Power and Water Magazine GineersNow - How Wastewater Treatment Plants Help Keep Our Water Clean

C O V E R
S T O R Y
What is Wastewater Treatment?
Wastewater treatment is the process of
removing contaminants from wastewater
using mechanical, chemical, or biological
processes. Wastewater can be contaminated
with a variety of pollutants, including chemicals,
oils, and debris. Wastewater treatment plants
are crucial for protecting public health and
the environment. They play an important
role in ensuring that wastewater is properly
treated and disposed of without contaminating
waterways.
How Does a Wastewater Treatment
Plant Work?
A wastewater treatment plant is a facility
that is used to treat wastewater. Wastewater
treatment plants use a variety of technologies
to remove pollutants from wastewater. Some
of the most common technologies used in
wastewater treatment plants are primary,
secondary, and tertiary processes.
Primary processes involve using natural
processes such as oxidation and biological
degradation to break down pollutants. Primary
processes are the least expensive option but
can be less effective at removing pollutants.
Secondary processes involve using physical
or chemical methods to break down pollutants.
Secondary processes are more expensive
than primary processes but can be more
effective at removing pollutants.
Tertiary processes involve using combinations
of primary and secondary processes to
effectively remove all types of pollutants.
Tertiary processes are the most expensive
option but can be the most effective at removing
all types of pollutants from wastewater.
The Step-By-Step Process of
Wastewater Treatment
1. Identification of the wastewater stream.
2. Collection of wastewater from the point of
discharge.
3. Preliminary treatment to remove
suspended and dissolved material.
4. Secondary treatment to remove pollutants
and odors.
5. Discharge of treated wastewater into a body
of water or another wastewater treatment
facility.
The wastewater treatment process begins with
the collection of wastewater from commercial
or residential sources. Wastewater is then
processed to remove contaminants and
disposed of in an appropriate manner.
Wastewater treatment plants use a variety
of methods to treat wastewater, including
primary, secondary and tertiary treatment.
Primary treatment uses a simple process
that separates water from contaminants by
contact or filtration. Secondary treatment
uses physical and chemical processes to
remove more complex pollutants. Tertiary
treatment uses advanced technologies such
as microorganisms to clean water molecules
of pollutants.
How Do Wastewater Treatment
Plants Remove Contaminants?
Wastewater treatment plants remove
contaminants by three primary methods:
adsorption, flocculation, and sedimentation.
Adsorption is the process of attaching
molecules to a surface to be removed.
Contaminants that are adsorbed onto the
plant’s surfaces will then be removed by the
plant’s filter systems.
Flocculation is the process of large water
droplets forming into small ones and
sedimentation is the deposition of solids from
a liquid. Wastewater treatment plants use
different types of filters to achieve these goals.
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