AWWA B116-19 pdf download.Electrodialysis and Ion-Exchange Membrane Systems
23. Electro-deionization (EDI): A variant of ED in which dilutate (and sometimes concentrate) solution compartments are filled with ion-exchange material to reduce the resistance to current flow and achieve improved salt removal. EDI systems are typically used for production of low-conductivity water.
24. Electrode compartment: Water flow compartment containing the metal electrode where oxidation or reduction occurs; generally related to ED, EDR, EDM, and EDI.
25. Electrodialysis (ED): A demineralization process in which ions are transferred through ion-selective membranes by application of an electromotive force, voltage-driven direct electric current, from a less concentrated solution to a more concentrated solution. Note: ED is not a “membrane filtration” process, as defined in USEPA’s Membrane Filtration Guidance Manual, because the demineralized (product) water does not pass through the membrane barrier. Related term: Electrodialysis reversal (EDR).
26. Electrodialysis metathesis (EDM): A type of ED process that utilizes repeating units of two distinct cell-pairs and four process streams (two concentrate streams and two dilutate streams). The two distinct cell-pairs may employ different types of anion or cation exchange membranes (e.g., monovalent selective membranes). Related term: Electrodialysis (ED).
35. Membrane: An engineered material designed to remove solids (dissolved or suspended) that are rejected from the system as either backwash or a concentrate stream, and that produces a stream containing less solute or particles (the product or filtrate stream). This standard focuses on treatment processes that employ IEMs, which selectively allow or restrict ionic transport. Membrane types in pressure-driven standards include low-pressure membranes such as microfiltration (MF) and ultrafiltration (UF), as well as higher-pressure membranes such as nanofiltration (NF) and reverse osmosis (RO). Other definitions are more restrictive including the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR), which defines membrane filtration as “a pressure- or vacuum-driven separation process in which particulate matter larger than 1 micron is rejected by a non-fibrous engineered barrier.”
36. Membrane cleaning system: Tanks, filtration devices, pumps, and associated equipment and appurtenances that are periodically used to prepare and feed chemical solutions to the membrane element(s) to recover lost performance.
37. Microfiltration (MF): Membrane filtration process with pore diameter nominally at least 0.1 µm that provides at least 3-log removal of Giardia cysts or Cryptosporidium oocysts or similar-sized 3 µm and larger surrogate materials based on challenge testing in accordance with the USEPA Membrane Filtration Guidance Manual.AWWA B116-19 pdf download.