aussiemike
Chemical
- Jan 29, 2003
- 14
G'day All.
I recently recommended one of my clients (running a municipal WWTP) should replace his old 1940s rock media trickling filters with an MLE bioreactor for a number of indisputable reasons. I expect to be engaged to prepare detailed designs for this upgrade in the new year some time.
The client would like to retain much of his existing plant (apart from the trickling filters) and I agree that this is a sensible strategy in this case.
I've checked the capacity of the primary clarifiers, digesters and other parts of the plant, which all seem OK, but I am a little concerned about the existing humus tanks.
The plant has 2 off 50' diameter humus tanks that I would like to reuse as secondary clarifiers for the MLE process.
All the literature values suggest the size of the tanks should be more than adequate based on overflow rate and solids loading but I am a bit concerned with the side wall depth (only 8').
I would normally design secondary clarifiers for BNR plants with at least 12' SWD, and preferably 15'.
I have this vision of sludge cascading over the effluent weirs and the scraper mechanisms shearing off due to excessive solids loading.
The capacity of the plant in question is around 10,000EP (2.5ML/day ADWF) with a peak flow to the clarifiers of 7.5ML/day.
Does anyone have any experience (good, bad or ugly) with reusing relatively shallow humus tanks for activated sludge service?
Cheers,
Aussie Mike
I recently recommended one of my clients (running a municipal WWTP) should replace his old 1940s rock media trickling filters with an MLE bioreactor for a number of indisputable reasons. I expect to be engaged to prepare detailed designs for this upgrade in the new year some time.
The client would like to retain much of his existing plant (apart from the trickling filters) and I agree that this is a sensible strategy in this case.
I've checked the capacity of the primary clarifiers, digesters and other parts of the plant, which all seem OK, but I am a little concerned about the existing humus tanks.
The plant has 2 off 50' diameter humus tanks that I would like to reuse as secondary clarifiers for the MLE process.
All the literature values suggest the size of the tanks should be more than adequate based on overflow rate and solids loading but I am a bit concerned with the side wall depth (only 8').
I would normally design secondary clarifiers for BNR plants with at least 12' SWD, and preferably 15'.
I have this vision of sludge cascading over the effluent weirs and the scraper mechanisms shearing off due to excessive solids loading.
The capacity of the plant in question is around 10,000EP (2.5ML/day ADWF) with a peak flow to the clarifiers of 7.5ML/day.
Does anyone have any experience (good, bad or ugly) with reusing relatively shallow humus tanks for activated sludge service?
Cheers,
Aussie Mike