VectoBac – Red Worms in Wastewater

Vectobac is a highly effective, US EPA-registered biological larvicide.

It contains a species of bacteria called bacillus thuringiensis, an approved larvicide for controlling redworms and midge flies in wastewater treatment plants and waterways.  Vectobac 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.

If left alone, redworms can wreck havoc on your bacterial population as they consume your mixed liquor.  If left alone they can result in reduced solids, stringy or clumpy sludge, and poor nutrient removal.  Not to mention the midge flies are a nuisance that attract birds and spiders.

This is a highly effective technology, and is a great alternative to methoprene based growth regulators like Strike TM.

Not registered for use in the state of New York.

5 Gallon Case


Midge Fly Impact on Wastewater

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 buildings entrances.  Some operators have told us they couldn’t see past their hand in some buildings.

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 midge flies.  With no aquatic life to feed on the midges, their life cycle runs uninterrupted, and they multiply fast. If left alone midge flies will cause poor settling, high TSS, and disrupt the bacterial environment.

*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, even other aquatic insects can’t be killed by the active ingredient in the formulation.  VectoBac 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 milliliter

Red Worm Midge Fly


  • Wastewater Plants
  • Pond Systems
  • Drain Lines


  • Kills Red Worms and resulting Midge Flies
  • Stops Red Worms from eating MLSS
  • Bacterial Based

Product Info Downloads

Download Vectobac SDS


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