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Ashoori

Ex Member

High SRT?
May 21^st, 2012, 11:55pm

Hi Experts.
At first I should thank all of you for every thing I learn from this fabulous site.

I have a question about SRT. There is a system of MBBR with 20 days SRT and after that a post anoxic by additional methanol with 18 days SRT then a clarifier exist. this is designed to reduce sludge production.
Isn`t the SRT so high for the whole system? has it any effect on performance?
I ve asked some friends and they said SRT of each system is different and it wouldn`t cause any problem. but I`m still worried.
Thankyou in advance
Regards
Ashoori

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WasteH2ODave Ex Member	Re: High SRT? Reply #1 - May 22^nd, 2012, 8:31am Ashoori, Is the system operating as you wish or are you having troubles?
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The sludge judge

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Re: High SRT?
Reply #2 - May 22^nd, 2012, 8:36am

Being an MBBR your SRT is next to impossible to calculate. You have biomass on the media which make up a considerable amount of your bugs.

There's no golden rule for SRT. You need to find what works for your plant and what feels right. I personally know of a system operating at nearly a 100 day SRT and it works for them.

It seems like your post anoxic zone is larger than needed since all of the methanol is degraded very quickly. If this isn't causing any problems I wouldn't change anything though.

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Ashoori

Ex Member

Re: High SRT?
Reply #3 - May 22^nd, 2012, 1:38pm

Dear Experts
I should say that this treatment plant hasn`t performed yet, it is just designed in this way.
feed wastewater comes from 2 parallel anaerobic pond (stabilization pond) , and then 2 facultative pond in series. Effluent of second facultative goes to MBBR. So effluent BOD reaches near 70 mg/l.
Can this plant work as well? Have you any suggestion?
Regards
Ashoori

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Tom Keenan - nesa God Member Offline Environmental Consultant - contact info@nesa.ie Posts: 2103 Gender: Company or Organization: nesa environmental consultants	Re: High SRT? Reply #4 - May 23^rd, 2012, 4:45am If the 70 mg/l BOD represents the feed to the proposed MBBR process, then this is a relatively low BOD in the feed, and it should not be too difficult to treat this water, (provided it does not contain any hazardous or toxic materials). There does not seem to be any reason why it should not work for you.
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Ashoori Ex Member	Re: High SRT? Reply #5 - May 23^rd, 2012, 12:33pm Thank you very much for the help. Now I feel better! With the best wishes. Ashoori
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