• Journal of Korean Society on Water Environment
• /
• v.20 no.3
• /
• pp.241-244
• /
• 2004

Radiation treatment with gamma-rays and electron-beams was used to remove polyvinyl alcohol(PVA), one of the main components of dyeing wastewater. PVA was effectively decomposed by radiation treatment, thus the removal was near 100 % at an initial PVA concentration of 44 mg/L. However, total organic carbon(TOC) removal was less than 5 % due to lower transformation of PVA to $CO_2$. This directly indicates the radiation treatment alone is not appropriate for the complete decomposition of PVA. In this sense, the improvement of biodegradability($BOD_5/COD$) of PVA by radiation treatment was studied. Both gamma-ray and electron-beam treatments significantly increased the biodegradability of PVA by transforming non-biodegradable PVA to biodegradable by-products. This suggests radiation treatment, especially electron-beam treatment that showed better improvement of biodegradability, can be used as a pre-treatment of biological degradation process of PVA.

• Journal of Wellbeing Management and Applied Psychology
• /
• v.6 no.3
• /
• pp.19-23
• /
• 2023

Purpose: High concentrations of nitrogen exist in food wastewater, and when nitrogen is not properly treated and discharged, it can cause eutrophication in the aquatic ecosystem. Research design, data and methodology: In order to remove nitrogen using sodium hypochlorite, the BNCR tank was designed and installed in the step behind the biological treatment tank, and the data of pH, TOC, and T-N were collected after about a month of demonstration. Results: As a result of operating the BNCR tank, total nitrogen decreased by about 83% on average. The total nitrogen in the second sedimentation tank before going through the BNCR tank must be removed and finally discharged after nitrogen is removed above the legal standard of 60 mg/L. Conclusions: If BNCR tank is added to the process currently applied to nitrogen removal and operated, ammonia nitrogen can be removed more efficiently. However, the disadvantage is that nitric acid nitrogen and nitric acid nitrogen cannot be removed. If these disadvantages are supplemented and optimized in the future, it will be helpful for workplaces that are having difficulty removing nitrogen.

• Journal of Environmental Science International
• /
• v.7 no.6
• /
• pp.761-772
• /
• 1998

This study was performed to determine the optimum coagulant dosing amount for effective treatment of raw water. The removal rate of turbidity and the variations of water qualities according to various dosage of coagulants such as Alum, PAC and PACS were investigated. The optimum coagulant dosing amount to make the lowest turbidity of water were 35mg/ι t of Alum, 30mg/ι of PAC and 10mg/ι of PACS in case of 5 NTU of raw water turbidity, and 30mg/ι of Alum, 25mg/ι of PAC and 10mg/ι of PACS in case of 10 NTU of that, respectively. The removal rates of turbidity at 4 min. and 8 min. of settling time were 10 and 72% of Alum, 44 and 62% of PAC and 25 and 55% of PACS in case of 5 NTU, and 52 and 70% of Alum, 90 and 95% of PAC and 10 and 28% of PACS in case of 10 NTU, respectively. Judging from the settling capability of floc., the reaction time of floe. formation and removal efficiency of turbidity, PAC was evaluated as more effective coagulant than Alum and PACS. Also PAC was regarded as the most effective coagulant when the water supply was changed sharply and the fluctuation of the surface loading occured with wide and sharp in settling basin. pH and alkalinity of the water were decreased with increasing coagulants dosage. But pH and alkalinity were not decreased below 5.8 which is the standard for drinking water quality, and 10mg/ι which is the limit concentration of floc. breakage, respectively. Residual Al of the treated water was decreased with increasing coagulants dosage in case of 5 and 10NTU of raw water turbidity. $KMnO_4$ consumption of the water was decreased with increasing coagulants dosage. The reduction rate of $KMnO_4$ consumption at the optimum coagulants dosage were 39% of Alum. 18% of PAC and 11% of PACS in case of 5 NTU of raw water turbidity, and 42% of Alum, 27% of PAC and 36% of PACS in case of 10 NTU of that, respectively. Any relationship was not found between the removal rate of turbidity and KMnO$_4$ consumption. TOC of the water was a bit decreased with increasing coagulants dosage up to 30mg/ι but not changed above 30mg/ι of coagulants dosage. The degree of TOC reduction was increased in the order of Alum, PAC and PACS treatment. Zeta potential of the colloidal floe. at the optimum coagulants dosage was in the range of -20~-15mV in case of 5 NTU of raw water turbidity and 0~0.5mV in case of 10 NTU of that. respectively. Although the kinds and dosages of coagulants were different, zeta potential range were fixed under the conditions of the best coagulation efficiency.

• Proceedings of the Korean Society of Dyers and Finishers Conference
• /
• 2008.04a
• /
• pp.172-174
• /
• 2008

The study has attempted to compare the behavior of reactive, disperse and acid dyes when wastewater from these three kinds of typical dyestuffs were treated by chemical coagulation and NF membrane in pilot scale. Disperse dyeing wastewater showed the tendency of easier removal in TOC and COD and especially in color. This is probably due to low water-solubility of disperse dyes compared with reactive and acid dyes and is a positive result in terms of water reuse. Bio-kinetic constants, ${\mu}$max, $K_s$ of reactive, disperse and acid dyes were obtained, implying that their biodegradability are not significantly different.

• Journal of Korean Society of Water and Wastewater
• /
• v.19 no.5
• /
• pp.655-659
• /
• 2005

Pre-filter system that was consisted of wasted-tire, non-woven fabrics, and sponge was developed as a primary treatment process prior to rainwater reservation or a pre-treatment process of rainwater reuse system for reclamation. By using this system, SS concentration, TOC, COD, and turbidity could decreased by 86.7%, 62.6%, 69.1% and 66.5%, respectively. From the results of particle size distribution of treated water, the particles over than $30{\mu}m$ of diameter were completely removed by pre-filter system. But 90% of particles less than $20{\mu}m$ of diameter were passed through pre-filter. Optimal depth of wasted-tire and non-woven fabrics were 15cm and 2.4cm, respectively. Pre-filter system was considered as an effective alternative for pre-treatment of rainwater including non-point pollutants and it could be also applied for the treatment of combined sewer overflow (CSO).

• Journal of environmental and Sanitary engineering
• /
• v.15 no.4
• /
• pp.35-43
• /
• 2000

Aqueous solutions of chlorobenzene and chlorinated phenols were exposed to 200kHz ultrasound with a power of $6.0W/\textrm{cm}^2$ per unit volume on sonochemical reactor under ambient temperature and pressure conditions. The concentration of chlorobenzene and chlorinated phenols decreased with ultrasound, indicating first-order kinetics. Degradation rate constants are calculated from the slope of plots. The order of the rate constants is as follows : 2-chlorphenol(2-CP)$\leq$ 4-chlorophenol(4-CP)<3-chlorophenol(3-CP)$5.63~9.96({\times}10^{-2})min^{-1}$ under argon. The degradation was suppressed by the addition of t-BuOH and the suppressed yield was agreed with their reactivity for hydroxy radical. The main products of these systems were formic acid, acetic acid, small amount of methane and inorganic carbon forms as carbon dioxide, carbon monoxide in sonolysis of chlorinated phenols, and also these results agreed with change of TOC.

• Journal of Korean Society of Water and Wastewater
• /
• v.30 no.4
• /
• pp.381-389
• /
• 2016

Jeju Eoseungsaeng lake which is a main water resource of Eoseungsaeng water treatment plant($Q=15,000m^3/d$) experienced high chromaticity(40 CU) and pH(9.46) in 2013. This could decline customer's confidence on drinking water quality unless proper identification and removal of chromaticity were implemented. To find cause of chromaticity, water monitoring on various water parameters including TOC, algal cell count, Chl-a, turbidity, SS, conductivity, etc. were implemented. Iron and manganese were excluded from the cause of chromaticity due to its low concentration (i.e., < 0.02 mg/L). Correlation among water parameters showed that relationship between algal cell count and chromaticity was the highest(R=0.43), which suggested that presumably the main reason of chromaticity occurrence in Jeju Eoseungsaeng lake was algae.

• Journal of Korean Society of Environmental Engineers
• /
• v.29 no.1
• /
• pp.40-46
• /
• 2007

A laboratory scale experiment on phenol conversion properties by pulsed corona discharge process was carried out. Effects of operating parameters such as applied voltage, input oxygen, and electrode geometry on phenol conversion and solution properties were investigated. Electrical discharges generated in liquid phase increased the liquid temperature by heat transfer from current flow, decreased the pH value by producing various organic acids from phenol degradation, and increased conductivity by generating charge carriers and organic acids. The oxygen supply enhanced the phenol conversion through the ozone generation dissolution and the production of OH radicals. Series type electrode configuration induced more ozone production than reference type configuration because it produced gas phase discharges as well as liquid phase discharges. Therefore, the higher phenol conversion and TOC(total organic carbon) removal efficiency were obtained in series type configuration.

• Environmental Engineering Research
• /
• v.25 no.4
• /
• pp.529-535
• /
• 2020

The present study investigated the photodegradation of synthetic organic dye; violet-3B, without and with the addition of C-N-codoped TiO₂ catalyst using a visible halogen-lamp as a light source. The catalyst was synthesized by using a peroxo sol-gel method with free-organic solvent. The effects of initial dye concentration, catalyst dosage, and pH solution on the photodegradation of violet-3B were examined. The efficiency of the photodegradation process for violet-3B dye was higher at neutral to less acidic pH. The kinetics reaction rate of photodegradation of violet-3B dye with the addition of C-N-codoped TiO₂ followed pseudo-first order kinetics represented by the Langmuir-Hinshelwood model, and increasing the initial concentration of dyes decreased rate constants of photodegradation. Photodegradation of 5 mg L^-1 violet-3B dye achieved 96% color removal within 240 min of irradiation in the presence of C-N-codoped TiO₂ catalyst, and approximately 44% TOC was removed as a result of the mineralization.

• Journal of Korean Society on Water Environment
• /
• v.29 no.5
• /
• pp.648-655
• /
• 2013

Nonpoint source pollution characteristics of recreation park was investigated. Runoff ratio of recreation park ranged 23-57%, which was lower than other urban area since impervious area was less than 37%. The average BOD, COD, TOC, SS, T-N, T-P, were 14.09, 32.86, 12.19, 121.51, 7.78 and 0.72 mg/L, respectively. First flush of recreation park was analyzed by normalized cumulative load - volume curve and mass first flush ratio(MFFn), MFF10 for BOD, COD, SS, T-P, T-N, TOC were 2.90, 1.59, 2.15, 2.74, 2.60, and 1.59, respectively. Observed data showed that 62% of pollutant could be removed by storaging 5 mm rainfall-runoff and even 3 mm depth could store up to 50% of pollutant in runoff.