Poor Aeration or Mixing

Previous Ice Covered Lagoons

Duckweed Growth

Excess weed growth on lagoon banks harboring flies, and mosquitoes, trapping grease and organics

Alter aerator run time, change or supplement type of aeration

Increase aerator run time, change type of aerator to eliminate ice cover

Increase aerator run time, chemical treatment (DiQuat), physical removal (harvest), add ducks or geese

Physical removal by pulling, mowing, burning, or chemical treatment (Diquat). In winter, lower pond level and allow ice to freeze around weed stem. Increase water level.

Short Circuiting

Ice Covered Lagoons

Recent Reduction in Lagoon Temperature

Algal Bloom

Improve inlet-outlet conditions, add baffles, add recirculation to improve mixing, add or improve aeration of lagoons

Change or add aerator

Increase hydraulic detention time

Increase mechanical mixing, add physical shade (Aquasahde, Photoblue), floating cover such as swimming pool cover, styrofaom sheets or balls, duckweed cover, addition of algal predator such as Daphnia, add chemicals (copper sulfate), addition of constructed wetlands to polish effluent.

Excess Lagoon Mixing or Short Circuiting

Spring or Fall Turnover

Excessive Solids Build Up in Bottoms of Lagoons

See short circuiting solution in previous section

Add different types of aeration to eliminate stratification or add supplemental aeration, add recirculation
 

Physically remove solids by pumping or sludge barge; proper sludge disposal in conformance with State and Federal regulations

Increase in chlorine demanding substance in effluent (H2S1, NO2)

Water Fowl Contamination

Remove solids from chlorine contact chamber, increase chlorine feed rate

Increase chlorine feed rate

Extensive nitrification

Organic Overloading

Excessive Daphnia Growth

Increase aerator run time, add recirculation

Increase aeration capacity, add recirculation

Increase aeration capacity or run time