The slow decomposition of organic matter present in the solid waste produces a biogas, rich in methane, which permeates the layers of material covering the landfills and is released into the atmosphere, contributing to harmful climate change.
Through this process of decomposition São Paulo was emitting approximately 950,000 tonnes of methane from municipal solid waste and 25,000 tonnes of methane from wastewater treatment, representing about 1% of Brazil’s net greenhouse gas emissions. The impacts of climate change are already being felt across the country providing a strong incentive for action to help mitigate the problem.
The gas from landfill sites also posed a threat to the wellbeing of residents living close by. As in many countries around the world, weak planning restrictions allowed homes to be built within close proximity of the waste sites. As such, some residents faced health hazards like the risk of injury through explosion, poor air quality, and serious illness from chemical and waste exposure, such as cancer.
City of São Paulo officials instigated the Bandeirantes Landfill Gas to Energy Project (BLFGE) as a combined response to tackle the dual problems of dangerous greenhouse gas emissions from waste and the city’s increased reliance on fossil fuels. It became one of the first and largest methane-capture systems in the world.
The BLFGE is a system for collecting, filtering, pressuring, and burning the biogas from the city’s waste site at Bandeirantes. Burning this gas in thermal electric plants prevents it from being released into the atmosphere and instead it is used to generate power for the city. The result is a twofold environmental gain: in addition to reducing the amount of methane released into the atmosphere, the need for sourcing more dirty energy is reduced.
It is estimated that the project has prevented the release of methane gas equivalent to 8 million tonnes of CO2 into the atmosphere between 2004 and 2012, while simultaneously producing clean energy. On top of this, the project has generated $35.5 million through the Clean Development Mechanism of the Kyoto Protocol.
This money was reinvested by city officials in surrounding communities through initiatives such as protecting housing in high-risk areas; creating parks to restore vegetation and control floods; building bicycle lanes; and launching environmental education and citizen engagement programmes.
Urban areas are responsible for 70% of global greenhouse gas emissions and city governments are institutions with huge potential for tackling this problem. São Paulo demonstrated this with the Bandeirantes project, which has now been replicated at the Sao Joao landfill and shared with other cities including Mexico City and Lagos.