Design and operation considerations for wastewater treatment using a flat submerged membrane bioreactor

A resaerch paper from on" Design and operation considerations for wastewater treatment using a flat submerged membrane bioreactor " by Jin Kie Shima, Ik-Keun Yoob, and Young Moo Leea .

Abstract

Combining a flat submerged membrane with a biological reactor was investigated for synthetic wastewater treatment of high concentration. The increase of suction pressure as a result of fouling of the submerged membrane, nitrification and chemical oxygen demand (COD) removal efficiencies were monitored during 4-9 months operation. In order to find a proper geometry of the reactor with respect to the long-term stability of membrane filtration, three types of membrane bioreactor with a different ratio of cross-sectional area of the downcomer to the riser were operated and the time profiles of suction pressure increase were compared. While maintaining a filtration flux at 12-16 l m−2 h−1, a higher ratio of downcomer to riser area gave a better filtration stability of submerged membrane over several months of operation. A sharp increase of suction pressure was also observed when sludge bulking occurred during normal operation. Recovery of initial pure water flux for the membrane, which has been used over 6 months, was possible after 96 h of chemical cleaning. Under operating conditions with 12-16 h hydraulic retention time and 8000-16 000 mg l−1 sludge concentration in the bioreactor, COD removal efficiency was above 98% for 900-1600 mg l−1 influent COD and nitrification above 95% with 50-600 mg l−1 total nitrogen fed to the membrane bioreactor.

http://www.sciencedirect.com/science/article/pii/S0032959202000778

Its a paid one . But at least the abstract gives a glimpse of the article.