Toxicity and genotoxicity of hospital laundry wastewaters treated with photocatalytic ozonation

The aim of the present study was to assess the efficiency of advanced oxidative processes based on photocatalytic ozonation (O-3, UV, UV/O-3, UV/O-3/Fe2+ 50 mg L-1 and 150 mg L-1) in the treatment of hospital laundry wastewaters. The analysis of the investigated wastewater revealed high chemical oxygen demand (COD - 3343.8 mg L-1), biochemical oxygen demand (BOD5 - 1906.4 mg L-1), total Kjeldahl nitrogen (TKN - 79.8 mg L-1) and Daphnia magna toxicity (EC50 = 1.73). Genotoxic effects were also detected for Minim cepa. Reductions of some parameters occurred after photocatalytic ozonation. The UV/O-3/Fe2+ 150 mg L-1 method was more efficient in reducing COD (59.1%), BOD5 (503%) and TKN (86.8%). There was significant reduction (p<0.05) in D. magna toxicity, O-3 (EC50=47.3%), UV (EC50=50.6%) and UV/O-3/Fe2+ 150 mg L-1 (EC50=45.4%) processes. Normalization of the mitotic index and reduction of micronucleated cells were observed in A. cepa after the treatments. Results demonstrate that these methods were efficient in the degradation of hospital laundry wastewaters, representing a thriving alternative for the removal of pollutants that cause toxicity and genotoxicity. (C) 2012 Elsevier B.V. All rights reserved.