• Journal of Environmental Science International
• /
• v.20 no.7
• /
• pp.811-818
• /
• 2011

Daphnia Magna Stratus has been widely accepted as useful species for estimating the toxicity of chemicals to aquatic invertebrate and recommended as species for the testing chemicals from the international guideline as well as Korean guideline. The study was performed for the acute toxicity test by using water flea(D. Magna) for effluents from several wastewater treatment plants and drainage canals in GyeongBuk area. Five heavy metals, 1,4-Dioxane and Perchlorate were tested. Most Toxicity Units(TU) of Industrial wastewater effluents were less than 1 which means effluent was not toxic to D. Magna. However, effluents containing 1,4-Dioxane and Perchlorate were significantly toxic to D. Magna. Therefore, facilities should reduce the 1,4-dioxane since new regulations will force them after the year of 2011.

• Journal of Microbiology and Biotechnology
• /
• v.13 no.1
• /
• pp.15-21
• /
• 2003

Two microbial communities of activated sludge in the same municipal wastewater, but treated with different systems, were studied and compared using molecular microbiological approaches. The bacterial 16S rDNA sequences from 124 clones were analyzed, however, the majority of them were not closely related to any known species, and found to belong to 8 different phylogenetic groups and 3 different unidentified groups. The relative frequencies of each group were similar between the two microbial communities. Fingerprinting using terminal restriction fragment length polymorphism (T-RFLP) showed that the putative Nitrospira-related populations were more diverse and quantitatively higher in the KNR process system than in the other system using a conventional activated sludge process. The relationship between the bacterial community composition and the higher removal efficiency of nitrogen and phosphorus in the KNR process is discussed.

• Journal of Korean Society on Water Environment
• /
• v.22 no.1
• /
• pp.37-44
• /
• 2006

Ecotoxicity assessments of 90 selected effluents of 22 industry types from 2002 to 2004 in Korea were evaluated by a toxic battery of bioassay test using fish Oryzias latipes, invertebrate Daphnia magna, algae Selenastrum capricornutum and bacteria Vibrio fischeri with the physicochemical measurement items and permit concentrations on the present Water Quality Conservation Act in Korea. Total toxic unit (${\Sigma}TU$) of 8 industry types of 22 industry types by the toxic battery appeared in order of the value site as follows; Pigment Dye Manufacturing (${\Sigma}TU$ 217.1) > Textile and Dye (${\Sigma}TU$ 39.3) > Semiconductor Electronic Manufacturing (Small) (${\Sigma}TU$ 25.6) > Wastewater and Sewage Treatment Plants (${\Sigma}TU$ 25.4) > Coating (${\Sigma}TU$ 23.8) > Leather Skin Manufacturing (${\Sigma}TU$ 18.0) > Synthetic Resin Manufacturing (${\Sigma}TU$ 15.6) > Assemble Metal Manufacturing (${\Sigma}TU$ 10.7). Our results demonstrate that ecotoxicity assessment, by bioassay test, is effective and practical for industrial wastewater management for 90 selected effluents with the limitation of the physicochemical permit. Among 90 effluents, 9 samples failed physicochemical permit limitation and 81 passed it. In result of ecotoxicity assessment of 90 effluents by the toxic battery, 76 effluents exhibited ecotoxicity and the others did not. The physicochemical measurement items and permit concentrations on the present Water Quality Conservation Act in Korea were low related to the ecotoxicity value by the toxic battery and appeared limited for water quality management to water-ecosystem and environment-friendly management of water.

• Microbiology and Biotechnology Letters
• /
• v.23 no.6
• /
• pp.770-776
• /
• 1995

For the purpose of development of non-toxic and biodegradable flocculant, chitosan complex was isolated from Ganoderma lucidum wastes. The isolated complex was identified as the expected chitosan-glucan complex by IR specta. The complex was extracted by treatment of 50% NaOH solution at 120$\circ$C for 5 hrs, namely optimal condition and solubilized with 2% acetic acid for fur-ther use as flocculant. Preliminary experiments showed that the solubilized complex had higher flocculation activity of 1.3 fold than commercial chitosan at 400 mg/l concentration in soybean curd wastewater. Also the solubilized complex removed 83% of MLSS and 60% of COD in the soybean curd wastewater treated by photosynthetic bacteria, 50% of turbidity and 21% of MLSS in sugar industry wastewater, and 90% of turbidity and 89% of MLSS in alcohol fermentation wastewater. Bacterial cell flocculation activities of the solubilized chitosan-glucan complex were 89% in Bacillus subtilis broth, 81% in Streptococcus lactis broth, and more than 90% in Escherichia coli broth after standing for 2 days. The results reveal that chitosan-glucan complex from Ganoderma lucidum wastes can substitute for commercial chitosan as non-toxic and biodegradable flocculant.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2017.05a
• /
• pp.69-69
• /
• 2017

For several decades, industrial processes consume a huge amount of raw water for various objects that consequently results in the generation of large amounts of wastewater. There effluents are mainly treated by conventional technologies such are aerobic, anaerobic treatment and chemical coagulation. But, there processes are not suitable for eliminating all hazardous chemical compounds form wastewater and generate a large amount of toxic sludge. Therefore, other processes have been studied and applied together with these techniques to enhance purification results. These techniques include photocatalysis, absorption, advanced oxidation processes, and ozonation, but also have their own drawbacks. In recent years, electrochemical techniques have received attention as wastewater treatment process that show higher purification results and low toxic sludge. There are many kinds of electrode materials for electrochemical process, among them, boron doped diamond (BDD) attracts attention due to good chemical and electrochemical stability, long lifetime and wide potential window that necessary properties for anode electrode. So, there are many researches about high quality BDD, among them, researches are focused BDD on Si substrate. But, Si substrate is hard to apply electrode application due to the brittleness and low life time. And other substrates are also not suitable for wastewater treatment electrode due to high cost. To solve these problems, Ti has been candidate as substrate in consideration of cost and properties. But there are critical issues about adhesion that must be overcome to apply Ti as substrate. In this study, to overcome this problem, TiN interlayer is introduced between BDD and Ti substrate. TiN has higher electrical and thermal conductivity, melting point, and similar crystalline structure with diamond. The TiN interlayer was deposited by reactive DC magnetron sputtering (DCMS) with thickness of 50 nm, $1{\mu}m$. The microstructure of BDD films with TiN interlayer were estimated by FE-SEM and XRD. There are no significant differences in surface grain size despite of various interlayer. In wastewater treatment results, the BDD electrode with TiN (50nm) showed the highest electrolysis speed at livestock wastewater treatment experiments. It is thought to be that TiN with thickness of 50 nm successfully suppressed formation of TiC that harmful to adhesion. And TiN with thickness of $1{\mu}m$ cannot suppress TiC formation.

• Journal of Surface Science and Engineering
• /
• v.9 no.1
• /
• pp.1-7
• /
• 1976

• Journal of environmental and Sanitary engineering
• /
• v.14 no.4
• /
• pp.172-179
• /
• 1999

In this research, biological treatability test was conduced using seawater flocculated tannery wastewater by fixed biofilm reactor. During one cycle, the removal efficiency of organic corbon obtained with fixed biofilm process for treating tannery wastewater was considerably greater than that with activated sludge process. As the hydraulic retention time increased form 0.5day to 4day, removal efficiency of organic carbon was increased from 72% to 87.3%. Attached biomass in media increased with influent organic loading up to 29g MLSS/L, that could reduce the specific organic loading rate. The continual measurement of attached biomass was possible for the operation of the biofilm reactor. Equal and low nitrication rates were observed in both suspended growth activated sludge process and fixed biofilm process, despite commercial nitrifier was seeded. Through the process of treating the tannery wastewater, EC50 values which is measured by the use of Ceriopdaphnia dubia, were decreased to the extent of 50% after treatment of seawater flocculation and of 83% after biological treatment, respectively, compared to those of the untreated wastewater.

• KSBB Journal
• /
• v.16 no.2
• /
• pp.183-187
• /
• 2001

The biological activities of wastewater and sludge taken from the wastewater treatment process of Hyangnam pharmaceutic factories in Hwaseong, Kyeonggi-Do was measured using a respirometer. Oxygen uptake rate (OUR) was used as a tool for measuring biological activity. OUR was measured for varying amounts of sludge and organic chemicals in wastewater, and its toxicity was evaluated. Maximum OUR was observed as 61, 75, and 89 mg O$_2$/L/hr when sludge was added as 3, 5, and 10% of total volume, respectively. When the concentration of organic chemicals was changed to 1,486, 337, and 164 mg COD/L, maximum OUR was 53, 13, 8 mg O$_2$/L/hr, respectively. The toxicity test results showed that there seemed that there seemed to be no observable toxic effect on microbes in pharmaceutic wastewater.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.39 no.3
• /
• pp.64-71
• /
• 1997

Floating aquatic plant system using water hyacinth was applied to examine feasibility as a wastewater treatment system for the industrial complex in rural area. The wastewater from the industrial complex does not likely contain toxic pollutants because the industries which generate wastewater with toxic compounds are not allowed to move in. Pilot plant was installed at Baeksuk Nongkong Danzi in Chunahn-City, Chunchungnam - Do , and field study was performed during summer and fall of 1996. Hydraulic loading rate was 0. $0.19m^3/m^2$.day. The effluent concentration of DO was higher than influent, and it implies that 0.6m depth reactor was reaerated enough to increase DO level. The influent concentration of BOD varied significantly from less than 30 to 120mg/${\ell}$ during the study period, however, effluent concentrations were generally lower than the water quality standard and removal efficiency was up to 85%. The influent concentration of COD also showed wide variation from less than 40 to 160mg/${\ell}$ and effluent concentration was higher than water quality standard when influent concentration was over l00mg/${\ell}$. The influent concentrations of T-N and T-P were lower than water quality standard and no further treatment was required, and these compounds were also removed in the system. Although some improvement and refinement are still required, overall* the floating aquatic plant system was proved to be feasible to apply to treat wastewater from industrial complex in rural area.

• Environmental Analysis Health and Toxicology
• /
• v.19 no.4
• /
• pp.375-382
• /
• 2004

This study was designed to investigate potential endocrine disrupting effects of several industrial wastewater effluents discharged from cosmetic, plaiting, paint, textile industry using EROD bioassay and E-Screen assay. The results of E-screen assay showed that textile industrial wastewater could act as a full agonist and cosmetics and plaiting industrial wastewater could act as a partial agonist. On the contrary, the wastewater discharged from paint industry did not show any estrogenic effect. Estrogenic activity in the effluents of cosmetic and paint industrial wastewater was lower than that in the influents indicating that the wastewater treatment process minimized the effects of discharges on water quality. Despite of these results, it was recognized that wastewater treatment was not always minimize toxic impact. In this study, increased estrogenic effect was observed in the effluents of plating and textile wastewater, and EROD activity was increased in the effluents of cosmetic and plating wastewater.