Joon-Seok Park

Bioremediation of diesel-contaminated soil with composting.

The major objective of this research was to find the appropriate mix ratio of organic amendments for enhancing diesel oil degradation during contaminated soil composting. Sewage sludge or compost was added as an amendment for supplementing organic matter for composting of contaminated soil. The ratios of contaminated soil to organic amendments were 1:0.1, 1:0.3, 1:0.5, and 1:1 as wet weight basis. Target contaminant of this research was diesel oil, which was spiked at 10,000 mg/kg sample on a dry weight basis. The degradation of diesel oil was significantly enhanced by the addition of these organic amendments relative to straight soil. Degradation rates of total petroleum hydrocarbons (TPH) and n-alkanes were the greatest at the ratio of 1:0.5 of contaminated soil to organic amendments on wet weight basis. Preferential degradation of n-alkanes over TPH was observed regardless of the kind and the amount of organic amendments. The first order degradation constant of n-alkanes was about twice TPH degradation constant. Normal alkanes could be divided in two groups (C10-C15 versus C16-C20) based on the first order kinetic constant. Volatilization loss of TPH was only about 2% of initial TPH. Normal alkanes lost by volatilization were mainly by the compounds of C10 to C16. High correlations (r=0.80-0.86) were found among TPH degradation rate, amount of CO2 evolved, and dehydrogenase activity.

A Continuous Strategy Game for Power Transactions Analysis in Competitive Electricity Markets

This article presents a game theory application for analyzing power transactions in a deregulated energy marketplace such as PoolCo, where participants, especially generating entities, maximize their net profits through optimal bidding strategies (i.e., bidding prices and bidding generations). In this article, the electricity market for power transactions is modeled as a noncooperative game with complete information, where the solution is determined in a continuous strategy domain having recourse to the Nash equilibrium idea. In order to provide more apprehensible analysis, we suggest a new hybrid solution approach employing a two-dimensional graphical approach as well as an analytical method. Finally, the proposed approach is demonstrated on a sample power system.

Biofiltration of gasoline vapor by compost media.

Gasoline vapor was treated using a compost biofilter operated in upflow mode over 4 months. The gas velocity was 6 m/h, yielding an empty bed retention time (EBRT) of 10 min. Benzene, toluene, ethylbenzene and xylene (BTEX) and total petroleum hydrocarbon (TPH) removal efficiencies remained fairly stable approximately 15 days after biofilter start-up. The average removal efficiencies of TPH and BTEX were 80 and 85%, respectively, during 4 months of stable operation. Biodegradation portions of the treated TPH and BTEX were 60 and 64%, respectively. When the influent concentration of TPH was less than 7800 mg TPH/m3, approximately 50% of TPH in the gas stream was removed in the lower half of the biofilter. When the influent concentration of BTEX was less than 720 mg BTEX/m3, over 75% of BTEX in the gas stream was removed in the lower half of the biofilter. Benzene removal efficiency was the lowest among BTEX. A pressure drop could not be detected over a 1-m bed height at a gas velocity of 6 m/h after approximately 4 months of operation. Results demonstrated that BTEX in gasoline vapor could be treated effectively using a compost biofilter.

Recycling of Remediated Soil for Effective Composting Of Diesel-Contaminated Soil

Soil contaminated with diesel oil was remediated by the addition of remediated soil. Several mix ratios of contaminated soil to remediated soil were tested. Judging from TPH degradation rate and biochemical parameters, the optimum mix ratio (wet weight basis) was 1:1. In this mix ratio, the first order degradation rate constant of diesel oil based on TPH was 0.099/day. Degradation rate of TPH and total amount of CO2 evolved in this condition were two times larger than those of contaminated soil without adding remediated soil. The addition of remediated soil was a very effective treatment option to facilitate the degradation rate of diesel oil in contaminated soil.

Effect of Moisture Content on Direct Landfilling Prohibition of Organic Sludge

This research was conducted to evaluate the effect of moisture content on direct landfilling prohibition of organic sludge. Organic sludges with moisture content (Me) of 75 and 85% were filled in two lysimeters. The lysimeters were named as Exp.75 and Exp.85, respectively. LFG of 2,064 l was generated greatly for Exp.85, compared to 1,500 l for Exp.75. LFG generations in Exp.75 and Exp.85 were 64.1 l/kg and 157.1 l/kg as dry TS basis, and 113.6 l/kg and 266.2 l/kg as dry VS basis. Total generation in LFG for Exp.85 was 1,238 l, while 1,050 l for Exp.75. of ppmv was generated from Exp.85, which was 5 times higher than ppmv from Exp.75. Leachate was not generated from Exp.75 during operation time. However, 420 ml of leachate was generated from Exp.85. From the results of gas generation, composition, odorous compounds, and leachate generation, landfilling of organic sludge with high MC was more harmful to the environment in spite of great LFG generation. However, direct landfilling of organic sludges without great difference of MC made a severe odor problem. Therefore, it was thought that current direct landfilling prohibition law for all organic sludge was appropriate.

Effect of Sonication and Reducing Agent Addition on Soil Washing of Heavy Metals-contaminated Soil

This research was conducted to estimate the effect of sonication and reducing agent addition on soil washing of heavy metals-contaminated soil. Sonication trained in soil washing did not significantly increased extraction efficiency of heavy metal compared to soil washing only. The extraction efficiency of sonication trained in soil washing was 12% increased for Pb in 0.01M EDTA leaching solution. Pb and Cd showed higher extraction efficiency in case of reducing agent treatment with mechanical shaking than that with sonication. However, the extraction efficiency of Cu and Zn in case of reducing agent treatment with sonication was over 2 times higher than that in with soil washing. Therefore, application of reducing agent addition with sonication or mechanical shaking should be decided differently for pretreatment of soil washing, according to the kind of heavy metal. It was estimated that sonication after adding reducing agent could increase removal efficiency of Zn or Cu-contaminated soil and shorten the treatment time.