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naserhamidieh

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MLE Process
Apr 12^th, 2008, 4:04am

Hi every body
I have calculated a MLE process for a raw wastewater as follow:
Q=16000 m3/d
BOD5=275 mg/l
TKN=42 mg/l
the desired effluent quality
BOD5=20 mg/l
NO3_N=5mg/l as N

the internal recycle obtained from calculation is about 6 times the influent Q and isn't in the range of 1-4 times which suggested in references

what I should do for designing the internal recycle equipment ?
Is MLE a suitable choice for desired effluent quality?
with the best regard
naser

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DS God Member Offline sapere aude Posts: 1583 Company or Organization: Indept. Freelance Consultant	Re: MLE Process Reply #1 - Apr 13^th, 2008, 8:10am Dear Naser, could you explain what you mean by MLE process?
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The_Solution Senior Member Offline Water and Wastewater.com is the best! Posts: 329 Gender: Company or Organization: Andrew Stewart Ltd	Re: MLE Process Reply #2 - Apr 13^th, 2008, 11:05pm This stands for: modified Ludrack-Etringer (MLE) activated sludge process. The process is used for enhanced N removal by utilising a 2 stage process, the first of which is a pre-anoxic stage.
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Brito YaBB Newbies Offline Water and Wastewater.com is the best! Posts: 7 Gender: Company or Organization: sabesp	Re: MLE Process Reply #3 - Apr 14^th, 2008, 12:41am Hi naserhamidieh, I think that only way to reduce the recirculation with this level in efluent, is using a carbon source with a pos-denitrifiication. I imagine that your system is like a UCT process, it's correct? I hope this help
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DS

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Re: MLE Process
Reply #4 - Apr 14^th, 2008, 6:34am

Dear,

So a Modified Ludzack-Ettinger process, we hardly call it this way anymore...

Naserhamidieh, I think you should redo (redefine) your calculations, based on COD values, corrected for non-biodegradable COD (if this is a relevant fraction).

Besides this small side remark, it is correct that the recirculation flow goes up pretty high if effluent nitrate-N has to be lower, so 6 times might be not too wrong. Also be aware that the amount of N removed via the waste sludge is dependent on the SRT.

Another way to bring down high internal recirculation flow rates is to intermittently shut down aeration into the AT (Acronym!: Aeration Tank), and have denitrification over here.

Post denitrification requires again an aerated stage in which the excess COD has to be removed...

best regards

DS

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RoCSmith Junior Member Offline Posts: 68 Ohio Gender: Company or Organization: YSI	Re: MLE Process Reply #5 - Apr 14^th, 2008, 3:58pm Indeed, I calculate an overall R (RAS + IMLR) of 6.4 for your conditions. Have you factored in N removal by assimilation? It could be considerable with a BOD of 275. In any case a ratio over 4 is probably not beyond the practical capabilities of the MLE process.
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badal YaBB Newbies Offline I love Water and Wastewater.com Posts: 4 Company or Organization: iitgn	Re: MLE Process Reply #6 - Mar 7^th, 2013, 4:44am HIII i am interested to do this experiment. but i couldn't get the supplier address from google. can any body pz gave the info about this???
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