Reliability of solid phase microextraction in estimating bioavailability of pyrene in soil.

Solid phase microextraction (SPME) coupled with gas chromatography was employed to estimate bioavailability of pyrene in soils with different properties of textures, organic matter contents (SOM) and aging periods. Experimental results indicated that biodegradation rates increased from 0.10 (sandy loam) to 0.

Bioavailability evaluation of naphthalene in soil using persulfate oxidation and ultrasonic extraction method.

Bioavailability is defined as the fraction of a soil contaminant readily available for microbial degradation and for naphthalene it could be estimated by conventional exhaustive extraction methods. In this study, a novel method that employed persulfate oxidation in combination with ultrasonic extraction (POUSE) was developed. Three parameters, temperature, duration of persulfate oxidation, and the ratio of persulfate to soil organic matter (2S,082 /SOM; g g-1), were investigated to obtain an optimum operating conditions.

Biogenic substrate benefits activated sludge in acclimation to a xenobiotic.

Activated sludge that originated from a biogenic fed-batch reactor under steady-state was re-cultivated with the same biogenic substrates to test the changes in the sludge's performance in acclimation and degradation of a xenobiotic. Re-cultivations with varying biogenic concentrations were conducted at time points ranging from 16 d before to 4 d after the acclimation reactions. Biogenic re-cultivation energizes sludge cells thereby benefiting the re-cultivated biomass by shortening its acclimation lag time.

Xenobiotic substrate reduces yield of activated sludge in a continuous flow system.

The biomass yield of a continuous flow activated sludge system varied when the system treated influent containing different compositions of biogenic and xenobiotic substrates. Both the biogenic substrate and a test xenobiotic 2,4-dichlorophenoxyacetic acid (2,4-D) were degraded at steady-state activated sludge operations. The true yields, determined from steady-state activated sludge treatment performances, were at the maximum and the minimum when the activated sludge treated the influent of sole biogenic substrate and sole 2,4-D, respectively.

Estimation of bioavailability and potential risks of naphthalene in soils with solid phase microextraction.

A series of batch experiments were conducted to observe the variations of bioavailability of naphthalene in different types of soil with indigenous microorganisms. Solid phase microextraction (SPME) was employed to estimate the bioavailability of naphthalene in the soils. Various soil properties were attained by artificially modifying soil organic matter (SOM) with the addition of bagasse compost and textures with the addition of original silt and clay to determine the correlation between the amount of biodegraded naphthalene after 300 h and the amount of extractable naphthalene by SPME.

Continuous dechlorination of tetrachloroethene in an upflow anaerobic sludge blanket reactor.

Influences of hydraulic retention time (HRT) on dechlorination of tetrachloroethene (PCE) were investigated in an upflow anaerobic sludge blanket (UASB) reactor inoculated with anaerobic granular sludge non-pre-exposed to chlorinated compounds. PCE was introduced into the reactor at a loading rate of 3 mg/l d. PCE removal increased from 51+/-5% to 87+/-3% when HRT increased from 1 to 4 d, corresponding to an increase in the PCE biotransformation rate from 10.

Emission factors and characteristics of criteria pollutants and volatile organic compounds (VOCs) in a freeway tunnel study.

Carbon monoxide (CO), nitrogen oxide (NO(x)), hydrocarbon (HC), sulfur oxide (SO(2)), particulate matter <10 microm (PM(10)), and 57 VOC species of emissions were confirmed in a freeway tunnel in southern Taiwan. Emission factors were 1.89 (CO), 0.

Adsorption characteristics of benzene on biosolid adsorbent and commercial activated carbons.

This study selected biosolids from a petrochemical waste-water treatment plant as the raw material. The sludge was immersed in 0.5-5 M of zinc chloride (ZnCl2) solutions and pyrolyzed at different temperatures and times.