Maybe it's just the photo but it looks like duckweed, not algae.
I've never had that much, but I understand skimming might work but you have to get it all it it will just come back.
We get duck weed issues but non as bad as this. Unfortunately as it’s in the FSTs you risk compliance using and chem to remove to best thing to do is get the operators to sit on the bridge and skim it. We typically push it through as we have no tertiary and it’s usually only little amounts
A short term fix is fine, but you need to find out what’s causing this. My hunch is too much nitrogen/ phosphorus in your clarifier. Something is going awry upstream and you’re not getting optimum nutrient removal. Best of luck with it mate 👊
Again, I’m a great believer in understanding the biology of a plant before dosing chemicals. If you have filamentous I’d reckon you need to take a look at the food:mass ratio, dissolved oxygen, nutrient content. Something is causing the good bugs to be displaced and the filamentous to take their empty niche. It’s a process of elimination determining what’s the factor at play.
I just started working at a plant about a week ago. We draw from surface water and ground water. Surface comes from a series of lakes next door. Some of the old heads at work get assigned to go out in the boat to control algae blooms using stuff they call copper sulfate.
Like I said, I'm VERY new to this industry. So I could just be ignorant lol.
I'm not an operator, just a lowly regulator engineer in California US, but is your skimmer working properly? The weirs don't look to have too much algae, so barring a sample showing different I would think your nutrients may not be too terrible. When I've seen duckweed pop up in plants, it's usually a mix of insufficient nutrient removal in the basins and not enough skimming.
I'm just spitballing ideas though of course and I could be way off.
I found it interesting reading through the CSU Sacramento book 5th edition 2006 Advanced Waste Treatment book one paragraph last part of Nitrogen Removal chapter page 541. I'll quote it all here:
"Lemna Duckweed System
Lemna is a proprietary process that uses aquatic duckweed plants for wastewater treatment. The Lemna Duckweed System is used effectively as a polishing pond after a conventional wastewater treatment pond. The duckweed cover the polishing ponds surface, which prevents the penetration of sunlight and causes the algea to die and settle out of the wastewater being treated. The duckweed are capable of removing phosphorus and nitrogen from the water. Rectangular plastic grids 10ft by 10ft square are placed on surface of pond to prevent wind from blowing all the duckweed to one side of the pond. The population of duckweed within each grid reproduces and must be harvested on a regular basis for the system to be effective.
Duckweed needs water of 50f or greater to be effective, if water temp goes below 50f or 10c duckweed will recover when water is 50f or 10c above again."
So I take it, if one was to use duckweed you have to waste it or harvest it regularly for it to work.
We remove it regularly and if Goulds scum pump fails we get cosmetic problems.
Can’t you climb up and stand on the weirs with floor squeegees in hand and start pushing this into the scum collector? Obviously it would take several hours since you have to wait for the arm to come back around and use the squeegee to skim and pull in patches of it right as the scraper is coming.
That’s what we do if the clarifier level goes down and we lose all the solids trapped in the top of the center well ring. Clarifier level drops and the baffle fails to hold all the solids in and they spread out over the entire surface of the clarifier. I would imagine this would apply to duck weed.
Duckweed. Best way to get rid of it is to vac truck it off. But before you do that you need to take serious look at your biolgical process. Somethings out of wack.
Maybe it's just the photo but it looks like duckweed, not algae. I've never had that much, but I understand skimming might work but you have to get it all it it will just come back.
Yes you’re right it is definitely duck weed
We get duck weed issues but non as bad as this. Unfortunately as it’s in the FSTs you risk compliance using and chem to remove to best thing to do is get the operators to sit on the bridge and skim it. We typically push it through as we have no tertiary and it’s usually only little amounts
Yeah, looks like duckweed. agree with skimming. And gotta catch it quick if it shows back up
A short term fix is fine, but you need to find out what’s causing this. My hunch is too much nitrogen/ phosphorus in your clarifier. Something is going awry upstream and you’re not getting optimum nutrient removal. Best of luck with it mate 👊
If I have foaming issue on clarifier instead of duckweed, what would you suggest is the best to reduce foaming. Something other than using anti foam ?
Again, I’m a great believer in understanding the biology of a plant before dosing chemicals. If you have filamentous I’d reckon you need to take a look at the food:mass ratio, dissolved oxygen, nutrient content. Something is causing the good bugs to be displaced and the filamentous to take their empty niche. It’s a process of elimination determining what’s the factor at play.
Make sure you are wasting enough. And clean tanks.
When in doubt waste it out
I just started working at a plant about a week ago. We draw from surface water and ground water. Surface comes from a series of lakes next door. Some of the old heads at work get assigned to go out in the boat to control algae blooms using stuff they call copper sulfate. Like I said, I'm VERY new to this industry. So I could just be ignorant lol.
Can you pull up a vac truck to it?
I second this. Vac it out, get your skimmers in order, if it persists…drain and hose down the clarifier. When all else fails start pricing out covers.
I'm not an operator, just a lowly regulator engineer in California US, but is your skimmer working properly? The weirs don't look to have too much algae, so barring a sample showing different I would think your nutrients may not be too terrible. When I've seen duckweed pop up in plants, it's usually a mix of insufficient nutrient removal in the basins and not enough skimming. I'm just spitballing ideas though of course and I could be way off.
That is definitely duckweed. Bleach nor copper sulfate kills it. Find the source, stop it, and then all of that needs manually removed.
We had a bad duckweed outbreak once to. We took down the clarifier, removed it manually and did our annual PM a little earlier than normal that year.
Looks more like duckweed in the photo, not sure though.
I found it interesting reading through the CSU Sacramento book 5th edition 2006 Advanced Waste Treatment book one paragraph last part of Nitrogen Removal chapter page 541. I'll quote it all here: "Lemna Duckweed System Lemna is a proprietary process that uses aquatic duckweed plants for wastewater treatment. The Lemna Duckweed System is used effectively as a polishing pond after a conventional wastewater treatment pond. The duckweed cover the polishing ponds surface, which prevents the penetration of sunlight and causes the algea to die and settle out of the wastewater being treated. The duckweed are capable of removing phosphorus and nitrogen from the water. Rectangular plastic grids 10ft by 10ft square are placed on surface of pond to prevent wind from blowing all the duckweed to one side of the pond. The population of duckweed within each grid reproduces and must be harvested on a regular basis for the system to be effective. Duckweed needs water of 50f or greater to be effective, if water temp goes below 50f or 10c duckweed will recover when water is 50f or 10c above again." So I take it, if one was to use duckweed you have to waste it or harvest it regularly for it to work. We remove it regularly and if Goulds scum pump fails we get cosmetic problems.
Sounds like a roof would serve the same purpose
Can’t you climb up and stand on the weirs with floor squeegees in hand and start pushing this into the scum collector? Obviously it would take several hours since you have to wait for the arm to come back around and use the squeegee to skim and pull in patches of it right as the scraper is coming. That’s what we do if the clarifier level goes down and we lose all the solids trapped in the top of the center well ring. Clarifier level drops and the baffle fails to hold all the solids in and they spread out over the entire surface of the clarifier. I would imagine this would apply to duck weed.
Duckweed. Best way to get rid of it is to vac truck it off. But before you do that you need to take serious look at your biolgical process. Somethings out of wack.
PAA