Circulating fluidized bed bioreactor: A cost-effective technology for wastewater treatment

Nabin Chowdhury, George Nakhla, Bill Cairns, Jesse Zhu

Research output: Chapter in Book/Conference proceedingConference contributionpeer-review


This study was focused on evaluating the economic feasibility of a newly developed technology, the Circulating Fluidized Bed-Bioreactor [CFBBR] compared to alternative technologies e.g. activated sludge process [AS], moving bed bioreactor [MBBR], and sequencing batch reactor [SBR] for municipal wastewater treatment. The CFBBR combines a circulating fluidized bed and a fixed-film process for an enhanced solid-liquid mass transfer that provides higher removal rates of nitrogen and phosphorous compared to the AS, MBBR, and SBR processes. Both lab-scale and pilot-scale CFBBRs demonstrated > 90% COD, > 80% N and 70% P removal at a hydraulic retention time of 2 h without primary clarification. Furthermore, the observed sludge yields of 0.12-0.16 g VSS/g COD consumed in the CFBBR resulted in 75% reduction in total biosolids production compared to conventional activated sludge non BNR treatment processes. The CFBBR demonstrated the potential for significant capital cost reduction, compliance with stringent regulations, reduction of biosolids, and up to 80% reduction in space requirements. Cost modules have been developed using CapDet Works 2.5 for the different processes employing reactor sizes designed for an average daily flow of 2.6 MGD (10,000 m3/d). The cost modules consist of screening, grit chamber, primary clarifier, biological nutrient removal units, secondary clarifier, UV-disinfection, thickening, anaerobic digestion, energy recovery, dewatering and sludge handling and disposal. The CFBBR was determined to be the most cost effective technology compared to the conventional BNR-AS and other available technologies for a completely new wastewater treatment facility. Even though the CFBBR does require high recirculation volume (12 times influent flow) to fluidize particles, energy consumption of 0.33 kWh/m3 in the CFBBR is less than the energy required in the MBBR (0.39kWh/m3), SBR (0.41 kWh/m3), and in the same range of the BNR-AS (0.31 kWh/m3) for biological nutrient removal from municipal wastewater.

Original languageEnglish
Title of host publicationWEFTEC 2012 - 85th Annual Technical Exhibition and Conference
PublisherWater Environment Federation
Number of pages11
ISBN (Electronic)9781510870437
Publication statusPublished - 2012
Externally publishedYes
Event85th Annual Water Environment Federation Technical Exhibition and Conference, WEFTEC 2012 - New Orleans, United States
Duration: 29 Sept 20123 Oct 2012

Publication series

NameWEFTEC 2012 - 85th Annual Technical Exhibition and Conference


Conference85th Annual Water Environment Federation Technical Exhibition and Conference, WEFTEC 2012
Country/TerritoryUnited States
CityNew Orleans


  • Biological nutrient removal
  • Energy costs
  • Fixed-film
  • Fluidized-bed bioreactor
  • Life-cycle costs

ASJC Scopus subject areas

  • Ecological Modelling
  • Environmental Chemistry
  • Pollution
  • Waste Management and Disposal
  • Water Science and Technology


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