Abstract:
TRADITIONALLY IN SRI LANKAN villages domestic wastewater,
especially grey-water generated from kitchens and bathrooms of a
household, fl ows along open unlined wastewater drains and is collected
in a garden pool known as kohila wala or vegetation pool. This pool
is a kind of traditionally constructed wetland. Main vegetation type
cultivated in the wetland is kohila (Lasia spinosa) which is used as a
leafy and stem vegetable. Medicinal and other important plants are also
grown along the drains that utilise the wastewater and its nutrients.
This system of grey-water disposal and utilisation was always kept
separate from the black-water disposal system as the latter is disposed
to individual cesspits located in home gardens. In the traditional sys tem, natural capacity to treat wastewater without any harmful effects
to groundwater was possible due to low population density and land
availability. With the population expansion in urban centres, the land
value increased and land area available for the traditional wastewater
treatment process shrank.
