Guyoung Kang

Pentachlorophenol and crystal violet degradation in water and soils using heme and hydrogen peroxide

An abiotic method for oxidative PCP degradation in soil under unsaturated conditions and neutral pH was developed. Reagents used were heme (a catalyst) and peroxide (an oxidant). The aqueous phase degradation of crystal violet and PCP, and the mineralization of PCP in soil were determined. Five factors were investigated to assess their impact on PCP degradation in a soil contaminated with wood preserving chemicals. The results showed that heme and peroxide could efficiently degrade PCP and crystal violet in a short period of time in either liquid or unsaturated soil systems. In soil, three control runs showed little degradation of PCP, but treatments with heme and peroxide showed a maximum of 13% mineralization of PCP. Heme and peroxide concentration were the two most important factors in improving degradation of PCP in soil.

Development of an Advanced Evaporation System with Fouling-Free Technology Using a Circulating Fluidized Bed Heat Exchanger

The heat transfer rate and fouling characteristics of a circulating fluidized bed heat exchanger (CFBHE), and the treatability of landfill and municipal incinerator disposal pit leachate by advanced evaporation were investigated experimentally. The heat exchanger used glass beads (3.0-mm diameter with a specific gravity of 2.54) to control fouling. Glass beads enhanced heat transfer coefficients independently of water velocity within a superficial velocity range from 0.4–0.8 m/s. Fouling control tests using a 3,000-mg/L ferric oxide slurry revealed that the glass beads effectively removed deposits formed prior to introduction of the beads and enhanced the heat transfer coefficient. The beads also prevented the formation of deposits. Leachate from an industrial landfill in Yeochun, Korea, containing petroleum and chemical waste was treated using the CFBHE system. Treatment efficiency for CODCr, BOD5, and NH4+-N were 91, 91, and 50%, respectively at an influent pH of 7.0. Treatment of leachate from a second...

Oxidation of pyrene using a hemoglobin-catalyzed biocatalytic reaction

The efficiency to remove polycyclic aromatic hydrocarbons (PAHs) was determined using a hemoglobin-catalyzed biocatalytic reaction. The present study employed pyrene as a model of PAHs to study its oxidative removal in the presence of H2O2 and hemoglobin in mass ratio of 3:1. The extent of pyrene removal reached up to 91.1% in the presence of H2O2 and hemoglobin. However, the extent of pyrene removal was 21.3% in the presence of H2O2 only. The results indicate that pyrene removal might be due to pyrene oxidation by the biocatalytic reaction. Overall, this study demonstrated that hemoglobin-catalyzed biocatalytic reactions could remediate pyrene effectively.

MINERALIZATION OF HAZARDOUS CHEMICALS BY HEME REACTION

The catalytic degradation of pentachlorophenol contaminated soil by heme and hydrogen peroxide has been reported. Here we studied evidence for the mechanism and mineralization by the heme catalyzed reaction for hazardous organopollutants. Ferryl heme radical and non-radical ferryl heme were generated rapidly by the interaction of heme and hydrogen peroxide (H2O2). The activated heme radical could initiate the oxidation of 5-aminosalicylic acid (5-ASA). The reactions by heme with H2O2 could support the redox cycling between the ferryl species of heme and 5-ASA as the mechanistic routes of the heme catalyzed reaction. Hazardous compounds such as pentachlorophenol, phenanthrene and benzo[a]pyrene were mineralized 20, 6, and 7%, respectively, with 30 mM heme and 1500 mM H2O2, after 24 hr reaction. This catalyzed degradation of organopollutants could be used as a novel technology for hazardous waste remediation.

Role of hemoglobin in hemoglobin-based remediation of the crude oil-contaminated soil

This study investigated the changes in the indigenous microbial community structure with hemoglobin (Hb) application to determine the role of Hb in Hb-based remediation of crude oil-contaminated soil. The phylogenetic diversity of the bacterial community showed that the Hb addition selected surfactants-producing species, thereby, promoting TPH degradation. The significant increase in the CO2 generation, which can be related to the increase in the bacterial abundance inferred from the 16S rRNA gene copy number, supports the enhanced TPH degradation with Hb application. The similar residual TPH concentrations in the presence of only hydrogen peroxide (H2O2) and both Hb and H2O2 suggested that the role of Hb as a catalyst was not as significant as the role of Hb as a nutrient. Also, in the presence of H2O2, a greater recovery of the microbial community structure was observed with the double Hb injection than the single Hb injection. Overall, this study shows that the Hb-based remediation strategies via microbial metabolism can be successfully applied to remediate the crude-oil contaminated Kuwaiti soil.

Toxicity identification and evaluation for the effluent from a nonmetallic mineral mining facility in Korea using D. magna

Industrial wastewater has attracted increasing attention in recent years because of its impact on ecosystems and human health. Whole-effluent tests are generally used to monitor toxicities of unknown chemicals and conventional pollutants from industrial effluent discharges. This study described identification evaluation (TIE) procedures to determine the acute toxicity of a nonmetallic mineral mining facility effluent that was toxic to Daphnia magna. In the characterization step (TIE phase I), toxic effects of heavy metals, organic compounds, oxidants, volatile organic compounds, suspended solids, and ammonia were screened. Results revealed that the source of toxicity was beyond these toxicants. Chemical analysis (TIE phase II) of total dissolved solid showed that the concentration of chloride ion (15,302.5 mg/L) was substantially higher than the predicted EC50 value for D. magna. Chemical analysis for heavy metal and ionic materials used ion chromatography and induced coupled plasma–optic emission spectroscopy. In the confirmation step (TIE phase III), using spiking and deletion approaches, it was demonstrated that chloride ion was the main toxicant in this effluent. Concentrations of potassium (317.5 mg/L), magnesium (970.5 mg/L), sodium (8595.3 mg/L), and sulfate (2854.3 mg/L) were not high enough to cause toxicity to D. magna. Finally, we concluded that chloride was the main toxicant in the nonmetallic mineral mining facility effluent. Based on these results, advanced treatment processes such as ion exchange and reverse osmosis technology are recommended to treat wastewater in this and similar situations. Further research is needed to provide technical support for toxin identification and evaluation of various types of wastewater treatment plant discharge.

Development of biological process for Kuwait crude oil contaminated soil

ABSTRACT Seven hundred ninety-eight oil wells were set fire, damaged, and gushed oil and resulted on a crude oil contaminated area over 300 km2 include dry oil lakes at the end of Iraqi war. The Un...

Enhanced Biodegradation of Total Petroleum Hydrocarbons (TPHs) in Contaminated Soil using Biocatalyst

Biocatalytic degradation of total petroleum hydrocarbons (TPHs) in contaminated soil by hemoglobin and hydrogen peroxide is an effective soil remediation method. This study used a laboratory soil reactor experiment to evaluate the effectiveness of a nonspecific biocatalytic reaction with hemoglobin and H2O2 for treating TPH-contaminated soil. We also quantified changes in the soil microbial community using real-time PCR analysis during the experimental treatment. The results show that the measured rate constant for the reaction with added hemoglobin was 0.051/day, about 3.5 times higher than the constant for the reaction with only H2O2 (0.014/day). After four weeks of treatment, 76% of the initial soil TPH concentration was removed with hemoglobin and hydrogen peroxide treatment. The removal of initial soil TPH concentration was 26% when only hydrogen peroxide was used. The soil microbial community, based on 16S rRNA gene copy number, was higher (7.1 × 10 6 copy number/g of bacteria, and 7.4 × 10 5 copy number/g of Archaea, respectively) in the hemoglobin catalyzed treatment. Our results show that TPH treatment in contaminated soil using hemoglobin catalyzed oxidation led to the enhanced removal effectiveness and was non-toxic to the native soil microbial community in the initial soil.