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HOSPITAL WASTEWATER TREATMENT BY MEMBRANE BIOREACTOR: PERFORMANCE AND IMPACT ON THE BIOMASSES


M. ALRHMOUN 1, M. CASELLAS 1, C. DAGOT 1
1. GRESE EA 4330, UniversiteÂŽ de Limoges, 123 avenue Albert Thomas, F-87060 Limoges Cedex, France

Issue:

PLUMEE, Number 1, Volume I

Section:

Issue No. 1 - Volume 3(2013)
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Abstract:

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. A pilot-scale membrane bioreactor (MBR) was installed and operated for 75 days at a laboratory. It was fed an influent directly from the hospital’s sanitary 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), which allowed visualization of isolated stained cells in the three-dimensional structure of damaged ïŹ‚ocs, combined with a ïŹ‚uorescent viability indicator (BacLightÂź Bacterial Viability Kit, Molecular Probes), allowed us to study pharmaceutics compounds time-kill activity, and which allowed direct visualization of bacterial exopolymires (EPS) in fully hydrated dairy products. This technique involved staining EPS with concanavalin A tetramethylrhodamine and fluorescein isothiocyanate solution. Samples were observed using confocal scanning laser microscopy to characterize the extracellular polymeric substances of sludge (soluble EPS content). Results suggested that after 20 days of exposure the pharmaceuticals compounds induced a significant increase of concentration soluble EPS in flocs. This was attributed to a protection mechanism of the bacteria. Under operating conditions, the pharmaceuticals compounds not inhibited COD removal and the nitrification during the experiments. These ïŹndings are in agreement with the microscopic studies, which showed a significant increase of concentration EPS. A value of the ratio COD/BOD5 higher of 2 indicated an incomplete biodegradation. The presence of the pharmaceuticals compounds and its main metabolites stimulates mechanisms of protection and production of EPS with a slightly higher production of polysaccharides than 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 semble as technique very important for elimination the organics polluents from the hospital wastewater.

Keywords:

Membrane bioreactor, hospital wastewater, biomass, Exo polymers, Confocal microscopy (CLSM).

Code [ID]:

PLUMEE201301V01S01A0001 [0003957]

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