Artificial wetlands helping hoteliers manage waste water

Sarova Mara Hotel and Lodge Manager Duncan Mwangi shows a constructed Wetlands, a new technology in waste Management. [Joseph/Standard]

Sounds of croaking frogs and quacking ducks in a pool of water draws one to an expansive field of a hotel within the Masai Mara National Reserve.

The field aptly mirrors the new technology fast being adopted by hoteliers in managing waste through sustainable initiatives.

The technology, known as constructed wetlands, seeks to solve challenges of waste management in institutions like schools and hotels through adoption of the technology that imitates a wetland.

“It is an excellent technology where we artificially construct wetlands to clean the waste water before releasing it to the environment. In the process, wetlands are constructed in small ponds and reeds planted across,” Duncan Mwangi, the Sarova Mara Hotel manager says.

The need to properly treat and recycle the 93 cubic metres of water used daily before releasing it to the environment birthed the idea. Besides being environmentally friendly, it also incorporates conservation of animals naturally residing in wetlands.

In a constructed wetland, frogs, toads, turtles, earthworms and geese are key indicators along the chain that purifies waste water from the bathrooms and toilets.

“Frogs, toads and turtles here are vital. They are our key indicators. In case something goes wrong, their populations reduce and when the croaking keeps on increasing, then we are on the right path. Geese, too, make a home in the final pond where water is treated, solely by sunlight, before being released,” Mr Mwangi said.

Natural function

The technology mimics the natural function and services of a wetland, while removing pollutant load that would otherwise pollute water sources.

In the system, waste water from bathrooms and toilets is channeled into a septic tank where it is retained for suspended solids to settle. The waste water is also treated in the first phase to kill bacteria.

From the septic tank, the liquid is then channeled into a shallow depression, a constructed wetland, with waterproof lining to deter contamination. Pebbles in its foundation and reeds all across help sieve the liquid waste.

The flow of the waste water into the wetland is, however, controlled using perforated pipes that spread water across the system. The waste water stays for two weeks in the system where it is further filtered. The reeds absorb the solid material.

Frogs and toads, Mwangi says, are key indicators of a toxic environment, a situation that keeps the system moving. Whenever a hitch occurs within the system, their population reduce and croaking becomes rare.

The water is then drained to another depression where a similar process is repeated before it is released into a wide pond. In the pond, water is exposed to sunlight for two weeks before being released into another larger pond. At this stage, the key indicator, is algae.

In the final pond that holds 1.2 million cubic metres of treated and safe water, the key indicators are turtles and Egyptian geese that lay eggs and nest within the reeds.

The water can finally be used for irrigation.

Mwangi said the project had become a model for schools, where they learn to manage waste and recycle water for irrigation activities.

The project, Mwangi says, has run for more than a year, and has tremendously reduced pollution without use of much chemicals.