Caribbean Environment Programme - UNEP

UNEP(DEC)/CAR WG.18/6
Anexo V
Apéndice 2
Página 1
APPENDIX 2
WASTEWATER GARDENS
A NEW APPROACH TO WASTEWATER TREATMENT
Gonzalo Arcila G.
PCRF together with ECORED have developed a biological, sub-surface flow wastewater
treatment system designed for use both inland and by the sea. When used along the coast, they
can help protect coral reefs from the damaging impacts of human sewage. of the adjacent
businesses.
The Wastewater Gardens are a low cost, low maintenance solution to the problem of
human waste in coastal developments. They have no mechanical or moving parts and use no
chemicals. Using only plants, microbes, limestone gravel, cement, plastic pipe and gravity, these
systems remove over 99.9% of fecal coliform and more than 86% of the environmentally
harmful phosphates and nitrogen. Locally available plants are selected to make an elegant
ecosystem.
The system works by letting wastewater from toilets, showers, and kitchens flow by
gravity into sealed septic tanks and then into these specially designed concrete units. A layer of
limestone gravel interacts chemically to remove phosphorous, protozoa consume fecal coliform,
a special cache of microbes feed on the waste breaking it down into nutrients that are absorbed
by the plants roots, and the plant roots pump oxygen to the lower level.
Fifty percent of the water is evaporated and the remaining water produced by the system
is reclaimed to irrigate gardens or fields and for flushing of toilets. PCRF’s special garden
ecosystems add beauty to any landscape and create new habitats, provide food, flowers, or other
usable products as well as enriching and sustaining local biodiversity.
The wastewater is kept at least two inches below the top of the gravel, eliminating odors
and prevention of accidental human contact. This living system grows more efficient with time
and has an effective life span of several decades. Wastewater Gardens are a natural way to
purify human sewage before it gets to the groundwater or ocean and help protect these marine
environments from the harmful effects of untreated wastewater.
Range of applications
Wastewater Gardens can be designed in a range of applications form single family
dwellings, to hotels, parks, schools, and other public facilities, as well as for municipalities,
including landfill leachates, and industry