Bicarbonate (HCO3)

A monovalent anion. The solubility of calcium bicarbonate is low and can cause a RO scaling problem in the back-end of a RO. Calcium bicarbonate solubility is measured using LSI (Langlier Saturation Index) for brackish waters or the Stiff-Davis Index for seawaters and is lower with increasing temperature and increasing pH. Bicarbonate is one component of alkalinity and its concentration [....]

BOD (Biological Oxygen Demand)

           BOD is a non-specific test that measures the quantity of "biologically-degradable" organic matter and is reported as "ppm as oxygen". The test measures the quantity of oxygen depletion resulting from the ability of common bacteria to digest organic matter during a 5-day incubation period at 20 Deg C. [....]

Ammonium (NH4)

             A monovalent cation. Ammonium salts are very soluble and do not cause a RO scaling problem. The ammonium ion is the result of very soluble gaseous ammonia (NH3) being dissolved in water. Non-ionized ammonia ionizes in water to form the ammonium ion and hydroxide ion. The degree of ionization of ammonia to ammonium is dependent on pH, temperature, and [....]

Aluminum (Al):

                   Aluminum, based on its low solubility, is typically not found in any significant concentrations in well or surface waters. Aluminum, when present in an RO feed water, is typically colloidal in nature (not ionic) and is the result of alum carryover by an on-site or municipal clarifier or lime-softener. Alum (aluminum sulfate) is a popular coagulant that is [....]


           Alkalinity is comprised primarily of carbon dioxide, bicarbonate, carbonate and hydroxides. Naturally occurring alkalinity is the earth’s natural buffering system in that small doses of strong acids (e.g. acid rain) react with alkalinity and result in relatively small changes in pH. Carbon dioxide and bicarbonate are in a balance between the pH range of 4.4 and 8.2. At a [....]