In normal waters, midge larvae feed on decaying plant materials and associated decomposing bacterial/fungi. While this helps recycle nutrients in nature, the larvae finding an abundant food source in with wastewater MLSS can cause a major loss of total solids. Faster growing heterotrophic bacteria can usually keep up with the problem. It is the slower growing AOB/NOB and PAO organisms that are most effected during a midge fly outbreak.
What can be done? The EPA has approved two options for combatting midge fly larvae.
- Bacillus thuringiensis spores (Bt) are a natural insecticide to the midge larvae. Brandnames include VectoBac and AquaBac XT.
- Strike is an approved insect growth regulator that stops larvae development. (It is similar to growth regulators used for flea control in pets).