Biodegradation of pesticide-contaminated wastewaters from a formulation plant employing a pilot scale biobed

LESCANO, MAIA; FUSSONI, N.; VIDAL, E.; ZALAZAR, C.S.

SCIENCE OF THE TOTAL ENVIRONMENT

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2022

0048-9697

discharged from a formulation plant. The pre-treated wastewater was spiked withadditional pesticides in order to simulate a scenario of higher contamination:glyphosate, atrazine, imidacloprid, prometryn and carbendazim were added to reach afinal Total Organic Carbon (TOC) of 70 mg L -1 . An Intermediate Bulk Container(IBC) was filled with a biomixture of soil and foxtail millet stubble (50:50 % v v -1 ),and 200 litres of the wastewater was added to the system recycling tank. Therecirculation to the IBC was established for 12 h. After that (Day 0), the recirculationwas turned on during the assay only to maintain the moisture for 180 days. Biomixtureand wastewater samples were taken periodically to analyse pesticides andphytotoxicity in both matrices. In addition, hydrolytic and phenoloxidase activities, totalbacteria and yeast and fungi communities were determined in the biomixture.The designed pilot scale biobed allowed to treat wastewaters with high concentrationof pesticides reaching a complete removal of glyphosate, AMPA, atrazine,carbendazim and prometryn at 180 days. A good degradation percentage of therecalcitrant imidacloprid was achieved (60%) and the biomixture showed enoughbiological activity to continue treating additional wastewater. The root elongation indexfrom the germination test showed low toxicity on day 180 both in biomixture andwastewater.The millet stubble resulted an appropriate lignocellulosic material to be used in biobedsto treat a wide variety of pesticides. The application of the seed germination testproved to be a low cost and simple tool to determine the end point of process.