Patent ID: 7949432

Claim:
A method of monitoring and controlling surface associated microbiological activity in a process stream comprising: a. connecting an apparatus to a process stream, wherein said apparatus comprises a flow cell containing a plurality of openings, wherein at least one opening is a flow cell inlet for fluid drawn from said process stream and at least one opening is a flow cell outlet for fluid exiting said flow cell, a DO probe attached to one of said openings, optionally an ORP probe attached to one of said openings, optionally a cleaning device attached to one of said openings, optionally a first conduit attached to the flow cell inlet, optionally a second conduit attached to the flow cell outlet, and optionally a valve associated with said flow cell; b. drawing fluid from said process steam into said flow cell; c. opening the valve of said apparatus to allow fluid to be drawn into said flow cell; d. measuring at least once the DO concentration of said process stream with said DO probe, and wherein said DO probe is not cleaned prior to each measurement; e. cleaning the surface of said DO probe; f. measuring at least once both the DO concentration of the fluid inside said apparatus with said DO probe and optionally wherein prior to each measurement said DO probe surface is cleaned; g. calculating a Δ DO reading between step (d) and step (f); h. correlating at least said Δ DO in step (g) with surface associated biological activity; and i. controlling the amount of said microbiological activity by adding an effective amount of a treatment containing one or more oxidizing biocides to the process stream and/or an effective amount of a treatment containing one or more non-oxidizing biocides and optionally a mixture containing an n-hydrogen compound, an oxidizing biocide, and optionally a buffer to the process stream.