The study aimed to analyse the start-up of a submerged membrane bioreactor with complete sludge retention. A Zenon Zeeweed (ZW 10) hollow fibre membrane module in submerged configuration was installed in an aerobic reactor. The pilot plant was started-up without inoculum and the volumetric loading rate was kept constant. Many aspects related to the functioning of the pilot plant were analysed: COD removal, nutrients oxidation, disinfection and flocs size distribution. Since there was no excess sludge withdrawal, except for the samples used for the analyses, the biomass concentration in the reactor progressively increased reaching values much higher (16 gVSS L-1) than those observed in conventional activated sludge plants. The experimental campaign confirmed that membrane bioreactors can be quickly and easily started-up: in this study COD removal performance improved from 80% on the first days to 90% and above after the 20th day. The retention ability of the membrane assured a high quality of the permeate also as regards the microbiological parameters. Furthermore, the experiment showed that the mean sizes of the sludge flocs were gradually decreasing and, at the end of the experimentation, they reached values much lower than those found in conventional activated sludge systems.
Start-up of a submerged membrane bioreactor with complete sludge retention
DI BELLA, GAETANO;
2006-01-01
Abstract
The study aimed to analyse the start-up of a submerged membrane bioreactor with complete sludge retention. A Zenon Zeeweed (ZW 10) hollow fibre membrane module in submerged configuration was installed in an aerobic reactor. The pilot plant was started-up without inoculum and the volumetric loading rate was kept constant. Many aspects related to the functioning of the pilot plant were analysed: COD removal, nutrients oxidation, disinfection and flocs size distribution. Since there was no excess sludge withdrawal, except for the samples used for the analyses, the biomass concentration in the reactor progressively increased reaching values much higher (16 gVSS L-1) than those observed in conventional activated sludge plants. The experimental campaign confirmed that membrane bioreactors can be quickly and easily started-up: in this study COD removal performance improved from 80% on the first days to 90% and above after the 20th day. The retention ability of the membrane assured a high quality of the permeate also as regards the microbiological parameters. Furthermore, the experiment showed that the mean sizes of the sludge flocs were gradually decreasing and, at the end of the experimentation, they reached values much lower than those found in conventional activated sludge systems.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
