Africa Water, Sanitation & Hygiene November 2018 Vol.13 No.5 | Page 18

The multifunctionality of human-made wetlands 13
Domestic wastewater is made up of three basic com-
ponents: water (e.g. urine and greywater), carbon and
nutrients (e.g. bodily and food waste). Safely treated
and/or extracted, these are useful components for
various purposes such as growing food or producing
bio-energy (WWAP, 2017).
Human-made wetlands are intended to reduce organ-
ic matter and pathogens in wastewater to a minimum,
helping to make discharge safer. The effluent leaving
constructed wetlands can still have relatively high levels
of nitrogen and phosphorus, making it a highly suitable
source of water for irrigation.
Constructed wetlands are also among the world’s most
productive ecosystems, capable of producing relatively
large quantities of biomass. This biomass can be har-
vested at regular intervals to be used as biofuel. It is es-
timated that about 12% of the cooking fuel needs of a
60-person village in sub-Saharan Africa can be supplied
from the biomass of a constructed wetland (Avellán et
al., 2017), thereby reducing reliance on wood fuels.
Examples of human-made wetlands:
In Egypt, a constructed wetlands pilot project in Bilbeis,
55 km north of Cairo, resulted in a secondary-level treat-
ed wastewater effluent, which was used to irrigate Eu-
calyptus trees for the manufacture of packaging boxes.
Hence, the project has contributed to water conserva-
tion and the preservation of groundwater resources.
The Litani River in Lebanon is highly polluted due to
the discharge of untreated agricultural, industrial and
domestic wastewater. Wastewater treatment plants in
the region are either non-functional or only partially in
operation. This has resulted in soaring concentrations
of nutrients and pathogens in the river. A constructed
wetland system has been designed to treat water flows
in the Litani River and has removed between 30% and
90% of the pollutant mass, resulting in wetland effluent
quality that falls within the range permitted by interna-
tional environmental standards. The treated water ef-
fluents are directed through a discharge channel back
to the Litani River. (Difaf – Environmental Consultant,
supported by USAID)
13 WWAP (United Nations World Water Assessment Programme)/UN-Water. 2018. The United Nations World Water Development Report 2018
Nature-Based Solutions for Water. Paris, UNESCO.
Courtesy: Waterfront
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Africa Water, Sanitation & Hygiene • November 2018