At the beginning of April this year, at least eight towns in the north of Rio de Janeiro State could feel for themselves the effects of the neglect shown by an industrial concern with its waste. For several days, some 600,000 persons went without drinking water because the Paraíba do Sul River, which supplies these towns, was contaminated by the spillage of chemical products from the detention pond of a paper factory set up in Cataguases, Minas Gerais, on the border with Rio de Janeiro. The toxic foam left tons of dead fish in its trail, and put on alert entities linked to public health and the environment. Accidents like this one would not happen if due care had been taken and the factory had adopted principles and methodologies like those in use for six years, with success, by the Center for Nuclear Energy in Agriculture (Cena), of the University of São Paulo (USP), in Piracicaba.
The finding that it was necessary to establish standards for the disposal and recycling of the chemical products used for experiments was the starting point for developing, in 1997, a program for managing chemical residue and wastewater in that plant. The results can now be translated into environmental and economic gains. Last year alone, some 400,000 liters of chemical waste, containing dangerous materials, were recycled. Among the substances that are part of this volume are lead, silver, mercury, copper, zinc, selenium, bromine, ammonia, sulfides, methanol, acetone and chrome.
Several of them are reused in the lines of research pursued at the institute. ccording to calculations by chemical engineer José Albertino Bendassolli, the coordinator of the Stable Isotopes Laboratory and of Cena’s program for managing chemical waste, the monthly savings with the reuse of these products is close to R$ 5,000. “That is R$ 60,000 a year, but if we take into consideration the program for managing water and electricity, we will be able to arrive at annual savings of R$ 200,000. These successful examples can be transferred to research and teaching institutions”, says Bendassolli.
Just in the system for producing demineralized water adopted by Cena, the annual savings with expenditure on water and electricity may add up to R$ 140,000. With the conventional process of distilling – the one most used in teaching and research laboratories in Brazil –, for each liter produced, from 15 to 20 liters of treated water are consumed in the refrigeration system, and most of it is discarded after the process. By the calculations of the program’s coordinator, as Cena consumes about 60,000 liters of distilled water a month, the monthly wastage would be in the order of 900 cubic meters, which means 10.8 million liters a year. And the electricity spent to produce 1 liter of distilled water is in the region of 0.7 kilowatts, which means 42,000 kilowatts per month.
Filters and sand
With the funds brought in from FAPESP in 2001, by means of the Infrastructure Program V, the institute dimensioned and built a water production plant that uses basically gravity and pressure. With this process, demineralized water is obtained by ionic exchange (resins exchanging positive and negative charges). The liquid from the public supply network of Piracicaba, from the Municipal Water and Sewage Service (Semae), first of all passes from an activated charcoal filter and grains of sand of various sizes and, in succession, in big columns of transparent acrylic containing resins, responsible for retaining cations (calcium, magnesium, potassium, sodium and some heavy metals) and anions (chlorides, sulfates, nitrates and carbonates, amongst others).
Next, the water passes through a system for disinfecting by ultraviolet light and by polypropylene filters with 5-micron slits. “The result is that we have today 50% of our units using this water”, Bendassolli says. As some of them are a long way from the production center, where it is taken away in containers, the coordinator of the program believes that it is possible to improve the distribution, making it more efficient with its own piping.The work of managing Cena’s chemical waste started in 1997, in the Stable Isotopes Laboratory, the place where the largest quantity of the institute’s waste is produced. The laboratory is responsible for the whole Brazilian production of enriched compounds in the heavy isotopes of nitrogen and sulfur, therefore not radioactive, which are used mainly in agronomic research as tracers in assessing the cycle of nitrogen and sulfur in the soil-plant system.
As in recent years there has been an increase in the consumption of these compounds, production needed to be expanded, which generated a larger volume of chemical effluents and the need for adopting a program for managing the waste. Along with Esalq, Cena is part of USP’s campus in Piracicaba. There are 37 teaching researchers, some 100 staffers and 150 postgraduate students working in 19 research laboratories.
Bendassolli recalls the beginning of the program, when the first task already gave an idea of what was awaiting the team involved. In an open deposit, without any kind of organization, they found 5 tons of waste, precariously packed and, to a great extent, without any kind of labeling. The first step was to classify what they could identify. “In all, about 2.1 tons of the material was incinerated, because they were not set aside at the source where they were generated”, he says. The incineration was done by Basf, in Guaratinguetá, and was accompanied by the Environmental Sanitation Technology Company (Cetesb).
The original deposit was then remodeled, within strict criteria for storing material, and the waste divided into 11 classes. Bendassolli notes that as this environment is a provisional storage place, the discarded material must remain there for 120 days at the most. Afterwards, it has to be recovered or incinerated. A computerized database developed by Cena’s Information Technology Laboratory supplies detailed quantitative and qualitative data on the stored waste generated in the institution’s lines of research and teaching, besides technical information on over 200 dangerous chemical compounds. The team also produced a videotape with the results of the waste management program, shown to groups that visit the institution.
One important result displayed to the visitors is the recycling of a great deal of aqueous waste containing such dangerous products as cyanide, ammonia, sulfide, bromine and others. They are recycled and used again in other lines of research at Cena, while solids like fluorescent lamps are sent to a company that carries out the recycling of mercury. Silver waste, for example, is recovered and used as silver oxide in other analytic processes. “This material is an expensive reagent that we use, for example, in determining the sulfur in plants”, says Bendassolli. Then there is chrome, which is used as potassium dichromate in several analytic processes.
Metallic copper, used to extract the excess of oxygen from samples of soil, sediments and plants before passing through a mass spectrometer, is recycled in its original form. By retaining the excess oxygen from the samples, the copper becomes oxidized and loses its function, besides being toxic. To bring it back to metallic copper, it undergoes a process known as oxidation-reduction, which consists of using hydrogen at 450° C to remove the oxygen. The recycling of the copper that comes from three pieces of Cena’s equipment means annual savings of this imported raw material in the order of USD 12,000.
Although many of these processes are conventional, they are not always used by the universities or even by industrial concerns. “Companies produce a large quantity of waste, but with less variety. Universities, though, produce a lower quantity, but there is much more diversity. Our objective is to make it possible for the processes developed here to be transferred”, says the program’s coordinator. In his assessment, one way of passing this knowledge on is by means of the undergraduate course in Environmental Management at Esalq, which has the purpose of forming environmental managers.
Bendassolli is responsible for one subject matter – which features on the scheduled curriculum for 2005, when the pupils of the first intake of this new course are in their final year – which addresses the question of safety and the treatment of chemical waste in laboratories. Another way of passing it on is to receive secondary school and university students at Cena’s laboratories.
Program in the shopping mall
One of these visits has already borne fruit. Two students who work in a factory in Piracicaba realized that some of the procedures adopted by the company could be modified, and they put into practice techniques they had learnt at Cena. Bendassolli also regards it as important to show the university’s work to the community. So, at the beginning of June, Glauco Tavares, Gleison de Souza and Felipe Rufino Nolasco, who are members of the team, presented the waste program at a shopping mall in Piracicaba, as part of the activities connected with the Environment Week.
One month from now, Cena will be finishing its participation in Infrastructure V. This program was launched by FAPESP in 1999, carrying on with the Infrastructure Program created in 1995. It has the objective of recovering and modernizing laboratories and other research installations in São Paulo institutions, which were in a deteriorated state and even made the research activity impracticable. Infra V was split into two large modules: the treatment of chemical waste and information centers, including libraries, museums and archives.
Participating in the chemical waste module are ten laboratories from USP, three from the São Paulo State University (Unesp), one from the State University of Campinas (Unicamp), one from the Federal University of São Carlos (UFSCar) and one from the University of Ribeirão Preto (Unaerp), besides the Zoonoses Control Center of the Municipal Government of São Paulo, the Nuclear and Energy Research Institute (Ipen) and the Southeast Embrapa Cattle research unit, of the Brazilian Agricultural Research Corporation (Embrapa), which received in all R$ 4.2 million.
According to Bendassolli, for Cena’s program to continue, some R$ 60,000 a year will be needed for inputs, maintenance of the equipment and development of new methods, besides hiring technical personnel (staff exclusive to the program). “As research is dynamic, with various experiments, we always have to think of new methodologies of treatment for the other compounds that arise”, says the program’s coordinator. This amount represents a small fraction, compared to what has been invested up to now, about R$ 1 million, amongst funds from FAPESP, the Program for Supporting Centers of Excellence (Pronex), run by the National Council for Scientific and Technological Development (CNPq), USP and from Cena itself. After so much effort and the results shown, it would make no sense, as Bendassolli says, to abandon what has been done.
Treatment of Chemical Waste; Modality Infrastructure Program V; Coordinator José Albertino Bendassolli – Center for Nuclear Energy in Agriculture/USP; Investment R$ 497,960.00 and US$ 22,940.00