Eficiência da detoxificação de efluentes da lavanderia hospitalar através do uso de métodos eletroquímicos.

Abstract

Due to the large volumes of wastewater generated in the laundry and the characteristics that make these effluents a high level of environmental impact, the hospital laundry is in an area of great importance in relation to the need of environmental management. Therefore, the present study aimed to carry out the analytical characterization of wastewater generated in a hospital laundry, as well as the treatment. The analytical characterization identified the presence of two most critical fractions in the stages of the hospital laundry process: initial rinse from the compresses and the washing stage, which were submitted to the treatment assays. The treatment assays employed in this research involved three methods: electroflotation (EF), electroflotation combined with the process of ozonation (EF/O3) electroflotation and then the process of ozonation (EF + O3). These assays occurred in a bipolar electrochemical reactor column type with a capacity of 10L, in acrylic, equipped with air diffuser with porous stones, four electrodes SAE 1045 connected in series, sampler and gas outlet. The cathode of the reactor was connected to the meter, while the anode was connected to an external power supply. The ozonation process occurred with the help of an ozone generator for electrical discharge, with a generation capacity of up to 2,000 mg O3 h-1 - fed stream of air has been dried with CaCl2 trap's and SiO2 gel. Due to the low conductivity, occurred assays where were added 1000mg L-1 NaCl to the wastewater. Were performed analyzes of load parameters (BOD5 and COD), and ecotoxicological tests using the test organism Daphnia magna before and after the each every assay. Thus we sought to evaluate the efficiency of the methods employed in reducing the loading parameters and the detoxification of wastewaters from the hospital laundry in question. The tests involving the process of EF with conductivity induced by the addition of NaCl performed for 60 minutes got the best performance. The wastewater generated in the initial rinse of the swabs passed from the condition of extremely toxic (12,58%) to moderately toxic (61,59%), while reductions of BOD5 and COD are respectively 32% and 9%. With respect to the wastewater coming from the washing stage, the COD was reduced by 41%, while toxicity was reduced considerably from the condition of extremely toxic (6.89%) for low toxicity (76.65%). Based on these results, it appears that the EF process constitutes an interesting alternative for the treatment of wastewaters from hospital laundry showing detoxication potential and can be integrated with other processes such as pre-or posttreatment.