Durable Plastics that Remove Microplastics
We call the very first island we launched the 520 because it’s 520 square feet in size. I still remember the launch because nearly everything we planted on the island that day in August was edible and perennial and native to North America. The plants took longer to establish, but eventually tied into BioHaven’s recycled plastic matrix and are still there today. It took the 520 about a year to fully naturalize, and today the island still looks splendid.
That launch was fourteen years ago, before we learned about armor, a protective coating that provides long-term UV protection and top-surface rigidity and is now applied to every one of our islands. BioHavens are much easier to walk on than before, when it was more like walking on a waterbed. Now it’s like walking on a plush carpet!
Recycling PET into Floating Islands is an EPA Approved Process
BioHavens are made of recycled PET, the EPA-approved polyester used in drinking water bottles. The internal structure of this recycled material is superior to most virgin polyester. It doesn’t break down in water like organic materials, such as coconut-fiber or jute. Additionally, it provides a flexible structure that is easy to anchor and absorbs wave energy.
You can sink a BioHaven, but you will have to work at it! And then when you turn back around you may very well find it floating aright again.
One spring, in a river in China, a BioHaven took a direct hit from a massive tree…a deadhead that pulled the island down and under. When the water receded, the tether line was cut and the island sprang back up to the surface. Only the plants were damaged which was an easy fix. This is a really good sign for long-term durability. BioHavens have demonstrated their strength through hurricanes and typhoons in the southern hemisphere, a tornado here in Montana, and powerful ice storms in southeast Alaska. Imagine a 48-inch snow dump! And all of these events were before the days of armor.
PET used in BioHavens is not part of the microplastics problem
Initially, it sounds like these large, plastic islands would end up contributing to plastic debris (microplastics) like so many other human contrivances? Actually quite the opposite is true. We’ve found that BioHavens can even pull harmful plastics out of waters.
Today there’s front line research showing how microbeads of plastic – a completely different type of plastic than the PET used in BioHavens – actually bond onto the sticky biofilm that grows on and within BioHavens. One day, hopefully soon, BioHaven StreamBeds will be positioned at the tail end of wastewater treatment facilities where they will suck the microplastics out of the treatment train and trap them in biofilm. Currently, they pour out of the facility into streams and rivers and into the gullets of fish. BioHavens could be a vital cog in the effort to clean up water.
BioHavens® and Plastics – questions and answers
News flash (WaterOnline, January 2018): “Kansas University researchers […] will be testing biofilms with extracellular polymeric substances (EPS) that may prove an effective barrier for microplastics.
“We think when there is more EPS in the system, we will get better removal,” Sturm said.
So, BioHaven floating islands may well be part of the remediation for water-borne microplastics – those omnipresent micro-beads that are impossible to filter by mechanical means. BioHavens grow biofilms that engender EPS: far from being part of the problem, BioHavens are part of the solution.
We have been asked whether FII’s polymer-based floating island products might:
- release breakdown products such as Bisphenol A into water;
- release plastic particles that could be detrimental if ingested by fish and other animals;
- be related to the issue with microplastics (exfoliant and other micro-beads).
Concerns about plastics are legitimate and can be addressed as follows:
Not all plastics are the same. The plastic used in BioHaven products is appropriate for use in sensitive areas such as streams and lakes, being made of the same plastic (PET) that is used in drinking water bottles, that millions of people use every day without harm. No BPA is used in its manufacture so it cannot leach into waterways.
BioHaven matrix is manufactured from recycled polyester that has the same integrity as virgin polyester (get more on this from Americo).
All BioHaven floating islands leave our factory with a protective polyurea coating covering the top and sides. This coating is the same as that used for lining municipal concrete water tanks and is certified safe to potable water standards. It protects the islands from UV damage (it’s also used to protect truck beds) and from breakdown under severe wildlife pressure (waterfowl and muskrats, for example).
What are microplastics, exactly?
Microplastics are specifically the tiny beads that are used in exfoliants and other products, that are too small to be trapped by wastewater treatment plants, and that find their way into rivers and streams.
Because BioHavens promote the growth of biofilm that emits EPS, it is likely that BioHavens are one of the few available technologies that provide an immediate solution to this issue.
Data on water contaminants in over 40 US states paint a shocking picture of the many poisons that are unregulated and present in our water. BioHavens’ “concentrated wetland effect” can address many of these contaminants by substituting for the natural wetlands that have been systematically destroyed by human development activities.
Experiments conducted at the Shepherd Research Center and at other locations indicate that:
- BioHaven floating islands have been shown to actually remove at least one deleterious plastic byproduct (bisphenol A) from water; and
- the presence of BioHaven floating islands in a pond or aquarium has had no detrimental effect on fish; in fact, the opposite has been demonstrated, namely that BioHavens stimulate fish growth rate for all sizes of fish, including fry and small immature fish.
These high growth rates indicate no detrimental ingestion of polymer particles by the fish and no adverse reaction to the presence of the islands.
Below are several case studies that demonstrate the multiple benefits of BioHaven floating islands for wildlife and water quality in general.
Bisphenol-A Case Study
The first case study tracked behavior of Beta Fighting Fish exposed to an estrogen mimicker (bisphenol A). Gill flares thought to be associated with fish virility and sex drive decreased upon exposure to BPA. After three days, incidence of gill flares recovered to pre-exposure levels in a test aquarium with a BioHaven floating island. Gill flare recovery did not occur in the test aquarium without a floating island.
Case Studies at Shepherd
Two case studies and ongoing data collection at Fish Fry Lake at FII headquarters show sustained game fish harvest of 26 pounds of game fish per acre-foot of water, as well as a range of other improvements in water quality parameters.
Minnow Pond case studies track a BioHaven floating streambed’s ability to maintain adequate dissolved oxygen conditions in a high-BOD setting. The result was high cycling of phosphorus into fathead minnow biomass, at the rate of 860 pounds of fish per acre-foot of water. This corresponds to over four pounds of phosphorus removal when the minnows were harvested.
Numerous additional peer-reviewed papers demonstrate a range of improved water quality parameters associated with BioHaven floating treatment wetlands, including BOD removal and reduction in eutrophication. Nearly 30 additional case studies add to these data.
Improved water quality parameters associated with BioHaven floating treatment wetland include reduction in all forms of nitrogen, phosphorus, and several heavy metals. Islands are also associated with reduction in concentration of hazardous bacteria including fecal coliform. Another benefit of floating treatment wetlands is apparent mitigation of conditions associated with harmful algae blooms.
Conclusion: Based on the best availbale information, the BioHaven matrix material is of positive benefit to the system: any possible (and as yet unproven) negative impact to the ecosystem it is more than made up for by the net benefits.