Biofilm Growth and Biodegradation of Ozonated Natural Organic Matter on Granular Activated Carbon
Public Deposited- Last Modified
- February 28, 2019
- Creator
-
Grimberg, Stefan Johannes
- Affiliation: Gillings School of Global Public Health, Department of Environmental Sciences and Engineering
- Abstract
- Biological activity on granular activated carbon (GAC)offers an encouraging possibility for removal of organic material in water purification processes. Natural organic matter (NOM), the main organic pollutant in drinking water, is generally considered to be resistant to biological degradation. Preozonation enhances the NOM biodegradabi1ity. Ozonated NOM could therefore serve as a primary substrate for biofilm establishment. The degree of NOM biodegradation in a GAC column is a function of column length due to the heterotrophic NOM characteristics. Readily degradable NOM fractions are degraded at the top of the column whereas fractions more resistant to microbial metabolism are degraded deeper in the bed. Three fixed-film CSTRs in series were used to observe the performance of the full scale GAC column. NOM biodegradation along the GAC column was described with biofilm observations and biokinetic tests in each of the CSTRs. Steady state removal of ozonated NOM through the three CSTRs (EBCT = 15 min) was 40%. Scanning electron microscopy revealed that the observed biofilm consisted of filamentous growth, extracellular material, actinomycetes and distinct singular organisms. No significant difference between the biofilm structure among the CSTRs was observed. High pressure size exclusion chromotography conducted on the NOM effluents of the three CSTRs suggest that specific NOM fractions are removed at different locations in the bed. First order NOM blodegradation rate coefficients of 1 x 10 1/day, determined in-situ, were found in each CSTR. However, the concentration where no biodegradation could be observed decreased in each subsequent reactor. This suggests that the microbial community adapts to the specific NOM composition and maximizes its metabolic rate. An attempt was made to determine in-situ biomass concentration in the fixed film CSTR using 32P uptake rates. The uptake rate of radiolabled phosphorus was correlated to the amount of cells in suspended cultures. However, adsorption of HPP4 onto GAC interfered with the interpretation of the 32P uptake rate tests conducted on the fixed film CSTRs.
- Date of publication
- December 1989
- DOI
- Resource type
- Rights statement
- In Copyright
- Advisor
- DiGiano, Francis A.
- Aitken, Michael
- Pfaender, Frederic K.
- Degree
- Master of Science in Environmental Engineering
- Academic concentration
- Water Resources Engineering
- Degree granting institution
- University of North Carolina at Chapel Hill
- Graduation year
- 1989
- Language
- Deposit record
- ad7e9272-7c4f-43e0-afeb-7a5f2526ad76
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