Caenge supports an unprecedented project for recycling construction industry rubble.
Construction company donates engineering know-how for pioneer action in Brazil to make use of solid residues stemming from construction activities.
The demolition, begun at the end of January through a public-private initiative, of the skeleton of a 16 thousand ton, 12 storey, concrete building, a disused former hotel on the shores of the Paranoá lake, marks yet another historic stage of the construction industry in Brasília (Federal District) and its purpose is to serve as a model for handling a serious ecological, economic and social problem that affects all the municipalities in the country. It represents a response to the question of what to do with the leftovers, the rubble resulting from the construction of new buildings or when brick and concrete buildings and structures are demolished.
Two civil organizations of public interest (OSCIP in Portuguese), Eco Atitude Ações Ambientais (Eco Attitude Environmental Action) and Ecoterra – Instituto de Preservação Ambiental (Ecoterra - Environmental Preservation Instute), both based in Brasília, sponsored by national and international bodies to implement projects for environmental recuperation, have signed an agreement with the Government of the Federal District through its Urban Cleaning Service (SLU) and its Public Works Secretariat, for the carrying out of what is a pioneering venture in Brazil: the recycling of solid waste resulting from construction activities, as well as well as its operational economic and social and ecological aspects. The Caenge S.A. Company, a traditional construction company based in the Federal District but with operations in other states as well, has been offering its collaboration with the initiative in the form of equipment, most of it of the Caterpillar brand, supplied by Sotreq-Goiânia and Brasília as well as making available its extensive experience in public and private works.
According to unofficial data, around 50% by weight of the solid waste that arrives at controlled and sanitary waste dumps are made up of rubble from construction works and the demolition of buildings, corresponding to a significant burden for civil society, which in some capital cities is doubly taxed by the urban cleaning services. The simple removal of such material, which is capable of being totally recycled, removes from the economy the possibility: of income for cooperatives formed by waste pickers; of those bodies contracting to execute public works reducing their costs; and of reducing the environmental impact caused by the consumption of non-renewable natural resources and the costs of the construction companies (the great sources of such residues), who pay for the removal transport and accommodation of these material which are in fact authentic raw materials.
ENVIRONMENTAL RESOLUTION - The bustle of activity that is now taking place in the Federal Capital in regard to the matter of recycling construction industry waste is not an isolated occurrence. Its representativity can be assessed by Eco Atitude's participation in formulating the directives, criteria and procedures of Resolution 307 of the Brazilian National Environment Council - CONAMA, which has been in force since July 5, 2002. The Engineer who runs the NGO, Marco Aurélio B. Gonçalves, did his specialization in Holland, a European country that recycles 90% of all rubble resulting from construction activities, and home to the headquarters of the International Recycling Federation (FIR) of which Brazil has been a full-scale member for three years. "The challenge facing the Federal District is to recycle 2.5 thousand tons of construction rubble a day" declares the specialist, who at the same time ponders that this model is an example that can be replicated in thousands of Brazilian municipalities and indeed, serve to put into practice the institutional role and the role of multiplier of his social-environmental organization.
Apart from being restrictive, resolution 307 calls the attention of municipal governments to the need for an action that will have a great public impact. Cities like São Paulo, Rio de Janeiro, Belo Horizonte, Curitiba and Brasília have already passed municipal laws that regulate the management of construction industry residues. The demand for them to be adopted in the municipalities is growing, insofar as those great urban centers serve as models and the NGO's act as agents fomenting the process. For the building companies themselves, the greatest generators of such residues, the greatest attraction is the savings obtained in resources, insofar as their collaborators have been educated to, and indeed do, segregate the materials at the worksites thus making free-of-charge collection by the waste-pickers cooperatives, easier.
Most of the solid waste produced in building works, classified as level A, presents physical-chemical characteristics that allow for its direct use as raw material provided that the technical standards regulated by the ABNT are complied with. These regulations define directives for projects, implantation and operation of solid waste and voluminous materials from construction activity in: screening and re-directing areas; in landfill-type solid waste dumps for inert materials; and in areas destined for re-cycling.” It also sets out norms designed to stimulate the use of re-cycled aggregates obtained from the treatment of construction industry residues in the base courses of paved structures and in non-structural concrete-paved areas", explains Marco Aurélio Gonçalves.
MOBILE MODEL – Recycling the building demolished by explosives in the Setor de Clubes Sul area of Brasília will take 60 days to finish activities up to the point of environmental recovery of the area by Ecoterra, which will also undertake the removal of the material to the selected cooperatives. The engineering of the process is the responsibility of Eco Atitude and it includes the Caterpillar Equipment of the Caenge Company, training personnel and creating a format that will enable the repetition of such services on-site, as preference has been given to mobile recycling due to the savings it offers in time and costs. Carlos Richter, an advisor to Caenge in regard to specifying and acquiring the CAT machines from the retail outlet in Brasília, states that two 320C hydraulic excavators are in operation at the site one of which has an ALLU screener-crusher attached and the other a standard bucket of 1.2 cubic meter capacity.
Eco Atitude's technical advisor David Jussier explains that the mobile recycling operation has been divided into segments. The first function is carried out by a crane that breaks up the blocks of concrete from the top of the pile of the demolished building using a 1,250 kilogram pile driver ram, letting it fall from a height of 15 meters. Following that, a 320C excavator with a standard bucket moves the blocks broken up by the pile-driver ram from the top of the pile to the bottom and puts them in position for further breaking by a hydraulic hammer unit coupled to a back-hoe. Trained waste-pickers cut the steel rods with acetylene torches, separating them and piling them up. Finally the great "star" of the process goes into action: a CAT 320C excavator equipped with an ALLU screener-crusher imported from Finland by the Caenge Company, which crushes the concrete, transforming it into aggregate.
Every morning, professor Paulo Cesar dos Reis Gomes, coordinator of the environmental safety laboratory of the post-graduate course in Work Safety Engineering of the Federal University of Brasília (UnB) gives a training course for different groups of waste pickers from the partner cooperatives and during the rest of their day's work, they are monitored by the technical advisor. "The purpose of the training is to ensure that the waste pickers work without any risk of accidents in an environment that is new to them, with special regard to risks of cuts from the steel rods and of flying particles of concrete coming from the operation of the heavy machinery" states the professor. He estimates that around 200 professionals will undergo training during the 60 days of recycling operations at the site.
Processing the rubble on site is a more viable alternative in terms of time and costs.
After being broken up by the pile driver ram on the crane, the blocks are brought down to ground level by the 320C with a standard 1.2 cubic meter bucket
Demolished at the base using explosives, the 16 thousand ton, 12 storey building will have its steel reinforcing rods and concrete recycled to model this pioneering process in Brazil.
A hydraulic hammer unit is used to shatter the blocks brought to it after they have been broken up by the crane and whose reinforcing rods are cut by hand using acetylene torches.
The executive team working on this recycling process, unprecedented in Brazil (from left to right): Virmondes Luiz Martins (Caenge General Works Supervisor) Paulo Gomes (UnB), Marco Aurélio Gonçalves (Eco Atitude), Lúcio Christiansen (Caenge Supplies Manager) and Carlos Richter (Sotreq-Brasília)
“The processing bucket can be adapted according to the material it will be handling ”
These various materials are divided into four classes for purposes of reusing, recycling and processing them.
Diversity of applications
The ALLU processing bucket, manufactured in Finland, operates coupled to the hydraulic system of hydraulic excavators, wheel mounted loaders, mini-loaders, and backhoes, and carries out the functions of crushing, mixing, sifting, aerating and loading in a single operation lasting 15 to 30 seconds per load. Patented worldwide, it is offered in Brazil in various sizes by Máquina Solo, of São Paulo, and it is essentially a mobile unit.
Built of special steel, the bucket has drums that spin horizontally at a rate of 300 rpm. all of them in the same direction but capable of spinning in the reverse direction using a two-way hydraulic system. "Its versatility means that it can offer a wide range of applications going well beyond the recycling of construction industry rubble", explains Fábio Damásio, director of the commercial representatives in Brazil.
The bucket can also process contaminated earth, carry out composting, mix together various materials, sift soils, pulverize salt in mines, cover oil and gas pipelines in trenches, and grind glass and wood residues. Several Brazilian companies are already going ahead testing its operating capacity in various specialized situations and the lines available offer light, standard or heavy-duty options.
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