Fouling of reverse osmosis membrane for municipal wastewater reclamation: Autopsy results from a full-scale plant

A fouled RO membrane from a full-scale municipal wastewater reclamation plant was autopsied to elucidate fouling characteristics and behavior associated with feed water quality. Organic pollution (occupied 75% of the deposit) was the major problem for the RO membrane. The deposit dissolved in NaOH solution was 2.37 g-DOC/m(2) and largely comprised of microbial-derived organic matter (OM) and humic-like OM. Hydrophobic acids (HOA) and hydrophilic neutrals (HIN) were the two largest fractions in the deposit among the six fractions of HOA, hydrophobic bases (HOB), hydrophobic neutrals (HON), hydrophilic acids (I-HA), hydrophilic bases (HIB) and HIN. HOA fraction could deposit on the membrane easily and should be monitored as key fractions to predict the organic fouling of RO membrane. HIN fraction occupied 34.2% of the total DOC in the deposit, but it was suggested that HIN fraction in the deposit was produced by the microorganisms on the membrane instead of depositing. The inorganic scaling of the RO membrane was mainly caused by element Fe, Ca and Si. The content of Fe was the highest (349.18 mg/m(2)), since Fe deposited on the RO membrane much more easily than other elements. Ca presented the lowest deposition ratio (0.0017%) due to the effective function of the antiscalant. (C) 2014 Elsevier B.V. All rights reserved.