tailieunhanh - Membrane fouling in anoxic oxic MBR system operated at low dissolved oxygen

There was a significant increase of TMP during first 15-days experiment at DO mg/L. After that the TMP was increased slowly and lower than 16 kPa to until 30-days. In contrast, when DO was reduced to , , and , the TMP was increased sharply almost from 1 to over 20 kPa within about 15 days. | Vietnam Journal of Science and Technology 55 (4C) (2017) 258-263 MEMBRANE FOULING IN ANOXIC-OXIC MBR SYSTEM OPERATED AT LOW DISSOLVED OXYGEN Khac-Uan Do1, *, Jim C. Chen2 1 School of Environmental Science and Technology, Hanoi University of Science and Technology, Dai Co Viet Road, Hanoi, Viet Nam 2 School of Civil and Environmental Engineering, Nanyang Technological University, Block N1 Nanyang Avenue, 639798, Singapore * Email: Received: 13 July 2017; Accepted for publication: 17 October 2017 ABSTRACT Membrane fouling in a lab-scale anoxic-oxic MBR operated at low dissolved oxygen (DO) was investigated in this study. The system includes an anoxic, an oxic and a membrane basin with the working volumes of 73 L, 124 L, and 68 L, respectively. A hollow fibre membrane module with a pore size of µm and with total filter area of m2 was submerged in the membrane basin. The system was operated at various low DO concentrations of ; ; ; and mg/L. The results shown that at DO higher than mg/L, COD and TN removal efficiencies were higher than 90 % and 60 %, respectively. However, low DO (less than mg/L) lead to poor sludge flocculation which deteriorate the membrane filterability. The TMP increased dramatically at different DO levels. There was a significant increase of TMP during first 15-days experiment at DO mg/L. After that the TMP was increased slowly and lower than 16 kPa to until 30-days. In contrast, when DO was reduced to , , and , the TMP was increased sharply almost from 1 to over 20 kPa within about 15 days. Keywords: filterability, fouling, low dissolved oxygen, membrane bioreactor, wastewater. 1. INTRODUCTION Membrane bioreactor (MBR) which combines biological treatment and membrane separation is an increasingly attractive option for the treatment and reuse of industrial and municipal wastewater [1, 2]. Compared to the conventional activated sludge (CAS) process, MBRs have various .