Biodegradation kinetics of batch and continuous wood chip (Betula sp. and Pinus sp.) reactors activated with white-rot fungus (Phanerochaete chrysosporium).

摘要

This dissertation presents the experimental design and results of research which studies in the laboratory and in models the biodegradation kinetics of batch and continuous wood chip reactors seeded with white-rot fungus and exposed to hazardous liquids. Batch reactor tests are conducted using 4-chlorophenol (4-CP) as a model compound to evaluate the effect of carbon and nitrogen deficiencies on the ability of white-rot fungus immobilized on wood chips to degrade 4-CP. The white-rot fungus degraded 4-CP (71.1-83.0%) under all tested treatment conditions including the non-glucose and non-nitrogen treatment. 4-CP is degraded to a greater extent in the non-glucose treatment (83.0%) than in the glucose treatment (78.6%). Continuous-flow reactor tests are conducted in specially designed reactor systems. These continuous reactor tests use 2,4-dichlorophenol (2,4-DCP) as a model compound to evaluate important reactor parameters and the inhibition effect of 2,4-DCP on the biodegradation enzymes in wood chip reactor systems. Under non-glucose treatment conditions the wood chip reactor system is seen to have a high degradation efficiency and operate continuously without excessive fungal biomass buildup on the wood chips. In the presence of added glucose, a clogging problem and an effluent contamination problem of fungal cells are found during reactor operation. Further, 2,4-DCP is effectively degraded both under low-nitrogen (0.012 g/L of NH{dollar}sb4{dollar}Cl) as well as high-nitrogen (0.12 g/L of NH{dollar}sb4{dollar}Cl) treatment conditions. 2,4-DCP is degraded to a greater extent with small size wood chips (5 mm dia x 5 mm long) and birchwood chips (Betula sp.) as opposed to pine (Pinus sp.) as a carbon source. The inhibition kinetics of 2,4-DCP is modeled with a mass balance equation of plug-flow reactor and a substrate inhibition equation for the reaction rate. Two statistical techniques are developed in this research to determine a steady state in laboratory and field bioremediation tests. The results of this research demonstrate a potential application of wood chip reactor systems for the treatment of contaminated water streams while expanding the use of historically wasted forest products. A buffer strip using fungi-activated wood chips is suggested to attack herbicide or pesticide contaminated water flowing from agricultural land to receiving rivers or streams.