Biohavens – the only truly bio-mimicking floating wetland- Case Study #9 – marine applications

31 October 2015

The BioHaven range of floating wetlands, also known as floating islands, provides a wide range of wetland aesthetic, habitat and treatment options designed from nature.  DH Environmental Consulting (Pty) Ltd (South Africa) has been partnered with Floating Island International, the designers of the BioHaven range, since 2008.  Over the next while our blog will document some Biohaven case studies.

9. Marine Environment Case Study

Project Location: Elfin Cove Area, Southeast Alaska, USA

This case study demonstrates the capabilities of patented BioHaven® technology to function in a harsh marine environment. The purpose of this application, which was the first seawater evaluation of the BioHaven floating treatment wetland (FTW) from Floating Island International (FII), was to study plant survival, biota colonization and island durability under marine conditions.

Two BioHaven islands were launched—a large module at Port Althorp (the “Port Althorp” FTW) and a small module in a private setting near Elfin Cove (the “Hobbit Hole” FTW). The larger island was moored to a piling at one end and chained to a mooring block at the other; the smaller island was tethered to an existing dock with nylon line. The Port Althorp FTW was constructed as a dock, with Trex decking applied to the top surface.

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Results

  •  The BioHaven matrix was not adversely impacted by exposure to seawater and Alaska wintertime temperatures/wave action
  • Numerous marine biota, including mollusks, starfish, worms and filter feeders such as anemone, populated the BioHavens. Several species of kelp also took up residence.
  • Perennial plants survived the winter and reemerged in the spring.
  • Both BioHavens remained buoyant under snow loads up to five feet.
  • The BioHavens remained intact with up to two-foot waves. The Port Althorp BioHaven was towed five miles in the summer of 2009 to the Hobbit Hole location to replace an existing section of dock. It is still in use and performing well.
  • Boats were able to tie and moor to the BioHaven FTW.

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Biohavens – the only truly bio-mimicking floating wetland – Case Study #8 – Floating islands outperform constructed wetlands

30 October 2015

The BioHaven range of floating wetlands, also known as floating islands, provides a wide range of wetland aesthetic, habitat and treatment options designed from nature.  DH Environmental Consulting (Pty) Ltd (South Africa) has been partnered with Floating Island International, the designers of the BioHaven range, since 2008.  Over the next while our blog will document some Biohaven case studies.

8. Floating Islands Outperform Constructed Wetlands

Project Location: Rehberg Ranch Residential Subdivision, Billings, Montana USA and McLean’s Pit Landfill, Greymouth, New Zealand

Promising pilot studies with BioHaven® floating islands or floating treatment wetlands (FTWs) show superior results when compared to constructed wetlands. In comparing municipal wastewater and landfill leachate treated with both systems, BioHavens had higher removal rates and percent removal for ammonia, total nitrogen, biochemical oxygen demand (BOD) and total suspended solids (TSS).

FTW for Municipal Wastewater

Located on the outskirts of Billings, Montana (pop. 120,000), the Rehberg Ranch residential subdivision (pop. 560) was built beyond the reach of the city’s municipal sewer system. Developers constructed an aerated lagoon wastewater treatment system engineered and designed to meet US EPA secondary standards for BOD and TSS.

In November 2009 Floating Island International (FII), with funding from the City of Billings and the Montana Board of Research and Commercialization Technology, installed an experimental FTW design in one of the subdivision’s two aerated lagoons. The City implemented a rigorous monitoring regime to measure efficacy of the FTW system in comparison to the control lagoon with no FTW. Both lagoons received the same wastewater.

FTW for Landfill Leachate

Landfill leachate is a problematic water stream in New Zealand and worldwide. Greymouth is a South Island town of approximately 3,000 people. The town identified a need for improved treatment of its municipal landfill leachate, which is a dilute stream because of the area’s extremely high annual rainfall (3.5 m or 140 inches).

In Stage 1 of the project, FII licensee Waterclean Technologies constructed and installed 288 m2 (3100 ft2) of BioHavens to cover approximately 20% of the lagoon surface in half of the lagoons, in November 2009. The wetland plants being utilized are Carex virgata and Cyperus ustulatus.

Constructed Wetlands

Constructed wetlands with horizontal sub-surface flow have been used for wastewater treatment for more than 30 years. Most wetlands have been designed to treat municipal or domestic wastewater, but are now also used to treat wastewaters such as landfill leachate, industrial waters and agricultural wastewater. In a 2009 review article in the journal “Ecological Engineering,” data from several hundred constructed wetlands for municipal and domestic wastewaters, and from approximately ten landfill leachate installations, were summarized (Vymazal, J., 2009, The Use of Constructed Wetlands with Horizontal Sub-Surface Flow for Various Types of Wastewater, Ecological Engineering 35, 1-170).

Results

Table 1 shows the performance of the Rehberg Ranch FTW compared to the average performance of several hundred constructed wetlands for municipal/domestic wastewater as consolidated in the Vymazal study. The percent removals of BOD, total nitrogen and ammonia were much higher for the FTW. Due to its smaller size (Table 1), the load removed was much higher in the FTW for these parameters and TSS.

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Table 2 shows performance of the BioHaven at McLean’s Pit compared to the average performance of approximately ten constructed wetlands for landfill leachate. The percent removals of BOD, total nitrogen and TSS were much higher for the FTW, and the load removed was much higher in the FTW for BOD and total nitrogen.

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Screen Shot 2015-10-23 at 11.01.32Compared to the small size required for FTWs (see above), the large area typically required for constructed wetlands is illustrated in the aerial photo below:

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Biohavens – the only truly bio-mimicking floating wetland – Case Study #7 – habitat for endangered birds

29 October 2015

The BioHaven range of floating wetlands, also known as floating islands, provides a wide range of wetland aesthetic, habitat and treatment options designed from nature.  DH Environmental Consulting (Pty) Ltd (South Africa) has been partnered with Floating Island International, the designers of the BioHaven range, since 2008.  Over the next while our blog will document some Biohaven case studies.

7. BioHaven® Technology Provides Habitat for Highly Endangered California Clapper Rail

Project Location: Oakland, California USA

BioHaven® floating treatment wetlands (FTW) can provide critical habitat for the endangered California Clapper Rail. BioHavens offer an effective habitat alternative to traditional islands or marshes, as they provide upland roost habitat during fluctuating tides and sea levels. Use of FTWs by the California Clapper Rail has thus far exceeded expectations.

Background

The California Clapper Rail, a chicken-sized bird that rarely flies, is found principally in California’s San Francisco, Monterey and Morro Bays. Population levels are precariously low due to destruction of its coastal and estuarine marshland habitat for land development and shoreline fill. Recent estimates of its current population and survival rate indicate a high likelihood of extinction without intervention.

Under recent climate change scenarios, sea levels may rise as much as 1.9 m (6.2 ft) in San Francisco Bay by 2100. For species such as the California Clapper Rail that require a tidal marsh environment, large changes in water levels may inundate its primary habitats and further threaten its existence.

A project team was assembled by the U.S. Geological Survey (USGS) to address this issue. Project goals were to examine the:

  1. Effects of future sea level rise on the California Clapper Rail,
  2. Potential for improving high-tide habitat, and
  3. Effects of invasive weed control.

Arrowhead Marsh Project

Arrowhead Marsh in Oakland’s Martin Luther King, Jr. Regional Park was selected as the project site. Ten BioHaven floating islands (FTWs) were deployed in September 2010. Each BioHaven measures 2 m x 3 m (6.6 ft x 9.9 ft), is constructed of recycled plastic bottle materials, and is covered with woven palm screens (“duck blind” material) to provide cover. Plastic bird avoidance spikes were installed on two islands in January 2011 to deter use by predatory birds. BioHavens were supplied by Floating Island International Inc. (FII) and Floating Islands West (FIW).

Waterproof digital cameras with time lapse capability and motion sensors were set up on each island. A sub-sample of 11 rails was radio-marked and located weekly to examine survival and area use. The project is documented on the USGS web site, www.werc.usgs.gov. Project updates are available at this site.

Preliminary Results

Use of BioHavens by the California Clapper Rail has thus far exceeded expectations. The USGS team reports that clapper rails at Arrowhead Marsh quickly adapted to the presence of FTWs, with all ten islands receiving moderate-to-heavy use from a clapper rail population estimated at 30-40 birds. Island use by the birds tends to coincide with diurnal high tides, suggesting that the BioHavens are being used for habitat when the marsh is mostly or completely inundated.

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Implications of the findings to-date are that roosting habitats may be limited for clapper rails, not only during king tides (especially high tides) and periods of extreme elevation, but even during daily tides in the winter. Elevated areas, FTWs or levees may be used by clapper rails if located within their home range. Restored areas may be missing key features such as areas above the highest water tides, resulting in less use and lower survival by species vulnerable to predation such as the California Clapper Rail.

Possible sea level rise suggests that habitat management is critical to protect the California Clapper Rail and other species requiring marsh habitat. Sea level rise is likely to exceed natural island formation in many San Francisco Bay marshes, especially after the next few decades. The USGS study indicates that adaptation for sea level rise should include:

  •   Selection of marshes with the best habitat for clapper rails, and
  •   Management for habitat elements, including elevated islands or FTWs that provide clapper rails with adequate cover.

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Biohavens – the only truly bio-mimicking floating wetland – Case Study #6 – wildlife habitat

28 October 2015

The BioHaven range of floating wetlands, also known as floating islands, provides a wide range of wetland aesthetic, habitat and treatment options designed from nature.  DH Environmental Consulting (Pty) Ltd (South Africa) has been partnered with Floating Island International, the designers of the BioHaven range, since 2008.  Over the next while our blog will document some Biohaven case studies.

6. BioHaven® FTWs Remove Algae and Create Wildlife Habitat

Project Location: Barrington, Illinois

This case study summarizes results of Floating Island International’s patented BioHaven® floating treatment wetland (FTW) technology to mitigate runoff from urban and rural developments. The Lake County Stormwater Management Commission named this project “Best Management Practice (BMP) Project of the Year”.

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Overview

As part of a negotiated settlement by Citizens for Conservation (CFC) with a subdivision developer, several ponds were constructed to capture stormwater run-off. This water then flows through restored wetlands for discharge into Flint Creek. To address high algae levels, several BioHaven® floating islands were built on-shore and “launched” into the ponds.

Prior to 2006, the two stormwater ponds were completely covered with algae during the growing season. Algae reduction through use of hay bales as a Best Management Practice was unsuccessful. The CFC’s goal was to transform these water bodies, located only 30 miles from downtown Chicago, into vibrant, productive wetlands in an urban setting, hopefully through the use of floating islands.

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Results

The large pond is about 1.5 acres and the small pond is about 0.25 acre. Each pond contains floating islands.

Dissolved oxygen (DO) levels greatly increased after island launching and subsequent plant growth, resulting in much lower algae levels and lower turbidity. CFC members note that most algae have disappeared and discharged water is much cleaner than before island installation. As the first photo demonstrates, plant growth on the islands developed quickly, a visual manifestation of the nutrient and metals removal occurring in and beneath the islands. Turbidity and DO levels were monitored but data transfer has been hampered by volunteer turnover.

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In addition to native wetland plant habitat, the islands also provide a key riparian environment in this quasi-urban setting. Sandhill cranes were noted nesting on the islands in 2007, just over a year after they were launched. The cranes have successfully fledged young in two of the past three years, even though coyotes and other predators are now abundant in the area.

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The executive director of the Lake County Stormwater Management Commission wrote the following testimonial:

On behalf of the Lake County Stormwater Management Commission (LCSMC) board and staff, congratulations on being awarded the “BMP Project of the Year.”

Your efforts to improve the Flint Creek watershed is a history rich in caring for the environment, for those that live in the watershed and for the generations to come… In our eyes, the Floating Islands Project is yet another example of your vision for the watershed that ties in water quality, habitat and technology to create what is believed to be the first use of “BioHaven” technology in Illinois that can be replicated in other parts of Flint Creek and in Lake County watersheds.

Flint Creek stakeholders … are grateful for the work of Citizens for Conservation. Congratulations and thank you for your dedication to water quality improvements, and taking the lead on grassroots efforts that benefit us all.

Michael Warner, Executive Director, LCSMC

Biohavens – the only truly bio-mimicking floating wetland – Case Study #5 – Bisphenol removal

27 October 2015

The BioHaven range of floating wetlands, also known as floating islands, provides a wide range of wetland aesthetic, habitat and treatment options designed from nature.  DH Environmental Consulting (Pty) Ltd (South Africa) has been partnered with Floating Island International, the designers of the BioHaven range, since 2008.  Over the next while our blog will document some Biohaven case studies.

5. Floating Treatment Wetlands May Remove BPA

Project Location: Test Tanks, Billings, Montana USA

This case study suggests that BioHaven floating island technology can reduce concentrations of the endocrine disruptor Bisphenol-A (BPA) in water. It appears likely that a microbial biofilm growing on and around the island in this study degraded BPA below the initial concentration of 50 ng/L.

Overview

One of the most common estrogen mimickers is known as Bisphenol-A (BPA), a chemical commonly used in production of plastics and epoxy resins. BPA has been directly linked to gender ambiguity in fish. BPA is one of many man-made chemicals that have been recently detected in the nation’s waterways through use of more sensitive analytical techniques. Along with pharmaceuticals, concentrations of estrogens and their mimickers have been detected well above background levels.

Previous studies showed that BioHaven floating treatment wetlands (FTWs) will remove contaminants such as nitrogen, phosphorus, biochemical oxygen demand (BOD), total suspended solids (TSS) and propylene glycol from water. The focus of this test was to determine whether a BioHaven could reduce levels of BPA, as measured by gill flares exhibited by male betta (beta) fish.

Background

In 2008, two Billings West High School students, along with their academic advisor, began studying the behavioral effects of estrogen sulfate and BPA. Their initial data showed that either chemical reduced aggression levels of male Betta splendens, the Siamese fighting fish commonly known as betta fish. The focus of their last test was to investigate the effects BPA has on the aggression levels of male bettas in the presence of a BioHaven.

Two small BioHavens (approximately 2 feet long x 1 feet wide x 6 inches thick) were planted with potting soil and a wildflower mix. After the FTWs were grown for two weeks, BPA was added to water at a concentration of 50 ng/L. The following test conditions were run:

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Condition 4 was the actual experiment with BPA in the presence of the FTW, with the other three conditions serving as controls. To measure gill flaring, male betta fish (three per condition) were exposed to a mirror for two minutes while gill flares were tallied. It was beyond the scope and budget of the test to directly monitor BPA concentrations.

Results

Condition 1, the first of the three control groups, did not contain BPA or an FTW. This group exhibited an average of 20 gill flares in two minutes, which is consistent with data collected in an earlier study. Therefore, 20 gill flares was the baseline.

Condition 2 contained BPA with no FTW. Results from this test agreed with the previous year’s data, in that gill flares were reduced from 20 to an average of 6. A standard t-test showed that this was a statistically significant difference at a 95% confidence level. In condition 3, with an FTW but no BPA, male bettas exhibited an average of 19 gill flares per two-minute time trial, which is statistically equivalent to the baseline.

The experimental group (condition 4) exhibited significantly fewer gill flares after one day of exposure to BPA, similar to condition 2. After three days, however, the male betta aggression level (as measured by gill flaring) steadily rose until reaching the baseline of approximately 20 flares in two minutes. The experiment was repeated a week later, with very similar results.

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Conclusions

This test confirmed earlier findings that the presence of BPA in water at a concentration of 50 ng/L significantly reduces aggression levels of male betta fish, as measured by the number of gill flares. The test also showed, in two replicates, that aggression levels increased to normal in the presence of a BioHaven floating treatment wetland (FTW). One possible explanation is that roots of the plants growing on the BioHaven absorbed BPA, thereby removing it from the aquatic system. A more likely explanation, based on previous FTW experience, is that the microbial biofilm growing in and around the BioHaven degraded the BPA. This could be confirmed by repeating the experiment and chemically analyzing for BPA.

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Biohavens – the only truly bio-mimicking floating wetland – Case Study #4 – Bird habitat

26 October 2015

The BioHaven range of floating wetlands, also known as floating islands, provides a wide range of wetland aesthetic, habitat and treatment options designed from nature.  DH Environmental Consulting (Pty) Ltd (South Africa) has been partnered with Floating Island International, the designers of the BioHaven range, since 2008.  Over the next while our blog will document some Biohaven case studies.

4. Floating Islands Enhance Salmonid Recovery by Creating Alternative Nesting Habitat for Caspian Terns

Project Location: Dutchy Lake, Oregon and Sheepy Lake, California USA

Bird monitoring results have demonstrated that floating islands can provide secure nesting habitat for Caspian terns and other bird species in areas where no natural nesting habitat exists, and where construction of rock islands is not feasible. Two recent projects have enhanced recovery of salmonids (salmon and steelhead) by encouraging relocation of Caspian terns to areas far from where juvenile salmonids migrate. Floating islands offer a potentially effective habitat alternative to traditional rock islands if the water depth is greater than 18 inches, or if the water body cannot be drained for construction of a traditional island.

Background:

In 2008, the U.S. Army Corps of Engineers (USACE) began implementing the actions outlined in the January 2005 Final Environmental Impact Statement for “Caspian Tern Management to Reduce Predation of Juvenile Salmonids in the Columbia River Estuary.” This management plan, which was developed jointly by the USACE, U.S. Fish and Wildlife Service, and NOAA Fisheries, seeks to redistribute Caspian terns from the Columbia River estuary to alternative colony sites in interior Oregon, interior California and the San Francisco Bay area by 2015.

The goal of the plan is to reduce Caspian tern predation on migrating juvenile salmonids in the Columbia River estuary, and thereby enhance recovery of salmonid stocks from throughout the Columbia River basin. Thirteen of 20 evolutionarily significant units of Columbia River salmonids are currently listed as either threatened or endangered under the U.S. Endangered Species Act.

Caspian terns require unvegetated, sandy habitat that is proximate to water and isolated from predators, i.e., they require islands upon which to nest. Normal USACE practice for habitat enhancement is to construct a nesting island by simply piling rock, gravel and sand into an existing body of water that has been drained or drawn down until it is higher than the water surface when the water body is at full pool. This labor‐intensive process requires huge trucks and heavy equipment, disturbs the water body, benthic zone and shoreline, and does not guarantee that the new island will remain isolated from land (if the water level drops) or above water (if the water level rises). Floating Habitat Islands suffer none of these limitations since they float on the surface of the water, but they are typically more expensive.

The USACE teamed with the U.S. Geological Survey, Oregon State University (OSU), Oregon Department of Fish and Wildlife, Real Time Research, U.S. Fish and Wildlife Service, Floating Island International (FII), and Floating Islands West (FIW) in an innovative program to create “floating tern islands.” Two large floating islands have been installed, one in Interior Oregon and the other in the Upper Klamath Basin, by a contractor, Just Buckets Inc., in conjunction with FII and FIW.

Dutchy Lake – Oregon:

In February 2009, FII and Just Buckets built and launched a 22,000‐sq. ft. floating island at Dutchy Lake, which is in the Summer Lake Wildlife Area in Oregon. The island is 19 inches thick and has a flat stone perimeter. The interior of the island contains six inches of crushed stone, pumice and rhyolite mix. This island also has a floating observation blind attached to one corner of the island, as well as audio playback systems (broadcasting Caspian tern calls) and tern decoys.

Bird Research Northwest’s monitoring team characterized the 2009 nesting season on the Dutchy Lake floating islands as a great success, with eight nesting pairs having hatched 13 young terns, of which eight succeeded in fledging. In 2010, no Caspian terns initiated nests on the Dutchy Lake floating island, although they and other water birds frequently used it as a roost site. Instead, Caspian terns in 2010 nested on the rock core island in the East Link Impoundment at Summer Lake Wildlife Area, which is approximately five miles away.

Sheepy Lake – California:

In February 2010, FIW and Just Buckets built and launched a 40,000‐sq. ft. floating island at Sheepy Lake in Lower Klamath National Wildlife Refuge. The island thickness was 22 inches, with sloped ends of paving stone to enable access to the water by pre‐fledged young terns. One long side and half of one end included a planting area designed as a wind break. Bullrush, red‐twigged dogwood and sand willows were planted in the seven‐foot‐wide perimeter areas.

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Figure 1 shows the number of Caspian terns colonizing the new floating island during the 2010 nesting season. This innovative island has been a tremendous success, as the Sheepy Lake tern colony appears to have had the highest nesting success of any Caspian tern colony in the region during 2010.

The island interior contains seven inches of the same crushed stone, pumice, and rhyolite mix used at Dutchy Lake. An extensive anchoring system was connected to all four corners. A floating observation blind was attached to one corner of the island, with two audio playback systems, and 250 Caspian tern decoys were placed on the island.

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2010 was a very poor nesting season for Caspian terns in interior Oregon and northeastern California. Small numbers of breeding terns and low nesting success was widespread, but the Sheepy Lake floating island colony was a notable exception.

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Biohavens – the only truly bio-mimicking floating wetland – Case Study #3 – Bioswales

25 October 2015

The BioHaven range of floating wetlands, also known as floating islands, provides a wide range of wetland aesthetic, habitat and treatment options designed from nature.  DH Environmental Consulting (Pty) Ltd (South Africa) has been partnered with Floating Island International, the designers of the BioHaven range, since 2008.  Over the next while our blog will document some Biohaven case studies.

3. Elevated BioSwales for Water Quality and Habitat Enhancement

Project Location: Shepherd, Montana

Contaminated surface runoff from stormwater events is a major potential cause of water pollution in urban, residential and agricultural settings around the world. Elevated treatment swales (Elevated BioSwalesTM) containing vegetation are one promising method for treating stormwater and agricultural runoff.

In August 2008, three Elevated BioSwales were installed in irrigation ditches at the Shepherd Research Center located northeast of Shepherd, Montana. The Center is the international headquarters of Floating Island International, Inc., a research and development business focused on developing technologies for water quality improvement and habitat enhancement. The bioswales were durable, successfully grew and maintained vegetation, reduced turbidity and performed well during high-water events. A typical bioswale is depicted in Figure 1.

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These Elevated BioSwales contain a recycled polymer-based nonwoven filter matrix that provides about 250 square feet of surface area per cubic foot of matrix. Numerous independent studies have confirmed that this matrix represents an effective substrate for biofilm development, and that in combination with circulation, it can be highly effective at transitioning agricultural-based nutrients and urban contaminants out of water and into local food webs. A Shepherd bioswale before and after installation is shown in Figures 2 and 3.

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Elevated BioSwales at Shepherd were designed to form-fit into irrigation ditches of irregular dimensions. They were monitored for several criteria:

  •   Plant success
  •   Durability and weathering
  •   Performance in flood or high-water events
  •   Turbidity and nutrient reduction
  •   Laboratory determination of hydraulic conductivity.

Plant Success

The Elevated BioSwales were overlaid with Kentucky bluegrass sod to provide immediate protection of the plastic matrix from potentially-degrading ultraviolet light, and were then sprinkled with a mix of native grass seed. Native plants (both from seeds and neighboring “volunteer” plants) quickly took over the bioswales. The bedding material in each bioswale’s planting pockets included hydrophilic foam to hold and wick up water to the sod. Two elevated bioswales were installed in a shallow ditch (18” deep) with only periodic water flow, while the third bioswale was located in a deeper ditch (40” deep). Even the shallow ditch, with periodic flow and precipitation, provided enough water for native plants to survive and thrive in Montana’s dry climate over two years. While hydrophilic-based bedding soil can lift water up to 16 inches, consistent water flow may be required in deeper ditches until plant roots are established.

Durability and Weathering

The bioswales were inspected weekly and required no maintenance. Although some matrix was exposed on the upstream side, it did not degrade significantly during the three-year study. The bioswales continue to be used as bridges by people and wildlife.

Performance in High-Water Events

Elevated BioSwales essentially serve as a “leaky dam” by reducing water velocity and mediating storm events. During high water flow, up to a six-inch difference in water level was noted between the upstream and downstream sides. Water was high enough at times to create soggy conditions at the top of the swale, with no detrimental effects. The system’s ability to reduce water flow rate suggests that it can function as an erosion mediation tool.

Turbidity

Turbidity in the ditches preceding the Elevated BioSwales is variable. When turbidity is high, the bioswales substantially reduce it visually, although the effect has not yet been quantified. It is also anticipated that the efficacy for water quality improvement will be proportional to bioswale length, although data have not yet been collected to demonstrate this. The stormwater treatment process is illustrated in Figure 4.

Parameters such as nitrogen and phosphorus were not monitored but it is expected that they will be reduced in similar proportions. Nutrients are present primarily as dissolved constituents, so elevated bioswales will mitigate them in the same manner as floating islands—conversion into bacterial and plant biomass, along with biotransformation of ammonia and nitrate to nitrogen gas (Figure 4).

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Hydraulic Conductivity

Controlled bench-scale tests were conducted in the Shepherd Research Laboratory using constant-head permeameters in order to determine hydraulic conductivity values for the Elevated BioSwale matrix. In a first series of tests, new matrix (without biofilm growth) was tested with clean water under constant flowrate conditions. In a second series of tests, matrix was subjected to a constant recirculation flow for a two-week period using water high in dissolved nutrients and native bacteria, which resulted in a rich growth of biofilm on the matrix fibers. Results of these tests indicated an average hydraulic conductivity of the new matrix of 0.042 ft/sec and an average conductivity of the biofilm-coated matrix of 0.007 ft/sec. These values can be used to estimate water backup and required channel cross-sectional area for different flow scenarios using Elevated BioSwales.

Biohavens – the only truly bio-mimicking floating wetland – Case Study #2 – propylene glycol removal

24 October 2015

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The BioHaven range of floating wetlands, also known as floating islands, provides a wide range of wetland aesthetic, habitat and treatment options designed from nature.  DH Environmental Consulting (Pty) Ltd (South Africa) has been partnered with Floating Island International, the designers of the BioHaven range, since 2008.  Over the next while our blog will document some Biohaven case studies.

2. BioHavens Remove Propylene Glycol from Airport Stormwater

Project Location: Bangor International Airport, Maine USA

A BioHaven® floating treatment wetland (FTW) installed to remove propylene glycol from airport stormwater has thrived during harsh conditions but its efficacy has not been measurable due to its small size and low glycol concentrations. However, glycol concentrations were reduced from greater than 500 mg/L to less than 1 mg/L in subsequent lab-scale BioHaven tests.

Overview

In early 2008, Bangor International Airport personnel began evaluating BioHavens to enhance water quality discharged from the airport property, with three objectives:

  1. Reduce trace amounts of propylene glycol, which is added as a deicing agent in the winter;
  2. Reduce levels of nutrients such as nitrogen and phosphorus; and
  3. Reduce the water temperature.

Results from other sites using BioHavens supplied by Floating Island International (FII) had already shown that Objective #2 could be achieved. Shade provided by BioHavens would achieve Objective #3. Thus, testing focused on the efficacy of glycol removal with BioHavens.

Installation Data

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Results

The BioHaven was installed in 2008 but because of its small size (0.2% of the pond surface area) and the pond’s low glycol concentration (consistently below the detection limit of 5 mg/L before FTW treatment), its effect could not be measured. To better determine the efficacy of this technology, a pilot-scale BioHaven with an area of 0.88 ft2 was used in a series of lab tests. These tests were run in batch mode and outstanding glycol removal was measured, with results shown in the table below.

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Conclusions:

Glycol concentrations were reduced from greater than 500 mg/L to less than 1 mg/L in lab-scale BioHaven tests. It is believed that glycol is converted to carbon dioxide by aerobic bacteria attached to roots and other underwater surfaces of the FTW.

The full-scale BioHaven vegetation has survived three Maine winters and thrived each summer. To better determine its efficacy, this FTW may be moved to a smaller pond farther upstream in the process where glycol concentrations are 5-10 mg/L or higher. In the current location, a series of larger BioHavens may be required to measurably improve water quality.

Biohavens – the only truly bio-mimicking floating wetland – Case Study #1 – Ammonia removal

23 October 2015

The BioHaven range of floating wetlands, also known as floating islands, provides a wide range of wetland aesthetic, habitat and treatment options designed from nature.  DH Environmental Consulting (Pty) Ltd has been partnered with Floating Island International, the designers of the BioHaven range, since 2008.  Over the next while our blog will document some Biohaven case studies.

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BioHaven® Technology:

1. Ammonia Removal in Aerated Wastewater Lagoons

Ammonia removal with BioHaven® floating treatment wetlands (FTWs) is summarized in this study. Removal rates in aerated wastewater lagoons were improved up to nearly 200% compared to control lagoons without FTWs.

Since their initial implementation nearly a decade ago, one of the primary objectives of BioHaven technology from Floating Island International (FII) has been to reduce nutrient levels. Potential applications include waterways degraded by agricultural runoff, ponds and lakes impacted by waterfowl and/or septic systems, polishing of municipal wastewater and even treatment of raw wastewater.

Table 1 illustrates ammonia removal at five sites equipped with FTWs. The table includes ammonia concentrations, percent removals and removal rates in pounds of ammonia- nitrogen removed per year per cubic foot of FTW material.

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All five systems presented in Table 1 are variations of wastewater lagoons at different scales. The earliest study conducted by FII researchers for a Montana Board of Research and Commercialization Technology (MBRCT) grant was a small-scale BioHaven which did not include a “control” lagoon. The next three studies included controls, which were parallel lagoons treating the same influent wastewater but without FTWs. The Wiconisco and Rehberg Ranch FTWs are small systems treating average flows of 16 and 12 gallons per minute (gpm), respectively. The Hunt Facility FTW is a full-scale production system in Louisiana treating about 200 gpm.

Ammonia removal ranged from 38% to 87% in the five systems. The Rehberg Ranch FTW removed 26% more ammonia than the control lagoon (84% vs. 58%), while the Wiconisco FTW was 9% better than the control. The highest ammonia removal rate, 5.3 lb/ft3/yr, was measured in the Hunt system, which was installed in 2011. This rate was 194% higher than the control removal rate measured before BioHaven installation.

Ammonia concentrations at Rehberg Ranch are illustrated in Figure 1.

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Nitrification (biological conversion of ammonia to nitrate under aerobic conditions) is the primary mechanism for ammonia removal in these systems. Both the Wiconisco (Pennsylvania) and Rehberg Ranch (Montana) FTWs are located in cold-weather climates, which has traditionally limited biological ammonia removal. Researchers have estimated that approximately 80% of FTW efficacy is due to bacteria attached to plant roots and the FTW polymer matrix itself, with the other 20% attributed to nutrient uptake by plants. The plants create the platform for biological activity in a biofilm, while also contributing nutrient uptake and aesthetic benefits. This is illustrated in Figure 2.

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The Rehberg Ranch system, installed in late 2009, is a new-generation FTW called LeviathanTM that includes a pump for circulation and aeration. The Wiconisco system was one of the first full-scale BioHavens installed in 2005 and a solar-powered aeration system was added in 2008. The FTWs at Rehberg Ranch (Billings, Montana) and Wiconisco (Pennsylvania) are shown in Figures 3 and 4.

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Conclusion

The need to reduce nutrient levels in wastewater is increasingly critical as rivers, lakes and coastal waters become more nutrient-loaded worldwide. This is the entry point for cutting edge, “green” floating treatment wetland (FTW) technology such as BioHavens.

Although traditional facultative and aerated lagoons can reduce Biochemical Oxygen Demand (BOD) and Total Suspended Solids (TSS), their ability to remove nitrogen and phosphorus from municipal wastewater is limited. BioHaven technology enhances these lagoons with the “concentrated wetland effect,” facilitating compliance with increasingly stringent wastewater nutrient, BOD and TSS criteria.

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Lots of apparent irregularities around the Elandsfontein phosphate mine?

13 October 2015

Elandsfontein looking west towards the lagoon (Carika van Zyl)

Elandsfontein, looking west towards the lagoon (Carika van Zyl)

The goings-on around the approval of mining rights for the proposed phosphate mine on the South African west coast at Elandsfontein (in the buffer zone of the West Coast National Park no less!), seem a tad murky.  There seem to be a slew of procedural anomalies and some of the specialist work, for a project that could, potentially, have ecological implications that extend into the marine environment, appears somewhat superficial – with concerns raised on review.  Political interference in favour of the mining has been alleged.  Legal opinion shows that the mining company may have been ill-advised in terms of their procedural obligations to seek approval under NEMA.  Anyway, readers need to draw their own conclusions from the following letter prepared by the stalwart conservationist heading up the opposition to the mine, Carika van Zyl.  Last week she circulated this letter with associated documents (published here with her permission):

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