Investigation of organic foulants behavior on hollow-fiber UF membranes in a drinking water treatment plant

Abstract

a b s t r a c tIn the present work, a ultrafiltration (UF) low pressure membrane (LPM) made of polyvinyl chloride (PVC) was used with an inline poly-ferric sulfate coagulation in a full scale drinking water treatment plant. The organic foulants and their accumulation behavior in the membrane filtration were investigated during a whole year operation. The evolutions of the surface morphology of the membranes were characterized by scanning electronic microscopy (SEM) and atomic force microscopy (AFM). The results revealed that the cake layer and pore blocked were responsible for the flux declining. Moreover, the roughness of the surface of the membranes continuously increased with the filtration. In order to identify the constitutes of organic foulants, attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR), high pressure size exclusion chromatography (HPSEC) and fluorescence excitation-emission matrix (EEM) spectrometry were used to examine the desorbed organic matters from the fouled membranes. The results showed that humic substances kept a very stable situation, indicating that it would not be important in the formation of the combined organic fouling layer. Protein/protein-like substances and soluble microbial product-like (SMP-like) substances were the dominant components in the organic fouling layer in a long-term ultrafiltration of surface water used as a drinking water source. A decrease of protein/protein-like substances and an increase of SMP-like substances with the filtration time were found, which could be attributed to the transition from proteins to SMP in the fouling layer. Thus, the increase of SMP-like substances in the fouling layer would play a significant role on the accumulation of irreversible fouling.

Performance and fate of organics in a pilot MBR–NF for treating antibiotic production wastewater with recycling NF concentrate

“…These bands correspond to the carbonyl, amide I, and amide II bands of an amide structure, which would be indicative of proteins (Xiao et al, 2012).…”

Identification of key factors affecting the organic fouling on low-pressure ultrafiltration membranes

“…Each module contains 10 fibers, with an effective length of 23.0 71 cm. The contact angle of the PVC membrane is measured as 33.67170.46, indicating a hydrophilic property [20].…”

Influence of coagulation process on the ultrafiltration performance – The roles of Al species and characteristics of algae-laden water

“…Xiao et al found that aromatic protein had a highly correlation with irreversible fouling. Humic substances were not found to be important in the formation of the combined fouling layer [36]. And some other studies had showed that the concentration of SMP had a key role in membrane irreversible fouling, while humic substances were not found to be important in the formation of the combined fouling layer [38].…”

“…Many researches had suggested that the humic substances fraction of natural organic matter (NOM) is a major foulant which controlled the rate and extent of fouling [34,35]. But some other researches had showed that hydrophilic (non-humic) NOM might be a more significant foulant [36]. However, the organic matter in the feed water was important in the membrane fouling process.…”