MICROBIAL RESPONSES TO ORGANIC SPECIES IN
INDUSTRIAL LANDFILL LEACHATE
Patricia Corbo, Graduate Student
R. C. Ahlert, Professor II
Department of Chemical and Biochemical Engineering
Rutgers University
Piscataway, New Jersey 08854
INTRODUCTION
Industrial landfill leachate refers to liquid residuals produced by water runoff due to rain, surface
water, and/or groundwater that has become contaminated as it passes from or through a landfill.
Such leachate differs from other leachates, not in the manner by which it is produced, but in the
composition of the contaminants because of the site's industrial rather than sanitary character. The
liquid usually contains several oil and aqueous phases; these can be physically separated. The bulk
aqueous phase contains synthetic organic compounds, dispersed oil, suspended particles, colloids and
heavy metals. Typical leachate gross contaminant parameter levels exceed those of domestic wastewater and may include high levels of individual contaminants (Table I).
The aqueous phase of a leachate can be considered a high strength industrial wastewater. Renovation techniques typical for these wastewaters are being evaluated, including physical/chemical treatments and biological methods. Biological treatment is of particular interest because of extensive experience with rapid stabilization of domestic wastewaters and some industrial wastewaters. Biological
treatment employs a mixed population of microorganisms to remove a very broad array of organic
species from the wastewater by: (1) ultimate disposal as C02 and H20 (aerobic) or C02, CH4, N2,
and H2 (anaerobic); (2) partial breakdown to lower molecular weight compounds; (3) absorption on
or into cellular material; or, most likely, (4) a combination of these processes. Pretreatment of wastewater or leachate may be necessary to remove large suspended particles, heavy metals, and other
materials that inhibit the metabolic pathways of microorganisms.
There is virtually no literature pertaining to biological treatment of industrial leachates. Biological
treatment of sanitary landfill leachates has been addressed, however, with variable success. COD
removal rates of 60-99% have been reported for aerobic and anaerobic treatment methods [1-4].
EXPERIMENTAL
Description of Leachate
The leachate used in this study was supplied by the USEPA Oil and Hazardous Materials Spill
Branch. The bulk aqueous phase was separated from the bulk oil phase by gravity separation and
stored at 10 C or below. Pretreatment of the aqueous phase with lime at about 6 gm/1, was necessary
to remove remaining dispersed oil, suspended particles, and complexed metals. The TOC contributed
by the dispersed oil was minor, i.e., approximately 3-5%. The final pH was adjusted to 7 for all biological studies.
Development of Activated Sludge Culture
An activated sludge culture seed was obtained from the Somerset-Raritan Sewage Authority in
Bridgewater, New Jersey, which receives industrial (15-20%) and domestic wastewaters. The culture
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