TOC stands for Total Organic Carbon, it includes all organics that contain carbon except for CO2, bicarbonate and carbonate.

1. TOC Article - Brent Stewart - Applications Engineer
TOC stands for Total Organic Carbon, it includes all organics that contain carbon except for CO2,
bicarbonate and carbonate. TOC is common on the NE coast of America where vegetative
matter leaches tannins into the water giving it a tea like color (water softeners). The naturally
occurring TOC is typically negative charged colloids or suspended water. Ideally, RO feed water
would have less than 3 ppm of TOC. Anthropogenic (man-made) sources of TOC can contribute
significantly higher levels.
Oxidation of TOC in potable water supply creates THM's which is carcinogenic. Municipalities
require TOC reduction before chlorination to remain under the THM target set by the EPA.
There are a number of techniques for the removal or reduction of TOC including,
coagulation/flocculation, activated carbon, oxidation, ion exchange, reverse osmosis and nano-
filtration.
For low levels of TOC, RO/NF technology is ideal, with the combination of post UV treatment,
TOC levels can be lowered to trace amounts. Nanofiltration (NF) membranes are well suited for
TOC reduction while maintaining minerals in the water. The selection of RO or NF membranes
is a function of the molecular weight (size) or the organic molecules, their distribution and
rejection requirements. As a general rule, Hydranautics states a molecular weight of less than
200 are rejected at levels greater than 99%.

2. Pure Aqua, Inc. specializes in RO/NF technology, to see Pure Aqua's standard line of packaged
RO equipment visit our website: http://www.pure-aqua.com/reverse-osmosis-systems.html.