It has long been known that natural
wetland areas (such as marshes, swamps, and bogs, for example) play an important
role in protecting water quality.
Constructed or artificial wetland systems
mimic the treatment that occurs in natural wetlands by relying on plants and a
combination of naturally occurring biological, chemical, and physical processes
to remove pollutants from water.
In fact, some constructed wetland system
designs closely resemble natural wetlands and even provide additional habitat
area for the many birds, animals, and insects that thrive in wetland
environments. But because constructed wetland systems are designed specifically
for wastewater treatment, they work more efficiently than natural wetlands.
Constructed wetlands can treat wastewater
generated by a variety of sources. One of their more common uses is to provide
additional or advanced treatment of wastewater from homes, business sites, and
entire communities. This means they are used by homes and communities to treat
wastewater that has already had most solid materials removed from it through
some type of primary or secondary treatment (for example, in a septic tank,
lagoon, aerobic unit, or treatment plant).
While the exact roles of some of the
natural treatment processes in wetlands are still not completely understood,
enough information currently is available for experienced wastewater consultants
to design systems that perform reliably and meet environmental treatment
standards. Communities should hire a consultant or engineering firm that has
specific experience designing wetland systems.
A Low-Cost, Low-Energy Option
Constructed wetland systems have only been
used for wastewater treatment since the 1970s, which makes them a relatively new
wastewater treatment technology. However, interest in their use has
quickly become widespread.
For example, in a recent survey of
Pipeline readers, constructed wetland technology was recommended most frequently
as a topic for future articles.
Wetland systems also are a popular subject
with the many community leaders, health officials, and homeowners who call the
National Small Flows Clearinghouse’s (NSFC) technical assistance hotline (800-624-8301
One of the reasons that people are curious
about constructed wetlands is the low cost associated with these systems.
Compared to many other treatment methods, wetland systems are inexpensive to
construct and maintain, and operating costs are low because energy is not
required to provide treatment.
This article offers a basic overview about
constructed wetlands. How they work, and some of the advantages and