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Zafri

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Sludge Wasting Guide
Apr 26^th, 2012, 9:36pm

Good day,

I'm still new to this waste water industry. Hope that can get some guidance from you all.

I'm using DAF-UASB-AICAR system to treat dairy waste water. Designed parameters as follow

Capacity : 1200 m3/day @ 50 m3/hr
BOD : 3000 mg/L
COD : 5000 mg/L
FOG : 500 mg/L
TSS : 1000 mg/L
pH : 4-11

It has been operated nearly 1 year. Recently we having problem with sludge washout with the final discharge.

The SV30 for both AICAR (no1 & no.2) is around 95+%.
MLSS: 2200 mg/l (AICAR 1) , 3200mg/l (AICAR 2).

I have thought to do wasting but my colleague said no because of FM ratio, bla..bla...bla...

Is there any other solution for this problem? If it is need to do wasting, is there any guidelines for it?

Your help is much appreciated.

Thank you.

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grrun God Member Offline WaterandWastewa ter.Com is the best! Posts: 3525 Pekin, IL Gender: Company or Organization: Freelance Environmental Engine	Re: Sludge Wasting Guide Reply #1 - Apr 26^th, 2012, 10:48pm The AICAR process is essentially an activated sludge process and as such should have some sludge wasted. At this point, I cannot tell you how much to waste, but you may want to contact the vendor for this system for their recommendations. I suspect that this system may require differing sludge ages for No.1 and No.2. grrun
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Zafri YaBB Newbies Offline I love Water and Wastewater.com Posts: 3 Company or Organization: Trident Innovation	Re: Sludge Wasting Guide Reply #2 - Apr 26^th, 2012, 11:21pm Thank you for your reply. FYI, AICAR system is much the same as ICEAS. So the best practice is?
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Tom Keenan - nesa

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Re: Sludge Wasting Guide
Reply #3 - Apr 27^th, 2012, 3:37am

Not surprised to hear that there is some sludge loss in a situation where the SV30 is 95+%.
Do you know what the design operating conditions were based on, i.e. Sludge Age, f/m etc?
If you could establish the design parameters, then review the monitoring data for the year that you have been operating to see under what operating conditions the best treated effluent quality was achieved, then perhaps you can establish what the optimum operating conditions for the plant are.
Used water from a dairy is generally easy to treat, but pH can be an issue from time to time when cleaning is taking place, (unless of course you have adequate buffering or pH correction).
This type of effluent can also give rise to filamentous sludge bulking if the sludge age is allowed to increase significantly above its optimum.
I hope that these comments are helpful.

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Zafri

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Re: Sludge Wasting Guide
Reply #4 - Apr 27^th, 2012, 8:39pm

Thanks Keenan...

I already asked my vendor. The designed operating condition is only based on f/m ratio (0.2) and the mlss for the aeration tank (3500mg/l). The effective volume for the AICAR is 1515m3 each.

As for the pH issue, there is no problem with it as they also designed a tank for pH correction.

I try to establish the design parameter based on the vendors design but somehow i feel that something is missing. The information regarding civil design and equipment size i already have. So can you suggest any good reading materials to guide me?

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grrun

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Re: Sludge Wasting Guide
Reply #5 - Apr 27^th, 2012, 10:11pm

Have you been wasting any sludge at all? What is your WAS routine?

I would try wasting 3% of the total mass of sludge daily as a starting point. From there, I would increase wasting by about 1% every few days until the 30 min. sv falls below 50%. After that, I would continue to waste sludge even more slowly while continuing to monitor discharge parameters for compliance.

Now, I've had no experience with this type of system so that I cannot just tell you exactly how much sludge to waste, but only to start you in the right direction and establish some goal (50% sv in 30 min.) It'll be up to you to decide if this is the right direction and how to manage the wasting to optimize the system.

grrun

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NorCal_Wastewater1 God Member Offline "Wastewater rules! Give sludge a chance!!!" Posts: 1780 CA. Gender: Company or Organization: Wastewater	Re: Sludge Wasting Guide Reply #6 - Apr 30^th, 2012, 9:22am Zafri; You mention that you've confirmed with the OEM the operational parameters yet you feel there is something "missing". (???) What leads you to believe this? As grrun said, start with a 3-4% wasting rate initially then increase by 1-2% every few days & re-check your results. Dallas
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The sludge judge God Member Offline Posts: 649 Wisconsin Gender: Company or Organization: private	Re: Sludge Wasting Guide Reply #7 - Apr 30^th, 2012, 10:37am You really need a microscopic evaluation of your MLSS to determine the cause of the high SVI. Otherwise we are just speculating things. Are there problems with the DAF or the anaerobic pretreatment right now? Is there sufficent dissolved oxygen in the aeration tank?
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