Pollution of water resources by improperly or
inadequately treated wastewater (sewage) contaminates
ecosystems, drinking water supplies and is a leading cause of human
disease worldwide (some 3.5 million people, mostly children
under 5 die every year, about 9,000 people every day, from
diseases caused by sewage pollution such as diarrhoea, cholera and
typhoid). In addition to urgent human health issues, we know that
untreated sewage is a leading cause of global coral reef decline,
oxygen depletion, fish kill and ecological degradation of rivers
and lakes - with the increasing pollution of already limited underground
water tables and sources of our drinking water.
Yet, this is not the fault of what is called
"sewage" but rather by the way we handle some of its components.
In organic-type wastewater from human habitations for example, urine
and faeces are among the very few natural substances of extreme
ecological importance; their richness and potential
productivity are such that they were highly valued for millenaries
in human societies throughout the globe. Faecal matter (which when
mixed with water is commonly called "black water") is very rich
in nutrients: 5-7% nitrogen and 3-5% phosphorus, while urine is
even more concentrated. These two elements ("materials")
alone belong to the most valuable nutrients there are, often referred
to in the field of Ecology and Botany as 'limiting factors' to plant
growth because of their relative scarcity and irreplaceable value.
These nutrients are the main components of most chemical fertilizers.
Life promoting, both to microbes and plants, these materials greatly
facilitate the formation of rich soils.
Used for centuries as potent fertilizers, urine
and faeces are being treated today mostly as waste to be disregarded,
and in order to evacuate them, mixed with water (it takes 1000
to 2000 tons of water to move 1 ton of excrement),
which, in addition to wasting a precious resource, spreads the pathogens
(disease causing organisms) in the environment. Organic wastewater
especially becomes a problem when it is released in great quantities:
when sewage coming from a few humans is released to the milieu,
it often breaks down and biodegrades without being a dangerous source
of contamination (unless close to a water table). But when population
increases, what is otherwise rich and life bearing, becomes dangerous
and disease causing: directly sent to natural groundwater, rivers
or oceans, this mixture of water becomes a toxic pollution, as an
increasing quantity of these elements eventually exceeds ecosystems'
natural capacity of digestion and causes eutrophication by excessive
Constructed Wetlands to treat Wastewater?
(WWG) ecotechnology belongs to the family of constructed wetlands.
What WWG units do is reproduce the conditions of natural wetlands,
called by scientists the "kidneys of the
Earth" for their high capacity of water recycling in
the biospheric cycles. Unlike many natural wetlands however, WWG
belongs to the family of subsurface flow designs, which means that
at no moment is the sewage water in contact with the air, thus
preventing all bad smells, mosquito breeding or accidental human
A variety of natural mechanisms effectively
treat effluent and purify all water which passes through a wetland,
in this case through your WWG unit. These mechanisms are biological, chemical and physical.
One of the principal factors of purification are plants which are
able to live in water saturated soils, directly assimilating nutrients
(especially nitrogen and phosphorus) and metals, removing these
"pollutant" elements from the water and incorporating them into
their plant tissue. The top part of the plants above the gravel
brings down oxygen to the roots, which in turns enables microorganisms
to live. A kind of symbiosis develops whereby the plants are consistently
nourished via the water and its nutrients, among which some of the
breakdown material produced by the microbes able to live through
the oxygen generated by the same plants.
Highly efficient at removing potentially harmful
compounds before they reach rivers, lakes and the ocean, wetlands
also support diverse vegetation and provide important habitat for
many animals which are essential to the overall health of the Earth's
ecosystem. In addition to their purifying capacity, constructed
wetlands literally create life. Plants are our "3rd lung"
as they create the oxygen which we need to breathe, and metabolize
carbon dioxide which we exhale; they are also important contributors
to the rain cycle.