Submodule 12 B, Water Quality
Below is a slide overview of water quality issues. Let me suggest you review the slides before you read Chapter 14 of your textbook. The book has some important details that you should be aware of, but it will make more sense after you look at the slides. Also that chapter deals with Clean Water Act only, that is discharges to fresh surface water. The slides mention two other cases, discharge to groundwater and discharges to salt water.
First a little introduction to the introduction. The clean water act deals with point source discharges. Anyone who discharges to surface waters through a pipe, canal, or ditch must get an NPDES permit (National Pollution Discharge Elimination System). "Anyone" includes municipalities and the army, as well as industries. The permit will establish what can be discharged. So far, it is simple and logical. But simple it does not remain. The regulations tell the agencies (usually the EPA, but some states have the authority) what the permit conditions must be. They are different conditions for old (discharging before the law was passed) versus new industries. Permit conditions will also vary for the "use" of the receiving water. Finally conditions might vary with particular chemicals in the discharge. The regulations specify very general classes of treatment, such as "best practical technology" which is defined for some industries and not for others. The industries have lobbied EPA to permit certain treatments. Environmental groups have lobbied and filed lawsuits to require more stringent standards. From these pressures and legal framework, EPA has struggled to produce some involved regulations. In 1970 only about one third of the US fresh waters were fit for swimming and fishing. Today about two thirds are fit for those purposes - on that basis the CWA has been a success, in my opinion.
For discharges to the city sewers (POTW) the industry does not need an NPDES permit (the POTW is supposed to have that) but must meet "pretreatment standards" before it goes into the sewer.
Storm water often goes to a water body without any treatment, but these sources must get a permit as well. Again there are classes of permits. Because storm water is omnipresent, "general permits" are often issues for a class of industry, "construction sites less than 5 acres" for example, might be covered by a general permit.
Discharges to the groundwater of any chemical are generally forbidden by a section of a different law, the Safe Drinking Water Act. There are permitted injection wells, however, and these may be permitted to accept certain hazardous chemicals.
Discharges to salt water are governed by a different set of laws.
Here's the slide show.
Look at the quiz here. The actual quiz is on Blackboard.