In search of zero waste: An experiment in progress

Abstract

In Cantagalo, a city located in the mountain region of the state of Rio de Janeiro (Brazil), a pioneering experiment in solid waste management has been under way in recent years, in which the aim is to avoid having to rely on landfills for final disposal of waste by instead recycling or otherwise reusing all the solid waste generated. The experiment dates to 2006 when the cement maker Lafarge, with a plant located in the city, requested COPPE/Federal University of Rio de Janeiro to conduct a study of the use of solid waste in its industrial activities through coprocessing. The study involved joint work among the Waste Treatment Study Group of COPPE, the company, and the municipal government in order to provide better knowledge of the solid waste materials produced in the city and their possible uses. The resulting findings led to improvements in the process of collecting and sorting waste by the municipal government, with the recycling or use of a significant portion of the solid waste for the production of compost for soil improvement. Most of the material left-over from these two processes (waste not suitable for recycling or use as compost) started to be sent to the cement plant to be burned together with coke as fuel in the industrial process, thus taking advantage of the calorific energy of this material. The ash left from this burning was removed periodically from the furnaces, and a part was used as a cement ingredient. The rest was either used in civil construction or other activities or sent for burial in a landfill for inert substances. Cantagalo is perhaps the first “zero waste” city in Brazil that can be said to have truly sustainable waste processing. This chapter presents the results of the studies and laboratory tests for determination of the calorific power, ash percentage, and chlorides concentration of the city’s solid waste and other important information regarding the implementation of the process.