Introduction – FloatingIslands
FloatingIslands have emerged as an innovative new products to treat water and restore lakes and rivers. But very few people actually understand how Floating Islands (Technical Term – Floating Treatment Wetlands) actually work.
FloatingIslands are modular platforms that float on water and have wetland species of plants such as Canna, Cattail, Elephant Grass, Vetiver Grass, etc planted on top of them.
FloatingIslands were designed and implemented with the idea to harness nature’s capability to uptake nutrients and treat water. The idea is to artificially create a wetland like an effect to mimic nature’s model of restoring itself and thereby improving water quality.
The Problem – Nutrients
Every living organism needs food and nutrients to survive. Wherever there are nutrients, living organisms thrive. In places devoid of nutrients such as Deserts, life is not able to thrive.
In the urban lakes today, untreated sewage is discharged which brings along with it lots of nutrients. When these nutrients are available in plenty; algae, water hyacinth, duckweed, etc, start to develop on the lake. These plants consume the nutrients and multiply and start covering the lake. These species actually remove nutrients from the water, so then why do we consider them invasive and bad for lake health?
The problem with water hyacinth, duckweeds, etc is that since they are generally never taken out from the water. When these plants reach maturity and die, they fall into the same lake and begin to decompose so the nutrients undergo a cycle but are never actually taken out of the water. These species when cover the surface of the lake, reduce the oxygen getting transferred from the atmosphere into the water. When the dissolved oxygen in the water begins to reduce, it becomes more and more difficult for the aquatic life to survive which eventually begin to die thereby harming the ecosystem and the overall lake health.
The first solution that comes to mind is to stop these nutrients from entering the lake in the first place. This is easier said than done. With sewage treatment infrastructure not in place today in India, sewage is entering the lakes and stopping it completely is going to take some time.
In many areas with unplanned development, there is no place to setup a STP (Sewage Treatment Plant). Even if we are able to setup STPs at all the lakes, nutrients would still enter the lake in other forms such as dead leaves and branches getting blown into the lake. Nutrients in fertilizers eventually find their way into the lake by surface or sub-surface channels. So, completely stopping the nutrients from entering the lakes is not possible.
If we can’t stop the Nutrients, What Do We Do?
The best way to deal with the nutrients problem is to transform the liability of Nutrients into something of value. This is where FloatingIslands come in. Just like water hyacinth, FloatingIslands are able to uptake nutrients from the water, thereby reducing the pollutants in the water, but it has no side-effect but multiple positive effects.
FloatingIslands are able to uptake nutrients from water by the help of friendly bio-film and the action of plants.
The roots of plants planed on top of the FloatingIslands eventually extend into the water. On these roots, friendly bacteria come and attach to form bio-film. Together the bio-film and plant roots take out nutrients from water and utilize them to grow themselves.
FloatingIslands are in a sense, a competitor of algae and water hyacinth.
When FloatingIslands are present on a lake, they reduce the nutrients available for water hyacinth and algae to grow. Since the plants are fixed on top of the Island, they do not invade the lake environment and doesn’t cause harm to the ecosystem.
Tell me More, What Happens Beneath the Island
Beneath the Floating Islands, bio-films and plants are uptaking nutrients from the water. Additionally, the plant roots dissipate oxygen in the water thereby aiding the process. A combination of aerobic, anoxic and anaerobic processes occur simultaneously beneath the Islands to ensure completion of Nitrogen cycle and removal of harmful Nitrates & Nitrites from the water.
In simple Islands made up of PVC pipes or plastic bottles, only plants are doing the treatment since there is very little area for bio-film to form. Floating Islands (www.floatingislands.in), a product of Clean-Water (www.clean-water.co.in) designs its Islands to ensure maximum biofilm formation to ensure maximum water treatment. Biomedia is provided on the bottom side of the Islands so that maximum bio-film formation takes place. The idea is simple; if more bio-film forms, the water treatment efficiency of the Islands would be higher.
Bio-films also help in removal of BOD & COD which is most frequently observed in Waste-Water Treatment Plants (STPs & ETPs). Underneath the Islands, plants increase the Dissolved Oxygen and the massive bio-film formation act as the reactor tanks of STPs.
In STPs aerobic and anaerobic bacteria are cultivated to ensure water treatment. Floating Islands mimic the aeration tank of a MBBR (Moving Bed Biofilm Reactor) based STP where by attached growth method, biofilms are able to break down complex material into smaller simpler compounds thereby reducing BOD (Biological Oxygen Demand) & COD (Chemical Oxygen Demand).
We are experimenting with different volumes and different types of bio-media to increase the treatment efficiency of Floating Islands even further.
The Islands and its roots also act as a barrier in the path of flowing water helping to settle sediments and reduce solids and turbidity from the water.
The increased Dissolved Oxygen in the water helps to support more and more aquatic life. When the DO increases in water, it boosts the entire ecosystem. Population of all kinds of aquatic organisms such as fishes, etc begins to increase which eventually helps in restoring the ecosystem as well.
Conclusion & Summary
So, the Floating Islands:
- Remove BOD
- Remove COD
- Remove Nutrients such as Nitrogen & Phosphorous
- Remove Heavy Metals
- Remove Sediments & Suspended Solids
- Increase Dissolved Oxygen
Thus Floating Islands are a perfect natural tool for improving the water quality of the lake.
- The technology of Floating Islands does not involve any chemicals or machinery.
- It is very low maintenance and requires roughly the same amount of effort as maintain plants on land.
- It removes harmful pollutants from the water and converts them into other revenue generating resources.
- It helps aquatic life and the entire eco-systems to thrive.
- It also acts as a beautification tool.
- It reduces the chance of algae and water hyacinth getting formed
- It reduces evaporation since it covers a certain portion of the lake
Clean-Water (www.clean-water.co.in) is registered as Sustainable Water Technologies Pvt. Ltd. and is head-quartered at Indore, India.
Floating Islands (www.floatingislands.in) is a product of Clean-Water.
Clean-Water is constantly doing Product Development and Research & Development on Floating Islands with a vision of Complete Restoration of the lake.