Affiliations: Department of Environmental Science and Engineering,
Tsinghua University, Beijing 100084, China | Contaminated Land Assessment and Remediation Research
Centre, Institute for Infrastructure and Environment, School of Engineering and
Electronics, The University of Edinburgh, Edinburgh EH9 3JL, United
Kingdom | Chinese Academy of Transportation Sciences, Ministry
of Communications, Beijing 100029, China | Environmental Engineering Division, School of
Engineering, the University of Queensland, St. Lucia QLD 4072 Australia | Centre for Eeo-Environmental Modelling, Hohai
University, Nanjing 210098. China
Abstract: Pollution by polycyclic aromatic hydrocarbons (PAHs) is widespread
due to unsuitable disposal of industrial waste. They are mostly defined as
priority pollutants by environmental protection authorities worldwide.
Phenanthrene, a typical PAH, was selected as the target in this paper. The
PAH-degrading mixed culture, named ZM, was collected from a petroleum
contaminated river bed. This culture was injected into phenanthrene solutions
at different concentrations to quantify the biodegradation process. Results
show near-complete removal of phenanthrene in three days of biodegradation if
the initial phenanthrene concentration is low. When the initial concentration
is high, the removal rate is increased but 20%–40% of the phenanthrene
remains at the end of the experiment.The biomass shows a peak on the third day
due to the combined effects of microbial growth and decay. Another peak is
evident for cases with a high initial concentration, possibly due to production
of an intermediate metabolite. The pH generally decreased during biodegradation
because of the production of organic acid. Two phenomenological models were
designed to simulate the phenanthrene biodegradation and biomass growth. A
relatively simple model that does not consider the intermediate metabolite and
its inhibition of phenanthrene biodegradation cannot fit the observed data. A
modified Monod model that considered an intermediate metabolite (organic acid)
and its inhibiting reversal effect reasonably depicts the experimental
results.
Keywords: biodegradation model, phenanthrene, microbial growth and decay, Monod growth model
