Fouling Mitigation for Pressurized Membrane of Side-Stream MBR Process at Abnormal Operation Condition

Abstract

Pressurized membrane used for side-stream MBR process requires fouling control strategy both for normal and abnormal operation conditions for stable operation of the facilities. In this study, 85 m 3 /day of pilot-scale side-stream MBR process was constructed for the evaluation of fouling mitigation by air bubble injection into the membrane module. In addition, fouling phenomena at abnormal operation conditions of low influent and/or loading rate were also investigated. Injection of air bubble was found to be effective in delaying transmembrane pressure (TMP) increase mainly due to scouring effect on the membrane surface, resulting in expanded filtration cycle at a high flux of 40 L/m 2 ･h (LMH). At abnormal operation condition, injection of PACl (53 mg/L as Al) into the bioreactor showed 19% reduction of TMP increase. However, inhibition of nitrifying bacteria by continuous PACl injection was observed from batch experiments. In contrast, injection of powdered activated carbon (PAC, 0.6 g/L) was able to maintain the initial TMP of 0.2 kg/cm 2 for 5 days at the abnormal conditions. It may have been caused from the adsorption of extracellular polymeric substances (EPS), which was known to be excessively released during growth inhibition condition and act as the major foulants in MBR operations.

Application of Double Piping Theory to Parallel-Arrayed Low-Pressure Membrane Module Header Pipe and Experimental Verification of Flow Distribution Evenness

“…These low-pressure membrane processes selectively remove particulate contaminants larger than the pores through a straining mechanism via the differential pressure between the membrane pores [ 1 , 2 , 3 ]. Membrane filtration is used extensively as it can remove particulate matter, organic matter, inorganic salts, etc., as well as yield stable water quality, depending on the pore size [ 4 , 5 ]. However, despite the many advantages of membrane filtration technology, the decrease in filtration efficiency over the operating time (i.e., the periodic occurrence of membrane fouling) has been identified as a significant problem in the introduction of membrane filtration technology to water treatment fields [ 4 , 5 , 6 , 7 ].…”

“…Membrane filtration is used extensively as it can remove particulate matter, organic matter, inorganic salts, etc., as well as yield stable water quality, depending on the pore size [ 4 , 5 ]. However, despite the many advantages of membrane filtration technology, the decrease in filtration efficiency over the operating time (i.e., the periodic occurrence of membrane fouling) has been identified as a significant problem in the introduction of membrane filtration technology to water treatment fields [ 4 , 5 , 6 , 7 ]. Generally, raw water flows into each membrane module installed parallel to the header pipe.…”

A Study on the Evaluation of Flow Distribution Evenness in Parallel-Arrayed-Type Low-Pressure Membrane Module Piping

“…These low-pressure membrane processes selectively remove particulate contaminants larger than membrane pores by a straining mechanism using the differential pressure between the pores [1,2]. Membrane filtration is a widely used technology because it can remove particulate matter, organic matter, inorganic salt, etc., and can produce stable water quality, depending on the size of the pores [3,4]. However, despite the many advantages of membrane filtration technology, the reduction in filtration efficiency over operating time, that is, the periodic occurrence of membrane fouling, has been identified as a major problem in the introduction of membrane filtration technology into water treatment fields [3][4][5][6].…”

“…Membrane filtration is a widely used technology because it can remove particulate matter, organic matter, inorganic salt, etc., and can produce stable water quality, depending on the size of the pores [3,4]. However, despite the many advantages of membrane filtration technology, the reduction in filtration efficiency over operating time, that is, the periodic occurrence of membrane fouling, has been identified as a major problem in the introduction of membrane filtration technology into water treatment fields [3][4][5][6]. In general, raw water flows into each membrane module installed parallel to the header pipe.…”

A Study on Membrane Fouling Control by Immobilized Microbial Media for Nitrification in Membrane Bioreactor

“…하지만 높은 MLSS로 인하여 EPS (extracellular polymeric substances) 및 SMP (soluble microbial products)가 생성되어 막 표면 및 공극 사이에 쌓여 막 오염(membrane fouling)을 일으키기 때문에 MLSS 범위에 따른 운전 조건 도출 및 대비책을 마련해야 한 다. 5,6) 이를 위해 하부에 설치된 산기관으로 물리 세정(air scouring) 7,8)…”