As a partner of the government of São Paulo, the most populated and industrialized state in Brazil, Kemira is working on an innovative project to clean up a severely polluted urban river. The project, started in August 2007 and still in its pilot phase, aims to depollute the Pinheiros River, which crosses São Paulo, a city of more than 18 million inhabitants.
The initiative is carried out in cooperation with EMAE – Empresa Metropolitana de Águas e Energia (Metropolitan Company of Water and Energy), a state-owned company for power generation. The plan is to reverse the river’s flow to the Billings Dam, which runs the turbines of the Henry Borden hydro power plant.
“Depollution is not only a legal condition to increase the output of the power plant, but also a consequence of the environmental concern of the government, which decided to invest in the treatment of the entire river,” explains Fernando José Moliterno, Engineering Manager at EMAE.
The current pilot phase involves two points of treatment in the river itself. The first one is located just before the Billings Dam, and releases coagulant ferric chloride and anionic polymer into the water. Simultaneously, an injection system of microbubbles of air promotes the flotation of agglomerated solid particles. The second point is just one kilometer further along the river and uses the same technology to reinforce the treatment. Kemira is responsible for the supply of ferric chloride and anionic polymer which produce the flocculation effect.
Valuable experience from the pilot project
After the pilot phase, which can now treat 10 cubic meters of water per second, EMAE intends to deploy the system to the full expanse of the river (25 kilometers or 17 miles), in three different dosage points. Its completion is expected by 2013, when the flotation technology will have the capacity of 50 cubic meters of water per second, removing pollution and spurring the rebirth of aquatic life.
The acquisition of Nheel Química Ltda in 2008 was a decisive measure by Kemira to take part in this ambitious project. Nheel is a Brazilian manufacturer of inorganic coagulants based in Rio Claro, a city in the countryside of São Paulo state. Before this acquisition, Kemira did not have local production of ferric chloride, the coagulant chosen by EMAE to promote the first step of flotation – the agglomeration of polluting particles.
Besides ferric chloride, the Nheel unit produces both polyaluminum chloride and aluminum sulfate coagulants. The plant is only 170 kilometers from the city of São Paulo, a benefit for the logistic operation that entails the daily arrival of 10 trucks of ferric chloride to treat the Pinheiros River.
According to Wanderley Ferreira, Marketing Manager at Kemira, taking part in this Pinheiros River depollution project is of strategic importance to the company globally: the use of flocculation-coagulation in-situ is highly uncommon and the Brazilian experience can be used as a learning case for similar projects in other countries where Kemira has commercial presence.
Text: Marcelo Furtado
Original article published in Kemira’s stakeholder magazine Just Add 2/2009.