In recent decades, biofiltration has been widely accepted for the treatment of contaminated air stream containing low concentration of odorous compounds or volatile organic compounds (VOCs). In this study, conventional biofilters packed with flexible synthetic polyurethane (PU) foam carriers were operated to remove toluene from a contaminated air stream. PU foams containing various amounts of pulverized activated carbon (PAC) were synthesized for the biofilter media and tested for toluene removal. Four biofilter columns were operated for 60 days to remove gaseous toluene from a contaminated air stream. During the biofiltration experiment, inlet toluene concentration was in the range of 0-150 ppm and EBRT (i.e., empty bed residence time) was kept at 26-42 seconds. Pressure drop of the biofilter bed was less than 3 mm H2O/m filter bed. The maximum removal capacity of toluene in the biofilters packed with PU-PAC foam was in the order of column II (PAC = 7.08%) > column III (PAC = 8.97%) > column I (PAC = 4.95%) > column IV (PAC = 13.52%), while the complete removal capacity was in the order of column II > column I > column III > column IV. The better biofiltration performance in column II was attributed to higher porosity providing favorable conditions for microbial growth. The results of biodegradation kinetic analysis showed that PU-PAC foam with 7.08% of PAC content had higher maximum removal rate (Vm = 14.99 g toluene/kg dry material/day) than the other PU-PAC foams. In overall, the performance of biofiltration might be affected by the structure and physicochemical properties of PU foam induced by PAC content.

Microorganisms capable of degrading trichloroethylene(TCE) using phenol as a induction substrate were isolated from industrial effluents and soil. The strain MS-64K which had the highest biodegradability was identified as the genus Micrococcus. The optimal conditions of medium for the growth and biodegradation of trichloroethylene were observed as follows; the initial pH 7.0, trichloroethylene 1,000ppm as the carbon source, 0.2% (NH_4)_2SO_4 as the nitrogen source, respectively. Lag period and degradation time on optimal medium were shorter than those on isolation medium. Growth on the optimal medium was increased. Addition of 0.1% Triton X-100 increased the growth rate of Micrococcus sp. MS-64K, but degradation was equal to optimal medium. Trichloroethylene degradation by Micrococcus sp. MS-64K was shown to fit logarithmic model when the compound was added at initial concentration of 1,000ppm.

In order to find the most fitted biodegradation model, biodegradation kinetics model to the initial phenol and p-cresol concentrations were investigated and had been fitted by the linear regression. Bacteria capable of degrading p-cresol were isolated from soil by enrichment culture technique. Among them, strain M1 capable of degrading p-cresol has also degraded phenol and was identified as the genus Micrococcus from the results from of taxonomical studies. The optimal conditions for the biodegradation of phenol and pcresol by Micrococcus sp. M1 were NH_4NO_3 0.05%, pH 7.0, 30℃, respectively, and medium volume 100㎖/250㎖ shaking flask. Micrococcus sp. M1 was able to grow on phenol concentration up to 14mM and p-cresol concentration up to 8mM. With increasing substrate concentration, the lag period increased, but the maximum specific growth rates decreased. The yield coefficient decreased with increasing substrate concentration. The biodegradation kinetics of phenol and p-cresol were best described by Monod with growth model for every experimented concentration. In cultivation of mixed substrate, p-cresol was degraded first and phenol was second. This result implies that p-cresol and phenol was not degraded simultaneously.

Optimal biodegradation kinetics models to the initial nonylphenol ethoxylates-30 concentration were investigated and had been fitted by the linear regression. Microorganisms capable of degrading nonylphenol ethoxylates-30 were isolated from sewage near Ulsan plant area by enrichment culture technique. Among them, the strain designated as EL-10K had the highest biodegradability and was identified as Pseudomonas from results of taxonomical studies. The optimal conditions for the biodegradation were 1.0 g/l of nonylphenol ethoxylates-30 and 0.02 g/l of ammonium nitrate at pH 7.0 and 30℃. The highest degradation rate of nonylphenol ethoxylates-30 was about 89% for 30 hours incubation on the optimal condition. Biodegradation date were fit by linear regression to equations for 3 kinetic models. The kinetics of biodegradation of nonylphenol ethoxylates was best described by first order model for 0.1 ㎍/l nonylphenol ethoxylates-30 ; by Monod no growth model and Monod with growth model for 0.5 ㎍/ml and 1.0, 5.0 ㎍/ml, respectively.

In order to find the most fitted biodegradation model, biodegradation models to the initial 4-chlorophenol concentrations were investigated and had been fitted by the linear regression. The degrading bacterium, EL-091S, was selected among phenol-degraders. The strain was identified with Pseudomonas sp. from the result of taxonomical studies. The optimal condition for the biodegradation was as fellows: secondary carbon source, concentration of ammonium nitrate, temperature and pH were 200㎎/l fructose, 600 ㎎/l, 30℃ and 7.0 respectively. The highest degradation rate of the 4-chlorophenol was about 58% for 24 hours incubation on the optimal condition. Biodegradation kinetics model of 5 ㎎/l 4-Chlorophenol, 10 ㎎/l 4-chlorophenol and 50 ㎎/l 4-chlorophenol were fitted the zero order kinetics model, respectively.