Hydrolysis of hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6) and dodecamethylcyclohexasilane (D6_silane) and their sorption to digested sludge was studied in batch experiments. Hydrolysis was affected by the type of the compound and the applied temperature, while the relevant half-life values ranged between 0.07 +/- 0.01 d (D3, 55 degrees C) and 48.4 +/- 17.1 d (D6_silane, 4 degrees C). D5 showed the greatest affinity for sorption to digested sludge (logK(d): 3.84 +/- 3.42), the lowest LogK(d) value was found for D3 (1.46 +/- 0.95). Prediction of investigated compounds' fate in a single-stage anaerobic digestion system indicated that volatilization seems to be the major fate in both mesophilic and thermophilic conditions. The addition of a pre-digester with 3 d retention time would significantly decrease the expected concentrations of all siloxanes in bio-gas, enhancing their removal through hydrolysis and sorption to sludge. (C) 2016 Elsevier Ltd. All rights reserved.