If you are experiencing problems downloading PDF or HTML fulltext, our helpdesk recommend clearing your browser cache and trying again. If you need help in clearing your cache, please click here . Still need help? Email help@ingentaconnect.com

A NEW PROCESS FOR ENRICHING NITRIFIERS IN ACTIVATED SLUDGE THROUGH SEPARATE HETEROTROPHIC WASTING FROM BIOFILM CARRIERS

$17.50 plus tax (Refund Policy)

Buy Article:

Abstract:

A new process, the BASIN process (Biofilm-Activated Sludge Innovative Nitrification), consisting of a MBBR (Moving Bed Biofilm Reactor) with separate heterotrophic wasting, followed by activated sludge (AS), has been proposed to reduce the volume requirements of the AS process for nitrification. The basic principle is to complete COD removal on the biofilm carriers by heterotrophic organisms and then to waste a portion of the heterotrophic biomass before it has the chance to pass onto the aeration basin. By this means, the amount of heterotrophic organisms grown in the aeration tank 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 was used to prove the concept. During Phase 1, intermittent biomass removal was practiced in one MBBR while another served as control. Compressed air was used to simulate the airlift pumping that was anticipated for full-scale use. It was demonstrated that about one-half of the heterotrophic biomass was stripped by the once per day cleaning method established. MBBR functioning was not impaired by intermittent stripping, as overall sludge yields and COD removals were the same for both MBBRs tested. During Phase 2, three lines were tested: 1) the BASIN process, 2) a MBBR (without intermittent biomass removal) followed by intermediate settling (IS) and then an AS process and 3) a control AS process. AS sludge yields in the BASIN process were one-half of that in the control and twice that of the MBBR/IS/AS line. Critical washout solids residence times for nitrifiers were the same for all three lines, so AS volumes for the BASIN process could be reduced by 50 percent compared to the control. For comparison, the process with intermediate settling (MBBR/IS/AS line) could reduce its aeration volume for nitrification by 75 percent, although at the expense of the intermediate sedimentation tank.

Overall, originally conceived process concepts for the BASIN process have proven out. The next step is their confirmation at large pilot or demonstration-scale.

Document Type: Research Article

DOI: http://dx.doi.org/10.2175/193864700784608054

Publication date: January 1, 2000

More about this publication?
  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

    WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.
  • Subscribe to this Title
  • Membership Information
  • About WEF Proceedings
  • WEFTEC Conference Information
  • ingentaconnect is not responsible for the content or availability of external websites

Tools

Favourites

Share Content

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
X
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more