Abstract
Hospitals discharge considerable amounts of chemicals and microbial agents in their wastewaters. Problem chemicals present in hospital wastewater belong to different groups, such as antibiotics, X-ray contrast agents, disinfectants and pharmaceuticals. Many of these chemical compounds resist normal wastewater treatment. They end up in surface waters where they can influence the aquatic ecosystem and interfere with the food chain. Humans are particularly exposed by the drinking water, produced from surface water. Microbial agents of special concern are multiresistant microbial strains. The latter are suspected to contribute to the spread of antibiotic resistance. In this paper, we will discuss the different approaches towards hospital wastewater treatment. The principle of uncoupling hospitals from public sewers warrants in depth evaluation by technologists and ecotoxicologists as well as public health specialists. A pilot-scale membrane bioreactor (MBR) was installed and operated for 75 days at laboratory. It was fed an influent directly from the hospital drainage collection system. To study pharmaceutics compounds toxicity with micro pollutant concentrations ranging from low ng /L to mg/L, toward activated sludge. Lab scale experiments were conducted and microscopic techniques as confocal laser scanning microscopy (CLSM). Samples were observed using confocal scanning laser microscopy to characterize the extracellular polymeric substances of sludge (EPS content). The study was focused on efficacy the membrane bioreactor in treatment the hospital effluent and the extra cellular polymeric substances (EPS) as indicator of bacteria sensitivity to toxic agents. Results suggested that after 20 days of exposure the pharmaceuticals compounds induced a significant increase of concentration soluble EPS in flocs, the pharmaceuticals compounds not inhibited COD removal and the nitrification during the experiments. These findings are in agreement with the microscopic studies, which showed a significant increase of concentration EPS. The presence of the pharmaceuticals compounds and its main metabolites stimulates mechanisms of protection and production of EPS with a slightly higher production of proteins. The removal of PPCPs by biological treatment processes including membrane bioreactor (MBR) was studied during the experience. The performance of MBR was demonstrated to be stable after 20 days of the experience. Although presence the fouling, the membrane look as technique very important for elimination the organics micro pollutants from the hospital wastewater.
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