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Reduce algae to improve the water quality

Treated wastewater is nutrient-rich, and those nutrients fuel algal blooms across the surface of storage and stabilisation ponds. As the algae grow, they drive up pH, BOD, and TSS, the very parameters your discharge permit is written around, making safe discharge or reuse harder and putting you at risk of an exceedance.

Some species also form harmful algal blooms that release toxins and bioactive compounds, a problem the U.S. EPA links directly to nutrient pollution in treated water.

Controlling the algae at the source keeps your effluent within limits without dosing chemicals into water you’re about to release back into the environment.

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Wastewater discharge pipes

What is a wastewater reservoir?

A wastewater reservoir, often a stabilisation pond or lagoon, is an in-ground earthen basin that holds treated or partially treated wastewater for a set retention time before it is discharged or reused. These ponds are a widely used treatment and storage method, relying on natural biological processes over time rather than intensive mechanical treatment. They range widely in size, depth, and degree of treatment.

Because treated wastewater is rich in nutrients, these ponds are highly prone to algae. The nutrients that remain after treatment fuel blooms across the pond surface, which drive up pH, BOD, and TSS, the parameters a discharge permit is written around, and can clog the filters, emitters, and pipes used for irrigation and reuse. Some species form harmful algal blooms that release toxins. Controlling algae in the pond keeps effluent within permit limits without adding chemicals to water about to re-enter the environment.

What defines a wastewater stabilisation pond?

Wastewater reservoirs and lagoons share a set of defining features:

  • Earthen holding basins: in-ground ponds that detain wastewater for a set retention time.
  • Nutrient-rich water: treated effluent retains the nutrients that fuel surface blooms.
  • Classified by oxygen and mixing: types include anaerobic, facultative, aerobic, and aerated lagoons.
  • Permit-bound discharge: pH, BOD, and TSS must meet limits before release or reuse.

Why wastewater reservoirs need source-level algae control

Wastewater reservoirs differ from other water bodies because the algae problem sits right at the compliance boundary. Treated effluent is nutrient-rich by nature, and those residual nutrients fuel blooms across the pond surface that push pH, BOD, and TSS beyond permit limits, the exact parameters against which an exceedance is measured, while also clogging the filters, emitters, and distribution pipes used for irrigation and reuse. Some species form harmful algal blooms that release toxins and bioactive compounds, adding a health hazard on top of the regulatory one. Because the water is about to be discharged or reused, the margin for error is narrow.

Dosing chemicals into water you are about to release back into the environment is self-defeating, which is why ultrasound suits wastewater ponds: it controls algae at the source, continuously and chemical-free, while monitoring water quality in real time so operators can hold pH, BOD, and TSS within limits. It works without cavitation and releases no algal toxins, keeping effluent compliant, protecting reuse infrastructure from clogging, and lowering the chemical and operating cost of staying within permit.

NPDES effluent guidelines
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Benefits of ultrasonic algae treatment

Lower chemical expenses

Improve operations of filters and pipes

Prevent toxic algal blooms

Wastewater pond

Algae growth in stabilization ponds

Algae in your storage and stabilisation ponds push up pH, BOD, and TSS, the exact parameters your discharge permit limits. Control it at the source, without adding chemicals to the water you’re about to release.

  • Comply with discharge standards for TSS, pH
  • Safe wastewater discharge
  • Algae can increase BOD levels

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Algae in Wastewater Ponds

An important issue to consider in wastewater reuse and treatment is algae growth, which is relatively common in warm and nutrient-rich waters. Treated wastewater usually contains high levels of nutrients that can cause algae blooms on the water surface of storage ponds and clog irrigation systems (filters, emitters, distribution pipes).

Some freshwater algae can form harmful algal blooms (HABs), and these specific species create health hazards for humans and animals by producing toxins and bioactive compounds that deteriorate the water quality, often driven by excess nutrients in treated wastewater, as described by the U.S. Environmental Protection Agency.

Although there are several methods to treat wastewater, this article focuses on stabilisation ponds (also called lagoons or waste stabilisation ponds). These types of ponds and lagoons consist of in-ground earthen basins in which the waste is detained for a specified time (retention time) and then discharged.

The size and depths can vary, as well as the degree of treatment. Lagoons are typically classified by their degree of mixing and the amount of oxygen dissolved in the water. Examples of lagoons are anaerobic lagoon, facultative lagoon, aerobic lagoon, partial-mix aerated lagoon, and completely mixed- aerated lagoon.

MPC-Buoy

All-in-one solution for controlling algae in wastewater reservoirs.

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Read full case study
American Water
Seven years ago, American Water was the first customer to believe in LG Sonic’s technology. We’re proud of our ongoing, strong partnership.
Anglian Water
Anglian Water reduced up to 95% of algae counts with ultrasonic treatment. The Alton WTW supplies water to 92,214 properties in the Suffolk area, U.K.
Drinking water reservoir
CAASD’s Valdesia reservoir has a surface of 7km²/1700 acres. After years of algae bloom contamination, the utility achieved 87% chlorophyll a reduction.
Vallecitos Water District
Vallecitos Water District significantly improved TSS, pH, and DO levels. Vallecitos can now provide even higher quality water to their customers.
Three Rivers
A popular public open space with 2 lakes used for water skiing, fishing and sailing was contaminated with algae blooms.
American Crystal Sugar
American Crystal Sugar Company is the first company in the sugar beets industry to start using ultrasound technology to improve water quality.
Auckland Utility
NZ utility needed to reduce blue-green algae in a dam used for water supply. During summer, algae cause damage and increase the process costs.
Dubai Municipality
Dubai Municipality selected MPC-Buoy systems to control algae blooms because it's chemical-free and offers real-time water quality monitoring.
Town of Emmitsburg
The main objective was reducing algae during summer, as well as reducing chemicals costs, decreasing backwashes, and preventing clogged filters.

Frequently asked questions

  • What is the impact of LG Sonic ultrasound on zooplankton?

    Recent studies commissioned by the Dutch water board and conducted by research agency Ecofide have concluded that the LG Sonic ultrasound is safe for fish, plants, zooplankton, and other aquatic organisms.

  • Why control the algae if nutrients are the problem?

    Reducing nutrients is, of course, also necessary but difficult to achieve, even in the long-term. The majority of nutrient management methods are costly and require frequent dosing with unknown side-effects for the aquatic ecosystem. Besides, the duration and intensity of algal bloom events is strongly depended not only on nutrients but also on a combination of environmental factors, such as climate change, weather patterns, and an unbalanced ecosystem.

  • What kind of water does your ultrasound work in?

    The MPC-Buoy technology can be installed in freshwater, salt water, and brackish water.

  • What’s the largest water body that has LG Sonic implemented? Any issues linking many buoys?

    We have multiple projects with large numbers of MPC-Buoy units installed. For example, in Dominican Republic, 50 MPC-Buoys are in operation in a 7km2 reservoir. The buoys communicate with each other for optimal treatment.

  • What's the minimum depth of water required for LG Sonic treatment?

    We recommend a minimum water depth of 3 feet / 1 meter.