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Effective midge fly control is essential in wastewater treatment plants to prevent red worm infestations and maintain plant efficiency.
Midge flies, or chironomids (Chironomidae), commonly occur in wastewater treatment plants and pond systems. The red worm that forms the midge loves the nutrient-rich conditions in a wastewater treatment plant and feeds off bacteria and sludge. The worms will eat mixed liquor and once transformed into adults, clog filters and building entrances.
Facilities looking for biological midge control solutions can rely on SELECT-Midge® to protect their wastewater ecosystem.
By using SELECT-Midge® with SELECT-Larvae®, operators achieve highly effective midge control, addressing both larvae and adult midge populations in wastewater treatment plants. Proper midge control is critical because uncontrolled midge populations can disrupt the microbial balance, damage equipment, and compromise treatment efficiency. The combined application of SELECT-Midge® and SELECT-Larvae® ensures red worms are targeted directly, breaking the midge life cycle and preventing adult emergence. This comprehensive midge control approach helps maintain optimal sludge quality, reduces the risk of filter clogging, and minimizes operational disruptions.
Consistent midge control also reduces odor problems and improves overall water quality by keeping the bacterial ecosystem healthy. Facilities that implement this program benefit from a proactive solution, rather than reactive treatments that only address symptoms. With SELECT-Midge® providing precise biological action and SELECT-Larvae® enhancing effectiveness by exposing hidden larvae, operators achieve superior midge control across the entire wastewater system.
In addition to improving operational efficiency, this midge control strategy is safe for non-target organisms, including fish, birds, and beneficial aquatic life. By focusing on targeted biological control, facilities can reduce chemical usage, prevent environmental harm, and maintain regulatory compliance. Effective midge control ensures a cleaner, more reliable, and low-maintenance wastewater operation while protecting the surrounding ecosystem.
SELECT-Midge® is a professional-grade, EPA-registered biological larvicide for use against midge flies and the myriad of issues they cause within a plant, detailed below.
It contains a species of bacteria called bacillus thuringiensis, an approved larvicide for controlling red worms and midge flies in wastewater treatment plants and waterways. SELECT-Midge® can either be poured into the aeration basin or secondary clarifiers, depending on where the redworm problem is. It also works extremely well in UV disinfection chambers. SELECT-Midge® has also been proven effective against bristle worms (aeolosoma) and water fleas in the field.
The SELECT-Midge® Advantage
SELECT-Midge® stands out in the market as it contains 6 complex biological larvicide compounds (called endotoxins) that are highly effective against red worms but safe for fish, birds, mammals, and other lifeforms. With 6 endotoxins, it is difficult for red worms to build a resistance, giving it an advantage over single endotoxin larvicides like Strike™.
SELECT-Midge® and SELECT-Sludge®:
SELECT-Midge® alone can eliminate 70–90% of the red worm population and significantly reduce midge fly activity. When used alongside SELECT-Sludge®, which breaks down cocoons and exposes more worms to the treatment, the effectiveness typically increases to nearly 100%, delivering complete control.
Midge flies (chironomids) are common in wastewater plants and ponds. Their larvae, called red worms, feed on bacteria and sludge in nutrient-rich wastewater. As adults, they can clog filters and entrances, sometimes limiting visibility for operators.
Effective control of midge flies is crucial in wastewater systems to prevent infestations and maintain proper sludge and nutrient balance. Red worms also called blood worms, are found in mixed liquor. Over a period of ten days, the eggs hatch into red worms and then pass through the pupa stage to become adult midges. With no aquatic life to feed on the midges, their life cycle runs uninterrupted, and they multiply fast. If left unchecked, these insects will cause poor settling, high TSS, and disrupt the bacterial environment. I mixed liquor infested by red worms can see reduced solids, stringy or clumpy sludge, and poor nutrient removal. Not to mention the adult midges are a nuisance that attracts birds and spiders.
*There is no LC50 for aquatic organisms except for mosquito larvae. All other organisms except nuisance flies and midges Psychoda, Chironomus, and Chironomine are not affected by the product. Minnows, fish, Daphnia, and even other aquatic insects can’t be killed by the active ingredient in the formulation. SELECT-Midge® is specific to mosquito, blackfly and midge larvae and again is not toxic to anything in the application sites except the larvae of these targets. The LC50 against susceptible mosquito larvae averages 0.15 micrograms per millilitre
Companion Products SELECT-Midge® + SELECT-Sludge®:
Although SELECT-Midge® alone can eliminate midge flies, the most effective and lasting results occur when it is used together with SELECT-Sludge®.
SELECT-Midge® is a potent, EPA-registered biological larvicide, but it must reach the red worms to work effectively. Red worms often form protective cocoons using BOD, which SELECT-Midge® cannot penetrate. SELECT-Sludge®, a biocatalyst, breaks down these tough cocoons, allowing SELECT-Midge® to fully target and eliminate the red worms.
– Wastewater Plants
– Pond Systems
– Drain Lines
– Kills Red Worms and Prevents Adult Midge Emergence
– Stops Red Worms from eating MLSS
– Bacteria-Based Larvicide
– Red Worm Impact on Wastewater – Breaks Midge Development Cycle
SELECT-Sludge® is a catalyst that degrades cocoons, exposing more of the worms to the SELECT-Midge® treatment. When used alone, we typically see SELECT-Midge® kill 70 to 90 percent of the redworm population, and dramatically decrease midge fly activity. By adding SELECT-Sludge® to the treatment, we can typically improve the kill to 100 percent, or very near 100 percent.
SELECT-Midge® + SELECT-Sludge®: while SELECT-Midge® alone can kill midge flies, powerful lasting results come when using it in conjunction with SELECT-Sludge®.
SELECT-Midge® is a highly effective, EPA-registered biological larvicide, but to work it must be able to reach the red worms. This is where SELECT-Sludge® comes in to aid the larvicide. Red worms will use BOD to build protective cocoons around themselves, which SELECT-Midge® cannot penetrate. SELECT-Sludge® is a biocatalyst that specializes in dissolving tough forms of undigested BOD. SELECT-Sludge® is able to easily degrade the red worm cocoons so that the SELECT-Midge® can fully reach the red worms.
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