Reimagine school lunches

NXplorers students in Niterói, Brazil, developed an integrated project that reduced and recycled waste in their school, ultimately to redirect waste away from the growing pollution building up in the Guanabara Bay area.

One of today’s global challenges is the accelerated increase in waste production and the consequent use of dumps and landfills in large urban centres, which causes many environmental and health problems.

Waste management is a permanent issue for the population of the cities around the Baia do Guanabara (Guanabara Bay), such as the municipality of Niterói. It is estimated that 500 million litres of untreated leachate (liquid that drains from landfill) is dumped into the waters of the Bay each year. The Bay is undergoing significant ecological degradation as a result, due to poor water quality and alteration to the natural habitat.

Using NXthinking and the NXplorer tools, the students looked at how they could change food disposal habits in their school community. They came to understand the interrelation between food, energy and water, and were able to promote sustainable solutions, where before they could only see problems.

These are the steps they went through to redirect their food waste…

Redesign a farm at sea

The students discovered that rooftop farming and vertical farming were already common practices in both urban and rural areas. The idea that presented the biggest opportunity was creating a farm at sea, as it had not yet been explored and could be developed at scale. They proposed creating a multi-use and expandable space that would be dedicated to the growing and farming of food. The foundation for this was a floating platform they designed, 20-40 acres in size, 10-20km away from land, that could be anchored to the ocean floor.

Rethink hydroponics

Plants expend a great deal of energy growing root systems to search soil for the water and nutrients they need to survive. The students therefore wanted to use hydroponics to maximise crop growth and quality on the floating platform. Rather than relying on soil, plants would be grown in a water-based, nutrient rich solution, with root systems supported by an inert medium like rockwool or peat moss.

The diagram is titled ‘Farm on Sea’. The NXplorers students have labelled ‘Solar panels’ at the top of five ‘Vertical farming’ pillars. At the base of the pillars is a section labelled ‘Traditional Farming’. The pillars are on a platform, which includes a ‘Deck for small boats to dock’ and an ‘Extensive draining network’. To the left of the ‘Vertical farming’ pillars, the students have labelled the direction of ‘NATURAL SUNLIGHT’. Next to the ‘Vertical farming pillars’ the students have labelled a ‘Small scale desalination plant’, an ‘Electrical water station’, as well as a ‘Small area for fishing’. A horizontal pipe leading off the mechanism is labelled ‘Water pipe to land’. Two vertical poles below the sea surface are labelled ‘Anchor to seabed’

Recollect water

The students considered a variety of ways to source water to sustain crops all year round. As sea level is lower than the land, the main source of water would come from connecting to reservoirs and pumping water across. Secondly, rainwater would be collected for irrigation, alongside an extensive drainage system to ensure the platform would not be flooded. Desalination of seawater would be the third source, but as it is expensive to install and maintain, it would only be used during emergencies.

Rewrite the rules of land usage

Though the floating farm would mainly focus on cultivation of crops, the students also saw an opportunity for excess deck space to be allocated to fisherman and boats. This would increase food production as well as providing additional income for people. Overall, the floating farm would provide multiple benefits - it would produce more crops, protect livelihoods and preserve the environment. It provides an alternative solution to a global issue around land management, and could be replicated across different regions, such as Singapore, where most land is currently used for infrastructure.

NXplorers students explain their findings at an NXplorers event

Not only was less waste sent to landfill, but they also created a clean energy supply

NXplorers participant, Singapore


By addressing an impending food shortage problem, the NXplorers students were able to build a long-lasting solution that would solve multiple issues surrounding production practices and the environment. Their floating farm idea contributes to several UN SDGs overall, including 2, 8, 9, 12, 14 and 15.

2. Zero Hunger

End hunger, achieve food security and improved nutrition and promote sustainable agriculture

8. Decent work and economic growth

Promote sustained, inclusive and sustainable economic growth, full and productive employment and decent work for all

9. Industry innovation and infrastructure

Build resilient infrastructure, promote inclusive and sustainable industrialisation and foster innovation

12. Responsible consumption and production
Ensuring sustainable consumption and production patterns

14. Life below water
Conserve and sustainably use the oceans, seas and marine resources for sustainable development

15. Life on land
Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss.

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UN SDGs diagram

Diagram of the United Nations’ Sustainable Development Goals numbered in a large circle, each with a smaller diagram below to represent the specific Development Goal. All of the Development Goals are faded, apart from six of them:

2. Zero hunger
8. Decent work and economic growth
9. Industry, innovation and infrastructure
12. Responsible consumption and production
14. Life below water
15. Life on land

Within the circle there are three circles in a triangle formation reading ‘Energy’, ‘Water’ and ‘Food’, with arrows to show how they are all interconnected.

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