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A double strategy based on the removal of sulfonamide antibiotics by Pleurotus ostreatus and adsorption on spent mushroom substrate was assessed to reclaim contaminated wastewater. P. ostreatus was firstly tested in a liquid medium fortified with five sulfonamides: sulfamethoxazole, sulfadiazine, sulfathiazole, sulfapyridine and sulfamethazine, to evaluate its capacity to remove them and to test for any adverse effects on fungal growth and for any reduction in residual antibiotic activity. P. ostreatus was effective in removing sulfonamides up to 83 to 91% of the applied doses over 14 days. The antibiotic activity of the sulfonamide residues was reduced by 50%. Sulfamethoxazole transformation products by laccase were identified, and the degradation pathway was proposed. In addition, P. ostreatus growth on a semi-solid medium of spent mushroom substrate and malt extract agar was used to develop a biofilter for the removal of sulfonamides from real wastewater. The biofilter was able to remove more than 90% of the sulfonamide concentrations over 24 h by combining adsorption and biodegradation mechanisms.

The effects, in greenhouse conditions, of Purified Urban Wastewater (PW) from Almería (Spain), in the fertigation of pepper (Capsicum annuum L.) on sandy mulch soil, were evaluated. Primary, secondary (active sludges) and tertiary (Chlorination + ozonation) purification treatments were applied to wastewater. Irrigation treatments applied were PW, natural Ground Water (GW), Fertilizer PW (FPW) and Fertilizer GW (FGW). The vegetal biomass, yield and fruit quality were controlled. Heavy metals (Cr, Cd, Pb, Ni, Mn, Cu and Zn), arsenic (As) and Polycyclic Aromatic Hydrocarbons (PAH) in water, soil, leaf, and fruit were analysed. The PW presented heavy metal, As and PAH contents acceptable for its use in drip irrigation. In the soil, fertigated with PW, the concentration of heavy metals and As did not increase, whilst the PAH concentration decreased. The PW treatment supplied enough nutrients to obtain yield and fruit quality equal to that of GW with fertilization. A significant saving on N, P and K fertilizers (37%, 66% and 12% respectively) was achieved by using PW. The Cd, Pb and As contents of the fruit did not show risk for human consumption. The total PAH concentrations in the fruit were low, the highest of which was phenathrene, with no carcinogenic signification.