The effect of alternative electron acceptors on the subsurface biodegradation rates of methanol and tertiary-butyl alcohol

This study evaluated the potential for increasing the biological degradation of methanol and tertiary-butyl alcohol (TBA), components of a gasoline-alcohol blend, in the subsurface by stimulating the growth of the microorganisms. The primary objective of this study was to evaluate the stimulatory effect of nitrate and sulfate (alternative electron acceptors) on the biodegradation of the alcohols in the absence of molecular oxygen. This study also evaluated the effect of adding hydroxide and bicarbonate to the groundwater as buffering agents in an attempt to raise the pH of the groundwater and stabilize it against the acidic by-products of microbial metabolism. The addition of nitrate resulted in increases in the initial rates of degradation of methanol ranging from 20 to 1040 percent. After a period of time, however, an inhibitory build-up of nitrite generally occurred, essentially halting the biodegradation. The addition of nitrate resulted in a varied response on the initial degradation rates of TBA, ranging from a 60 percent decrease to a 340 percent increase. The results of the sulfate additions with methanol were varied, ranging from an 80 percent decrease to a 930 percent increase in the initial degradation rates. In some cases, an inhibitory response was evidenced after a period of time, presumably due to a build-up of sulfide. The addition of sulfate resulted in a varied response on the initial degradation rates of TBA, ranging from a 90 percent decrease to a 380 percent increase. The effect of the hydroxide and bicarbonate additions were very similar, with both compounds inhibiting the biodegradation of methanol (SO and 65 percent decreases in the initial degradation rates, respectively) while stimulating the biodegradation of TBA (140 and 180 percent increases in the initial degradation rates, respectively).

Name thesis:degree_name

M.S.

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Environmental Sciences and Engineering

Department dc:contributor.department

Environmental Sciences and Engineering

Grantor dc:publisher

Virginia Polytechnic Institute and State University

Year dc:date.issued

1985

Author dc:creator

• Mulheren, M. Patrick

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Handle dc:identifier.uri

http://hdl.handle.net/10919/101458

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/101458