Combining submerged membrane technology with anaerobic and ...

Objectives and summaryalkalinity through the continous addition of NaHCO3 was shown to be essential in order toimprove COD removal efficiencies up to 70 % working with OLR up to 5.0 kgCOD·m -3·d -1 .A methane yield around 0.3 m³ methane·kgCOD eliminated-1with a methane concentration ofapproximately 60% was observed.Furthermore, typical fouling indicator concentrations recently studied during theoperation of aerobic membrane bioreactors MBR, such as biopolymer cluster (BPC) andtransparent exopolymer (TEP), were measured during the operation. Moreover, thefilterability properties of the sludge were also determined during the operation in order toexamine if the addition of PAC could improve the resistance to filtration of the mixed liquor.The concentrations of the fouling indicators measured during this studying were extremelyhigh, as well as specific resistance to filtration and the addition of PAC to the AnMBR didnot improve anyone of them. Membrane fouling was governed by the hydrodynamicsderived from the high MLTS concentration. Since this high MLTS concentration did notimprove organic matter removal, a diminution below 20 g·L -1 could enhance membranefluxes, especially when PAC would be added into the reactor, as suggested by literature.With the work performed in this thesis, important information for the operation ofsubmerged membrane technology and its application combined with anaerobic andaerobic wastewater treatments was obtained.28