Patent ID: 7169236

Claim:
A method of monitoring a cleaning process capable of cleaning a membrane separation system comprising the steps of: (a) providing an inert fluorescent tracer, wherein said inert fluorescent tracer is selected such that it is known in advance whether said inert fluorescent tracer is (i) capable of traveling through the membrane into the permeate stream, or (ii) not capable of passing through the membrane into the permeate stream; (b) providing a cleaning agent; (c) adding the inert fluorescent tracer and the cleaning agent, wherein the inert fluorescent tracer is added in a known proportion to the cleaning agent, to the membrane separation system; (d) providing one or more fluorometers to detect the fluorescent signal of the inert fluorescent tracer at one or more locations within the membrane separation system; and (e) using said one or more fluorometers to detect the fluorescent signal of the inert fluorescent tracer and from that detected signal, determine the amount of inert fluorescent tracer present at one or more locations within the membrane separation system during the cleaning process.