AquacultureBiological CleaningFishPlant Systems

World’s Largest Aquaponics Project, in China’s Third Largest Aquaculture Lake

Lake Taihu experienced its worst ever algal bloom at the height of summer 2004, pushing researchers to search for new solutions. They decided to try a new technology, floating wetlands, that are designed to remove nutrients that fuel algal blooms. An ambitious aspect of the project was to launch the world’s largest aquaponics system, over 4 acres in size, using new technologies in combination with old world bamboo that is used in traditional Chinese building. Experiments growing rice on fish ponds provided a foundation for scaling up to lakes and larger water bodies for earth and water repair. The AquaBiofilter team was invited to participate in the project in regards to project design and evaluation.

Growing rice aquaponics on fish ponds in China

Floating island and wetlands technology is part of the new wave of products that biomimics nature, using biomaterials and plant biology to remediate and restore nature’s balance with non-toxic and sustainable processes. The concept was adapted from natural wetlands that process nutrients and pollutants with soil and plants. Mature wetland ecosystems often develop self-sustaining floating wetlands that mop up pollutants. The benefit of floating wetlands over sediment rooted wetlands, is that they rise and fall with the water level, which means plants don’t die off and don’t release nutrients back into the water, which on its own is a compelling reason to utilize floating wetlands in dams, lakes and ponds. When also considering its excellent habitat provision and ecosystem restoration aspects, it is increasingly being utilized by land and water managers. The problem with many dams and lakes is that they experience variable water depths throughout the seasons, and expeience poor water quality or ecosystem dysfunction such as algal blooms, fish kills and aquatic weed overgrowth in summer. Most lakes and urban wetlands are highly modified or recently built, with polluted inflows, making it necessary for management intervention. Floating wetlands take the best of what nature has developed naturally to tackle pollutants that run-off from farming, urban and industrial areas. Floating wetlands are up to x200 times more efficient than conventional constructed wetlands, and don’t suffer the die off problems and nutrient release that free floating aquatic plants or conventional wetlands experience. For these reasons, floating wetlands are often the best management approach for open water bodies including lakes, ponds, aquaculture systems, waste water lagoons and even estuaries with marine waters. Often the only end of pipe alternative is emptying and dredging an entire lake or pond, which economically and ecologically is very problematic.

AquaBiofiler floating wetlands project, Australia. (Credit, Tom Duncan)

The floating wetlands provide fish habitat in the root zone, protection from predatory water birds, spawning protection for frogs and eels, and nesting sites for endangered water birds. In some circumstances such as aquaculture ponds or lakes, they are ideal for the growth of food crops, which brings another yield to fish farmers, and prevents building up of nutrients, with plant roots uptaking excess nitrogen and phosphorus, assisting with denitrification underneath the raft. Floating wetlands and islands are multi-functional design elements that stack uses vertically and horizontally, preventing and eliminating algal blooms and fish kills. If farms dedicated just 1% of their land to water quality improvement ponds with floating wetlands, at the landscape point where nutrient laden farm runoff leaves the property, modeling demonstrates its possible to eliminate algal blooms and associated fish kills, preventing inshore marine dead zones. Tom’s vision is for nearly every farm to have it’s own water quality improvement ponds with floating wetlands of some kind. Lake cultures of lake Titicaca use woven reeds to construct floating reedbeds and provide a natural prototype for floating wetland ecosystems. Modern construction methods and materials provide long lasting, durable and non-toxic materials to maintain treatment effectiveness over time.

Floating wetland project, Lake Taihu (Credit Tom Duncan)
Algal bloom removal shown in water
samples, Lake Taihu
Lake Taihu has extensive aquaculture industry that suffered mass die offs and threatened the future of the industry. The research team chose plant species that would beautify the lake, and also provide rapid root growth which serve as habitat for native fish to spawn and provide refuge from the toxic algal bloom.

Three months after project implementation, the water cleared completely with no visible algae and water transparency improved by 250%. The plants had soaked up the excess nutrients, cutting off the nutrient supply that algal blooms require to grow. Roots exert a strong biofilm that captures nutrients and pollutants, and de-nitrifies the water allowing natural balance to be restored.

Floating wetland project, Lake Taihu (Credit Tom Duncan)

Some 2000 square foot of Aqua Biofilter provides a root biofilm surface area of 1 acre, due to the vastly increased surface area of root zones compared to plant leaf and stalk zones, delivering incredible rates of nutrient and pollutant removal, at zero cost once installed. The lack of operational expenses makes the technology attractive to local governments and water managers who need quick results at an affordable price. The benefits of floating wetlands go beyond improving water quality, by also serving as habitat for diverse water fauna, enabling the kickstarting of the restoration of aquatic ecosystems.

Floating wetlands project, Lake Taihu, China (Credit Tom Duncan)

AquaBiofilter CEO Tom Duncan has done some interesting floating wetlands projects including growing rice on floating reedbeds, growing herbs on aquaculture ponds. growing samphire and marine salt marsh on estuaries in Sydney Harbor, and installing habitat islands on Local Government owned lakes for bird watchers and recreational fishers. The project below is massive in scale, with large floating wetlands with Chinese characters written with plants, in urban developments on waterways in mega cities to promote water treatment and conservation for urban waterways. The project also incorporated a biodigester to improve water quality, recycle biomass and produce local heat and power. The retrofit of mega cities with floating wetlands and biodigesters is one way to rapidly reduce end of pipe impacts on urban waterways, and increase the livability of a world that is rapidly urbanizing with dramatic impacts on waterway and receiving marine waters health.

Floating wetlands project, Nanjing (Credit Tom Duncan)

Check out the Aqua Biofilter website for more information on floating wetlands: or for small aquaponics systems and see their Facebook page.

For further information on small scale systems, visit Aquarium Garden DIY Aquaponics Kit


  1. Hi Tom, nice article of what your company does. The results are impressive.
    How much of the floating device is made from bamboo? how long on average does it last once it is in the water? I would like to make floating devices for large ponds using natural materials only (to avoid leaching from plastics in the sun, etc) – any tips to share to the community?
    Do the plants ‘slow down’ /become a lot less productive once the excesses are removed? Would be interested to know rice production of the systems once they are settled – like after a year or so?
    Thanks, best

    1. Hi Dylan,
      Biomaterials that we utilize on our aquaponic floating wetlands ( ) include coconut fibre, coco peat, bamboo structures, bamboo supports, and where possible locally harvested sustainable wood. Bamboo lasts for 1 year to 2 years max. For certain applications, clients demand a certain lifespan of the product, so we use food grade polyethylene which lasts a long time, particularly because sunlight does not come in contact with the polyethylene after 1 year of plant establishment (when using evergreen and self-renewing wetland species.) Rice can be harvested according to the growing cycle, which may be once or up to three times per year. Experiments have been done allowing rice to auto-seed itself on the biomaterials that will support new growth in a permaculture self-renewing system. Its a work in progress though :)

    1. In China there are many native species that thrive in a polyculture system including grass carp, bighead carp, common carp, crucian carp, black carp, mud carp, and several other native species. It is not suitable to grow carp in other regions where it is not native and indigenous.

    2. Hello sir my name is sanjay from Mauritius Island i would like to know how to manufacture the fish water waste that we used in plants i have a big lake area 3 kilometers it’s quite big there is tilapia fish and another small fish if you need some photos i can send it if you thanks you from sanjay

    1. The roots and algal bio-associates produce oxygen around the roots which is beneficial for aquatic ecology where ammonia is present due to anaerobic conditions of anaerobic stratification in the water body. The floating wetlands should not be installed beyond the oxygen carrying capacity of the water. We call is the Aqua Biofilter rule of thumb – do not install more than 45% of surface area, or the installation can lower dissolved oxygen. We have described in our scientific research that no more than 45% of surface area should be covered, if no oxygenation is provided such as a static lake, or on a pond outflow such as rip raps or gabion stone mattresses before water enters the receiving environment, or conversely in an intensive system with a mechanically powered (usually solar) aerator.

    1. Hi Dr Kamal, the rice can be harvested either into a boat or canoe that one paddles out onto the pond, or the aquaponics floating rice beds can be designed to be pulled back to the shore and harvest in knee deep water at the edge. Drying the rice can occur on shore. Other options for communities that live on lakes, is the building of floating islands ( or ) has examples of floating islands that are for habitat purposes or living purposes. These spaces can be utilized for agricultural processing also for drying fish, and crop processing without having to return to shore. We would like to help communities that live on islands such as in Bangladesh, Iraq, the Americas including Peru, Mexico and others, and many more that are being discovered around the world.

  2. when we to taihu on 2002 … not like this …. excellent …. we want to try in our country in Cirata Lake…. thank you

  3. This is wonderful, I am 57 I had never heard of aquaponics a year ago, I saw an article on the internet and was skeptical of course but, when I looked into it I was hooked line and sinker. I started researching how to design a system at such places as Bright Agrotech, Backyard Aquaponics, Aquaponics Solutions Au, then was greatly blessed to find Dr, Ben and Glenn and Aqua Zen at Aquaculture Hub which is how I got here. I was just about to start my own system when I had heart failure, I thought that was probably it but I couldn’t stop studying about aquaponics and I found out that some people who I hadn’t talked to in a while were looking for someone to design an aquaponics system and I’m it. The feil is about to open up like you may not believe so, keep inspiring more people and maybe we won’t lose this next generation after all.

  4. Very interesting information on Aquaponics. There are interesting development on this new technique. There are successes and failures but over a period, farmers or hobbyists will learn a lot and will be ultimately successful. The key take in Aquaponics is the usage of nitrites/nitrates and maintaining of Ammonia cycle. You will have then fish surviving and plants growing in multiples. Good Luck.

  5. Dear Tom,
    I have existing fishpond in the Philippines with Tilapia in it. Is floating rice field feasible with it?

  6. Hello! This sounds really interesting!! Do you have any information on what species were used in the project??? Or what types of plants are most beneficial to trap Nitrogen and Phosphorous excess? I study Landscape Architecture in Chile and am evaluating a system that could integrate parklands and lake cleaning methods and this could help me out a lot 💛

Leave a Reply

Your email address will not be published. Required fields are marked *

Related Articles

Back to top button