Central Victorian Aqua Biofilter™ Floating Reedbeds and Wetlands
Client dams overflow into local waterways carrying sediment and nutrients, affecting river water quality. Land owners wanted to improve their dam’s environmental performance, improve the water quality in the dam, and provide habitat for birds and amphibians that was aesthetically pleasing. The design team visited the site and proposed a design that would capture as much nutrient and sediment as possible before water overflowed into the local environment. Natural materials were used, giving the floating reedbed a natural island aesthetic that would suit any dam, lake or wetland.
Water bird refuge habitat in marine estuary – Aqua Biofilter™ floating islands
Sydney Olympics in year 2000 set the world benchmark for a Green Olympics that still sets the standard for excellence. Extremely rare, threatened and endangered marine estuary ecosystems exist within the Sydney Olympic Park Authority area over 1000 hectares within Sydney City, New South Wales (NSW), Australia. The Badu mangroves estuary has black swift water birds and also migratory birds that travel from Australia up to Korea and Siberia every year. The tidal water level variation is approximately 1 meter twice per day, and the floating islands were designed to rise and fall one meter per day, and provide an island habitat for the water birds.
The existing earth mound island was being inundated in high tide which destroys the rare and endangered bird nests and consequently their eggs which is keeping the marine estuary water bird population low. Due to very rare Salt marsh ecosystems on site, the sensitive ecosystem could not be subject to the impacts of earthworks machinery. A team of environmental scientists, planners and engineers surveyed the site with Sydney Olympic Park Authority (SOPA), identifying suitable sites for an Aqua Biofilter™ installation and appropriate materials for migratory and local water birds for nesting. Coconut fiber beds were combined with long lasting food grade plastic floatation frame covered to prevent UV degradation. Marine grade materials were utilized to ensure long term integrity of the floating islands. Sydney Olympic Park Authority rangers collected salt marsh bush seeds from on site, which the team sowed into the floating islands before launching the islands into the marine estuary. This is a world first that marine species have been integrated into marine floating islands for habitat and Bio filtration. The primary purpose is habitat, but over time there marine plants will add to Bio filtration benefits for the water quality. Installation of 120m2 of Aqua Biofilter™ in total was completed June 2012, made up of two islands, both 60m2 each. It is expected that bird watching enthusiasts will be able to utilize the bird hides located on site to view the rare water birds nesting, also alongside black swans which are a popular favorite with the locals.
Kuala Lumpur River of Life (RoL) – Aqua BiofilterTM Floating Reebdeds. Urban Storm water Floating Wetlands Case Study
Kuala Lumpur’s River of Life program is $US 1 billion program to clean up the Klang River to re-invigorate the city in regards to water quality the new river promenades and community living spaces. Aqua Biofilter was selected to provide products to a variety of engineering firms contracted to build out the River of Life project. The infill of exisiting flood control water bodies with floating wetlands is a low cost method of improving water quality in existing water assets that were experiencing algal blooms, aquatic weed infestations and breakout of illness in fish. Kuala Lumpur has significant storm water treatment challenges with a constraint on land availability for conventional storm water treatment wetlands so decided instead to install floating reedbeds into existing storm water and sediment ponds, with the reduced costs of not having to excavate new land and deal with issues of long lead times and three times the expense. It was decided to install 1000m2 into two sites in June 2012. After 12 months performance the plants have grown to maturity with leaves reaching 1.5 meter height and roots down to nearly 3 meters. Previous years algal blooms and azolla blooms have occurred, but after installation of the floating reedbeds, there have been no blooms. This indicates anecdotally that the floating wetlands have performed well and reduced nutrients to levels that prevent algal and azolla outbreak. Additionally installations in public garden ponds for water quality improvement and beautification were implemented with the GAB Foundation as part of the Malaysia National River Forum September 2012.
Gold Coast City Council – Aqua BiofilterTM Floating Reebdeds Urban Storm water Wetlands Case Study
Gold Coast City Council has significant storm water treatment challenges with a constraint on land availability for conventional storm water treatment wetlands so decided instead to install floating reedbeds into existing storm water and sediment ponds, with the reduced costs of not having to excavate new land and deal with issues of long lead times and three times the expense. It was decided to install 520m2 (520 square meters) into two sites in June 2011. After 12 months performance the plants have grown to maturity with leaves reaching 1 meter height and roots down to nearly 2 meters. Previous years algal blooms and azolla blooms have occurred, but after installation of the floating reedbeds, there have been no blooms. This indicates anecdotally that the floating reedbeds have performed well and reduced nutrients to levels that prevent algal and azolla outbreak.
Bega Urban Storm water Wetland Trial
Installation was completed Bega urban wetlands receive the majority of the town’s storm water with a catchment over 60 hectares in size. The urban wetland also becomes a flood plain flow path anna branch rising up 7 meters in height. The Aqua Biofilter™ demonstrated it’s high quality construction, rising and falling with the 7m flood, with it’s anchor performing well, and plants growing vigorously with the high pollutant loads being delivered to the wetland.
The Bega Urban Wetlands case study can be downloaded as a pdf document, that was published at the National Australian Storm water Conference 2009 uptakes of iron metals readily at 42,000 mg/kg. Uptake of manganese readily at 7,700 mg/kg, by some carex varieties that readily take up metals via phytoremediation process into rootzone. Total Nitrogen removal of approx. 40kg of in just 200m2 of treatment area. Bega floating reedbed rootzone of carex fascicularis is considerable. Note the lateral root growth and joining of root zones of adjacent plants. This strengthens the overall floating reedbed and provides better water quality improvement performance than compared to plants that send roots straight down, such as Carex Appraisal which in the same trial proved to grow only vertically, not laterally. This makes species selection important to attain lateral root growth for performance.
China Urban Storm water and Waste water Case Study
Professor Li hosted the team for involvement in the floating reedbeds and floating island projects in China, April 2007 and also in 2004. The images below give an indication of the scale of some of the trial sites. The floating reedbeds and floating islands are part of On Site Sewage Management (OSSM) approach, intergrating storm water treatment additionally. Large constructed wetland with weirs separates the floating reedbeds and floating islands, treating all sewage and storm water before discharge to river, whereby water is accessed for re-use.
Advanced Bio-filtration Research and Technology development has been an emerging science in China for many years with scientists from the Chinese Academy of Sciences and UNFAO affiliated organizations. The Floating Treatment Wetlands in China provided an opportunity for innovation, recycling nutrients and biomass energy. A Biodigestor was designed and built by Prof Ou. The biomass harvested regularly from the floating wetlands and contained water hyacinth is inputted to the Biodigestor, where bio-gas fuel is produced for energy applications. Local organic wastes are also inputted to the biodigestor, generating additional biogas for energy applications. The cycling of nutrient dense waste water, and storm water, with the addition of local organic wastes for biogas energy applications, demonstrates the effectiveness of the zero emissions approach.
Floating Reebeds Drinking Water Reservoir Heavy Metals Remediation
Mining run-off with contaminants including heavy metals and sediments was entering a drinking water reservoir that serviced over 10 million people. Solutions included installation of floating reedbeds with vetiver grass to uptake heavy metals and phytostablise heavy metals, for removal at a later date. Wave stabilization floating reedbed rafts were installed to prevent re-suspension of heavy metals in sediment and also prevent waves from from eroding water body banks and releasing sediments, metals, nutrients and impacting bank stability. Vetiver grass uptakes significant amounts of nutrient preventing algal blooms that had previously been a problem in the drinking water reservoir. The contestant uptake of available nutrient in the water, reduced nutrient concentrations to the point where algal blooms and aquatic weeds could not grow, which eliminated costly management of troublesome weeds and algal blooms. This also reduces the need for herbicides to be used in drinking water catchments which as a management practice is contrary to public health. As a total solution floating reedbeds provide a cost effective passive system that mops up pollutants and prevents further degradation of the water body and banks, slowly restoring ecosystem functionality.
China Lake Taihu
Research conducted by the Aqua BiofilterTM team on site in China at Lake Taihu, China’s third largest lake with extensive aquaculture farming and water users exceeding 300 million people, demonstrates that the aquaponic floating wetland approach can reduce chlorophyll (algae bloom and phytoplankton) at a rate of approximately 80% or above. The floating reedbed approach demonstrates clearly how algal blooms affecting a storm water, aquaculture or waste water lagoons, can rapidly clear after installation, reducing chlorophyll from 0.110 mg/L to a low 0.025mg/L.
The Lake Taihu project, yielded the monitoring results that demonstrated improvement from Class IV Lake Water (the worst category), improving to Class I Lake Water (best category) after three months installation. Photos of lake water before and after illustrate the reduction in algae content, associated with reduce nutrients available, due to the treatment removal of the floating wetlands. The author was involved in developing the floating reedbed strategy at Lake Taihu and developing a holistic approach to water management in addition to at source treatment of sewage and industrial pollution entering the aquaculture lake.”
Data monitoring is in treatment zones under the study, with differing coverage ratios of surface area, shortened to cov. and Category of water quality classification as Class. Class V is very degraded and Class I is designated under China’s National Lake Water Quality Targets.
Research Conclusions
The above data from tables 2 – 5 indicate the following reductions over 4 months establishment phase in pollutants when the surface area of 45% was covered by floating reedbeds:
56% reduction of ammonia
77% reduction in chlorophyll
57% reduction in total phosphate
84% reduction in Biological Oxygen Demand (BOD)
Lake Taihu, after 5 months growth, Egyptian sedge (Cyprus papyrus L.) and Canna lily generalis Bailey, root zone has grown dramatically in the constructed storm water weir with internal maze, part of LakeTaihu.
Wagga Wagga City Council
Wollundry Lagoon floating reedbeds project is approximately 120m2, maintained by rainfall and storm water runoff from the surrounding city and Peri-urban catchment. Located within Wagga Wagga, the lagoons are affected by nutrients and pollutants. The lagoon is valued for community amenity. The purpose of the floating wetlands is to provide an enhanced treatment above and beyond existing water quality. Plant establishment has been successful during winter with doubling of plant size in several months.
