AUTOMATION
According to the 2008 report from by the AWWA Subcommittee on Periodical Publications of the Membrane Process (2008), MFMicrofiltration (MF) membranes: Microfiltration membranes are typically hollow-fibers with a pore size range of approximately 0.1 – 0.2 μm (nominally 0.1 μm)./UFUltrafiltration (UF) membranes: Ultrafiltration membranes are typically hollow-fibers with a pore size range of approximately 0.01 – 0.05 μm (nominally 0.01 μm). membrane facilities are generally automated and have data logging and report generation built into the SCADASCADA: SCADA is an acronym of Supervisory Control and Data Acquistion. The term refers to computer systems including programmable logic controllers (PLCs) used to monitor and control water treatment processes and distribution systems including storing data and displaying the status of systems and historical trends. system. MF/UF filters are generally operated at a constant rate with backpulseBackpulse or backwash: 1) Backwash is a procedure in which periodically the flow direction is reversed through the membrane for a short period of time in order to remove particulates accumulated at the membrane surface. 2) Backwash also refers to the waste water produced as a result of the backwash procedure., air scrub, chemical enhanced backpulse, and indirect integrity monitoringIndirect integrity monitoring: Indirect integrity monitoring consists of measuring some water quality parameter of the filtrate, e.g., turbidity or particle concentration, as an indicator of treatment effectiveness. performed automatically according to user-selected set points. Chemical clean-in-placeClean-in-place (CIP) or in-situ chemical cleaning: Clean-in-place is a procedure performed periodically to clean a membrane more thoroughly than backwashing can achieve in order to restore the permeability of the membrane towards baseline levels. The process uses chemicals such as citric acid and chlorine or others to remove accumulated foulants on the membrane. is typically initiated manually which then proceeds automatically or semi-automatically.
It must be emphasized that the high degree of automation of MF/UF systems does not reduce the important role of the operator. For example, declining feed waterFeed water: The feed water is the water stream applied to the membrane unit. quality will foul the membranes more quickly and require more frequent backpulsing and possibly reduce the effectiveness of backpulse as well as require more frequent chemical cleaning. The operator may be able to adjust the pretreatmentPretreatment: In membrane treatment systems, pretreatment encompasses all treatment processes prior to the membrane, e.g., strainers, flocculation, and sedimentation. or backpulsing to avoid this sequence of events.
