Wastewater- Where does it go?

1. Environmental and Sustainable Design
By: Matthew Chapman

2.  Wastewater is water that has been changed
in some way and is no longer suitable, or
there are no means for reuse, and requires
disposal or discharge.
 Water can pick up pollutants, be changed
thermally (hotter or colder), have pH level
changes, or become more concentrated in
minerals, such as from evaporation or
purification.

3.  Human wastes (domestic sewage)
 Fats, Oils & Grease (“FOG”)
 Food preparation waste
 Toxic and poisonous substances
 Metals from process or picked up from piping
 Acidic or basic compounds
 Malodorous compounds (i.e. formaldehyde, mercaptans)
 Radioactive substances
 Suspended and dissolved solids (biodegradable and non
 biodegradable)
 Materials with high oxygen demand (to biodegrade)
 Biological substances

4.  Clean water is critical to plants and animals that live in water. This is
important to the fishing industry, sport fishing enthusiasts, and
future generations.
 Our rivers and ocean waters teem with life that depends on shoreline,
beaches and marshes. They are critical habitats for hundreds of
species of fish and other aquatic life. Migratory water birds use the
areas for resting and feeding.
 The scenic and recreational values of our waters are reasons many
people choose to live where they do. Visitors are drawn to water
activities such as swimming, fishing, boating and picnicking.
 If it is not properly cleaned, water can carry disease. Since we live,
work and play so close to water, harmful bacteria have to be removed
to make water safe.

5.  Primary treatment (mechanical) removes about 60 percent of
suspended solids from wastewater. This treatment also involves
aerating (stirring up) the wastewater, to put oxygen back in.
Secondary treatment removes more than 90 percent of suspended
solids.
 Secondary treatment (biological) removes the dissolved organic
matter that escapes primary treatment. This is achieved by microbes
consuming the organic matter as food, and converting it to carbon
dioxide, water, and energy for their own growth and reproduction.
 Tertiary treatment can remove more than 99 percent of all the
impurities from sewage, producing an effluent of almost drinking-
water quality. The related technology can be very expensive,
requiring a high level of technical know how and well trained
treatment plant operators, a steady energy supply, and chemicals
and specific equipment which may not be readily available.

7.  http://water.usgs.gov/edu/wuww.html
 http://water.worldbank.org/shw-resource-
guide/infrastructure/menu-technical-
options/wastewater-treatment