ION EXCHANGE Update 14 Jun 2013

Abbreviations and units
used in these pages


Abbreviation Description
Alk Alkalinity (essentially HCO3)
BOD Biological oxygen demand
BV Bed volume (1 BV = 1 m3 water per m3 resin)
BV/h = h–1 Specific flow rate or space velocity
(1 BV/h = 1 m3 water per m3 resin per hour)
CFR Co-flow ("co-current") regeneration
COD Chemical oxygen demand
(oxidisable organics)
DI De-ionisation
DM Demineralisation (is the same as DI)
DVB Divinylbenzene (cross-linker)
EMA Equivalent mineral acidity
(= Cl + SO4 + NO3 in raw water)
eq Equivalent (= mole divided by valency)
eq/L is a unit of ion exchange capacity,
meq/L is a unit of ionic concentration
FB Free base (regenerated) form of a WBA resin
FMA Free mineral acidity
(= Cl + SO4 + NO3 after cation exchange)
IX Ion exchange
kPa Kilopascal (unit of pressure = 0.01 bar)
MB Mixed bed
meq Milliequivalent (see eq)
ppb Part per billion (10–9 = µg/kg or µg/L or mg/m3)
(very dilute solutions)
ppm Part per million (10–6 = mg/kg or mg/L or g/m3)
(in dilute solutions)
ppt Part per trillion (10–12 = ng/kg or ng/L or µg/m3)
(extremely dilute solutions)
RFR Reverse flow (counterflow or "counter-current") regeneration
RO Reverse osmosis
SAC Strong acid cation [resin]
SBA Strong base anion [resin]
TDS Total dissolved solids
TH Total hardness (alkaline earth metals)
TOC Total organic carbon
WAC Weak acid cation [resin]
WBA Weak base anion [resin]
µS/cm MicroSiemens per centimetre (unit of conductivity)

See also units of concentration and capacity.


© François de Dardel