achieving optimal conditions of membrane bioreactors for dairy industry wastewater treatment

The optimization of membrane bioreactor (mbr) equipped with a submerged flat-sheet polyethersulfone (pes) membrane for the wastewater treatment from dairy processing facilities was investigated. the effects of key parameters such as the hydraulic retention time (hrt, from 8 to 16 hr), mixed liquor suspended solids (mlss, 3000 to 9000mg/l), and rate of aeration (qair: 1 and 2 l/min) on cod removal efficiency were systematically investigated. through the response surface method (rsm), the maximum the cod removal efficiency of 92.67% was obtained under the optimal conditions of hrt: 13.83 hr, mlss: 7239.84 mg/l, and qair: 1.75 l/min. the statistical analysis identified mlss as the most influential factor in the cod removal efficiency, accounting for 30% of the variation, followed by hrt with16%, and the rate of aeration showing the least impact of 8%. a notable reduction in the uv absorbance of wastewater between 200 and 500 nm, after treatment using mbr under optimal conditions, signified successful targeting of toxic or colored pollutants. finally, a mechanism for the wastewater treatment in mbrs, which included the biological degradation, adsorption on the surface of biomass and membrane, and separation through membrane filtration, was proposed.