The UV lamps were in serted in the quartz vessels and the following optimized program was used : step1 — power of 900 W,
ramp time of 10 min and ventilation of 127 m 3 h−1 ; step 2— power of 900 W, hold of 20 min and ventilation of 127 m 3 h−1 ; and step 3 —power of 0 W and ventilation of 190 m 3 h−1 (cooling)