Physiochemical and Biological Behaviors of Organic Contaminants in Multi-Phase Media Under Enhanced Treatment Conditions
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Abstract
The rapid increase of anthropogenic activities has led to the ubiquitous presence
of organic contaminants. There is an urgent need for understanding the fate and behavior
of organic contaminants in the environment.
In this dissertation research, the physiochemical and biological behaviors of
organic contaminants in multi-phase media have been investigated. Considerable research
efforts have been made in characterizing the transport of polycyclic aromatic
hydrocarbons (PAHs) at solid-liquid interface, as well as exploring the remediation of
pollutants through solvent extraction and composting.
The effects of short-chain organic acids (SCOAs) on the behaviors of PAHs in
soil-water system have been systemically investigated. The amendment of SCOAs could
influence the adsorption and desorption behaviors of pyrene in soil-water system. The
mobility of phenanthrene in soil could be also enhanced by introducing organic acids.
The biosurfactant-enhanced remediation of PAH-contaminated soil in the
presence of SCOAs has been studied. The results supported the combined use of
biosurfactant and SCOAs could further enhance the desorption of phenanthrene from soil
into aqueous phase. The quantity and species of organic acids could affect the tendency
of phenanthrene distribution in the presence of biosurfactant.
The adsorption of phenanthrene on fly ash in solid-liquid system was investigated.
The adsorption of phenanthrene onto fly ash showed significant stepwise pattern. The
developed stepwise multisite Langmuir model can help well simulate the adsorption
process. The solution chemistry played an important role in the distribution of
phenanthrene in fly ash-water system. The performance of food waste composting in the presence of fly ash and uric
acid has been investigated. Different trends of degradation intensity, O2 uptake amount,
microbial population and C/N ratio were observed in the series with additional fly ash
and uric acid.
The results can be used to understand the environmental patterns and mechanisms
of organic contaminant behaviors in a complex system. They have important implications for environmental risk assessment and pollution control at contaminated sites.