Untreated water polluting the water bodies is a most casually neglected issue in developing
countries like Nepal. The residents complain the Government for its negligence to take action on the
concerned industries for letting untreated water flow into the water bodies. Installing STPs(Sewage
Treatment Plants) are not that easy and expecting the Government to solve a public issue is next to
While installing STPs (Sewage treatment plants) are expensive and space consuming and
implementing a STP requires a whole restructure of the existing plumbing design, there seems
literally no immediate way to revive such dying lakes.
While there are also inspiring stories of people who live self sufficient by harvesting rain water,
harvesting sunlight etc., there seems to be a simple, natural way to treat grey water.
What is Grey water?
Greywater is the waste water generated in households or office buildings from streams without fecal
contamination, i.e. all streams except for the wastewater from toilets.
Purifying grey water from Canna indica?
Anything that comes for free is taken for granted – Man's common thought. Yet another example is
the way we have turned blind eye towards this magic plant Canna Indica.
The Canna indica absorbs heavy metals such as aluminium, iron, and phosphorous and their
compounds and grows on them.
How to install this in your household?
A dedicated PVC pipe can be installed to collect the grey water. The water then has to be made to
flow through the Canna plant bed. The Canna plant can be constructed over layers of blue
metal(broken blue stone used for road-making) and soil.
As the grey water passes through the
Canna bed, the Canna plant roots purify the grey water by decomposing the suspended solid
particles and the active microbes in the soil do their part in purifying the water. The filtered water can
be collected in a pit to be re-used or can be let to recharge the water table.
Canna plant beds in the sewage inlet of lakes might be a good way of treating grey water. These
plants are easy to grow and grows fast on almost al weather conditions and soil types. Once
established, they require zero human care. The flowers will provide beautiful backdrop to the water