Biohavens – the only truly bio-mimicking floating wetland – Case Study #18 – eutrophication

12 November 2015

BioHaven® FTWs Remove Nutrient Loads from Eutrophied Lake

Project Location: Yingri Lake, Jinan, China

At an urban lake in China, large reductions in chemical oxygen demand (COD), biochemical oxygen demand (BOD), total nitrogen and total phosphorus were measured within three months after BioHaven® floating treatment wetland (FTW) installation, which met the project objectives. The primary goal of reducing algae blooms was also achieved.

Overview

The purpose of this floating island application was to prevent summer algae blooms by reducing the nutrient load in an urban lake. Reductions in nutrient levels were anticipated to increase the overall health of the lake by decreasing algae growth, increasing dissolved oxygen levels and decreasing odors. The location is Yingri Lake at Quancheng Park in Jinan, a city of seven million people in North China near the east coast.

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Yingri Lake had typically experienced a severe algae bloom every spring; however, no algae bloom was seen in 2010 after the FTW installation in April.

Conclusions

  •   Large reductions in COD, BOD, total nitrogen and total phosphorus were measured within three months after FTW installation, which met the project objectives.
  •   The islands are aesthetically pleasing.
  •   It is unclear why dissolved oxygen concentrations decreased; however, the primary related goal of reducing algae blooms appears to have been achieved.

The looming water crisis, and its causes

11 November 2015

(Author: Anthony Turton)

Sitting on the Horns of a Dilemma: Water as a Strategic Resource in South Africa

South Africa is a water-constrained country with a vital need to conserve, manage, and expand its limited water resources as efficiently as possible. Since 1994, however, strategic planning has deteriorated, along with operational efficiency. Under the supposed imperatives of ‘transformation’, skilled engineering and other professional staff have been driven out of water boards (responsible for bulk water supply) and municipalities (charged with local reticulation and often also with waste management).

Municipalities are now discharging around 4 billion litres of untreated or partially treated sewage into the country’s rivers and dams every day. The Government refuses to admit the extent to which water quality has deteriorated, and a public health crisis now looms. Various reforms are feasible, but the ruling party shows little willingness to allow practical reality to prevail over its transformation ideology.

That water constraint

South Africa’s rainfall is half the global average, making it a water-scarce country. The first proposal for the construction of large dams was made in the 1870s.

In 1886 Thomas Bain, a civil engineer in the public roads department in the Cape, followed up with a book on ‘water finding’ and‘dam-making’, which urged state intervention in the construction of hydraulic (water-driven) infrastructure as an essential foundation for economic growth and social cohesion.

When South Africa became a republic in 1961, one of the State’s first major projects was the creation of a scheme to transfer water from one river basin to another. This was achieved via the Orange-Fish-Sundays scheme, which transfers water from the Gariep Dam in the Free State to arid areas in the Eastern Cape. This initiative was specifically designed not only to address the water challenge in parts of the Karoo but also to restore investor confidence after the Sharpeville shootings in 1960.

In 1970 came the report of the Commission of Enquiry into Water Matters. This report warned that South Africa’s economic development would always be water-constrained unless a coherent plan was implemented by the State to overcome this obstacle. In response, the Government imposed a tax on the bulk sale of water (the first of its kind in the world) to fund a new body called the Water Research Commission. This commission was given the task, in partnership with the Council for Scientific and Industrial Research (CSIR), of developing the science and engineering technology needed to address the country’s endemic water scarcity and so promote economic growth and prosperity.

Working from this foundation, South Africa became a global leader in the management of water. This allowed the country to develop the most diversified economy in the world compared with other nations with similar climatic regimes. One of its great achievements in the 1970s was the CSIR’s development of the first sewage recycling technology.

This cutting- edge innovation was put into operation in Windhoek (in what was then South West Africa and is now Namibia) in response to the absolute water scarcity in the city. This development was also part of a wider strategic initiative to harness water from a multiplicity of sources. South Africa thus became globally recognised for its ability to achieve economic growth and development despite its fundamental water constraint, which was largely overcome through high levels of technical ingenuity.

The National Water Act of 1998

After the transition to democracy in 1994, the new Government adopted the National Water Act of 1998 as one of its first ‘transformation’ interventions. This removed riparian and other common-law rights to water and made the State the public trustee of the nation’s water resources. It also gives the State the power to decide on ‘the equitable allocation of water in the public interest’, in order to address past racial and gender discrimination.

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Biohavens – the only truly bio-mimicking floating wetland – Case Study #17 – Wastewater treatment

8 November 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.

17. BioHaven® Floating Treatment Wetlands Remove Nutrients and Help Wastewater Facility Achieve Compliance

Scientific Summary

BioHaven® Floating Treatment Wetland (BFTW) Technology is designed around the same principles as a wetland. They are man-made floating islands that provide an optimal habitat for microbial and plant species. See Figure 1. Similar to a wetland, the plants and microbes improve water quality; however BFTWs enhance microbial growth by expanding available underwater surface area; i.e. microbial habitat.

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In fact, an eight-inch thick island covering one square foot of water surface contains 124 cubic feet of surface area. This phenomenon is created through patented island design. The result is a new and strategic means to achieve a concentrated wetland effect. Along with the nutrient removal processes, BFTWs also provide ancillary benefits for water treatment when launched into a water body. They immediately increase retention time as the flow of water is “redirected” through or around the BFTWs. The physical embodiment of the BFTWs also physically traps solids in the water body.

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Facility Background

The Elayn Hunt Correctional Facility has struggled meeting discharge compliance. Parameters of concern have been elevated levels of Biological Oxygen Demand (BOD), Total Suspended Solids (TSS), and Fecal Coliform. Secondarily, sludge accumulation in the pond has limited the ability for the pond to provide effective treatment. Remediation of this problem would have required extensive dredging of the pond and would have placed a high financial burden on the Department of Corrections at a time when budgets were decreasing.

The Primary goal for this project was to find out if the BFTWs could help the facility achieve and maintain compliance by removing unwanted nutrients. The BFTWs were installed strategically in front of the in flow pipe to have the greatest amount of inflow water passing through the Island matrix and to slow the water as it entered the pond ultimately increasing retention time. This installation location allowed for the greatest amount of treatment opportunity. The three plant species included: Common Rush (Juncus effusus), Pickerelweed (Pontederia cordata), and Arrowhead/Lanceleaf (Sagittaria lancifolia).

Results

At the start of this project enhancing facility compliance was a primary goal. The data suggests that the Islands have met this objective. The average of non compliance events exceeded 5 and sometimes 10 per year in the 5 years before the installation of BioHaven® Floating Treatment Wetlands. Since the installation of BFTWs in March of 2011, there have been only 6 noncompliance events through May 2014, all due to faulty facility equipment.

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Table 1 shows concentrations of the three parameters of concern before and after the BFTW installation. “Before” data were taken in January and March 2011, while “after” data are the averages of monthly data from April 2011 through December 2012. It is assumed that the higher nutrient concentrations seen post-BFTW were also seen periodically before BFTW installation.

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After BFTW installation, the average percentage removal has been 74%, 35%, and 29% for COD, Ammonia, and Phosphate, respectively. This is significantly better than without the FTWs. The BFTW removal rates are substantial and are even higher than those measured in other case studies. Considering these rates, BFTWs can be sized to remove a given contaminant load (concentration and flow).

Conclusions

The total cost of this project was $38,017.61. This included the BioHaven® Floating Treatment Wetlands, installation, plants, and monitoring for one year. Dredging the pond would have had a much higher ticket price estimated at over $1,000,000.00. BioHaven® Floating Treatment Wetlands were installed for 3.8% of that cost; demonstrating their ability to help communities as well as, public & private industry achieve and maintain consistent compliance in a very cost effective manner.

In December of 2012, the BFTWs were completely removed from the wastewater pond. All prior vegetation was removed. The BFTWs were re-planted with Vetiver Grass and re-installed in January 2013. This was done in anticipation of a new study with LSU AgCenter. The chart below shows the Average BOD and TSS removal rates from January 2013 to May 2014. The reduction of BOD and TSS has been an average of 67% for both over the 17 month period.

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In June 2013, Louisiana State University AgCenter began monitoring this project for water treatment and nutrient removal. They will continue to do so for two (2) years.

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Biohavens – the only truly bio-mimicking floating wetland – Case Study #16 – Odour elimination

7 November 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.

16. Eliminating Odors Using BioHaven® Technology

Project Location: Marton, New Zealand

This case study summarizes results of a unique configuration of Floating Island International’s (FII) patented BioHaven® floating treatment wetland (FTW) technology to mitigate wastewater odor. This was the first application of FTWs specifically to reduce/eliminate wastewater odors, which also removed biochemical oxygen demand (BOD) at a high rate. BioHavens have now been utilized to reduce odors, remove nutrients and metals, provide wildlife and fish habitat, and improve aesthetics.

Overview

An existing anaerobic pond was receiving municipal wastewater from the City of Marton, plus landfill leachate and other industrial waste streams from a nearby malting company; the odor from this mixture created a major problem. The Rangitikei District Council attempted to mitigate the odor by operating six 10-kW aerators 24/7. In addition to high costs, the community still had to contend with extremely unpleasant odors when the aerators frequently required maintenance.

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FII licensee Waterclean Technologies offered to provide a guaranteed solution. After thoroughly surveying the pond to accurately map the concrete wave band around the edge of the pond, Waterclean designed and manufactured a BioHaven system to fit tightly over the pond like a blanket, to “seal in” the odor. The FTW was planted with native sedge, Carex virgata, a resilient species to cope with the harsh environment.

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Results

The “floating blanket” has been an outstanding success, reducing BOD from about 450 mg/L to 85 mg/L, an 81% decrease. This removal rate of 395 g BOD/m2/day has greatly improved effluent quality. Waterclean believes that all wastewater treatment is occurring beneath the island, as the root zones do not penetrate far into the wastewater. The water temperature is a constant 27oC.

Most importantly, all objectionable odors have been eliminated from the facility and shutting off the aerators has saved approximately $150,000/yr in energy costs.

Special Features

The project is a leading-edge application, as it was the first in the world to use FTWs in this manner. The Rangitikei Council wanted a no-risk situation, which required the Waterclean solution to be successful. The wastewater blanket concept was initially presented to scientists, who agreed that it would work in principle.

Conclusion

The Marton wastewater blanket has essentially formed a low-rate anaerobic digestor. It has provided a unique solution by eliminating odor, improving effluent quality (primarily BOD) and reducing operating costs. As of September 2013 (after more than three years in operation), the system is still performing optimally.

Biohavens – the only truly bio-mimicking floating wetland – Case Study #15 – living shorelines

6 November 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.

 15. BioHaven® Living Shorelines; BioHaven® Floating Breakwaters

Project Location: Louisiana, USA

BioHaven® floating island technology is an improved approach for protecting shorelines from erosion and restoring natural vegetation. This technology is variously known as BioHaven Living Shorelines and BioHaven Floating Breakwaters. The BioHaven matrix is a robust and flexible support structure for plants that has exceptional wave‐dampening qualities: instead of simply redirecting possibly‐ destructive energy, waves are safely absorbed. The matrix has a very high tensile strength capable of withstanding 90‐mph winds; it is designed to rise and fall with the tide, and will rebound if inundated during a storm event. BioHavens have been installed in coastal areas, ponds and lakes. Living shorelines are intended to:

  •   Prevent erosion and/or reclaim land frontage,
  •   Provide wildlife and spawning habitat,
  •   Protect property,
  •   Encourage recreation,
  •   Improve water quality,
  •   Enhance natural beauty and
  •   Reduce restoration costs.

Installing BioHaven living shorelines requires relatively little heavy equipment and less labor than conventional alternatives such as bulkheads and riprap. The lightweight, modular system can be assembled and installed with minimal disruption to the environment it is designed to protect.

Martin Ecosystems of Baton Rouge, a licensee of Floating Island International using the BioHaven technology, has developed expertise in designing, installing and maintaining living shorelines. Since 2009, Martin Ecosystems has installed living shorelines at three locations in Louisiana.

Bayou Sauvage National Wildlife Refuge

At the nation’s largest urban national wildlife refuge, preserving marsh habitat is critical. Over time, low‐to‐moderate wave energies have eroded much of the shoreline. The cost‐effective solution chosen in August 2009 was to install 856 linear feet of BioHavens to buffer waves, increase sedimentation and grow new vegetation. Partners were the City of New Orleans, U.S. Fish and Wildlife Service, and Bayou Land Resource Conservation & Development Council (a division of NRCS).

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Catfish Lake

At Catfish Lake, part of the South Lafourche Levee District near Galiano, LA, the levee base was eroding from daily wave action. In March 2009, 1000 linear feet of BioHavens were installed to buffer the waves, protect the levee base and provide needed vegetation. Selected plants were marsh hay, seashore paspalum and vermillion smooth cord. Both the BioHaven matrix and the vegetation serve as buffers between the waves and levee.

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In only one year, the vegetation has spread and is providing 2‐3 feet of vegetative buffer between the waves and levee base. Sections of the project where matrix was installed without plants have shown signs of erosion, indicating that plants are necessary for this application.

Isle de Jean Charles

Significant marsh erosion has been noted on this island on a saltwater lake near Pointe Au Chene, Louisiana. To protect the small slivers of remaining marsh from erosion, provide a buffer between the open lake and a road, provide a suitable environment to trap sediment and allow vegetation to spread, 1560 linear feet of BioHavens were installed in September 2011 and planted with smooth cord and seashore paspalum. Results to date show:

  •   BioHavens are protecting the remaining marsh from shearing waves.
  •   Vegetation is noticeably greener than the nearby natural marsh.
  •   New shoots and roots are protruding from the BioHavens.

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Conclusions

Three floating treatment wetland systems have been successfully deployed at brackish water and saltwater environments in Louisiana. Living shorelines have also been installed in ponds and lakes in Shanghai, China and Singapore. Results include erosion protection, wave mitigation and enhanced vegetation. This cost‐effective option was installed with no heavy equipment and little‐to‐no damage to habitat or the shorelines’ natural appearance.

Biohavens – the only truly bio-mimicking floating wetland – Case Study #14 – mitigation of eutrophication

5 November 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.

 14. Floating Treatment Wetlands to Mitigate Lake Eutrophication: Enhanced Circulation and Nutrient Uptake Expand Fish Habitat

Project Location: Research Lake near Shepherd, MT, USA

Simple, cost‐effective water treatment strategies show the ability to transform agricultural effluent into world‐class fish habitat. This case study discusses an ongoing experiment to monitor the efficacy of a floating treatment wetland (FTW) that incorporates air diffuser technology to lift and circulate water through floating stream beds within the FTW. This combination of FTW and efficient water circulation/aeration is trade‐named LeviathanTM, a model of BioHaven floating island, and represents a novel approach to address nutrient loading.

Overview:

Determining whether biofilm‐based microbes can set the stage for high fish productivity along with nutrient removal was a primary objective of this test.

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Wetland areas have been reduced worldwide while human‐caused nutrient loading has expanded with growing human populations. Mass‐production agriculture as practiced in many developed nations has contributed to numerous cases of hyper‐eutrophication in bodies of water that were previously low in nutrient concentrations. In fresh water, partly as a result of normal seasonal stratification, nutrient loading can deplete oxygen levels within the livable temperature zone for cold‐water fish species.

Floating Island International (FII) is a private research and development‐focused business. Over the last 11 years, FII has developed the BioHaven FTW technology, which mimics the ability of natural peat‐based wetlands to purify water. The Leviathan maximizes surface area and circulation, which are key components of wetland effectiveness. The islands are also designed to provide optimal perennial plant habitat. The Montana Board of Research and Commercialization, along with FII, funded the work described in this case study.

System Background:

Dissolved oxygen and temperature measurements taken on FII’s 6.5‐acre lake outside of Shepherd, Montana in 2008/2009 indicated that stratified water near the surface was too warm to sustain a trout fishery. While temperatures below the stratified warm water layer were sufficiently cool for trout, that zone contained low dissolved oxygen (DO) levels. During late summer at this south‐central Montana lake, no strata of water could consistently provide the cool‐water, high‐DO environment demanded by fish such as rainbow, brown and, especially, Yellowstone cutthroat trout.

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Groundwater containing variable nutrient concentrations enters the lake at an average rate of 80 gallons per minute (gpm). Surface water also flows into the lake at variable nutrient concentrations and flow rates. Evaporative loss and outflow are balanced to maintain the lake level at full pool, which ranges between 29 and 30 feet of depth.

As the lake was filled, a series of BioHaven floating islands covering 5200 square feet of lake area and providing over one million square feet of saturated surface area was installed. Several islands were positioned next to the inflow to maximize exposure to the highest nutrient concentrations. These islands, in combination with the Leviathan system, were designed to maximize biofilm production and move nutrients into and through the food web as organisms attached to underwater surfaces (“periphyton”).

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Results:

A 1250‐square‐foot Leviathan system, incorporating floating stream beds and grid‐ powered water circulation, was installed in the lake in April 2009. This system circulates up to 2000 gpm through the stream channels within the island. The Leviathan was constructed of post‐consumer polymer ”matrix,” averaging 25 inches in thickness, with each cubic foot of matrix providing 375 square feet of surface area. The Leviathan pump enabled personnel to pull water from any depth and move it through the stream channels, exposing it to the concentrated surface area (containing a microbial biofilm) and atmospheric oxygen.

After 17 months of operation, water clarity had improved from a low of 14 inches of visibility to as much as 131 inches. The Secchi disk reading is now 228 inches (19 feet) during the winter. Simultaneously, the water temperature gradient was reduced, creating a larger zone of “livable” water for fish. Two age classes of Yellowstone cutthroat trout were introduced 13 and 14 months into the test. Through the summer of 2010, a favorable temperature/dissolved oxygen strata ranging from the water surface down to a depth of at least 12 feet was maintained as potential cutthroat habitat. One‐year‐old and two‐year‐old black crappies were also introduced two months into the test, and naturally‐occurring northern yellow perch were present in the lake when it was filled. All three species have flourished.

The shaded area in the first chart below contains favorable conditions (DO and temperature) for cold‐water fish, with a much larger zone of favorable habitat in 2010 after the Leviathan design was enhanced and additional aeration was installed. The second chart shows the extent of the larger zone of cool, high‐DO water that was available for fish in 2010.

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Fish catch rates and growth rates are now being monitored at the lake. Initial data show that experienced fishermen can catch up to one perch per minute. Visual observations from diving and an underwater viewing station indicate that perch approaching or exceeding the Montana state record of 2 pounds 2 ounces now inhabit the lake.

The research lake is relatively unique in that it supports fish accustomed to cold water (Yellowstone cutthroat trout), temperate water (perch) and warm water (crappies). Montana officials have made two unsuccessful attempts at sustaining cutthroat populations in an adjacent stretch of the Yellowstone River, which is located a half‐mile away from the research lake.

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The new aeration scheme in the lake improves water quality by incorporating dissolved phosphorus and nitrogen into the aquatic food web, in the form of periphyton, while limiting the growth of deleterious algae. Total phosphate concentrations are reduced from 0.040 mg/L to 0.025 mg/L, while total nitrogen concentrations decrease from 0.55 mg/L to 0.01 mg/L.

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Biohavens – the only truly bio-mimicking floating wetland – Case Study #13 – nutrient removal

4 November 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.

13. Nutrient Removal with Passive Floating Treatment Wetlands

Project Location: Elayn Hunt Correctional Facility, St. Gabriel, Louisiana, USA

This case study demonstrates the ability of patented BioHaven® floating treatment wetland (FTW) technology to clean water by substantially reducing nutrient levels. At a wastewater facility in Louisiana, BioHavens more than doubled removal rates for chemical oxygen demand (COD), ammonia and phosphate.

Overview

Martin Ecosystems of Baton Rouge, Louisiana, an FII licensee, installed BioHaven floating islands into the Elayn Hunt Correctional Facility oxidation pond in March 2011. The primary objective was to determine whether the islands could remove unwanted nutrients that were periodically creating noncompliance with the facility’s discharge permit. The goal is to have the facility continually achieve and maintain compliance.

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The BioHavens installed at Elayn Hunt are passive islands without aeration and were planted with three types of vegetation. Most of the removal efficiency attributed to islands has been found to be due to biofilm attached to both the plant roots and the island matrix itself.

Table 1 shows concentrations of the three parameters of concern before and after BioHaven installation. “Before” data were taken in January and March 2011, while “after” data are the averages of monthly data from April 2011 through September 2012. It is assumed that the higher nutrient concentrations seen post-FTW were also seen periodically before BioHaven installation.

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After BioHaven installation, the average percentage removal has been 73%, 38% and 29% for COD, ammonia and phosphate, respectively. This is substantially better than without the FTWs (52%, 23% and 9%, respectively). Table 2 shows contaminant removal rates before and after BioHaven installation, along with the net removal rates that can be attributed to the islands.

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The BioHaven removal rates are more than double the previous rates for all three parameters and are substantially higher than those measured in other case studies. Based on these rates, FTWs can be sized to remove a given contaminant load (concentration and flow).

Conclusions

BioHavens have a demonstrated capability to remove excess nutrients such as COD, ammonia and phosphate, along with total suspended solids and other parameters (data not shown). The total cost of this project was much less than other treatment alternatives, demonstrating that FTWs can help public facilities and private industry achieve and maintain compliance in a cost-effective manner. BioHaven technology can enhance existing waterways with the concentrated wetland effect, facilitating compliance with increasingly stringent wastewater nutrient, BOD/COD and TSS criteria.

The Louisiana Department of Environmental Quality provided funding for this project, which is owned and operated by the Louisiana Department of Corrections.

Biohavens – the only truly bio-mimicking floating wetland – Case Study #12 – wastewater treatment

3 November 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.

 12. BioHaven® Floating Treatment Wetlands Improving Waste Water Treatment!

Project Location: Harrisonburg, Louisiana

Overview

The Village of Harrisonburg has struggled to meet Louisiana discharge permit regulations for several years due to the ineffective design of their waste water oxidation pond. The design of the system limits their ability to treat their waste water by confining treatment to two-thirds of an acre when their pond is actually 5 acres in size. The entire pond is not being used efficiently and effectively. The discharge parameters of concern have been Total Suspended Solids ( TSS), Ammonia, and Carbonaceous Biochemical Oxygen Demand (CBOD). Due to limited budgets, the Village of Harrisonburg has been unable to correct the system problems.

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Project Cost

Martin Ecosystems assisted the Village of Harrisonburg in applying for and securing $50,000 of Strategic Economic Development Program (SEDAP) funding through the Delta Regional Authority for this project.

System Design

Martin Ecosystems strategically installed BioHaven Floating Treatment Wetlands in front of the influent pipe and against the existing curtains in order to have maximum water flow through the BFTWs. This increases retention time and provides maximum treatment.

Challenges

In May, Martin Ecosystems discovered that nutria were climbing onto the Islands and eating the recently planted Vetiver grass. It appears that the damage is minimal as not all BFTWs have been effected.

Martin Ecosystems has plans to install fencing around the perimeter of the islands in order to keep nutria, turtles, and other wildlife off of the islands until the vegetation has had enough time to establish itself.

Results

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Challenges

In May, Martin Ecosystems discovered that nutria were climbing onto the Islands and eating the recently planted Vetiver grass. It appears that the damage is minimal as not all BFTWs have been effected.

Martin Ecosystems has plans to install fencing around the perimeter of the islands in order to keep nutria, turtles, and other wildlife off of the islands until the vegetation has had enough time to establish itself.

April discharge reports have shown reductions of 30%-50% in all three parameters of concern with two achieving compliance. This is only one month, but is very encouraging.

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Biohavens – the only truly bio-mimicking floating wetland – Case Study #11- Bass benefit

2 November 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.

 11. Floating Island Provides Bass Spawning Habitat

Project Location: Elephant Butte, New Mexico USA

The New Mexico Bass Fishing Association’s mission is to enhance bass fishing habitat and opportunities within the state. A subgroup of the association, Kids of the Southwest, undertook a project in 2009 to increase the bass population at Elephant Butte, NM. These youth partnered with the New Mexico Game and Fish Department, marina owners and other local interested parties after discovering a Floating Island International licensee, Floating Islands West, which has developed floating botanical gardens to increase fish and other wildlife habitat, along with providing water quality improvements.

Floating Islands West designed a portable spawning bed for fish that includes a cover and protection for the fry. After Kids of the Southwest arranged for the island purchase, they assembled the island, gathered and transplanted the necessary plants, filled the spawning beds with gravel, and used paddle boats to deploy the island.

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Kids of the Southwest is a Junior Bassmaster Club based in Las Cruces, NM, and is affiliated with Cedar Cove Bass Anglers in Elephant Butte, NM. The group strives to develop life skills in young people while educating them to exercise leadership and support for responsible recreational fishing, and stewardship of aquatic resources.

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Biohavens – the only truly bio-mimicking floating wetland – Case Study #10 – Phosphorus to fish

1 November 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.

10. From Phosphorus to Fish: Beneficial Use of Excess nutrients

Project Location: Shepherd, Montana

Fishing can be the primary method for transitioning excess nonpoint source nutrients from water, according to recent studies performed by Floating Island International (FII). This case study summarizes results of FII’s patented floating treatment wetland (FTW) technology and associated lake stewardship to remove nutrients from Fish Fry Lake, a 6.5‐acre lake at FII’s research center, along with producing outstanding fishing opportunities. Nearly all of the phosphorus and nitrogen entering the lake from agricultural runoff is now mitigated through a moderately aggressive fish‐harvesting program. The next goal is to address nutrients accumulated at the lake bottom in organic accretion.

The primary factors transforming Fish Fry Lake from a eutrophic pond to a productive fishery have been:

  • Higher dissolved oxygen (DO) concentrations due to aeration and mixing;
  • Lower overall water temperatures and a greatly expanded livable zone for fish due to aeration and mixing;
  • Introduction of substrate to support periphyton, which provides a food source for fish; and
  • Better penetration of sunlight into the water column from reduced turbidity, which enhances growth of diatom‐based periphyton

The last two factors are directly due to introduction of floating islands, while the first two are derived from features installed with the latest embodiment of floating islands.

Background

As recently as July 2008, Fish Fry Lake was a small pond with low DO concentrations, high summer water temperatures, colorful algae blooms and a small population of wild northern yellow perch. Today it supports crappie, a burgeoning population of perch and possibly the easternmost population of Yellowstone cutthroat trout. This dramatic change was made possible by:

  • Deepening the pond to 28 feet and extending its reach to 6.5 acres;
  • Strategically locating several aerators throughout the lake;
  • Adding and growing 5,200 square feet of FTWs; and
  • Introducing crappie and cutthroat.

The FTWs are a mix of BioHavens® (passive islands) and one LeviathanTM (Figure 1). The Leviathan is a new embodiment of FTW with aeration and forced circulation via an airlift directional diffuser. All islands in Fish Fry Lake, which are constructed of recycled post‐consumer plastic matrix, have been planted with native vegetation.

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Over 4,400 of FII’s floating islands have been launched around the planet over the past decade, with the largest (51,000 square feet) recently installed in New Zealand’s Lake Rotorua. Seven other island projects exceeding 20,000 square feet have been launched in New Zealand, Singapore and the U.S. Over $3 million has been invested in research through FII, the Center for Biofilm Engineering at Montana State University and the National Institute of Water and Atmospheric Research in New Zealand. In combination with these pre‐eminent research centers, FII has compiled a unique database between floating islands and fisheries enhancement.

By biomimicking nature, floating islands provide the “concentrated wetland effect” that transitions nutrients up the food chain. Instead of nutrients short‐circuiting into monocultures of algae, floating islands provide substrate‐‐the enhanced surface area that transitions nutrients from periphyton (the microbial and algae community attached to underwater surfaces) to fish (Figure 2).

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Results

Fish Fry Lake now supports a very productive perch fishery. From June through October 2011, 1,928 perch were harvested from the lake. Experienced fishermen averaged one perch every two minutes, with a typical harvest of 26 lbs/wk. On October 13, 2011, several fishermen caught 166 perch weighing a total of 35 lbs. On March 10, 2012 (shortly after ice‐out), five people caught 161 fish in two hours. Two hundred fish were tagged and introduced to the lake in 2011. Six of these tagged fish were among the 161 fish caught, suggesting that about 5,400 harvestable fish now inhabit the 6.5‐ acre lake. Figure 3 shows a typical perch harvest in 2011.

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In the 2011 study, perch were measured and classified by age, through otolith and scale aging. Perch in Fish Fry Lake were significantly larger than perch in the 95th percentile measured in a study by Jackson and Quist:

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Fish in Fish Fry Lake consume periphyton and organisms generated by nutrients flowing into the lake, from surface water and groundwater, and are not directly fed. In contrast, aquaculture ponds feed fish to maximize productivity. The fish yield measured at Fish Fry Lake was 26 lbs/wk or 4 lbs/acre/wk. Tilapia yield in fertilized freshwater ponds in Indonesia (Hansen et al., 1991) was measured at about 5 kg/ha/day, or 31 lbs/acre/wk. Therefore, fish yield at Fish Fry Lake is 10‐20% of yield in the fertilized ponds. Yield is consistent with the inflow of nutrients, since Fish Fry Lake has about 10% of the nitrogen inflow (0.01 g N/m2/day) as the fertilized ponds in the study.

Phosphorus inflow to Fish Fry Lake is estimated at 0.28 lbs/wk, based on an average concentration of 0.041 mg/L at an estimated flow of 80 gallons per minute. The average phosphorus concentration in perch is 1.0%, based on measurements by FII and other researchers. This means that the average fish harvest of 26 lbs/wk removed 0.26 lbs/wk of phosphorus. Thus, the amount of phosphorus removed via fishing was 0.26/0.28 or 93% over the study period. In a follow‐up study, FII is now tracking whether the total annual phosphorus load can be harvested during 2012.

An experienced fisherman at Fish Fry Lake can catch perch at a rate of one fish every two minutes. For the average fish weighing 0.25 lb, 3.7 hr/wk of fishing time is required to keep up with the incoming phosphorus, and to maintain a healthy waterway (Figure 4). This would require a fish harvest of 110 lbs/mo.

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Water Quality Improvements

During the first 12 months after the lake was filled, water clarity averaged 14 inches via Secchi disk. Introduced substrate, the filter‐like polymer matrix comprising the islands as well as plant roots that grow through the islands and their biofilm‐based periphyton, reduced turbidity significantly. In December 2011, three‐and‐a‐half years after the pond was filled, water clarity exceeded 19 feet. A summary of the water quality improvements is shown in Table 2.

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Similar waterways in the region are typically much more turbid due in part to clay colloids associated with the region’s geomorphology. Another contributing factor to regional waterway turbidity has been phytoplankton blooms associated with nonpoint source nutrient loading of nitrogen and phosphorus.

Biofilm present on the island matrix mechanically removes suspended solids, including colloidals and algae that bond to it. Competition for nutrients provided by biofilm‐ based microbes also reduces the turbidity level associated with algae blooms. Sunlight can then energize additional oxygen and food‐generating diatom‐based periphyton, even at depth.

In addition to the positive effect of sunlight, laminar aeration has also contributed to higher DO levels at depth. In summary, the combination of sunlight and dissolved oxygen at depth has resulted in the natural transition of excess nutrients into fish via periphyton.