Toxicity of the effluent from an anaerobic bioreactor treating cereal residues on Lactuca sativa

• Published in: Ecotoxicology and environmental safety 2012-02, Vol.76 (2), p.182-186
• Main Authors: Young, Brian Jonathan, Riera, Nicolás Iván, Beily, María Eugenia, Bres, Patricia Alina, Crespo, Diana Cristina, Ronco, Alicia Estela
• Format: Article
• Language: English
• Subjects: anaerobic digesters; Anaerobic digestion; Anaerobic treatment; Anaerobiosis; Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Biological Oxygen Demand Analysis; Biomonitoring; Bioreactors; Bioreactors - microbiology; chemical oxygen demand; dissolved oxygen; Ecotoxicology, biological effects of pollution; Edible Grain; Effects of pollution and side effects of pesticides on plants and fungi; Effluent treatment system; Effluents; Food Industry; Fundamental and applied biological sciences. Psychology; General aspects; Germination - drug effects; Germination index; grains; Lactuca - drug effects; Lactuca - growth & development; Lactuca sativa; Oxygen - analysis; Phytotoxicity; Ponds; Ponds - chemistry; Reduction; Relative growth index; root growth; Sampling; seed germination; Seeds; temperature; Toxicity; toxicity testing; Waste Disposal, Fluid - methods; Water Pollutants - toxicity
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2011.09.019

Effluents generated during the process of anaerobic digestion should be treated before their disposal into the environment. The aim of this study was evaluating the effectiveness of the effluent treatment system from an anaerobic bioreactor, assessing the toxicity reduction with the Lactuca sativa seed germination and root elongation inhibition test. Three sampling points were selected along the effluent treatment system: inflow into the first treatment pond, outflow from the third pond and recirculated flow to the bioreactor. Effluent dilutions tested for each sampling point were 25% and 50% (v/v), undiluted sample and controls. The pH, conductivity, temperature, dissolved oxygen, BOD 5 and COD were measured. The decrease in the organic and inorganic loads was correlated with a reduction in the phytotoxicity. The use of the seed toxicity test allows evaluating the quality and effectiveness of the studied effluent treatment system. ► An anaerobic bioreactor effluent was treated by conventional physical methods. ► Treatment progress was assessed with physicochemical parameters and toxicity testing. ► Good correlations were observed between COD or Conductivity with a toxicity index. ► Treated effluent could be used for feeding the anaerobic bioreactor. ► Treated effluent reuse avoided drinking water or water quality consumption.