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crackcrack Ex Member	Cloudy effluent Apr 09^th, 2012, 7:26pm Hi again, I have cloudy effluent post aeration/secondary clarification. I am waiting for the BOD results... After using a floc on it, the level of settlement after 30 minutes is as per the picture: The question is... Can i send these floc solids back as RAS to the aeration system? Would this floc solids be biomass or organics?
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crackcrack Ex Member	Re: Cloudy effluent Reply #1 - Apr 9^th, 2012, 9:17pm And then 2 hours later...
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Geoff God Member Offline Posts: 1007 Gender: Company or Organization: Retired. :-)	Re: Cloudy effluent Reply #2 - Apr 9^th, 2012, 9:25pm Can you describe fully the type of process you have plus a few operating parameters? Your question: "Can i send these floc solids back as RAS to the aeration system?" is somewhat confusing - what is your RAS situation now? Cheers
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crackcrack

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Re: Cloudy effluent
Reply #3 - Apr 9^th, 2012, 9:35pm

Hi Geoff,

Primary settlement via screen. Aeration tank 5 x the size of daily flow.

Activated basin is pumps from its base to secondary clarification. RAS pumps deliver AS from clarifiers back to aeration tank.

The cloudy effluent is at the final end of the secondary clarifiers.

I am thinknig of floccing this and sending the floc back to aeration tank as well.

What do you think?

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Geoff God Member Offline Posts: 1007 Gender: Company or Organization: Retired. :-)	Re: Cloudy effluent Reply #4 - Apr 9^th, 2012, 9:42pm Do you have any operating parameters you can quote? i.e. - influent strength - MLSS - SVI - DO setpoints - Effluent BOD & SS? - RAS rate The more info the better. Cheers
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The sludge judge

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Re: Cloudy effluent
Reply #5 - Apr 9^th, 2012, 9:53pm

the settled solids should be returned to the aeration tank and a percentage wasted every day. The flocs are roughly 80% organic material (bacteria, protozoa, metazoa, slime) and 20% inorganic material (inert solids) on average.

It appears your effluent is cloudy because you don't have enough biomass (MLSS) for the applied amount of BOD. Waste less and increase your MLSS. A microscopic examination never hurts to be completely sure, but that's my opinion based on the picture.

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crackcrack Ex Member	Re: Cloudy effluent Reply #6 - Apr 9^th, 2012, 9:54pm Hi Geoff, No, I dont have enough information yet. We are only needing to achieve a BOD down to approx 1000 in order to reduce the load on the community system. This is a pre-treatment only and I am curious about the floc solids
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The sludge judge God Member Offline Posts: 649 Wisconsin Gender: Company or Organization: private	Re: Cloudy effluent Reply #7 - Apr 9^th, 2012, 9:54pm Also an investment in a settleometer is a good idea. Leave the beer mugs for beer! best regards, Ryan
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crackcrack Ex Member	Re: Cloudy effluent Reply #8 - Apr 9^th, 2012, 9:57pm Yeah, ok... Any suggestions here?
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Geoff God Member Offline Posts: 1007 Gender: Company or Organization: Retired. :-)	Re: Cloudy effluent Reply #9 - Apr 9^th, 2012, 10:06pm The sludge judge wrote on Apr 9^th, 2012, 9:54pm: Also an investment in a settleometer is a good idea. Leave the beer mugs for beer! best regards, Ryan I wondered why there was a handle on the settlement cylinder. Doh!
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The sludge judge God Member Offline Posts: 649 Wisconsin Gender: Company or Organization: private	Re: Cloudy effluent Reply #10 - Apr 9^th, 2012, 10:08pm yes, I gave my advice in the previous post.
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crackcrack Ex Member	Re: Cloudy effluent Reply #11 - Apr 9^th, 2012, 10:21pm Thanks Ryan, I didn't see that post. Yes the plant is very new, so I had a feeling the MLSS wasn't up to scratch yet, but was not 100% sure. I will check the MLSS in a week or two.
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mohan01

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Re: Cloudy effluent
Reply #12 - Apr 11^th, 2012, 11:23am

Using flocculant to remove solids and returning to Aeration Basin can be a tricky situation. The concentration of flocculant is the key and very difficult to control in a recycle system. It is likely that you will overdose flocculant and hamper settleability in the clarifier. Do some jar testing before yuo make a decision. How do you plan to administer the dosing to the clarifier? I mean how much per day or will it a continuous dose. Continuos dose may build up excess flocculant in the system.

From the look of it your sludge looks very young and fluffy. It may be a good idea to maintain the sludge age in the system.
Also try and improve sludge settling before you do any polymer addition. If you can figure poor settleability causes than you don't have to add flocculant. Once you add the floculant in the system it will remain in the system for a long time.

If you decide that you should dose flocculant make sure you dose it in a line before an static mixer so that it is mixed well. Clarifer center well is also and option but line dosing with static mixer provides better mixing.

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crackcrack Ex Member	Re: Cloudy effluent Reply #13 - Apr 11^th, 2012, 4:04pm Interesting...Cheers
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