Algae growth will become a bigger challenge than plastic pollution

Blue-green algae will lay a carpet over Dutch lakes again this summer . That is bad news for recreational users and crippling for aquatic life. “A lot of attention is paid to plastic pollution. Justifiably. But we should be equally concerned about global algae plagues,” says Richard Hardiman, founder of the Rotterdam cleantech company RanMarine Technology. “It is within our power to control plastic, but climate change makes algal growth a much tougher opponent.”

The Rotterdam high-tech company develops and produces water drones in the form of a catamaran that collect waste in lakes, harbours and rivers. These WasteSharks – the design is inspired by the wide mouth of a whale shark – are now active all over the world, from India to the United Kingdom. Disneyland in Florida uses the drones to keep the lakes in the famous park clean and the drones are also active closer to home, in the port of Rotterdam.

The ‘vacuuming’ drones can also collect algae with some adjustments, and that is exactly what the company is doing. According to Hardiman, suffocating algae layers on water pose a major threat to lakes and rivers, but receive less attention than plastic pollution. “Of course we must continue to collect plastic, limit plastic packaging and look for even smarter recycling solutions. Legislation and other packaging materials can also help the environment,” said Hardiman. “Algae will be a much bigger challenge.”

Algae growth can suffocate an entire ecosystem

Global warming is very favourable for algae growth. “We are seeing increased use of growth-stimulating fertilizers to meet agricultural demand and accelerate crop production, as well as for golf courses. These substances also partly end up in the environment and encourage the growth of organisms such as algae in the water and disrupt the delicate balance. The consequences range from unattractive views and unpleasant odors – bad for tourism and overall well-being – to serious disturbances in aquatic ecosystems and essential activities. If an excessive, untreated layer of algae forms on the surface, everything below can die; plants and fish.”

The oceans are also at risk. Many beaches on the east coast of the US are now full of rotting and smelly seaweed: sargassum. This algae species floats in island-like masses between Africa and Mexico, does not adhere to the sea floor and is known as the “Great Atlantic Sargassum Belt.” This seaweed is rich in nutrients and also absorbs
CO2, but too much of it is a threat to people and nature. It leads, among other things, to suffocation of coral, plants and fish.

Lots of nuisance due to blue-green algae

In the Netherlands, cyanobacteria, also known as blue-green algae, cause a lot of nuisance every year. According to Hardiman, these tenacious organisms are difficult to eliminate. “The most effective approach may vary depending on the specific circumstances, the severity of the outbreak and the characteristics of the wetland. Some of
the approaches used are nutrient management, bioengineering (introducing fish or invertebrates for control), water flow and aeration, or chemical treatments. The latter solution can be harmful to aquatic life and cannot be considered environmentally friendly.”

Although Hardiman started his company with fighting floating debris like plastic in mind, drones now also sail to collect algae. The founder states that the Rotterdam company now generates 30 to 40 percent of its turnover from this activity. “Three years ago it was less than 5 percent. In a few years, perhaps 60 to 70 percent of our customers will need help to combat algae.”

Good news for the Netherlands: RanMarine Technology is working with partners in the US to launch a solution for blue-green algae. Hardiman: “With a modified drone that really kills the blue-green algae, without using chemicals. The first pilot in the US is successful, we are excited and will be able to offer this solution soon.”

Published by WaterForum