We have had an issue with our clarifiers for a few years, since our plant upgrade. We now in the warmer seasons, continually deal with excessive amounts of algae in our clarifiers. How can we get this to stop, slow down, or be less out of control? We know it's possible to buy covers for the clarifiers but it's too expensive for our municipality. We have to frequently hose down the clarifiers and scoop algae out to keep things under control.
Algae growth can be excessive in warm weather. Besides covers some companies such as Ford Hall market an automatic brush cleaning system which may be an option for you to consider.
A pressure washer can be used and will speed up the cleaning process especially with the right nozzle. You could also use a small sewer jet if you have one and can access the clarifiers easily and safely with it.
Street brooms and brushes can also be used but may be dangerous if one has to walk the walls of the clarifiers to gain access.
If you clean the weirs and then shut off the flow to a clarifier for a short while and drop the level possibly by opening the drain valve and then spray a mixture of bleach and water on the weir surfaces and allow it to make contact with the remaining algae it may slow down the regrowth some.
In warm weather we use a pressure washer every two weeks and spray the algae off the weirs. Frequent cleaning is easier and faster than infrequent cleaning in warm weather and may do an acceptable job for you.