Degradation of naproxen and carbamazepine in spiked sludge by slurry and solid-phase Trametes versicolor systems

Abstract

rowth and activity of the white-rot fungus Trametes versicolor on sewage sludge were assessed in bio slurry and solid-phase systems. Bioslurry cultures with different loads of sludge (10%, 25% and 38%, w/v) were performed. A lag phase of at least 2 d appeared in the 25 and 38%-cultures, however, the total fungal biomass was higher for the latter and lower for the 10%-culture after 30 d, as revealed by ergosterol determination. Detectable laccase activity levels were found in the 10 and 25%-cultures (up to 1308 and 2588 AU L 1 , respectively) while it was negligible in the 38%-culture. Important levels of ergosterol and laccase were obtained over a 60 d period in sludge solid-phase cultures amended with different con centrations of wheat straw pellets as lignocellulosic bulking material. Degradation experiments in 25%- bioslurry cultures spiked with naproxene (NAP, analgesic) and carbamazepine (CBZ, antiepileptic) showed depletion of around 47% and 57% within 24 h, respectively. Complete depletion of NAP and around 48% for CBZ were achieved within 72 h in sludge solid cultures with 38% bulking material. CBZ degradation is especially remarkable due to its high persistence in wastewater treatment plants. Results showed that T. versicolor may be an interesting bioremediation agent for elimination of emerging pollu tants in sewage sludge.