Seog-Ku Kim

The removal of Microcystis ichthyoblabe cells and its hepatotoxin microcystin–LR during electrooxidation process using Pt/Ti electrodes

Electrooxidation is widely used to remove harmful organic and inorganic substances as well as pathogenic microorganisms. This study investigates the removal of Microcystis ichthyoblabe cells and their hepatotoxin microcystin–LR by the electrooxidation process using Pt/Ti electrodes. Additionally, the morphology changes and cell sizes were determined by scanning electron microscopy and a particle size analyzer, respectively. The algal cells were severely damaged by the electrooxidation process. During the initial treatment, intracellular microcystin–LR was released from the cells, increasing the extracellular microcystin–LR concentration. The electrooxidation charge required to remove cells and MC–LR was 3 × 104 C and 6 × 104 C, respectively. The removal efficiencies of M. ichthyoblabe cells and microcystin–LR were insensitive to initial cell density, initial microcystin–LR concentration and solution conductivity, but were heavily reduced at large algal suspension volume. Therefore, to achieve simultaneous removal of Microcystis cells and their MC, it is necessary to control the volume of algal suspension.

Road Runoff Treatment using Pilot Scale-NPS Treatment Plant Filling up Expended Polypropylene Media

Investigated the processing characteristics of the pollutants and runoff due to storm events in the actual application of the road fields and a Non-Point Sources (NPS) pilot scale equipment. This phenomenon has occurred in the influent bypass the blockage occurs after 90 min the expended polymeric media was filled with filtered column. When entering a treatment tank SS 200 mg/L or more high concentration of effluent treatment efficiency was reduced from the reaction time 60 min. Influent concentration less then SS 180 mg/L was stable handling. The CODCr/SS ratio were analyzed with 0.67, median value. Showed 92.1% and 82.3% respectively with an average removal rate of the SS and the CODCr. If the influent concentration of TP is the 0.5 mg/L or less, the quality of the treated water is 0.1 mg/L levels were expressed in a stable process. And when entering the 1.0 mg/L or more of the treated water, had a greater than average 0.2 mg/L. If the influent concentration of TN is 4~10 mg/L, the treatment water quality level was kept a 1.5~3.0 mg/L. The average removal efficiency of TP and TN respectively 73.9%, 50.4%.

Concentration Characteristics of Runoff Pollutants using Statistical Techniques during a Storm: the Case Research of Driveway Site in Korea

This research was conducted to investigate the magnitude and nature of the emission of runoff pollutants with the goal of quantifying stormwater pollutant concentrations from driveways site. A statistical summary for concentration characteristics of driveway runoff is provided based on the various analysis techniques. Runoff water qualities in temporal variation were generally higher in wet season than in dry season with a high degree of variability. The 95 % confidence intervals of washed-off pollutant concentration are ranged to 82.4-141.4 mgL -1 for TSS, 53.3-87.6 mgL -1 for Turbidity, 19.0-38.7 mgL -1 for BOD, 34.0-59.2 mgL -1 for COD, 16.4-27.4 mgL -1 for DOC, 4.3-5.6 mgL -1 for TN and 0.25-0.34 mgL -1 for TP, showing the high values based on the surface or lake quality standards in Korea. The first flush effect is mostly occurred within initial 30 min of storm duration. Concentrations of water quality constituents in urban stormwater are often expressed in probabilistic terms using statistics such as the mean and standard deviation and selected quintiles. Three probability distributions, weibull in TSS and Turbidity, lognormal in BOD and COD and gamma in DOC, TN and TP were fitted and the goodness-of-fit was assessed using the Anderson-Darling test. The correlation matrix of all water quality variables shows significant relationships between all parameters (P<0.001) and the correlation of between TSS and Turbidity showed relatively strong positive relationship (r=0.825). This research presents the concentration changes and characteristics during storm occurrence. The new concept explaining the relationship among the emission effects of runoff pollutants are suggested using statistical techniques.

An Overview of Problems Cyanotoxins Produced by Cyanobacteria and the Solutions Thereby

Cyanobacteria frequently dominate the freshwater phytoplankton community in eutrophic waters. Cyanotoxins can be classified according to toxicity as neurotoxin (Anatoxin-a, Anatoxin-a(s), Saxitoxins) or hepatotoxin (microcystins, nodularin, cylindrospermopsin). Microcystins are present within cyanobacterial cells generally, and they are extracted by the damage of cell membrane. It has been reported that cyanotoxins caused adverse effects and they are acculmulated in aquatic oganisms of lake, river and ocean. In natural, microcystins are removed by biodegradation of microorganisms and/or feeding of predators. However, in process of water treatment, the use of copper sulfate to remove algal cells caused extraction of a mess of microcystins. Microcysitns are removed by physical, chemical and biological methods according to reports. The reduction of nutrients (N and P) inflow is basic method of prevention of cyanobacteria bloom formation. However, it is less effective than investigation because nutrients already present in the eutrophic lake. In natural lake, cyanobacteria bloom are not formed because macrophytes invade from coastal lake by eutrophication. Therefore, a coastal lake has to recover to prevent of cyanobacteria bloom formation.

Local Winds Effects on the Water Surface Variation at the Shallow Estuary, Mobile Bay

A three-dimensional ocean circulation model was applied to a shallow estuary, Mobile Bay, to study local wind setup and setdown. Tides started from the northern Gulf of Mexico propagates up to the Mobile River system which is located in the north of the Mobile Bay. However, the tides started in the south of Mobile Bay were distorted when travelling upstream while affected by river discharge and local winds. The water surface elevation was less/over predicted responding north/south winds, respectively, when winds only at the Dauphin Island station (DPI) were used. However, the model predicted water surface elevation better when using two local winds from DPI and Mobile Downtown Airport (MDA). Wind speeds were greatly reduced (~ 88%) in about 43 km distance between DPI and MDA, and the canopy effects may be the reason for this. For this reason, the local winds are greatly responsible for local surface elevation setup and setdown especially at the shallow estuary like Mobile Bay.