• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.19 no.4
• /
• pp.223-231
• /
• 2014

In order to prevent the spread of non-indigenous aquatic species through the ballast water in commercial ships, International Maritime Organization (IMO) adopted in 2004 the International Convention for Control and Management of Ship's Ballast Water and Sediments. The Convention mandates treatment of ballast water for most transoceanic voyages and its confirmation of treatment is made with plankton live/dead assay. Fluorescein diacetate assay (FDA), which produces bright green light for live phytoplankton, has been a de facto standard method to determine the survival of marine plankton, but its staining efficacy has been in dispute. In the present study, we examined the limitation of FDA, and compared its efficacy with Neutral red (NR) staining, another promising assay and widely used especially for zooplankton mortality. For all phytoplankton species studied in the present study, except Ditylum brightwellii, the staining efficiency was <50% with FDA. The green FDA fluorescence interfered with phytoplankton autofluorescence in most samples. In contrast, NR assay stained over 90% of both phytoplankton and zooplankton species tested in this study. FDA assay also showed that green FDA fluorescence rapidly faded when phytoplankton cells were exposed to microscope light. Both FDA and NR assay were negative on formalin-killed individuals of both phytoplankton and zooplankton species. Our results suggest that NR assay is more effective for determining the survival of marine plankton and can be applied to test the efficacy of ballast water treatment.

• Journal of Industrial Technology
• /
• v.31 no.A
• /
• pp.135-145
• /
• 2011

This study was conducted to analyze the cost effectiveness in line with total phosphorus standard enforcement of public sewage treatment facilities. The additional cost for the total phosphorus removal process was calculated to analyze the cost effectiveness of the advanced water purification process. The analysis results showed that the T-P removal by coagulation sedimentation was more efficient than the advanced water purification facilities in terms of facilities investment cost, and if the coagulation filteration was used for T-P removal, the activated carbon process among the advanced water purification techniques was more efficient in terms of facilities investment cost. In this study, the effects of the T-P removal process that will be additionally introduced according to the tightening of the effluent T-P standard were analyzed within a limit. The actual benefits of improved T-P concentration in the water source will provide diverse values, including the leisure water, environment improvement water, eco-system in the water source and industrial water, in addition to the advanced water purification.

• Journal of Korean Society on Water Environment
• /
• v.25 no.2
• /
• pp.268-280
• /
• 2009

Oncheon basin which are located in Busan is divided into 43 basin on the basis of main pipe, constructed with Storm Water Management Model (SWMM). Occurrence situation for Outflow and pollutant loads by long-term continuous rainfall is examined for treatment district and river analysis point of Oncheon basin and a reduction vs effectiveness table for effective CSOs managements is made for each of treatment districts according to each of managements. In case that treatment equipment is located at the discharge point of CSO, treatment efficiency is analysed. It is supposed that treatment equipment have an efficiency on the basis of a concentration and runoff discharge over a critical flow is discharged with it untreated and treating runoff discharge with treatment equipment at each of runoff discharge points and treating it gathered at sewage treatment plant (STP) through trunk sewer is compared for a relative treatment efficiency.

• Journal of Korean Society of Water and Wastewater
• /
• v.29 no.4
• /
• pp.493-502
• /
• 2015

In accordance with the Watershed Sewer System Maintenance Plan enforced on February 2, 2013, the different compliance concentration of effluent limit be applied to effluent discharged from public sewage treatment works(PSTWs) in each watershed on the basis of water quality thereof. With the introduction of watershed sewer system, it is necessary to set the compliance concentration of effluent limit for PSTWs situated in the watershed, by region and PSTW size, to achieve water quality criteria for regional watersheds or target water quality under TMDL program. Watershed Environmental Agencies establish the Watershed Sewer System Maintenance Plan and set the compliance concentrations of effluent limit for PSTWs under the plan. The agencies plan to apply tougher effluent BOD concentration limits in Class I to IV areas. Effluent BOD concentration limits will be toughened from 5~10 mg/L to 3 mg/L in class II~III areas, from 10mg/L to 5mg/L in class IV areas. Uniform application of effluent BOD concentration limits to PSTWs in the watershed sewer system need to be complemented considering type of sewage treatment technology employed and watershed characteristics. Therefore, this study presents method to determine the compliance concentration of effluent limit from PSTWs in the watershed.

• Journal of Adhesion and Interface
• /
• v.17 no.3
• /
• pp.96-103
• /
• 2016

In this work, pellets consisting of cellulose-based natural fiber bamboo and poly(lactic acid) (PLA) was prepared by extrusion process and then bamboo fiber/PLA biocomposites with various fiber contents were produced by injection molding process. The water treatment effect of bamboo fibers on the flexural, tensile, and impact properties and heat deflection temperature of the biocomposites were investigated. The thermal stability of bamboo and the flexural properties, tensile modulus, and impact strength depended on the presence and absence of water treatment as well as on the fiber content, whereas the heat deflection temperature are influenced mainly by water treatment. The increase of the mechanical and impact properties of biocomposites is ascribed to the improvement of the interfacial adhesion between the bamboo fibers and the PLA matrix by the water treatment. The result suggests that the pre-treatment of natural fibers by using water, which is environment-friendly and labor-friendly, may contribute to enhancing the performance of biocomposites.

• Korean Chemical Engineering Research
• /
• v.52 no.2
• /
• pp.154-165
• /
• 2014

Development of unconventional natural resources such as shale gas, shale oil and coal bed methane, has been activated and improved the productivity due to the recent technology advance in horizontal drilling and hydraulic fracturing. However, the flowback water mixed with chemical additives, and the brine water containing oil, gas, high levels of salts and radioactive metals is produced during the gas production. Potential negative environmental impact due to large volumes of the produced wastewater is increasingly seen as the major obstacles to the unconventional natural resource development. In this study an integrated framework for the flowback and brine water treatment is proposed, and we reviewed the upcoming state of the art technology in water treatment. Basic separation processes which include not only membrane, evaporation, crystallization and desalination processes, but the potential water reuse and recycling techniques can be applied for the unconventional natural resource industry.

• Membrane and Water Treatment
• /
• v.14 no.3
• /
• pp.107-114
• /
• 2023

Graphene oxide (GO) membranes have attracted extensive attention in water treatment and related fields. However, GO films are unstable and have low permeability, which have hindered their further development. In this paper, a simple and effective method was used in which GO and single-layer graphene (GN) were mixed, and the layer spacing was effectively controlled by accurately controlling the ratio of GO to GN. GO-GN composite membranes have excellent stability, salt rejection (95.4%), and water flux (26 L m^-2 h^-1 bar^-1). This unique design structure can be used for precise and effective regulation of the layer spacing in GO, improving the rejection rate, and increasing water flux via the enhancement of low-friction capillary action. The rational development and use of this unique composite membrane provides a reference for the water treatment field.

• Membrane and Water Treatment
• /
• v.13 no.3
• /
• pp.121-128
• /
• 2022

A tremendous amount of energy resources is being wasted in cleaning wastewater to save the environment across the globe. Several different procedures are commercially available to process wastewater. In this work, membrane filtration technique is used to treat the textile wastewater because of its cost effectiveness and low environmental impacts. Mixed Matrix Membrane (MMM) consist of Polyvinyl Alcohol (PVA) in which Graphene Oxide (GO) was added as a filler material. Five different membranes by varying the quantity of GO were prepared. The prepared membrane has been characterized by Scanning Electron Microscopy (SEM), X-Ray Diffractometry (XRD), Fourier Transformed Infrared Spectroscopy (FTIR) and Water Contact Angle (WCA). The prepared membranes have been utilized to treat textile wastewater. The synthesized membranes are used for the elimination of total dissolve solids (TDS), total suspended solids (TSS), Methylene blue (MB) dye and copper metallic ions from textile wastewater. It is concluded that amount of GO has direct correlation with the quality of wastewater treatment. The maximum removal of TDS, TSS, MB and copper ions are found to be 7.42, 23.73, 50.53 and 64.5% respectively and are achieved by 0.02 wt% PVA-GO membrane.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1998.06a
• /
• pp.25-48
• /
• 1998

Current topics related to membrane technology under the recent water environment are as follows: - Cryptosporidum Outbreak - Integrity Control System - Water re-use - Recycle Society - Biotreatment and Membrane - Slurry or Sludge Treatment I would like to introduce the actual examples regarding water re-use. mainly on the above 5 topics.

• Journal of Korean Society on Water Environment
• /
• v.20 no.2
• /
• pp.110-119
• /
• 2004

The combination of biological and physical/chemical technologies is a promising technique to reduce highly concentrated pollutants in livestock wastewater. It is suggested to treat livestock wastewater efficiently as follows: firstly, biodegradable organic matters, nitrogen and some of phosphorus should be removed by a biological treatment process and then residual non-biodegradable organic matters, color and phosphorus be eliminated by physicochemical technologies. In this study, therefore, the integrations of chemical coagulation, activated carbon adsorption, Fenton oxidation and ozonation were evaluated to provide appropriate post-treatment processes for biologically pre-treated livestock wastewater. After chemical coagulation followed by ozonation or Fenton oxidation process, the quality of treated wastewater could meet the discharge limit in Korea. However, a yellowish brown color still remained in the treated wastewater after a single method such as coagulation and Fenton oxidation was applied. The ozonation was found to be the most effective technology for the decolorization. Neither simple biological nor physicochemical treatment provides adequate decolorization and sufficient depletion of organics in livestock wastewater so far. Consequently, the integration of Fenton oxidation and ozonation with a biological treatment process is recommended to treat livestock wastewater in terms of removal efficiency.