Electrokinetic transport of aerobic microorganisms under low-strength electric fields.

To investigate the feasibility of utilizing low strength electric fields to transport commonly available mixed cultures such as those from an activated sludge process, bench scale batch reactor studies were conducted in sand and sandy loam soils. A readily biodegradable substrate, dextrose, was used to test the activity of the transported microorganisms. Electric field strengths of 7V, 10.5V, and 14V were used. Results from this investigation showed that an electric field strength of 0.46 Volts per cm was sufficient to transport activated sludge microorganisms across a sandy loam soil across a distance of about 8 cm in 72 h. More importantly, the electrokinetically transported microbial culture remained active and viable after the transport process and was biodegrade 44% of the dextrose in the soil medium. Electrokinetic treatment without microorganisms resulted in removal of 37% and the absence of any treatment yielded a removal of about 15%.

Biodegradation of naphthalene, phenanthrene, and pyrene under anaerobic conditions.

The biodegradation of naphthalene, phenanthrene, and pyrene were studied in batch reactors using an anaerobic acetate-fed enrichment culture developed from the Greater Peoria Sanitary District Wastewater Treatment Facility. Baseline kinetic experiments showed that maximum specific substrate utilization for the acetate-fed enrichment culture was 2.72 mg acetate/mg cell/day and the endogenous decay coefficient was 0.043 day(-1). Maximum specific substrate utilization rates in mg substrate/mg cell/day for naphthalene, phenanthrene and pyrene were 0.57, 0.009 and 0.007, respectively. The half saturation constant K(S) in mg/L were 0.075, 0.01 and less than 0.01, respectively. The endogenous decay coefficient (in units of day(-1)) in the presence of naphthalene, phenanthrene and pyrene were 0.06, 0.07 and 0.04, respectively. Results from this study indicated that naphthalene and phenanthrene were more easily biodegradable than pyrene. These results suggest that technologies using anaerobic biodegradation using a relatively simple enrichment culture from a wastewater treatment plant may be successful in treating PAH contaminated wastes.

Uptake and elimination of naphthalene from liver, lung, and muscle tissue in the leopard frog (Rana pipiens).

The effects of a 0-12-hour naphthalene exposure on pulmonary CO(2) excretion and bioaccumulation in the leopard frog, Rana pipiens, were investigated. The data showed that naphthalene transport occurred from the aqueous phase into the frog tissue. The first-order rate constant (k in day-1) for the entry of naphthalene from the water into the frog was 0.079 +/- 0.007 (k +/- 95% C.I.). Bioaccumulation of naphthalene was measured in liver, lung, and thigh muscle tissue. Exposure to naphthalene caused a significant reduction in pulmonary CO(2) excretion, particularly following the first 30 minutes of exposure. Pulmonary CO(2) excretion returned to baseline levels after 8 hours of exposure, indicating that some degree of acclimation had occurred. Depuration experiments were used to monitor recovery from naphthalene exposure. Recovery of CO(2) excretion was evident following 2 hours of depuration and complete elimination of naphthalene from tissues occurred after 3 hours. The data indicate that accumulated polycyclic aromatic hydrocarbons (PAHs) may alter normal physiologic functions such as gas exchange. Since amphibians, such as frogs, are one of the first organisms to come into contact with contaminated water and sediments, the information in this study suggests that this species may be used to assess bioaccumulation and toxicity of PAHs in ecosystems.