100 Protec ting Communit y Water
Wastewater: A Problem or a Resource?
Because the amount of water in the world stays the same, all water is used
over and over again. But runoff water and water that has been used for
washing, farming, sanitation, or industry often contains germs and chemicals
that make it unsafe for drinking, bathing, or washing.
Water that is not contaminated with toxic chemicals or human waste can
be reused after simple treatment. The method best suited for your household
or community depends on the amount of wastewater to treat, what it is
contaminated with, what it is to be used for, and how much time, space, and
labor you have to treat the water.
Greywater solutions
Greywater is wastewater that has been used for washing and other household
chores, but does not contain human wastes. As long as you do not use toxic
soaps or cleaners (see page 373 for how to make safer cleaning products),
greywater needs only simple treatment before being reused in the garden, or
no treatment at all before being disposed of into the ground.
Important: Greywater is never safe for drinking.
There are many different types of greywater systems (see Resources).
Any greywater system works best when:
• it is easy to build and maintain.
• grease, concentrated bleach, solvents,
and other chemicals are kept out
of the water.
Constructed wetlands (reed beds) filter greywater
One way to treat greywater is to copy nature’s way of cleaning water by
making a wetland. Constructed wetlands (also called reed beds) treat
greywater by filtering water through layers of plants, soil, and rocks. Nutrients
in the wastewater feed the plants, and the plants add oxygen to the water,
which helps clean it. Reed beds also:
• provide irrigation water for food crops.
• grow plants you can harvest for other uses, such as bamboo or reeds.
• replace stagnant water with beautiful gardens.
Important: Constructed wetlands cannot treat solid human wastes (feces).
A Community Guide to Environmental Health 2012