Some of the organic chemicals used in our community can be harmful to the environment and human health if they are not handled or disposed of properly.  The chemicals tested for in the organics lab are some of the more dangerous chemicals that are regulated by the WDNR.  There are two types of compounds tested for in this lab: semi volatile compounds and volatile compounds. 

Semi Volatile Organic Analysis

Semi volatile chemicals have higher boiling points. In general this means that at room temperature they are either a solid or liquid. Polychlorinated Biphenyls (PCBs) and Chlordane are well known examples of these chemicals. There are 47 different chemicals of this type that are tested for by the organics lab at the Green Bay Metropolitan Sewerage District. In order to detect and measure these compounds they must first be removed from a wastewater sample and concentrated into a small amount of solvent. This task is accomplished by a technique called Liquid-Liquid extraction. After the chemicals have been extracted they can be analyzed with a Gas Chromatograph.

A Gas Chromatograph is used to detect the presence of a chemical and measure the amount of that chemical in the sample. These instruments are very sensitive, and are able to detect most semi volatile chemicals at part per trillion concentrations.

Volatile Organic Analysis 

Volatile chemicals have lower boiling points and evaporate at room temperature becoming gasses. Benzene, MTBE (Methyl-t-butyl ether) and Chloroform are common examples of these chemicals. The list of volatile chemicals tested for in the organics lab includes 80+ compounds.

Volatile chemicals are also removed from a wastewater sample in order to be detected and measured. The technique used is called Purge and Trap. Helium is bubbled through the sample to remove or "purge" the chemicals. They are then "trapped" on a carbon and silica trap. The chemicals are then transferred to a Gas Chromatograph for analysis. Volatile organic chemicals can be detected at part per billion concentrations.