• Ecology and Resilient Infrastructure
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• 제2권2호
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• pp.177-184
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• 2015

This study assessed the performance of activated carbon (AC) amendment to treat polycyclic aromatic hydrocarbons (PAHs) including both parent- and alkylated-moieties in sediment impacted by diesel. A field-collected, diesel-impacted sediment with a NAPL content of 1% was used for the study. No. 2 diesel fuel is weathered by heating at $70^{\circ}C$ for 4 days to obtain a weathered diesel sample having C3-naphthalenes to C2-phenanthrenes/anthracenes (N2/P3) ratio similar to the original sediment. The sediment samples spiked with the weathered diesel to obtain non-aqueous phase liquid (NAPL) contents of 1, 5 and 10% were contacted with AC with a dose of 5% as sediment dry weight for 1 month. By the AC-sediment contact, the freely-dissolved equilibrium concentrations were substantially reduced. Even for sediment with 10% NAPL content, the reductions in the freely-dissolved concentrations were 92% and 75% for total parent-and alkylated-PAHs, respectively. The effect of NAPL contents on the performance of AC was negligible for parent-PAHs, while for alkylated-PAHs, a slightly reduced AC performance was observed. The results suggest that the AC amendment can be an effective option for the treatment of petroleum-impacted sediment with relatively high NAPL contents.

• 한국물환경학회지
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• 제38권1호
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• pp.31-42
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• 2022

Dissolved organic matter (DOM), which changes according to various factors, is ubiquitously present from natural environments to engineered treatment systems. Only limited information is available regarding the environmental functions of DOM after bulk analyses are only applied for characterization. In this paper, latest DOM analytical techniques are briefly introduced, which include fluorescence excitation-emission matrix with parallel factor analysis (EEM-PARAFAC), size-exclusion chromatography with an organic carbon detector (SEC-OCD), carbon/nitrogen stable-isotope ratio, and Fourier transform-ion cyclotron resonance-mass spectroscopy (FT-ICR-MS). Recent examples of using advanced analyses to interpret the phenomena associated with DOM occurring in natural and engineered systems are presented here. Through EEM-PARAFAC, different components like protein-like, fulvic-like, and humic-like can be identified and tracked individually through the investigated systems. SEC-OCD allows researchers to quantify different size fractions. FT-ICR-MS provides thousands of molecular formulas present in bulk DOM samples. Lastly, carbon/nitrogen stable-isotope ratio offers reasonable tools for tracking the sources in environments. We also discuss the advantages and weakness of the above-mentioned characterizing tools. Specifically, they focus on single environmental factors (different sourced-DOM and interaction of sediment-pore water) or simple changes after individual treatment processes. Through collaboration with the advanced techniques later, they help the researchers to better understand environmental behaviors in aquatic systems and serve as essential tools for addressing various pending problems associated with DOM.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.123-127
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• 2003

Changes in pyrene partitioning due to mineral surface adsorptive fractionation processes of humic substances (HS) were examined in model environmental systems. For purified Aldrich humic acid(PAHA), carbon-normalized pyrene binding coefficients ( $K_{oc}$ ) for the residual (i.e., nonadsorbed and dissolved) PAHA components were different from the original dissolved PAHA $K_{oc}$ , value prior to contact with mineral suspensions. A positive correlation between the extent of pyrene binding and weight-average molecular weight (M $W_{w}$) of residual PAHA components was observed, which appeared to be unaffected by the specific mineral adsorbents use and fractionation mechanisms. A similar positive correlation was not observed with the adsorbed PAHA components, suggesting that conformational changes occurred for the mineral-associated components upon adsorption. Nonlinear pyrene sorption to mineral-associated PAHA was observed, and the degree of nonlinearity is hypothesized to be dependent on adsorptive fractionation effects and/or structural rearrangement of the adsorbed PAHA components.s.

• 한국해양학회지
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• 제19권1호
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• pp.89-93
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• 1984

진해만에서 83년 7월의 장마직후에 수직적 및 수평적 해양화학적 환경을 조사 하였다. 마산만-가덕수도의 종축면상에는 염분이 낮은 내만쪽의 표층수에서 높은 농도의 용존성 질산염, 암모니아, 클로로필 a, 입자성질소, 입자성탄소가 측정 되었다. 입자성 C/N비는 내만쪽에서 낮고, 외만에서 높은 값을 보였다. 이 해역 에서 무기질소와 인의 양은 적조가 발생하기에 충분한 향으로 나타났다.

• KSBB Journal
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• 제13권6호
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• pp.675-680
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• 1998

In both 7L and 20L fermentor experiments the level of dissolved oxygen (D.O) strongly affected growth and PHBV production of Azotobacter vinelandii UWD. A higher D.O. increased carbon substrate consumption rate and cell growth rate with a similar residual biomass production. However, a lower D.O. was a much better condition for PHBV production. In a 20L fermentor experiments controlled at 5% D.O. cell growth rate was about twice faster(0.555 hr-1 and 0.260 hr-1 at the acid and the glucose phase, respectively) with an equal amount(4.5 g/L) of residual biomass production. However, PHBV content in the cell(62.3 wt%) increased 17.3 times at 1% D.O.

• 상하수도학회지
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• 제22권1호
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• pp.31-38
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• 2008

The primary objective of this study was to evaluate the variation of the molecular size distribution by granular activated carbon (GAC) adsorption. GAC adsorption was assessed by using the rapid small-scale column test (RSSCT) and high-performance size-exclusion chromatography (HPSEC) was used to analyze the molecular size distribution (MSD) in the effluent of GAC column. RSSCT study suggested that GAC adsorption exhibited excellent interrelationship between dissolved organic carbon (DOC) breakthrough and MSD as function of bed volumes passed. After GAC treatment, the nonadsorbable fraction which was about 25percents of influent DOC corresponded to the hydrophilic (HPI) natural organic carbon (NOM) of NOM fractions and was composed entirely of <300 molecular weight (MW) in the HPSEC at the initial stage of the RSSCT operation. The dominant MW fraction in the source water was 1,000~5,000daltons. At the bed volumes 2,500, MW <500 of GAC treated water was risen rather than it of source water. After the bed volumes 7,300 of operation, the MW 1,000~3,000 fraction was closed to about 80percents of DOC found in the GAC influent. The Number-average molecular weight (Mn) value determined using HPSEC for the effluent of GAC column was gently increased as DOC breakthrough progress. The quotient p(Mw/Mn) can be used to estimate the degree of polydispersity was shown greatest value for the GAC effluent at the initial stage of the RSSCT operation.

• Ocean and Polar Research
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• 제27권1호
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• pp.1-13
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• 2005

The samples for organic carbon analysis were collected between $5^{\circ}\;and\;17^{\circ}N$ along $131.5^{\circ}W$ in the northeast Pacific KODOS (Korea Deep Ocean Study) area. The mean concentration of total organic carbon (TOC) in the surface mixed layer $({\sim}50 m)$ was $100.13{\pm}2.05{\mu}M-C$, while the mean concentration of TOC in the lower 500m of the water column was $50.19{\pm}4.23{\mu}M-C$. A strong linear regression between TOC and temperature $(r^2=0.70)$ showed that TOC distribution was controlled by physical process. Results from the linear regression between chlorophyll-a and TOC, and between chlorophyll-a and particulate organic carbon (POC), decreasing of dissolved organic carbon (DOC) in the surface layer caused by non-biological photo-oxidation process. Below the surface layer, biological production and consumption occurred. DOC accumulation dominated in the depth range of $30{\sim}50m$ and DOC consumption occurred in the depth range of $50{\sim}200m$. TOC was inversely correlated with apparent oxygen utilization (AOU) and TOC/AOU molar ratios ranged from -0.077 to -0.21. These ratios indicated that TOC oxidation was responsible fur $10.9{\sim}30.1%$ (mean 20.2%) of oxygen consumption in the NE Pacific KODOS area. In the euphotic zone, distributions of dissolved and particulate organic matter were controlled by photo-chemical, chemical, biological and physical processes.

• 한국환경보건학회지
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• 제32권6호
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• pp.539-542
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• 2006

The objective of this paper is to compare the applicability of assimilable organic carbon (AOC) or biodegradable dissolved organic carbon (BDOC) for quantifying biodegradable organic material (BOM) and bio-stability in distribution systems for a variety of finished waters. The study the data is derived from was part of an AWWARF and Tampa Bay Water tailored collaboration project to determine the effect of blending different waters on distribution system water quality. Seven different finished waters were produced from surface, ground, or brackish water on site and fed 18 independent pilot distribution systems (PDSs), either as single finished water or as a blend of several finished waters. AOC and BDOC have often been used as indicators of bacterial regrowth potential in distribution systems. In this study, AOC was the more useful assay of the two for the BOM concentrations observed in the PDSs. BDOC did not distinguish BOM while AOC did at the low BOM levels from many of the advanced treatments (e.g. RO, $O^3/BAC$). AOC in contrast allowed much more meaningful calculations of the consumption or production of AOC as the blends passed through the PDSs even for very low BOM blends. In addition, meaningful trends corresponding to changes in heterophic plate count (HPC) were observed for AOC but not for BDOC. Moreover, AOC stability was associated with waters produced from advanced membrane treatment.

• Corrosion Science and Technology
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• 제11권6호
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• pp.257-262
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• 2012

Flow accelerated corrosion (FAC) of the carbon steel piping in nuclear power plants (NPPs) has been major issue in nuclear industry. Rotating cylinder FAC test facility was designed and fabricated and then performance of the facility was evaluated. The facility is very simple in design and economic in fabrication and can be used in material and chemistry screening test. The facility is equipped with on line monitoring of pH, conductivity, dissolved oxygen(DO), and temperature. Fluid velocity is controlled with rotating speed of the cylinder with a test specimen. FAC test of SA106 Gr. B carbon steel under 4 m/s flow velocity was performed with the rotating cylinder at DO concentration of less than 1 ppb and of 1.3 ppm. Also a corrosion test of the carbon steel at static condition, that is at zero fluid velocity, of test specimen and solution was performed at pH from 8 to 10 for comparison with the FAC data. For corrosion test in static condition, the amount of non adherent corrosion product was almost constant at pH ranging from 8 to 10. But adherent corrosion product decreased with increasing pH. This trend is consistent with decrease of Fe solubility with an increase in pH. For FAC test with rotating cylinder FAC test facility, the amount of non adherent corrosion product was also almost same for both DO concentrations. The rotating cylinder FAC test facility will be further improved by redesigning rotating cylinder and FAC specimen geometry for future work.

• 설비공학논문집
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• 제15권9호
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• pp.718-726
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• 2003

Carbon dioxide ocean disposal is one of the promising options to reduce carbon dioxide concentration in the atmosphere because the ocean has vast capacity for carbon dioxide sequestration. However, the dissolution rate of liquid carbon dioxide in seawater must be known in advance in order to estimate the amount of carbon dioxide sequestration in the ocean. Therefore, in the present study, calculations of the solubility, the surface concentration and the dissolution behavior of carbon dioxide when liquid carbon dioxide is released at 1,000m and 1,500m in depth are peformed. The results show that the droplet is completely dissolved below 500 m in depth if the carbon dioxide droplet is released both at 1,000m in depth with the initial droplet diameter of 0.011m or less and at 1,500m in depth with the diameter of 0.016 or less. Also, the surface concentration of carbon dioxide droplet with the hydrate film is about 50% of carbon dioxide solubility at 1,500 m in depth and about 60% of carbon dioxide solubility at 1,000 m in depth.