Influence of abnormal water intake linked to underwater aeration on ceramic membrane fouling in a drinking water treatment plant in Yeoncho, Korea

Abstract

This study investigated the fouling of ceramic membranes, which led to an increase in the transmembrane pressure (TMP) in a drinking water treatment plant in Yeoncho, Korea. The TMP values of the ceramic membranes monitored from 2014 to 2018 ranged from 0.01 to 2.12 kg f cm–2 (average TMP = 0.61 kg f cm–2). The TMP values fluctuated significantly, and considerable differences were found for each ceramic membrane module. A high TMP value (>1.5 kg f cm–2), the criterion for clean-in-place, was frequently observed, and its duration was prolonged. In addition, the TMP values remarkably increased when the water level in the reservoir decreased after increasing and when the underwater aeration within the reservoir was activated. The TMP was also related to the depth of the water intake. Comprehensive analyses of the fouled ceramic membranes revealed that organic matter, microalgae (e.g., diatom frustule), aluminum, manganese, and silica were the main components of the membrane foulants (organic material content = 48.5%; inorganic material content = 51.5%). Thus, a large proportion of the source material in the reservoir strongly contributed to the fouling of the ceramic membranes. To comprehensively explore the behavior of foulants in the reservoir and alleviate membrane fouling, minimizing artificial disturbances in the water body in the reservoir in terms of raw water management was necessary. In particular, semienclosed medium-sized reservoirs that supply raw water to the membrane filtration process for producing drinking water are more vulnerable to membrane fouling.