Hello,

I have a problem about the rising sludge at the clarifier. The sludge rises mostly at the centre of the clarifier and it is like a 1 mm spherical sludge which start to hold each other after rising and accumulates at the clarifier surface.

The plant is domestic waste water plant which requires nitrification + denitrification.

Concentration are similar to domestic wastewater plant. The aeration tanks are carrousel which have apx. 4500 mg/lt MLSS. SRT is 14-19 most of the time.

Because of diffusers are placed all over the aeration tank i try to manage denitrification with 2 hours aerated 2 hour non aerated. I try to keep the oxygen at 1.5-2 mg/lt at the aeration period. Operation is continuous (not SBR)

Outlet
COD -   120 mg/lt ; Filtered COD = 43 mg/lt
SS -  94 mg/lt;
NH4-N - 0.7 mg/lt;
No3 - 0.45 mg/lt.

As you can see above the problem is the rising of small flocs that increases SS and COD.

The SVI is very high 220. But microscobic examination no filamentous growth seen.

I want to get your suggestions what is the problem and what to check.

Thank you

Im hoping for some clearance about that also ...I have quite similar problem..but not so much as u have....Had worse but took the SV down from 800ml/l to 490ml/l and now i dont get that so intesively.
Still have a SS problem tho.. MLSS here was 4800mg/l...SRT im trying to calculate...which i have problems with.

Ryan,

With microscobic examination i dont see any filamentous growth.

The nitrate entering to the clarifiers varies between 0.4--3 mg/lt.

I would be gladful if you watch the video and could tell which problem it looks like?

"Perhaps DS can be of some help?" I cannot see at the top of the page. Could you give more details ?

Thank you so much for your attention.

Hi frenz,

Ryan has given some good advice already. If you want, you can send me a small sample (some 20-15 mL AS in a water tight container of 50 mL, + a separate sample of the foam: "a teaspon full" in another water tight container) and I'll give it a good microscopic screening and see what the causality is/may be.
Please, check your pm-box.

best regards

DS

Ryan and Srknk,

I have already increase the RAS ratio to 1. (Qr/Q). I can not go above becuase of the pumps capacity. I operate the plant 2 hour aerobic and 2 hours anoxic to achieve nitrification + denitrification.

NH3 is below 2 mg/lt and Nitrate is vaires 1-4 mg/lt. (The samples taken before entering to the clarifiers and filtered.)


DS,

Thank you for your interest i send you a pm.


Thank you all.

The foam is light brown color. You can see it in the photo.

http://i47.tinypic.com/105wo75.jpg

No foaming at the aeration tank during denitrification phase.

I made a microscobic analyses with gram stain from the top sludge of the clarifiers.

There is a lot of filamentaous bacterias, nocardia. Now though days waiting for me . Thanks a lot.

Hi Frenz,

Nocardia can be tough to handle, just give ayell if you need help!

a good starting point indeed is to check for FOG (Fats Oils and Grease) entering the plant.

best regards,

DS

Sludge judge thank you so much for your help. I take down one clarifier and empty it because of a maintenance. When i get the tank in operation, sludge immediately rises like others. The surface foam has a lot bubbles in it.

Can you check the below image please.
http://i45.tinypic.com/jk83ue.jpg

And my nitrate is low than 1 mg/lt before clarifiers. I dont think it is denitrification.

Any other possibility? Air is trapped in the sludge.

THank you in advance