Evaluation of the BiomassBed system in bio-cleaning water contaminated water by fungicides applied in vineyard

BiomassBed is an indirect system designed to collect accidental pesticide spills as well as water remnants of tank sprayers. This system was installed in a vineyard and tested in bio-cleaning water that was contaminated by fungicides in a two-year-field experiment. At the end of each treatment, wastewater of sprayer tanks containing mixtures of cymoxanil, dimethomorph, metalaxyl M, folpet, penconazole, cyprodinil, fludioxonil, azoxystrobin, mandipropamid, pyraclostrobin at different concentrations were discharged into the BiomassBed and repeatedly circulated through an organic biofilter of pruning residues and straw for fungicide adsorption and biodegradation. Water collected was sampled and analysed for fungicide residues, and organic biofilter was analysed to assess fungicide dissipation. Fungicides were removed from water in a range of 92.4–100% of the initial concentration. Metalaxyl M was the least retained and probably desorbed during recirculation of water. However, metalaxyl M residues dissipated in 70 days in collected stagnant water. Abiotic and biotic factors contributing to the disappearance of metalaxyl M in water was hypothesised. Fungicide dissipation in the organic biofilter occurred in a 90-day period with the exception of penconazole that remained at 63.6% and 42.0% in 2008 and 2009, respectively. Owing to the advantageous combination of depuration and bio-degradation processes, fungicides were removed from water in a range of 92.4 to 100%. However more effort is needed to enhance adsorption of mobile fungicides and to achieve a faster degradation of more persistent active ingredients.