Soon-Uk Yoon

Degradation of the long-resistant pharmaceutical compounds carbamazepine and diatrizoate using mixed microbial culture

ABSTRACT The microbial degradation of two recalcitrant pharmaceutical compounds, carbamazepine (CBZ) and diatrizoate (DTZ), was studied in laboratory batch experiments. We used a defined mixed microbial culture comprising four distinct microbial species that were previously known to have high decomposition capacity toward recalcitrant substances. Biological decomposition in liquid phase cultures for either CBZ or DTZ, or in a combination of the two, was conducted for 12 days. DTZ and CBZ were degraded by 43.2% and 60%, respectively from an initial concentration of 100 µg L−1. When degradation was assessed using a mixture of the two compounds, the initial degradation rates of CBZ and DTZ were lower than those observed in the single-compound study. However, the final cumulative removal efficiency was very similar. The extent of dissolved organic carbon (DOC) removal was correlated with the degradation of the pharmaceuticals.

Study on Characteristics of Solubilization for Sewage Sludge Using Electronic Field and Ultrasonification

Sludge solubilization using sonification has been increasingly used for sludge volume reduction along with enhancing digestion efficiency during anaerobic biogas production. In this study, either electric field or ultrasonification or in combination with were investigated using three types of sludge (return, excess and mixed at G sewage treatment facility) for the most efficient solubilization. As a the closed loop, 200 L of sludge was continuously passing through the solubilization system at an average flow rate of 0.7 m/h, which is equivalent to 3.5 times treated per hour for up to 84 times (24 h). Only implying electric field showed no variation for sCOD/tCOD before and after treatment on sludge solubilization regardless of types of sludge. However, employing the ultrasonic or combined system could both increasingly solubilize sludge with regard to the number of passing-through, which more enhanced by the combined. In addition, VSS/TSS was lowered to in the range of 2 and 6% while its particle size, diameter (0.9) and diameter (0.5) were more minimized than that of raw sludge. For return sludge, ultrasonification was more efficiently facilitated for solubilization, whereas electric field-ultrasonification was more preferably applied for excess and mixed sludge. It is concluded that depending on types of sludge, solubilization system must be selectively applied for the most efficient break-up of them.

Activity of a Methanotrophic Consortium Isolated from Landfill Cover Soil: Response to Temperature, pH, CO2, and Porous Adsorbent

ABSTRACT A robust, naturally evolving methanotrophic community in landfill cover soil (LFCS) can be the simplest way to mitigate landfill methane emission. In this study, bacterial community composition in LFCS and methane oxidation potential of enriched methanotrophic consortium, in comparison to that of axenic Methylosinus sporium, was investigated. Growth and methane oxidation of the consortium was studied in liquid phase batch experiments under varying temperature (20–40°C), pH (5–10), headspace CO2, and in presence of porous adsorbent (1.3 cm3 sponge cubes). The 16S rRNA gene analysis revealed presence of both type-I and type-II methanotrophs along with few obligate methylotroph in LFCS. Though the optimal growth condition of the consortium was at 30°C and pH 7, it was more resilient in comparison to M. sporium. With increasing availability of porous adsorbent, methane consumption by the consortium was significantly improved (p < 0.001) reaching a maximum specific methane oxidation rate of 11.4 μmol mg−1 biomass h−1. Thus, inducing naturally thriving methanotrophs in LFCS is a better alternative to axenic methanotrophic culture in methane emission management.

Characteristics of Methanol Production Derived from Methane Oxidation by Inhibiting Methanol Dehydrogenase

This study was conducted to biologically convert methane into methanol. Methane contained in biogas was bio-catalytically oxidized by methane monooxygenase (MMO) of methanotrophs, while methanol conversion was observed by inhibiting methanol dehydrogenase (MDH) using MDH activity inhibitors such as phosphate, NaCl, , and EDTA. The degree of methane oxidation by methanotrophs was the most highly accomplished as 0.56 mmol for the condition at and pH 7 under 0.4 (v/v%) of biogas ( 50%, 50%) / Air ratio. By the inhibition of 40 mM of phosphate, 50 mM of NaCl, 40 mM of and of EDTA, methane oxidation rate could achieve more than 80% regardless of type of inhibitors. In the meantime, addition of 40 mM of phosphate, 100 mM of NaCl, 40 mM of and of EDTA each led to generating the highest amount of methanol, i.e, 0.71, 0.60, 0.66, and 0.66 mmol when 1.3, 0.67, 0.74, and 1.3 mmol of methane was each concurrently consumed. At that time, methanol conversion rate was 54.7, 89.9, 89.6, and 47.8% respectively, and maximum methanol production rate was . From this, it was decided that the methanol production could be maximized as 89.9% when MDH activity was specifically inhibited into the typical level of 35% for the inhibitor of concern.

Enhancement of Dewaterability of Sewage Sludge by Ultrasonification and Electric Field Treatment

The sludge disposal is a major economic factor in the sewage treatment facility operation. Moreover, since the ocean dumping will be prohibited by Korean environmental law from 2013, sludge should be eliminated or sludge volumetric reduction should be performed urgently. In this study, improvement of the sewage sludge dewaterability was investigated by ultrasound and electric field treatment. Sludge was treated by a single or in combination of either the electric field or ultrasound on a pilot pretreatment facility, then it was dewatered by lab-scale filter press. The operating input energy of ultrasound device was varied from 225~1,200 kJ/L and electric field device was varied from 4.5~24 kJ/L. The water contents of dewatered sludge cake treated with ultrasound (1,200 kJ/L) and combination of ultrasound/electric field (1,224 kJ/L) were decreased 10~12% by comparing non-treated sludge. At that time, water contents were 65~66%. The combination treatment of ultrasound/electric field was effective to reduce water content of dewatered sludge cake, however, water content was not changed by a single treatment of electric field because of low energy density.

Redox-mediator-free degradation of sulfathiazole and tetracycline using Phanerochaete chrysosporium

ABSTRACT The removal of two of the most commonly used antibiotics, tetracycline (TC) and sulfathiazole (STZ), using laccase-producing Phanerochaete chrysosporium was studied in liquid-phase batch experiments in the absence of any synthetic redox mediator. The removal of STZ and TC from single antibiotic spikes varied from 97.8% to 15.4% and 98.8% to 31%, respectively, with increasing initial doses of 10–250 mg L−1 within 14 days of incubation. The enzyme activity of P. chrysosporium was only minimally influenced by the concentrations of these antibiotics. The degradation of antibiotics initiated before an appreciable extracellular enzyme activity was noted in the fungal culture. The appearance of low-molecular weight molecular fragments from parent antibiotics in liquid chromatography–mass spectrometry confirmed the biodegradation process.

Development of adsorption treatment by iron oxide nanoparticles and biological degradation in mimetic column for maaged aquifer recharge

P Electrolytic Oxidation (PEO) is a very promising process that can enhance the corrosion and wear resistance by producing a relatively thick, dense and hard oxide ceramic coating on light alloys. The corrosion and wear behaviour of the treated samples strongly depends on some process parameters: current density, voltage, treatment time and electrolyte composition. In particular, the addiction of additives in the electrolyte produces significant changes in the resistance of the obtained coatings. In literature several works can be found concerning the addiction of silicon carbide or graphite particles in PEO coatings, in order to improve the wear resistance on aluminium alloys. However, there is little knowledge regarding the improvement of wear resistance of PEO treated magnesium alloys. In this work, 3g/l of graphite nanoparticles were added to an electrolyte containing sodium phosphates and sodium silicates in order to improve the wear resistance of the coatings produced on AZ91 and AZ80 magnesium alloy. Treatments were conducted at high current densities and short treatment times (two different treatment times were tested). The thickness, the morphology and the composition of the coatings were studied with SEM-EDS and XRD. The wear resistance was analyzed with a tribometer and the corrosion resistance of the samples was studied with potentiodynamic polarization tests and EIS tests. The results showed that the graphite nanoparticles seal the pores that characterize the typical surface of a PEO treated magnesium alloy. This fact produced an improvement both in the corrosion resistance and in the wear resistance.U of treated wastewater can be a sustainable water resource management policy. However, high organic matters and pathogen load along with the array of emerging recalcitrant micro-pollutants, that escape the sewage treatment plant, requires expensive advanced oxidation processes (AOPs) before use. Utilization of treated waste water in managed aquifer recharge (MAR), either in the form of riverbank filtration (RBF), lake bank filtration (LBF) and artificial recharge (AR) are costeffective and have been shown to degrade recalcitrant pharmaceuticals and personal care products (PPCPs). Carbamazepine (CBZ) and diatrizoate (DTZ) are two such persistent pharmaceuticals not degraded in in sewage treatment process. CBZ is an antiepileptic drug prescribed in seizure disorder, bipolar disorder, neuralgia, schizophrenia and depression. DTZ is used as iodinated X-ray contrast agents. Objective of this study was to evaluate removal of CBZ, and DTZ in simulated MAR with functionalized iron oxide nanoparticle and biological treatment. A long cylindrical acrylic column was filled with sand (0.8 ~ 1.2 mm). Hydraulic conductivity, flow rate and retention time were calculated before injecting CBZ and DTZ containing artificial wastewater at estimated load of 7.89 μg/g and 10.62 μg/g, respectively. The effluent concentration at different sampling point on the column during the experimental period was analyzed by SPE-HPLC. When inoculated with a mixed microbial culture, previously known for its metabolic potential, 89.63% of CBZ and 83.66% of DTZ were removed. Because the degradation capacity of pharmaceutical substances was more than 70% in the long-term operation in the soil layer, it will be combined the adsorption and bio-degradation process. This study not only confirmed the ability of MAR to treat the CBZ and DTZ in physicochemical and biological process, but also envisioned the possibility to treat the effluents from sewage plants.P which is a new branch of photonics, is based on the interaction of light with surface plasmon in nanostructured free-electron-rich metallic structures. Surface plasmon is a collective excitation of the electrons within the conduction band of a metal. Localized surface plasmon resonances occurring in metallic nanoparticles generates confined light fields, which enables enhancement of Raman scattering and nonlinear processes. Enhancement of signal amplification by localized surface plasmon was first discovered as surface-enhanced Raman scattering (SERS, in 1974) then made another techniques, tip-enhanced Raman scattering (TERS, in 2000) and surface-enhanced coherent anti-stokes Raman scattering (SE-CARS, in 1994). These three types of plasmon-enhanced vibrational spectroscopies have certain potential for the detection of any types of molecules at single-molecule level along with refinement of metallic nanostructures, however, only few specific molecules were reported as target molecules at single-molecule level. In this talk, the reported experiments which already succeeded plasmon-enhanced single-molecule detections using SERS, TERS and SE-CARS will be introduced and what is needed more will be discussed for universal detection of molecules using plasmon-enhanced single-molecule spectroscopy.T performance of polyamide lattices with electro-deposited metal was evaluated. This was achieved by irreversible compaction of the structures involved in the investigation. The versatility of additive manufacturing was utilized in order to fabricate the lattices. It demonstrated that metal coating of polymer lattices could significantly improve their compression properties. This methodology could provide new opportunities in terms of light weight energy absorbing structures in a wide variety of applications.

Biomimetic Acid Soil Amelioration using Indigenous Soil Isolates in Comparison to other Potential Microorganism

ABSTRACT In the present study, four different soil isolates were screened and evaluated for their acid neutralization capacity in liquid culture and soil column tests with either artificial soil or real acid soil. Miniaturized artificial soil column tests using Aspergillus fumigatus, Aureobasidium pullulans, and Myxococcus xanthus were also included. In the liquid-phase experiment, two isolates (designated ‘A’ and ‘B’) effectively increased the medium pH from 4 to 6.74 and 6.53, respectively, during the 6 d, and the ammonium-nitrogen (NH4+-N) concentration increased from 400 ppm to 1000 ppm (isolate A). The isolates A and B were identified as Enterococcus hirae and Clostridium sp. in 16S ribosomal ribonucleic acid (rRNA) analysis. Artificial soil pH increased more quickly with soil isolates than in comparison to A. fumigatus or A. pullulans. In real acid soil pH increased from 4.2 to about pH 6.5 within 4 d. This suggests that biomimetic approaches could be valuable for acid soil amelioration.

Assessment for

This study was conducted to characterize CO2 biomineralization on several minerals (i.e., CaO, MgO, SiO2) by bottle test in an aqueous solution and solidified sludge using different aerobic bacterial strains like Bacillus megaterium and Bacillus pasteurii by batch test. These bacteria promote the formation of microenvironments that facilitate the precipitation of mineral phases that were unsaturated in the bulk solution. For one type of mineral solely amended, the CO2 was reduced at the highest of 4.0 mmol for MgO while it was not that much lower for CaO and SiO2 showing 1.1 and 0.3 mmol CO2, respectively. For two types of minerals simultaneously amended, the CO2 was reduced at the greater extent for both Ca + Mg and Mg + Si showing 2.7 and 2.3 mmol, respectively whereas it was less for Ca + Si at 1.8 mmol. For solidified sludge, the CO2 reduction rate changed depending on the volume of solidified sludge placed in the medium and the input CO2 concentration.. The reduction rate of CO2 was increased with increasing the volume of solidified sludge. Results of XRD analysis indicate that CaCO3 (Calcite) was dominantly formed among others (e.g., Aragonite, Dolomite). SEM analysis showed that the sample with Bacillus pasteurii, could more form minerals rather than control. As demonstrated in this study, CO2 would be effectively sequestered in biomineralization process.