Colour Degradation of Simulated Textile Effluent by Electrolytic Treatment and Ecotoxicological Evaluation

Abstract

Since the last century, humanity has sought ways to minimize the impact of the industrial growth in the environment. The textile industry, as one of the major contributors to water pollution, has been dumping coloured effluents which cause great impact in water bodies. The electrolytic process not only degrades the colour of the effluent but also transforms recalcitrant substances by direct or indirect oxidation. The ecotoxicological tests are used nowadays as a way to verify the toxicity degree of water bodies polluted by industrial and farming activities. The ecotoxicological tests consist in exposing determined organisms to the samples with the intention to evaluate their toxicity by observing the organisms' responses. This study had the objective to degrade, by electrolytic process, a simulated textile effluent containing a mixture of Acid Blue 40 and Acid Red 151 dyes and the toxicity evaluation of the treated effluent by ecotoxicological tests. The bioassays used were tests with seeds of Lactuca sativa (lettuce), Eruca sativa (rocket), and Cucumis sativus (cucumber). Tests with the micro crustaceous Artemia salina and the yeast Saccharomyces cerevisiae were also conducted. The electrolytic treatment degraded the initial colour of the textile effluent, and the ecotoxicological tests indicated low toxicity to the treatment.

Adsorption of Remazol Brilliant Violet-5R Textile Dye from Aqueous Solutions by Using Eggshell Waste Biosorbent

“…After a 2-day examination, the irrigated seed germination decreased with increasing concentration. On the other hand, no toxicity to Acid Blue 40 and Acid Red 151 after 15 minutes of electrolytic treatment was found 61 .…”

“…A similar method was used in our previous work in which we studied the effect of two anionic and two cationic dyes on lettuce and mustard seeds 28 . The results showed that the shooting of germinated seeds (clover, wheat, lettuce, tomato) is dye dependent 61 . After a 2-day examination, the irrigated seed germination decreased with increasing concentration.…”

Saccharomyces cerevisiaeimmobilized onto cross-linked chitosan beads: application of a novel material for the removal of dye toxicity

“…The results comparison revealed that the yeast biomass and the cross-linked chitosan beads achieved a decrease in the toxicity of the dye in the solution (Table 5). Despite the lower microcrustacean mortality after dye removal, this reduction was not statistically relevant [20].…”

“…The number of living organisms was then counted. The tests were performed with four replicates and were submitted to non-parametric statistical analyses using the Kruskal-Wallis method with the aid of the BioEstat 4 program, which is the most suitable analysis for comparative bioassays [20].…”

Ecotoxicology of Pig Slaughterhouse Waste Using Lactuca sativa L., Raphanus sativus L., and Oryza sativa L.

“…Franco et al (2017) have evaluated the effects of different doses of sanitary landfill leachate on the germination of lettuce seeds and observed a 100 % inhibition of germination with 1.0 mL of the pollutant. In evaluating the efficiency of the electrolytic process in treating effluents from the textile industry through bioassays with seeds of lettuce (Lactuca sativa Linnaeus, 1753), arugula (Eruca sativa Linnaeus, 1753), and cucumber (Cucumis sativus Linnaeus, 1753), Moraes and Bidoia (2015) found that electrolytic treatment was successful and indicated a low toxicity to the organisms tested. According to Souza et al (2005), plant seeds are highly suitable for bioassays, mainly because the germination process begins when the seeds are rehydrated.…”