In the pollution control laboratories, routine analyses for the characterization of effluents and reactors monitoring use concentrated solutions of H2SO4, containing heavy metals such as chromium, silver and mercury and organic compounds as phenol. The presence of these elements in the laboratory effluent can cause inhibition of the biological activity, especially in the anaerobic treatment processes due to the sensitivity of the methanogens to some chemical compounds. This work had as objective to characterize the effluent from the Federal University of Rio de Janeiro Chemistry School Environmental Technology Laboratory (LTA/UFRJ) and to determine which constituents of the effluent one would be inhibitors for anaerobic microorganisms in the treatment of the sewage generated in the campus. The effluent one presents a weekly average production of 43.4 L, with pH = 0.7, COD = 1350 mg/L, sulfate = 33500 mg/L; 28.2 mg Hg/L; 82.1 mg Cr total/L; 30.8 mg Cu/L; 57.4 mg Fe total/L; 16.2 mg Al/L and 2.44 g Na/L. The parameters analyzed presented high variability as the study was conducted in function of the analyses and researches carried out in that period. In experimental design performed, the elements sodium, chromium, phenol and sulfate, as well as the interactions sulfate-mercury and sulfate-sodium, were significantly more effective on the inhibition of the specific methanogenic activity (SMA). The effects of the other elements (cupper, mercury, aluminum and iron), analyzed alone and their interactions were not significant for a confidence level of 95% in the t-Student distribution. The results indicate the necessity of a specific treatment for the laboratory effluent, since universities must be examples of combating pollution and encouraging the environmental control.
Laboratory effluents; sulfate; heavy metals; environmental control
