engleski

Applying of different tests in ecotoxicity measurement, Power of Microbes in Industry and Environment

Toxicity of wastewater can be measured only by means of living organisms that are exposed to the same medium. For that purpose a different test organisms like algae, invertebrates, some plants and fish are applied. Which of tests will be applied, or which organism will be used it depends where is wastewater discharged, is it purified and which method is applied, the duration of the test, etc. This work was aimed at comparing five methods for for two different industrial wastewaters prior to their treatment. The used wastewater originated from production of fresh baker’ s yeast (molasses slops) and mesalazine, a drug used for the treatment of ulcerative colitis. Toxicity was determined by: 1. aerobic method (bacterial growth inhibition test) ; 2. anaerobic method (production of biogas) ; 3. TTC-method (bacterial dehydrogenase activity) ; 4. YTT-method (activity of Saccharomyces cerevisiae), and 5. luminescent method (decrease of physiological activity of bacteria Vibrio Fisheri). Molasses slops diluted to 33.8 vol. % is not toxic to aerobic sludge neither to anaerobic sludge in dilution of 62 vol. %. However, this wastewater is neither toxic in dilution of 22 vol. % measured by YTT-test and applied TTC-test the result was 20.5 vol. %. Luminescent test showed only 2.91 vol. %. Toxicity of wastewater from mesalazine production to aerobic activated sludge was 1.8 vol. % but to the anaerobic sludge it was 0.00061 vol. %. YTT-test showed toxicity of 1.3 vol. %, TTC-test was 1.02 vol. %, while luminescent test was 4.27 vol. %. Considering specificities of each wastewater with respect to air action on used organisms, it has been shown that for toxicity determination of process wastewaters prior to their treatment it is necessary to compose and apply more methods.

Toxicity of wastewater; test organisms; determination of ecotoxicity

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