Any help here would be appreciated.
I have tried to include as much info as I could.

Lately I have had a large amount of foam on the aeration basin (tan in color, large bubbles). Also been having sludge rising in the clarifiers. Started wasting and this alleviated some of the foaming but not all.
Influent enters the plant, goes through screening and grit removal, poly aluminum chloride is added for phosphorus reduction. Then to anoxic zone where ras is mixed in. Flows into EQ tank and then to aeration basins. DO set point in basins is 2.0mg/l, avg DO leaving the aeration basin is 1.8.

0.3 MGD Extended Aeration Plant. Avg daily flow has been 0.18 gpd.
60,000 gallon anoxic tank (EQ tank#1 converted to anoxic zone)
60,000 gallon EQ Tank#2.
2 - 150,000 gallon oval aeration basins. Aerators are paddle style controlled by SCADA via LDO probes.
2 - 30ft diameter clarifiers, 12ft deep. Scraper has a revolution time of about 10 min.
RAS from each clarifier at 100% speed all the time, 145gpm is split 85% to the Anoxic zone/15% to the aeration basins.


Inf. BOD 270, TSS 250, DO <1.0, TKN 140

Eff. pH7.01,BOD 12, TSS 9.0, Total P 0.7, Ammonia 0.41, TKN 8.6, NO2+NO3 as N 74

MLSS#1 3400, 30 min settle 500, SVI 154, F/M 0.097, Sludge Age 11.2 days, pH 6.99, temp 12c, alkalinity 150

MLSS#2 3100, 30 min settle 500, SVI 173, F/M 0.108, Sludge Age  9.5 days, pH 6.95, temp 12c, alkalinity 148

Clarifier Depth of Blanket 1.0ft - 1.2ft

Thanks Dallas, I don not have the equipment to do a good microscopy, looking in the area to find a lab that can. Unfortunately I cannot reduce the RAS rate, only where it goes. Looking at upgrades in the near future to be able to adjust RAS rate. No new source on the septage. Blanket of 1 has been pretty normal throughout, even before foaming.

Since your sludge blanket is already very low (increase RAS even more if you are able to, which it sounds like isn't possible), another option is to increase the DO on the back end right before the clarifier. You won't get denitrification in the clarifier if you have enough free dissolved oxygen. In some cases, this is the least expensive fix. Don't be afraid to go high, this won't impact the biology. It's worth a shot.

Are there seperate RAS streams/ clarifiers for each aeration basin?

good catch Eric- if that's really how the flow goes he has no real EQ tank, just two anoxic zones in series.

You could potentially try taking the other clarifier offline (this will reduce retention time as long as your settling cooperates)

Due to piping and tank config, the EQ tank set up was the only way to create an anoxic zone for ammonia removal.

We have tried throttling back on the ras pumps before but it then caused the pump to rag-up and the pump had to be cleaned at least once per week.

The MLVSS is running about 700ppm below the MLSS #'s

The SVI number I provided was a monthly average, the last actual number I have was 144.

Well, I think you should you need to find out was your setting curve is. Do a sett test reading every 5mins until 30 min mark and a reading every 10 mins there after to at least you get two or three reading the same number. what you want to find out is how long just it take for the sludge to sett completely. From that number you can find out what your target RAS ppm will be. Keep an eye on the settlomiter and time when the sludge in the starts to rise. What ever this time is you want your RAS detention time to less then that time.  You can also do a diluted settbility take some Sec Eff and blend it with MLSS and do at different ratios but the first one do 50:50 mike and see what the number is. This will show if the your SVI is hi form bulking sludge.

I noticed Eff nitrates are a little high. I think you can  lower your luxury D.O by .25 ppm.  If you have the ability you can cycle the blowers to do a cycle of nitrification and a cycle of denitrification.  Another thing to  look it is the how well the mixing in the anoxic zone is And do you monitor the ORP in the anoxic zone.

As to the use of polymer. At the plant I currently work at we do use it and it allows you to control every aspect of the settling of the sludge. we don't use all the time but it is there if we need to use it. It makes the Clarifiers look awesome. I don't see a problem using it to get the control back over the plant if a problems arises. But it is costly if used all the time.

Just to add, i didnt go and bomb it with chlorine, i knew it was Nocardia. Sorry should have mentioned that. But i have had this problem many times before (Nocardia) and you can look on various places for solutions (reduce SRT, adjust DO, scrape foam off surface, adjust RAS, add external bacteria cultures etc.) and there are none. I have spend weeks washing tanks , adjusting parameters and anyone who has dealt with this will know that its not easy to beat. The poly and hypo has worked for me. Just also to note that my clarifiers look crystal clear this morning. Id love to hear of a quicker solution or any other at all