A new process for enriching nitrifiers in activated sludge through separate heterotrophic wasting from biofilm carriers.
Water Environ Res
; 74(1): 68-76, 2002.
Article
in En
| MEDLINE
| ID: mdl-11995869
ABSTRACT
A new process, the biofilm-activated sludge innovative nitrification (BASIN) process, consisting of a moving-bed biofilm reactor (MBBR) with separate heterotrophic wasting, followed by an activated-sludge process, has been proposed to reduce the volumetric requirements of the activated-sludge process for nitrification. The basic principle is to remove chemical oxygen demand on the biofilm carriers by heterotrophic organisms and then to waste a portion of the heterotrophic biomass before it can be released into the activated-sludge reactor. By this means, the amount of heterotrophic organisms grown in the activated-sludge reactor is reduced, thereby reducing the volume of that tank needed for nitrification. For nitrification applications, the simplest method for stripping biomass was to use an in-tank technique using high shearing rates with aeration. Bench-scale testing showed sludge yields in the BASIN process were one-half of that in a control activated-sludge process and twice that of a process line with intermediate settling between the MBBR and activated-sludge stage. Critical washout solids retention times for nitrifiers were the same for all three lines, so activated-sludge volumes for the BASIN process could be reduced by 50% compared with the control. Originally conceived process concepts for the BASIN process were confirmed by the experimental work.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Sewage
/
Bacteria
/
Waste Disposal, Fluid
/
Biofilms
/
Quaternary Ammonium Compounds
Language:
En
Journal:
Water Environ Res
Journal subject:
SAUDE AMBIENTAL
/
TOXICOLOGIA
Year:
2002
Document type:
Article
Affiliation country:
United States