Removing Duckweed from a Clarifier

[DrLewinstein]

We have a duckweed problem in a 70 ft clarifier. The clarifier is extremely underloaded - 50,000 gpd in a 70 ft clarifier. The flow is from a college student development and the plant is a former textile industry WWTP. The duckweed grew when the clarifier was pumped down for maintenance and then took a long time to fill back up. Does anyone have any thoughts on the best way to get the duckweed out and also to prevent reoccurance? Also, any experiences using diquat?

Thanks,

Paul

 

[adalinaabella]

I did not even use this. So, I don't have no idea.

 

[bimr]

A vac truck is the simple solution.

Consider installing a cover over the unit.

 

[ch81pc]

Diquat is not a good idea as will remain active through your final effleunt and will get into the river and kill that too. Your duck weed will double roughly every 24 hours, so skimming will control but not eliminate your problem. If the weed is staying in the tank and not contaminating your effluent, maybe better to let it just do its thing.
Otheriwse exlude light as Bimr suggests, or if your effluent is good enough, buy some Grass Carp who will eat it for you.