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 mu g per kg of dry matter (d.m.) in input materials and between 8 and 20 mu g 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. (C) 2008 Elsevier Ltd. All rights reserved.