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Citation/Abstract

Biological reduction of nitrate and perchlorate using autotrophic bacteria


2008 2008

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Abstract (summary)


Widespread contamination of ground and surface water with nitrate (NO3- ) and perchlorate (ClO4 - ) has been recorded in many US states. Nitrate and perchlorate are soluble anions that are known to affect human health. This dissertation presents the results of three studies of biological reduction ClO4 - and NO3- using autotrophic bacteria.

In the first study, hydrogenotrophic (H2 oxidizing) denitrifiers were inoculated into two hollow fiber membrane bioreactors (HFMB), which were set up in different configurations (I and II). In Configuration I, H 2 passed through the lumen of the fibers and nitrified water flowed through the shell. In Configuration II, liquid flowed through the lumen and H2 through the shell. Complete denitrification was achieved in both systems with pH and biomass control at hydraulic retention times (HRT) of 8.3 and 1.5 hours for configurations I and II, respectively. Influent dissolved oxygen (DO) did not inhibit denitrification.

The second study investigated reduction of NO3- and ClO4- in ion exchange (IX) brines using halophilic-hydrogenotrophic bacteria in a HFMB (Configuration II). Continuous operation of the HFMB resulted in partial denitrification (30%) of the brines. Batch HFMB operation resulted in average removal efficiencies of 30% and 42% for NO 3- and ClO4- , respectively.

The third study investigated ClO4- reduction using Sulfur Utilizing Perchlorate Reducing Bacteria (SUPeRB). SUPeRB cultures reduced 5-20 mg/L ClO4- to < 0.5 mg/L at varying salinities (0-30 g/L NaCl). Perchlorate (8-0.01 mg/L) reduction was achieved in packed bed reactors (PBR) inoculated with SUPeRB and filled with S° pellets and crushed oyster shells at empty bed contact times of 8-13 hours for low and high ClO 4- concentrations, respectively. Decreased ClO4- removal efficiency was observed at increased recirculation velocity and with small S0 particle sizes. Influent DO or NO3- did not inhibit overall ClO4- removal.

Indexing (details)


Subject
Microbiology;
Civil engineering;
Environmental engineering
Classification
0410: Microbiology
0543: Civil engineering
0775: Environmental engineering
Identifier / keyword
Applied sciences, Biological sciences, Nitrate, Perchlorate, Hollow fiber membrane bioreactor, Ion-exchange brines, Hydrogen, Sulfur, Autotrophic bacteria, Water contamination
Title
Biological reduction of nitrate and perchlorate using autotrophic bacteria
Author
Sahu, Ashish Kumar
Number of pages
265
Publication year
2008
Degree date
2008
School code
0118
Source
DAI-B 69/07, Jan 2009
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780549663980
Advisor
Ergas, Sarina J.
Committee member
Reckhow, David A., Nusslein, Klaus
University/institution
University of Massachusetts Amherst
Department
Environmental Engineering
University location
United States -- Massachusetts
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3315518
ProQuest document ID
304566032
Copyright
Copyright ProQuest, UMI Dissertations Publishing 2008
Document URL
http://search.proquest.com/docview/304566032