Hordes of children running across a heaving, steaming mountain of rubbish to fight for the contents spilling out of the latest rubbish truck to arrive at the dump.
This is where they eat, sleep and survive - on the detritus thrown out by the rest of society.
"To see children and adults disputing a little of food with horses, pigs ... the hunger of thousands of Brazilians provokes revolt, as does the situation and the conditions of work of the great majority of the catadores [rubbish-pickers]," says Heliana Katia Tavares Fields, of the non-governmental organisation Water and Life.
According to UNICEF, more than 40,000 children and teenagers live on rubbish dumps in Brazil. They make between 30 cents and $2 a day.
"Families construct slums at the edge of the dumps to survive, but they breathe poisoned air and live in life-threatening situations of extreme poverty," says Elisabeth Grimberg from the Instito Polis and general co-ordinator of the Rubbish and Citizenship Forum.
"When the lorries bring the rubbish, it is all mixed, and the children run to get the food. The first sacks sometimes have food that has been thrown away and is supposedly fit to eat but in reality it is not adequate, not recommended.
"Sometimes the trucks crush children; there
are many cases of this
Instito Polis and the Rubbish and Citizenship Forum
"One of the rights of people is to have enough food. Sometimes the trucks crush children; there are many cases of this in Brazil. Or their hands get mutilated in the mechanism of the truck," she says.
Others suffer from pneumonia, skin disease, fever and diarrhoea.
It has been like this for decades and exists in various extremes, from the hard end of those families living on the tips to those who ply their trade on the city centre streets. Some estimates put the figure of those who survive on rubbish in Brazil at half a million people.
But out of this desperate situation an extraordinary movement is developing. The catadores are organising, fighting for their rights and winning.
The idea of being able to get together a national congress of catadores sounds like a pipedream. Yet that is just what they did, 3000 of them marching on the capital Brasilia in 2001.
Catadores say they do not want
to work for multinationals
From this sprang an even more remarkable achievement - a Latin American-wide gathering bringing catadores from Columbia, Argentina, Uruguay, Paraguay and Mexico. And with street recyclers from France and Canada coming along to share their experiences they are going global.
"From a political point of view, this is very creative, very new and very strong," says Grimberg.
"One of the definitions, one of the choices made by the national movement of catadores is that they don't want to be employed by multinational companies who collect rubbish. Nor for the government.
"They take part in the public system but the entire organisation of the catadores, of the recycling co-operatives, is autonomous self-management," she says.
"The catadores show that the life can be different: solidarity and without misery," according to the governmental hosts of the Latin American-wide conference held in 2003 in the southern state of Rio Grande do Sul.
Marcelo de Jesus Marcario works
at Coopamare the oldest dump
"Articulating environmental protection and citizenship, recycling of lives and objects, the catadores give form to the historical flags supported by the society: social justice, environmental preservation and quality of life. They are collective dreams of the possibility of another worldwide order."
A second international encounter is due in January 2005.
"I work in the Coopamare, the first coop in Sao Paulo, the oldest. It's been there 15 years. Eight of us from the co-op took part in all the events.
"It was great, we met a lot of people from other different co-ops from other countries," says Marcelo de Jesus Marcario who is sitting on the floor with babe in arms, Marcelinho, surrounded by cardboard emblazoned with slogans.
Today is a demonstration on the third National Day of Catadores that was created to commemorate each year that first march on Brasilia.
"What we are doing here today is calling for our rights. In my case I've worked for eight years but many people I know have worked for 30, 40, 50 years and we have never been properly renumerated. We need more help," he says.
"Why do the authorities pay the big companies lots of money when we, the catadores, collect the rubbish, separate the materials in the correct way for recycling and we are not paid for our work?" asks the National Movement of Catadores of Recycled Materials.
Rubbish collectors were included
in the census only in 2002
In a few years the movement can already boast some amazing advances.
They are no longer officially invisible - catadores were included in the 2000 census for the first time. And street recycling has become a recognised occupation for the first time, winning the same rights as a self-employed worker.
A strong structure has grown up of Rubbish and Citizenship Forums in 23 Brazilian states made up of the recycling industry, non-governmental organisations and trade unions. More than 4,000 neighbourhoods now have selective collection of rubbish. There is now an inter-ministerial agenda looking at the issue.
And most municipalities are signed up to the UNICEF campaign Children in Rubbish - Never Again!
Brazilians throw away 134,000 tonnes of rubbish every day. The amount of waste produced in the world has risen three times faster than population growth. Cities such as Sao Paulo are simply bursting at the seams - there is nowhere else to put the trash.
But public perception is changing as to what is rubbish versus what is raw material primed for recycling - paper, metal, glass and plastic. In 2003, the recycling industry was worth a staggering $1 billion.
Back at the demonstration, the catadores are in full cry, singing their self-penned anthem about recycling of life. The mood is high-spirited, dignified and defiant.
"From day to night, if you lose your job and don't have a family to help you, you too can be in these conditions," says Grimberg. "There's a lot of work still to be done in Brazil."