Procedure to Quantify Biofilm Activity on Carriers Used in Wastewater Treatment Systems

Abstract

A procedure is presented for evaluating and comparing the biological activity of biofilms attached to various biofilrn caniers by measurement of the glucose consumption rate. 1111S technique allows for the economical design and selection of small particulate biofilm carriers that will maximize substrate removal when used in industrial-scale fluidized bioreactors. Methods for ensuring reproducible results are described. To support the glucose consumption rate findings, biofilm dty weights were obtained at the conclusion of activity rate experiments, and scanning electron micrographs were taken to evaluate the presence of biofilm and to view surface characteristics. Fourteen different biofilm carriers were evaluated ranging from commercially available products to novel carriers designed specifically for this study. Carriers that exhibited the highest reaction rates in descending order included: Syntrex 1220 (Kinetico. Inc.), Kaldnes Carrier Element·····Modified (Kaldnes North America, Inc.), Kaldnes Carrier Element······Original (Kaldnes North America, Inc.), Macrolite Modified CEPP-02 (Kinetico, Inc.), Macrolite 357 (Kinetco, Inc.), and Virgin Foam Cubes (BB Bradley Co.). Results showed that the accumulation of biofilrn depended most strongly on carrier surface properties, such as surface roughness and specific surface area. The bioillm activity as measured by glucose consumption rate correlated well with activity determinations made by COD measurements when a complex carbohydrate was used as substrate in place of glucose. Substrate consumption rates in microreactors were within ±43% of those measured in a 3-L bioreactor. The method presented here produced highly reproducible results and may be used to accurately and economically screen a large number of newly-designed carriers for application in industrial bioreactor processes.

Evaluation of Passive Treatment Technologies for Septic Lagoon Capacity Expansion

“…It is also possible that the microorganisms responsible for wastewater treatment were better able to attach onto, and populate, the biofilm media of the BioCord system. Bolton et al (2006) found that media surface properties, such as surface roughness and specific surface area, can strongly influence the accumulation and activity of a biofilm. Therefore, the inherent differences in the composition and surface of each of the attachment media could have contributed to how quickly and firmly microorganisms were able to attach onto the media and form a biofilm.…”

“…As such, a lower treatment performance would be anticipated because 'pseudo steady state' microbial growth conditions had not yet been achieved. Based on literature involving similar biofilm treatment technologies, it was estimated that a four-week period would be required for the biofilm treatment technologies to reach their maximum growth phase and pseudo-steady state conditions (Bolton et al, 2006;Lindfors, 2010;.…”

Reclamation of Municipal Wastewater using a Novel Liquid-solid Circulating Fluidized Bed Bioreactor

“…Upflow Sludge Blanket, Biofilm Fluidized Bed, Internal Circulation reactors) have gained considerable interest in the past two decades to meet more stringent regulations, due to high biomass retention time, compactness, and high volumetric conversion rates (Nicolella et al, 2000;Bolton et al, 2006). A new liquid-solid circulating fluidized bed (LSCFB) bioreactor has been developed by Nakhla and his coworkers Cui et al, 2004, Patel et al, 2006, Chowdhury et al, 2008 for biological nutrient removal (BNR).…”

Pilot‐scale Experience with Biological Nutrient Removal and Biomass Yield Reduction in a Liquid‐solid Circulating Fluidized Bed Bioreactor

“…Applications of different types of particulate biofilm reactors (for example, upflow sludge blanket, biofilm fluidized bed, internal circulation reactors) to meet more stringent regulations have gained considerable interest in the past two decades (Bolton et al, 2006). In these reactors, biofilm typically forms a spherical, compact layer over the particles, which enables attainment of large biofilm surface area and high reactor biomass concentrations (Nicolella et al, 2000).…”