Alternative to Copper based products for Algae Control
Algae problems are nothing new to water in the US. It’s a natural occurring part of the ecosystem, and most would agree it is an important component. However, the problems caused by an overgrowth of algae can be more of a nuisance than a benefit when it comes to dealing with the issues produced by algae overgrowth.
Common Types Of Algae And Why Does It Grow
There are three major groups of algae: Filamentous, Planktonic and Macroalgae. Among those groups, there are four different “kinds” of algae, which will make your water look different colors – Blue-Green, Green, Red and Golden.
The three most prominent algae types being treated in our lakes, ponds and reservoirs are blue-Green and Green algae and Diatoms, that can be either Planktonic, Colonial or Filamentous.
Filamentous algae are Single-Cell algae, that grow together to create long, “string-like” clumps of algae. They are more rigid in structure and can be picked up by hand.
Spirogyra - Green Algae
Planktonic Algae are Single-cell microscopic algae either Green or Blue-Green, the latter which contain gas vesicles, allowing them to float to the surface to improve photosynthesis by absorbing light photons. Photosynthesis allows them to convert CO2 to CH2O being their primary organic building block. The algal cells are free-floating or swimming via flagella in the water or collect in colonies of surface scum. Examples of Planktonic algae are: Microcystis, Anabaena, and Aphanizomenon.
Fire Pond in SC – Planktonic Algae
Microcystis is one of the leading culprits of Harmful Algal Blooms, or HABs, and has been the source of many national headlines around the US for its Microcystin Toxin releases, killing dogs and making humans sick, among other reports.
Macroalgae are very similar to plants and often time have stems and leaves. They will grow from the bottom of the pond, and depending on the depth of the pond, reach the surface. They are some of the most difficult algae to control and typically are mechanically removed.
Chara algae – Branching stems, plant-like
Algae Growth can be caused by several factors, including but not limited to high nutrient load (i.e.: Nitrogen and Phosphorus), stagnant water, lots of sunshine, and warm temperatures. Now, you would think that all ponds in the warmer clients, for example, across the southeast, would have an algae problem based on these four causes. Truth be told, while algae has a presence in most water bodies, it’s the overgrowth of algae that really causes headaches in the form of higher pH levels, increased TSS and TOC, and can also lead to Harmful Algae Bloomsor HABs.
It is these bodies of water that will be examined more closely in the form of two case studies performed over the last two years, and the non-chemical algae control approach taken.
Non-Chemical approaches to Algae Control There are about 70000 species of algae and about 2 million types when sub-species are totaled, making it virtually impossible to test and analyze effective solutions for all algae types out there. In the past 30 plus years, a variety of solutions have been used for algae control, most commonly copper sulphate-based products. But there are also a number of non-chemical solutions on the market. Aeration, bacteria and barley straw are some of the more familiar solutions used today, with ultrasound technology rapidly becoming a trusted alternative around the world.
How Ultrasound Works To Control And Eliminate Algae
Ultrasound was introduced for algae control in the late 1990’s, when a group in Belgium wanted a non-chemical way to treat irrigation ponds for growing flowers. In their research, they found that specific ultrasound frequencies used underwater were able to breakdown microscopic and single-cell algae, preventing growth, reproduction, and regrowth, in their irrigation ponds. By preventing algal growth, the irrigation lines remained clear and no chemicals needed to be used.
Fast forward 20 years, and ultrasound has been widely used in various pond and reservoir applications across the world in over 100 countries. Ultrasound technology can now effectively treat areas as large as 120 acres with a single ultrasound transducer, for the blue-green algae type. Through many generations of ultrasound products from a small, select number of manufacturers, ultrasound is quickly becoming the go-to non-chemical alternative for algae control.
Soundwaves are emitted from the transducer head (apparatus that sits under the surface of the water that converts electrical energy into sound (mechanical) energy, inaudible to the human ear (ultrasonic)). These ultrasonic soundwaves, of over 2000 varying frequencies, hit the harmonic value of the single algae cell, causing internal wall damage via structural resonance. Like an opera singer, who can shatter different sized and shaped crystal glasses their voice. The frequency of the glass can be found by ringing it and when that frequency is sung back to the glass it reverberates with increasing intensity and breaks. Ultrasound works much in the same way in algae cells breaking internal walls or by cracking gas vesicles.
When the algae inner cell wall is torn, internally pumped fluid flow and internal pressure is disturbed causing collapse of the inner cell wall and loss of nutrient transfer. This causes loss of viability in Green algae and Diatoms in 3-4 weeks. In Blue-Green cells, gas from broken gas vesicles migrate to and diffuse out through the outer cell wall making it heavier than water in 3-4 days. Sinking out of light prevents it from further growth due to limited access to sunlight.
In essence, ultrasound is effective in preventing the algae from growing, eating and reproducing, starves the cells, which then sink to the bottom of the water application, and die off. It is important to note that, for detected HABs, ultrasound does not lyse the outer cell wall so residual toxins will not be released. Most Blue-Green generated toxins are made of groups or amino acids and supply the cell or colony with needed Nitrogen. Once out of light, it cannot generate more of these toxins.
Ultrasound technology for algae control is a 24/7 solution. The ultrasonic transducer head, which runs on just 44 volts, and draws only 11 watts of power, is placed in the middle or on the edge of the water body (depending on size and shape). The units are line-of-sight technology, therefore for any irregularly shaped bodies of water, multiple units may need to be installed. For maximum results, the entire water body would need to be treated.
Things To Keep In Mind
Ultrasonic waves targeting algae is a lengthier process than other chemical methods. Whereas you can see more immediate results from using a chemical solution, ultrasound is a slower, more permanent process. Be aware that ultrasound is not effective on all types of algae. For instance, ultrasound is not effective on macroalgae, or plant-like algae. The branching nature of the algae creates a natural defense mechanism that ultrasound cannot penetrate and disrupt. It is recommended that an algae identification be performed prior to installation to determine genus of algae in the water.
Lastly, as with most other solutions, ultrasound should be considered a “tool-in-the-toolbox”, and not a silver bullet solution. Like anything in nature, ponds and their water are ever changing, along with the surroundings, weather, run off and nutrient load. Sometimes a multi-faceted approach needs to be taken for optimal results. An example is called a Water-Trifecta, where aeration, ultrasound and beneficial bacteria are all used simultaneously for overall health of the pond.