Chapter 17 - Introduction to Specialized Treatment Processes Flashcards
A chemical substance of animal or vegetable origin, having carbon in its molecular structure.
Organic Compound
The water treatment process used primarily to remove organic contaminants from water.
Adsorption involves the adhesion of the contaminants to an adsorbent, such as activated carbon.
Adsorption
The process of bringing water and air into close contact to remove or modify constituents in the water.
Aeration
A means of dissolving air into water (aeration) wherein water is distributed over the packing at the top of a tank and air is forced in at the bottom using a blower.
Also called Desorption.
Air Stripping
A common gas in the atmosphere that is very soluble in water.
High concentrations in water can cause the water to be corrosive.
This is added to water after the lime-softening process to lower the pH in order to reduce calcium carbonate scale formation; a process known as recarbonization.
Carbon Dioxide (CO2)
A toxic gas produced by anerobic decomposition of organic matter and by sulfate-reducing bacteria.
This gas has a very noticeable rotten egg odor.
Hydrogen Sulfide (H2S)
A colorless, odorless, flammable gas formed by the anerobic decomposition of organic matter.
When dissolved in water, this gas causes a garlic-like taste.
Also called swamp gas.
Methane (CH4)
A manufactured, synthetic chemical generally used as an industrial solvent.
These are classified as known or suspected carcinogens or as causing other adverse health effects.
They are of particular concern to the water industry because they have been widely found as contaminants in groundwater sources.
Volatile Organic Chemical (VOCs)
A pressure-driven process in which almost-pure water is passed through a semipermeable membrane.
Water is forced through the membrane and most ions (salts) are left behind.
The process is principally used for desalinization.
Reverse Osmosis (RO)
A process in which ions are transferred through a membrane as a result of a direct current applied to the solution.
Electrodialysis
A process used to remove hardness for water that depends on special materials known as resins.
The resins trade nonhardness-causing ions (usually sodium) for the hardness-causing ions, calcium and magnesium.
This process removes almost all of the hardness from water.
Ion Exchange
An excess chemical left in water after treatment.
Its presence indicates that an adequate amount of disinfectant has been added at the treatment stage to ensure completion of all reactions with some disinfectant remaining.
Residual
