The ability to quickly identify breaches or system breakthrough within the membrane process is
critical to ensure the consistent supply of high quality water and compliance with drinking water
guidelines and regulations. Direct integrity methodologies such as pressure decay and bubble
point tests are capable of identifying and isolating integrity breaches within a membrane
operating system. However, the intermittent nature of these tests does not provide real-time
information as to the performance of a membrane operating system. Therefore, the integration of
continuous indirect integrity monitoring of membrane permeate streams during operation is
recommended within the proposed guidelines of the US Environmental Protection Agency (USEPA) Membrane Filtration Guidance
Manual, such as turbidity meters and particle counters. Under challenged membrane operating
conditions, such as the treatment of high natural organic matter (NOM) source water or filter backwash water (FBWW)
applications, the sensitivity of these monitoring tools in detecting initial system breakthrough as
defined by chronic increases in dissolved material (e.g., NOM, metals) may not be optimal.
Therefore, the purpose of the present research investigation was to evaluate indirect integrity
testing methodologies on a pilot-scale ultrafiltration (UF) membrane treating FBWW. Indirect integrity test
methodologies were evaluated on an intentionally compromised system to determine the
capabilities of these monitoring procedures in detecting individual fiber pinholes. The two most
commonly employed indirect integrity procedures, namely particle counting and turbidity
measurements on the membrane permeate failed to detect the intentional breach created in the
membrane operating system. However, dissolved organic carbon (DOC) and color
measurements showed promising results in the ability of these alternative indirect test procedures
to identify significant increases in the concentration of dissolved contaminants within the
permeate stream. Includes 4 references, table.