AWWA B116:2015 pdf download.Electrodialysis and Ion-Exchange Membrane Systems
36. Log removal value (LRV): A measure of the removal efectiveness of a parameter expressed as the log 10 of the concentration in the feed minus the log 10 of the concentration in the fltrate or product. For example, given a 10-fold reduc- tion in a concentration, such as from 200 in the feed to 20 in the fltrate, the LRV equals 1.
40. Membrane: An engineered material designed to remove solids (dis- solved 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 fltrate stream). Tis 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 MF and UF, as well as higher-pressure membranes such as nanofltration (NF) and reverse osmosis (RO). Other defnitions are more restrictive including the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR), which defnes membrane fltration as “a pressure- or vacuum-driven separation process in which particulate matter larger than 1 micron is rejected by a nonfbrous engineered barrier.”
42. Microfltration (MF): Membrane fltration 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 USEPA Membrane Filtration Guidance Manual.
43. Nanofltration (NF): Membrane fltration process that removes dis- solved constituents from water—such as dissolved organics, color, calcium and magnesium (hardness) ions, and other ions. NF membrane elements provide a nominal organic molecular weight cutof in the range of about 200 to >500 daltons and sodium chloride rejection of 0 to 95 percent. NF is similar to RO with the key diference being that NF has lower sodium chloride rejection than RO and it exhibits more selectivity in the types of ions that are removed such that NF allows a comparatively higher percentage of monovalent ions to pass to the permeate than multivalent ions.AWWA B116 pdf download.