São Paulo tackles organic waste

Unconstrained by its vast size, the city of São Paulo, Brazil, has planted the first seed to grow an intricate network that could transform the city and may eventually extend across the entire metropolis. The innovation, modest in comparison to some of the city’s transport or buildings infrastructure, takes the form of the city’s first composting facility.

Launched in 2015, the pilot composting project is in Lapa, a district in the northwestern part of the city. The projects aim was to increase the capacity for a sprawling, hectic, jumbled megacity populated by 12 million inhabitants to unpick a single stream of discarded food, known as organic waste, from the millions of tonnes of mixed municipal solid waste it generates each year.

In 2016 the Climate and Clean Air Coalition provided technical assistance to the city to consolidate, enlarge and replicate the pilot project in the city’s other districts in order to maximise the potential benefits of the technology. These benefits are considerable.  Composting prevents methane emissions, a key concern for the Coalition, which build up in the anaerobic conditions of landfill sites. Waste is the third largest source of manmade methane emissions, which contributes to climate change and ozone air pollution.

Since 2016 São Paulo has established four additional composting plants throughout the city with a total capacity to treat 1,250 tonnes of organic waste per month. The current administration is committed to launching ten more by 2020, and 20-25 composting plants altogether.

Ground-breaking project

“A megacity such as São Paulo, with 12 million inhabitants, may find excuses not to separate waste, and in some cities the policies are not in place. So for São Paulo, this plant is a ground-breaking project”, says Sandra Mazo-Nix, coordinator of the Coalition’s Waste Initiative.

In such a large city, the easy option is to throw the rubbish together – rotten fruit and carrier bags from markets, straws and ice cream cartons from shopping malls, or margarine tubs and yoghurt pots from apartment tenants.

Pollution concerns

But concerns have been increasing over the last decade. Certainly, nearly all the city’s waste is collected by waste disposal companies. However, most is sent to São Paulo’s two landfill sites.  Efforts to achieve full coverage for separate collection of dry recyclables continues to face many of the barriers typical of urban populations, such as poor-quality materials and low rates of recyclability.

The millions of residents of this diverse, intense city, many of whom live in high-rise flats in densely populated areas, do benefit from daily solid waste collections. Individually, they produce 1.1 kilogrammes of waste each day. Together, they dispose of 12,000 tonnes each day, including 51% organic waste as well as 30% dry recyclables. However, not all of this is separated.

Housing density

The capacity to separate food from other waste is limited. Given the high-density characteristics of housing in the city, practical and resourceful solutions are required to encourage occupants of each flat to separate food waste in individual containers. Even if solutions could be rolled out across the entire population, collections might be obstructive. “Adding more trucks to collect food waste separately on a daily basis from so many high-rise flats could add to traffic gridlock,” notes Sandra Mazo-Nix.

Yet urgent action is needed. Data from the Brazilian Association of Public Cleansing and Waste Management Companies (ABRELPE) show that almost 60% of all urban waste collected was sent to landfill sites in 2017 while the other 40% was disposed in dumpsites or uncontrolled sites. Meanwhile, waste generation continues to grow.

At the same time, local authorities have had to ensure they marshal the 20,000 waste pickers who work São Paulo’s streets, in order to put their activities to good use to segregate waste. Efforts are also underway to clean up pollution caused by waste in the city’s Tietê river.

Cornering the markets

The composting facilities have become beacons on the city’s pathway to sustainable waste management. Sensibly, the project designers did not start with households. Instead, they concentrated on the retail trade, and an obvious source of food waste – street markets.

From its base in Lapa, the city’s first composting plant takes in biowaste collected from around 50 street markets as well as green waste from parks and gardens. The facility, taking up about a third of a hectare, can treat up to 60 tonnes of organic waste per week and produce approximately 900 tonnes of compost each year.

Blueprint for composting

Dwarfed by the hundreds of high-rise blocks of flats and office buildings, busy highways and bustling crowds, the inconspicuous composting plant employs just four people. Nevertheless, it represents a major forward-looking step in a city wrestling with waste policy and environmental technology.

Since the first plant viability assessment was completed in 2016 by the Coalition, Lapa has become a blueprint for São Paulo’s next 15 expected composting developments. This means expanding food waste collections from most of São Paulo’s 883 weekly street markets, which together generate almost 200 tonnes of biowaste per day.

The fulfilment of these plans will be a major landmark in the city’s environmental performance, by both reducing mountains of untreated food waste in landfills and slashing the amount of methane they release. Indeed, by diverting 15,000 tons of organic waste annually from landfills, the first five composting plants have already prevented 495 tonnes of methane emissions each year.

Learning from experience

Meanwhile, a parallel movement has been stirring in the household sector. “Home composting of food waste started officially with support from the local government and NGOs in 2014 with the programme called Composta São Paulo”, explains Gabriela Otero, technical coordinator for ABRELPE.

Working with the Coalition, educational initiatives are also in progress, such as an online platform for schools and a school handbook on organic waste. Further afield, more entrepreneurs have been attracted to the industry. “Environmentalists are more engaged, but we have also started seeing citizens of different backgrounds and interests composting their own waste, and even start-ups creating businesses from other people’s waste”, says Gabriela Otero.

Brazil’s first ecopark

In the meantime, another pioneering project has appeared on the horizon: an ecopark due to open in 2020 to deal with mixed waste, divert waste from landfills and mitigate methane emissions. “This would be the first ecopark in Latin America with the capacity to process 1,500 tonnes of waste per day,” points out Sandra Mazo-Nix.

It would constitute a considerable shift from the initial composting network towards the integrated municipal waste collection and management system foreseen in the city’s 2014 waste management plan.

Some of the skills and knowledge to fulfil this vision were lacking until the Coalition introduced São Paulo executives to counterparts in other countries through a series of international knowledge-sharing events and training programmes. The knowledge base obtained has underpinned further city planning. The Coalition also funded the ecopark feasibility studies.

Designed by ABRELPE in collaboration with the private sector and the City Waste Management Authority (AMLURB), the ecopark will accept and treat 1,200 tonnes of mixed household waste each day.

Unwanted organics will be one of its main waste streams. The ecopark will have a special line for organic waste segregated at source from large generators, that will be processed using mechanical biological waste (MBT) technology. MBT plants combine a sorting facility with biological treatments like composting or anaerobic digestion. They are designed to deal with mixed household rubbish and can produce fuel made from the high calorific content of the refuse, biogas to generate energy, and compost to improve soil conditions.

With the help of the Coalition, the jaws of São Paulo are finally chewing its waste back into useful products while improving air quality and reducing its impact on the climate.