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"Phoslock is very safe and has been successfully applied in over 320 projects around the world"

Today, Thursday, May 25th, Smart Water Magazine in collaboration with Phoslock Environmental Technologies, organized a live webinar titled Phosphorus pollution control: insights into Phoslock applications in which nutrient pollution, currently one of the most widespread and challenging environmental issues worldwide, was discussed in depth.

This form of water pollution occurs when an excess of nitrogen and phosphorous flow into water bodies, causing undesirable changes to aquatic systems. While it is a natural phenomenon, human activity can accelerate it, for example, a surge from industrial, urban and agricultural activities accelerates this phenomenon, known as eutrophication, in lakes, streams and coastal waters.

Readers may now watch it on-demand by registering here.

In this webinar, Phoslock Environmental Technologies explains in detail the causes of phosphorus pollution, the management costs, and the company’s solution: Phoslock®

Cristina Novo, Technical Editor at Smart Water Magazine, moderated the online event and in her introductory speech highlighted that nutrient pollution remains a serious problem in many waterbodies and continues to be a difficulty to get under control. Phosphorus can be retained within waterbodies and cycled from the bed sediments to overlying waters through internal loading. This way, continued poor water quality can delay recovery for potentially decades, leading to the deterioration of lake structure and function and ultimately biodiversity loss.

About Phoslock Environmental Technologies (PET)

Cristina Novo introduced Damian Whelan, General Manager at Phoslock Environmental Technologies, who began his presentation by introducing his company. Based in Australia, Phoslock Environmental Technologies (PET) offers water treatment and remediation solutions to address excess nutrients in water bodies. The firm’s flagship product, Phoslock®, was originally developed by the Australian national science agency (CSIRO) more than 20 years ago.

During his presentation, Whelan explained about how the company works: “We are an Australian company headquartered in Melbourne helping to solve global water quality problems. We address growing environmental, economic and human health challenges. We’ve been doing this successfully for over 20 years with our proprietary technology originally developed by CSIRO.”

Phoslock is an in-lake remediation solution made of Lanthanum-modified bentonite, used to aid quicker recovery times in lakes suffering from internal loading, by reducing phosphorus concentrations in the water column and reducing the amount of phosphorus released from lake-bed sediments.

Whelan also highlighted during the presentation that Phoslock® has been extensively assessed by independent experts. He said: “More than 150 peer-reviewed scientific papers have reported on the efficiency and environmental impact profile of Phoslock treatment.” Furthermore, the solution has been successfully applied in over 320 projects around the world. Currently, the firm is active in Canada, the United States, Australia, where its headquarters are located, New Zealand and several European countries, including the UK, Germany, The Netherlands and Belgium.

Whelan said: “Strong independent and scientific validation is a key requirement for not only our clients but governments and regulatory authorities.”

Phosphorus, a global issue

Phosphorus demand in the agricultural sector is predicted to double by 2050

Next, Dr Kate Waters-Hart, Group Manager, Aquatic Science at Phoslock Environmental Technologies, began her presentation focused on phosphorus pollution. Although phosphorus is an essential nutrient, an excess amount in surface water can lead to the explosive growth of aquatic plants and algae. Waters-Hart continued by saying that “elevated phosphorus concentrations in freshwaters are contributing to changes in their structure and function which are leading to unprecedented loss of freshwater biodiversity.” This is particularly worrying, she said because phosphorus demand in the agricultural sector is predicted to double by 2050. Moreover, losses of phosphorus from wastewater to freshwaters are set to increase globally by up to 70 per cent by 2050, according to the latest research.

Not only is phosphorus pollution worrisome causing fish kills and harm to other aquatic life, but it is also expensive to control once it has been released into the environment. Dr Kate Waters-Hart pointed out during her presentation that management costs of nutrient pollution in the United States are estimated at US$2.2 billion a year, a figure which has surely increased in these last years. “By 2080, we are expected to see loss by more than 400 million pounds due to climate warming in the UK alone,” highlighted Waters-Hart.

She next went on to speak about the directives that have been set up globally to safeguard freshwaters, but also trying to improve them. For example, in Europe, the Water Framework Directive. Even so, Dr Kate Waters-Hart stressed that “40% of lakes even under directives such as the EU one, are failing ecological water targets and more than 83% of freshwater habitats in the EU are classed as unfavorable.” 

What is Phoslock® and how it works

Dr Kate Waters-Hart explained the various technologies, physical solutions like sediment dredging, and physical and biological methods that currently exist on the market to remove excess phosphorus. These solutions according to Waters-Hart also had various disadvantages depending on the type of water body they were applied to. She then introduced the company’s flagship product, Phoslock®, which consists of lanthanum-modified bentonite. Phoslock® works by utilising the ability of lanthanum to react with phosphate. Removal of phosphate by lanthanum has a molar ratio of 1:1 which means that one ion of lanthanum will bind with one ion of phosphate. This binding forms the mineral Rhabdophane (an insoluble and biologically inert compound) which strips phosphate from the water. She then highlighted that “Phoslock is not a chemical, it is a geo-engineered product.”  The nature of the bond between lanthanum and phosphate is such that it will not be broken under any naturally occurring pH range (pH 4-11).

Dose calculation was later on discussed. The speaker mentioned that they look at how much total phosphorus concentration is in the water column, factoring in external factors. “The primary target of Phoslock is to control the phosphorus release of sediment.” To do this, the company does various sequential phosphorus extractions. There are several application techniques that can be used depending on the water body in question, for example, large or small scale.

Case studies

Waters-Hart then showcased several of the company’s success stories, including in The Netherlands, in Kralingse Plas, an artificial lake in Rotterdam. This case study is particularly important for the company as it is PET’s largest application to date. She then also mentioned a successful application in Germany, in a recreational water lake and in an artificial excavation lake in a commercial park. PET has also worked in Lake Elmo in Finland and in the UK.

“There was a paper published looking at 18 different kinds of lakes two years post-treatment and they reported a significant reduction of phosphate and phosphorus following the applications of Phoslock,” said Waters-Hart during her talk.

Dr Kate Waters-Hart also spoke about Phoslock’s ecotoxicity profile. This is an assessment that assesses the hazard potential of existing or new environmental chemicals regarding the ecosystem. She said that the highest Phoslock® TLa concentrations do not exceed the EC50 values of the various pelagic and benthic test organisms, therefore, there is no risk to aquatic life as the concentration is low. “Phoslock is very safe to use and there is no report that it has any effects on aquatic life,” she said.


The company also noted long-term phosphorus removal without an ecotoxic impact

To conclude, Waters-Hart mentioned that in the cases where Phoslock was applied, there was a reduction of both phosphate and phosphorus across different lake types, with either high lake alkalinity or low alkalinity. The company also noted long-term phosphorus removal without an ecotoxic impact.

The webinar finished with a question-and-answer session in which Whelan and Waters-Hart responded to the questions raised by the audience. The various questions included various topics, such as how the Phoslock solution worked with dredging, the kind of lake modelling used by the company and if the firm’s solution is safe for the lake ecosystem.