Dissipation of pesticides during composting and anaerobic digestion of source-separated organic waste at full-scale plants

In the present study, concentration levels and dissipation of modern pesticides during composting and digestion at full-scale plants were followed. Of the 271 pesticides analyzed, 28 were detected. Within the three windrows studied, total concentrations were between 36 and 101 μg per kg of dry matter (d.m.) in input materials and between 8 and 20 μg kg d.m.−1 in composts after 112 days of treatment. Fungicides and among them triazoles clearly dominated over other pesticides. More than two-thirds of all pesticides detected in the input materials showed dissipation rates higher than 50% during composting, whilst levels of most triazoles decreased slightly or remained unchanged. The investigation on semi-dry thermophilic anaerobic digestion suggests that pesticides preferentially end up in presswater after solid–liquid separation.