Deja vu… drought, wastewater re-use and the abandoned Athlone Power Station precinct

20 June 2017

Athlone’s towers have fallen down

[This post originally appeared in Droplets in January 2011…]

I understand that the huge building that was the Athlone Power Station is being considered for a museum of some sort?  The odds are probably quite good that it will be developed into a shopping mall.

The site is immediately opposite the long-overloaded Athlone wastewater treatment works – a works that has no space to expand to meet increasing demands.  When the cooling towers came down, I suggested (to the City) that it would be a good idea to fill the building with reverse osmosis water purification modules and treat the otherwise ghastly final effluent (see how the City responded here) to a useable, and saleable, quality (RO can achieve potable quality).  This, to my mind, would be a logical and strategic use of space.  There is already a pipeline from the works underneath the N2, as the effluent was used as cooling water for the towers.

The concept of converting waste, in this case wastewater effluent, into an asset (irrigation, drinking or industrial water) is not taking root in South Africa – but it needs to!  This approach would also allow recovery of the appropriately-named Black River from its present role as a wastewater drain.”

I have no doubt that my original idea is likely to be fraught with technical and perhaps economic challenges, but none so challenging as having no water at all!  The City subsequently (in July 2011) announced that the quality of Athlone effluent had improved substantially between 1998 and 2011 – a claim that I cannot confirm or deny as I have not seen any empirical proof thereof – but it does suggest that the proposed water quality treatment or pre-treatment would now be easier than I previously envisaged.

The City of Cape Town produces a lot of wastewater effluent every day – polluting the rivers and the marine environment on a continuous basis.  And, yes, the production of wastewater (and the disposal thereof) is an inevitable fact associated with human life and especially with large metropolitan areas.  Equally true is that the polluting impact of this wastewater can be  attenuated at or near source (= at or near the wastewater treatment works) into a product that is substantially less harmful to the environment, as well as being a revenue-earning commodity.

At the very least, the empty halls of the Athlone Power Station still provide a site for a decent pilot study.


Thames Water ordered to pay record £20 million for river pollution

31 March 2017

Thames Water Utilities Ltd sentenced in the largest freshwater pollution case ever taken by the Environment Agency

(Press Release First published:22 March 2017).

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Sewage “spilling continuously” into Butterworth river (South Africa)

31 March 2017

Residents and livestock suffer while year-old leak is unfixed

(Droplets comment: readers of this sad story might be interested in the one that follows it…)


Photo of bridge and dirty river

Sewage has been leaking into the Gcuwa River near Butterworth for more than a year. Photo: Mbulelo Sisulu

Sewage has been leaking into the Gcuwa River near Butterworth for more than a year, after damage to the pump mechanism caused by illegal electricity connections.

Amathole District Municipality spokesperson Siyabulela Makunga confirmed that two sewage pump stations in Butterworth were “spilling continuously” into the river.

According to Makunga “the community have connected illegally to the incoming electricity supply, damaging the cables and pumps”. Eskom had agreed to move the transformer at one of the pump stations, but had not done so.

But Eastern Cape Eskom spokesperson Ntombekhaya Mafumbatha said she did not have evidence that the municipality had reported the problem. “Leaking sewage is urgent and needs to be fixed very quickly because it affects many things,” she said.

The leakage started at the beginning of 2016. Residents say the matter was reported to the councillor, but nothing was done.

Read more »

SA’s Drinking Water Reservoirs are full of shit. Literally

30 September 2016

(Guest post by Graham Sell – republished with permission – emphasis added)

It was only when I started looking into the controversial award of a Water Use Licence (WUL) to Metsimaholo Municipality (enabling them to pump treated and partially-treated effluent from their Refengkgotso sewerage works into the Vaal Dam at Deneysville) that I realised how deeply in the pooh we are across the whole country – both literally as well as metaphorically.

Before getting back to the specifics of the Refengkgotso pipeline, take a look at the compliance table below to see how your province fares in the Green Drop stakes. The Department of Water Affairs and Sanitation (DWS) Green Drop awards program sets standards for processing raw sewage into an acceptable state for reintroduction into the environment.  As a cornerstone of the program, municipalities are required to regularly test the effluent from their waste water treatment plants to ensure that it complies with prescribed microbiological, chemical, and physical standards.

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A South African election promise that I would like to hear, but probably won’t

15 May 2016

I realise that quite some time back I missed the memo when it was announced that STOP signs were henceforth to be treated as a YIELD.  What I fail to grasp is why so many South Africans consider it clever or perhaps ‘cool’ to deliberately disobey this simplest and possibly most important rule of the road, STOP.  I understand that the present phenomenon is described by some or other psychological theory – something to do with sheep and incalculable stupidity I would imagine…

In the area where we live there are, inter alia, two occasions when anyone aware of these new ‘road rules’ needs to be especially vigilant.  The first is on Sundays when church congregations flee their sixty minutes of weekly piety.  They manner in which they ignore the STOP signs in their rush to get away is quite beyond belief – but I have to assume that it is due to a need to get out there and spread the word of God. On more reasoned and cynical consideration, however, I would hazard a guess that it’s rather a need to get out there and spread the lunchtime barbecue rolls.  Clearly modern religious practice has lost sight of the “do unto others as you would have them do unto you” clause?   In many countries of the world, not stopping at a STOP sign is a ‘lock up and go’ offence – the authorities lock you up and go off to catch another moron equally lacking in compassion for his or her fellow man.  Do this in Norway and you could end up down the passage from Anders Breivik.

The second danger period occurs shortly after schools close, especially the junior variety. I have lost count of the number of times that a paragon of motherly virtue, in her late-model ‘mommy-wagon’, flies through an intersection with hardly a pause.  Such inexplicable idiocy, and lack of any semblance of social ethics, is often compounded by the driver being on her mobile phone and/or with unrestrained small children in the vehicle.  On a couple of occasions I attempted drawing attention (let’s call it ‘constructive criticism’) to the fact that a collision was narrowly avoided, by hooting at said ‘mother’.  I don’t do this anymore – as the sound of hooting seems to precipitate some form of finger cramp, resulting in the driver having no hands on the wheel – the phone in one and cramp in the other (“Mommy, what does that sign you are making mean…?”).

Here’s an example:  CFM 32058 making a high speed run through the 3-way Stop intersection at Mountain and Gordon Roads, Somerset West.  She then makes off at very high speed – well over the urban limit – and disappears momentarily from sight, only to get held up at the next intersection… (just for the record she was not on her way to the hospital, she ducked away into Bizweni).

The air in South Africa is currently permeated with recently dusted off and warmed up election manifesto ‘promises’.  One I would like to hear would focus on the aforementioned problem – to the extent that it would advocate a change in the law that made not stopping a ‘suspension of drivers license for six months minimum’ offence.  Command and control is what is needed here, there is no leeway for waiting for society to heal itself.




So little water, so much poor management of it

17 November 2015

South Africa needs an infrastructure revolution and a change in values if it is to avoid being left high and dry, writes Mmusi Maimane

THEY say countries should never waste a crisis. We need to see South Africa’s drought and water shortages as such an opportunity.

Our water system has reached a point where it could limit economic growth and development, which will therefore affect our social wellbeing and stability. This applies to both the quantity and quality of water available to us. Right now, we need to urgently and strategically manage our transition from a demand-driven to a supply-constrained economy.

With respect to quantity, we are experiencing a rapid increase in demand coupled with a steady decrease in supply. Population growth, immigration and changing consumption habits are pushing up demand. Supply is falling due to crumbling, poorly managed infrastructure aggravated by a shortage of engineers; an El Niño event; and a climate change trend making South Africa a hotter, drier country. This constitutes a looming crisis, despite Water and Sanitation Minister Nomvula Mokonyane’s protestations to the contrary.

To make matters worse, the quality of water is also declining. Our municipal waste-water system, which treats and recycles used water, is under extreme pressure, with as many as 90% of waste-water treatment works dysfunctional. Urban and industrial effluent runs into our rivers, while acid mine drainage and the large amounts of hazardous waste that we are unable to deal with are further contributors to this problem.

It is generally agreed that at least a third but possibly up to two-thirds of our national stored water resources (in dams and watercourses) is eutrophic, meaning that it has dangerously elevated levels of nutrients that cause blue-green algae to flourish. This, in turn, produces chemicals toxic to our health. So pollution and waterborne diseases are also risking our supply.

The political and social risks of this deteriorating situation should be clear. Economic growth — and thus job creation — will be increasingly limited, leading to social instability. This will be exacerbated by rising food prices due to our increasing inability to withstand periodic droughts; our re-allocation of water from agriculture in an attempt to prevent job losses in more labour-absorbing sectors of our economy; and the general desiccation of our land due to overuse and poor farming practices.

Water insecurity will also drive energy insecurity, since energy production relies on water. Of course, water can be “imported” by means of food and energy imports that used water in their production cycle, but that option is becoming less likely because of our balance-of-payments deficit, a situation aggravated by our government’s penchant for presidential jets and the like.

As ever, the poor (particularly women and children, to whom it generally falls to collect water for cooking and washing) will suffer disproportionately — and are least able to adapt, move, or buy their way out of the problem. They are also afflicted by the least competent municipalities.

This is the bad news.

The good news is that a lot can be done to reverse this dismal state of affairs, avert the looming disaster and put South Africa back on the road to water security. Says water expert Professor Anthony Turton: “The transition can be managed, but it will require a carefully formulated strategy, driven by a policy that is based on the best available science, held together by sound political leadership embedded in robust institutions.”

Our challenge is to significantly boost water supplies, massively improve efficiency of use and increase our resilience to drought — all while ending the injustices of water provision in the past and ensuring the integrity of our ecology.

There is massive waste and inefficiency in our water systems. Wastage is due to poorly maintained infrastructure, with definitely at least a third but quite possibly up to two-thirds of all reticulated water being lost to failing infrastructure and theft. This means there is massive scope to boost our supply, but we need to channel resources — our best engineering talent and funds — to reverse the infrastructure decline.

This waste is compounded by the inefficient use of water by various sectors. We need to identify the sectors with the most potential for improvement. Here, the agricultural sector offers the greatest gains, because it uses 63% of our water for irrigation. Land management on farms has a major impact on water availability and quality. Soil erosion, for example, changes the flow of our rivers and reduces the storage capacity of our dams, resulting in the need for expensive water filtration and treatment systems. Poorly applied fertiliser and pesticides run off into rivers, polluting our water and killing aquatic life. Clearing alien vegetation is also a cost-effective, job-creating way to increase water supply on farms, because invasive plants use more than twice the water of indigenous vegetation.

Essentially, we need not only an infrastructure revolution, but also one of values. We need to recognise that our economy — and, ultimately, our wellbeing — are reliant on our national ecology, and start to treat our natural environment with the respect and care it deserves. Properly cared for and managed, our wetlands, rivers and organic-rich soil purify our water and provide resilience in times of drought. We need to restore, respect and protect our ecosystems. This requires strong leadership, which we’re not seeing right now.

Similarly, there is vast scope within our manufacturing processes and energy production for water saving, not only through efficiency gains, but through fundamentally changing the way we produce, consume and live. Once again, this begins with good governance.

As in so many other areas of state management, we know what needs to be done, but are falling short on implementation. As Mokonyane said in an interview with Chris Barron last weekend: “If you ask me, we need more bodies with the knowledge and capability, we need better management and better planning. Having the right people in the right place with the ability to do the job.” I couldn’t have said it better myself. All I would add is: “And with the government clearly having failed to rise to this challenge, it is time for a change of leadership, before we are left high and dry.”

•Maimane is the DA leader

(This article first appeared in the Sunday Times, 15 November 2015, page 18.  Republished with permission of the DA and the Sunday Times).


Biohavens – the only truly bio-mimicking floating wetland – Case Study #20 – nutrient removal

14 November 2015

Nutrient Removal from Reclaimed Water with Floating Treatment Wetlands

Project Location: Pasco County, Florida USA

An independent study conducted by CH2M Hill demonstrates the ability of BioHaven® floating treatment wetland (FTW) technology to further reduce nutrient levels in reclaimed municipal wastewater, which would assist in meeting total maximum daily load (TMDL) limits. In addition to removing total nitrogen (TN) and total phosphorus (TP), FTWs provided the ancillary benefits of:

  •   Increasing wildlife habitat;
  •   Reducing local nuisance insect populations; and
  •   Increasing pond aesthetics.


CH2M Hill supervised installation of 20 FTWs in a test pond containing approximately five million gallons of reclaimed water from the Pasco County Master Reuse System (PCMRS). Each FTW measured 8 ft x 10 ft and accommodated 154 plants. The primary objective of this study was to quantify nitrogen removal by the FTWs, in the hopes of demonstrating the benefits of FTWs in TMDL-limited watersheds. Total nitrogen is the parameter currently limiting reclaimed water use within the PCRMS. FTWs were envisioned as a more efficient alternate to treatment wetlands where land area may be constrained.

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The PCMRS is a regional reclaimed water transmission and distribution system providing wastewater effluent disposal for Pasco County and the City of New Port Richey. With 15 golf courses and approximately 12,000 residential users connected, the PCMRS reclaims approximately 20 million gallons per day (mgd) of advanced secondary treated effluent from seven local WWTFs.

Water Quality Effects

FTWs had a positive effect on TN, TP and pH as shown below:

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Removal of TN and TP was substantially higher during the FTW performance period than during the control period. Nutrients were still removed during the control period, probably due to some bacterial activity and solids settling in the test pond. However, bacterial and plant nutrient removal processes were substantially enhanced during the performance period. Net nutrient removal rates attributable to the FTWs can be calculated by subtracting the control removal from the performance removal. Those rates, based on the amount of FTW present in ft3, were 1.7 lb/yr/ft3 for TN and 0.54 lb/yr/ft3 for TP.

Most of the total nitrogen was present as nitrate. It was found that water temperature, which averaged 23oC during the performance period, did not affect nitrate removal over the temperature range examined.

pH increased in the test pond as algal photosynthesis produced a large amount of alkalinity. However, this pH increase was mitigated during the performance period and values (recorded automatically every hour) were much less variable with the FTWs.

No removal of TSS or BOD was seen in the study. TSS increased by over an order of magnitude due to algal growth in both the performance and control periods. The influent BOD was typically less than 5 mg/L.

Removal Mechanisms

It has been noted in previous FTW studies that only 10-20% of the nutrient removal is performed by plants, with the majority of nutrient removal performed by bacteria attached to the FTW matrix and plant roots (biofilm). In the Pasco County study, plant samples were harvested during the performance and control periods to analyze the nitrogen, phosphorus and carbon contained in the plants. It was estimated that only 0.3% of the nitrogen removed was contained in above-ground plant matter during the performance period, and 0.8% during the control period. The remaining nitrogen removal can be attributed to plant roots, bacterial activity and chemical/physical processes. A mass balance estimated that 57% of the TN removed during the performance period was denitrified to nitrogen gas.

Ancillary Benefits

Four main benefits have been historically attributed to FTWs:

  1. Water purification,
  2. Habitat improvement,
  3. Erosion protection and
  4. Enhanced landscapes.

Benefits identified in the Pasco County study were:

  •   Wildlife habitat. Wildlife was observed on several occasions utilizing the FTW habitat. Birds included black-necked stilts, clapper rails, boat-tailed grackles and ducks (which built nests). Turtles were also observed resting on the FTWs.
  •   Nuisance insect species control. The FTW habitat also benefits smaller organisms such as aquatic and terrestrial insects. These invertebrates find refuge and food sources within the dense submerged roots and emergent vegetation. Insects that are dependent on water bodies for habitat, such as dragonflies and damselflies, can help reduce the local populations of nuisance species through natural predation. During the performance period, WWTF staff noted no large hatches of midges, which can be a nuisance to people and even be vectors for the spread of diseases such as West Nile virus, and – contrary to previous years – there were no complaints by neighboring residents.
  •   Aesthetics. Adding FTWs to the WWTF pond increased the overall aesthetics. The variety of grasses, rushes and flower plants on the FTWs provided natural aesthetics to a pond otherwise devoid of vegetation.


  •   Floating treatment wetlands (FTWs) installed in a test pond removed substantial concentrations of total nitrogen and total phosphorus from reclaimed water. Nutrient removal with FTWs was significantly greater than when the FTWs were removed from the system.
  •   Plant uptake provided only a small percentage of the total nitrogen removal.
  •   FTWs provide productive habitant for invertebrates and wildlife. A diverseselection of vegetation and species was sustained on the islands.

{This is the last of 2o case studies published in this series}

Biohavens – the only truly bio-mimicking floating wetland – Case Study #19 – Fish habitat

13 November 2015

Evaluating BioHaven Floating Islands as Fish Habitat in the Chicago River

Project Location: Chicago, Illinois USA

Masters student Joshua Yellin conducted a study on the Chicago River, listed as one of America’s most endangered rivers, which showed that floating treatment wetlands (FTWs) may provide enhanced fish habitat. FTWs used in the study were BioHaven floating islands donated by Floating Island International. This project was undertaken by Mr. Yellin as part of a Master of Science degree in Natural Resources and Environmental Sciences at the University of Illinois at Urbana-Champaign.


The Chicago River is a prime example of an urban watershed facing many anthropogenic pressures, including pollution, invasive species and habitat destruction or severe alteration. In 2011, American Rivers named it one of America’s ten most endangered rivers because 1.2 billion gallons of treated, but not disinfected, wastewater is dumped into the river every day. Another major problem is habitat destruction and alteration caused by Chicago’s development. Over the past 150 years, much of the river has been dredged and channelized to accommodate barges, allow for easy maintenance and prevent erosion. A challenge now is finding a practical solution to the loss of habitat.

Channelized rivers like the Chicago River have lower-quality fish assemblages than natural rivers, in large part because of low habitat heterogeneity. Floating treatment wetlands (FTWs) were proposed as a viable enrichment option for fish habitat. The question is, could FTWs provide better fish habitat than either open water or standard docks?

To assess the effectiveness of FTWs as fish habitat, this study used minnow traps to collect and compare fish species and abundance at three locations: underneath the FTW (the experiment), underneath a floating dock (a control) and in an unshaded area of the river (a second control). All three sites were in the same 100-meter stretch of the Chicago River (Figure 1).

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This study found fish to be present more frequently at the FTW (Figure 2) than at the dock, at a statistically significant level. Fish were caught in the subsurface FTW minnow traps on nine occasions, while fish were caught in the subsurface dock traps on only three occasions. The FTW minnow traps produced 2.04 fish per sampling event, while the dock traps produced 1.11 and the open water traps produced zero fish overall. These results imply that FTWs may be effective habitat for fish in the Chicago River, even more effective than other cover that is currently available to them.

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Possible reasons for the fish increase at FTWs include food supply, plant roots and water quality. First, the woven plastic of the FTW used in this study provided significantly more surface area for bacterial and algae growth than did the dock. This could have supplied a more abundant food supply that could be consumed directly by fish, or indirectly by supporting plankton and macroinvertebrates consumed by fish.

Second, plant roots growing underneath the FTW made it more structurally complex than the nearby dock. These roots also provided more surface area for periphyton, as well as a potential habitat and food source for fish, plankton and macroinvertebrates.

Third, water quality may have been improved under the FTW, which could have played a role in the presence of fish. Other studies have shown that FTWs are effective at improving water quality in rivers and other waterways.


  •   Fish were found significantly more often under the FTW than under the nearby dock.
  •   More fish were caught underneath the FTW than either under the dock or in open water.
  •   These results would appear to justify larger-scale research to demonstrate whether and why FTWs are a sufficient fish habitat solution in the Chicago River and elsewhere.

Yellin, J.M. (2014). Evaluating the Efficacy of an Artificial Floating Island as Fish Habitat in the Chicago River: A Pilot Study. Unpublished Master’s capstone project. University of Illinois, Urbana-Champaign.

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).


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).


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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