• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.4
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• pp.61-68
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• 2004

The purpose of this study was to develop environmentally friendly constructed wetland system in order to improve the environment. This system was constructed with two constructed wetlands andone pond. The size of the first and second wetland was 2.5m in length, 2.5m in width and 0.7m in depth for the first wetland and 0.6m in depth for the second wetland. Those were filled with pebbles with about 16~32mm in diameter from bottom to 20cm depth and onto the pebbles with about 0.5 mm in diameter sand in depth 40cm. The first constructed Wetland was planted with pragmites communis. The second was planted with Iris pseudoacorus and Acorus calamus var. aneustatus.A vertical flow system was used in the first constructed wetland and a horizontal flow system in the second. The water of outflow from the second wetland flowed into the pond. This system was installed in Yangpyeong, Kyunggi Province. The Quality of inflow and outflow were analyzed at the first time from May 20 to May 30, 2002 and at second time from June 10 to July 18, 2002. At the second period wetland was implanted with microbes in order to improve the efficiency of constructed wetlands. Following standard methods for wastewater, BOD, COD, SS, T-N and T-P were analyzed. This system was effective in reducing COD, BOD, SS, T-N and T-P level. The result shows that wastewater was purified through constructed wetland system with plants and highly purified with microbes especially in T-P. The Average total phosphorous concentration of influent and effluent in constructed wetland with microbes was 2.8mg/${\ell}$ L and 0.21mg/${\ell}$ respectively. This system can be used in rural community because this is not only effective on purification of sewage but also is harmonized with the surrounding nature.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.5
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• pp.477-486
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• 2010

This study was performed with the object in which it improves the nitrification by using RBC, that is one of the biological waste water treatment process. By applying the Modified Dephanox process to RBC in this research in order to evaluate the improvement of the nitrification by RBC a research was conducted. There is the most conspicuous feature of the process of using RBC. it is that the nitrification can be smoothly performed even if the suspended solid of the high concentration as the interference factor in the nitrification tank is flowed in. Moreover, as a result of experiment, TCOD removal efficiency of the process showed up more than about 90%. when influent TCOD loading rate was 0.04~0.1 kg / $day{\cdot}m^3$. and T-N removal efficiency is high at about 75% in spite of the process operating of the laboratory scale was observed. Also, As increasing influent ${PO_4}^{3-}$-P, T-P loading rate, ${PO_4}^{3-}$-P, T-P removal efficiency was increased. Finally, it was elucidated that the utilization of RBC in external nitrification system resulted in not only high nitrification performance but also stable system operation by minimizing inhibitory effect of overflowed suspended solid (SS).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.668-676
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• 2018

Most reservoirs in Korea have a low water depth and are small in size. Water pollution of the reservoir is serious because of the organic matter flowing from livestock wastewater, domestic sewage, and farmland. In this study, an attempt was made to improve the water purification effect by replacing the secondary dam installed in the depression area of the agricultural reservoir with the riprap dam. To evaluate the long-term performance, a riprap dam was installed in a reservoir in Gyeonggi province and water purification effect for 36 months was measured. The field test results showed that COD was 14.6%, SS 38.6%, T-N 9.5%, and T-P 11.2%. The concentrations in the influent water exhibited a significant change according to season, and the water purification effect increased with increasing concentration of influent water. The pollutant flowing into the lake from the depression area can be blocked effectively if the secondary riprap dam for water purification is installed in the agricultural reservoir.

• Journal of Korean Society on Water Environment
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• v.20 no.2
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• pp.157-162
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• 2004

Constructed wetlands are considered as an important tool for wastewater treatment, wastewater management and flooding control. In addition, one of the most promising technologies for application in many countries seems to be constructed wetlands, due to their properties such as utilization of natural processes, simple construction, operation and maintenance, process stability, cost effectiveness, etc. This study considered possibility of treatment of livestock wastewater using a constructed wetland. The removal efficiencies of $COD_{cr}$, TOC, TN, TP, SS, and color were 97.6%, 96.6%, 97.0%, 96.7%, 99.0%, and 85.6%, respectively. In particular, SS was completely removed. However, $Cl^{-}$ concentration of the constructed wetland effluent was higher than that in influent. In conclusion, constructed wetlands could be applied to livestock wastewater treatment if $Cl^{-}$ would be properly treated. Further, it needs time for stabilization to reduce the pollutants which were accumulated in soil.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.2
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• pp.205-209
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• 1993

A new treatment system for animal waste water has been developed as an alternative to the activated sludge process. It consists of two treatments; one is operated with 7 tanks, and the other is soil and plant cultivation bed. Aerobic microorganisms are added to the influent water in the tanks where the water is aerated so that the microbes utilize the pollutants, while sedimentation removes the indigestible solids. In the secondary treatment the water, which has already received a primary treatment, is filtered through soil where it also receives treatment by soil organisms. In addition there is transpiration of water and absorption of minerals by plants. In the primary treatment BOD, SS, coliforms (E. coli), TP and total bacteria were removed 79-99%, but COD and TN were removed only 58% and 36%, respectively. In the secondary treatment removal of nutrients proceeded further, and 93-99% of pollutants were removed. The treated waters met the quality standard of discharge water in Japan except for TN, which was in too great a concentration to meet discharge standards. This problem requires further study.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.1
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• pp.13-23
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• 2014

A lab-scale Anaerobic Baffled Reactor (ABR) was applied to treat a primary sludge taken from a municipal wastewater treatment plant. In this experiment, acidogenic reaction was promoted by operating the ABR with short hydraulic retention time (HRT) to produce sufficient volatile fatty acids (VFA) instead of production of methane. The performance of ABR on the VFA production and total solids reduction was observed with different operating conditions with 2, 4, 6, and 8 days of HRT. Corresponding organic loading rates were 6.7, 3.4, 2.2, and $1.6kgCOD_{cr}/m^3{\cdot}day$. As HRT increased the removal rate of TCOD was also increased (82.5, 84.2, 96.9, and 95.9 % in average for HRT of 2, 4, 6, and 8 days, respectively) because the settlement of solids was enhanced in the baffle by the decrease of upflow velocity. At HRT of 2 days the average concentration of VFA in the effluent was measured at $1,306{\pm}552$ mgCOD/L corresponding to 107 % increment as compared to the VFA concentration in the influent. However, as HRT increased VFA concentraiotn was decreased to $143{\pm}552$ mgCOD/L at HRT of 8 days. The reduction rates of total solids were 12.2, 26.5, 24.8, and 43.0 % for HRT of 2, 4, 6, and 8 days. As HRT increased the hydrolysis of organic particulate matters in the reactor was enhanced due to the increasing of solids retention time in the baffle zone with low upflow velocity in long HRT condition. Consequently, we found that a primary sludge became a good source of VFA production by the application of ABR process with HRT less than 4 days and the 12-26 % of total solids reduction was expected at these conditions.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.3
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• pp.348-356
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• 2007

Statistical and probabilistic method was used in the analysis of data, which is the most effective one in describing the various natures, and the methodology relating the results with the design was developed. Influents and effluents of three treatment plants were analyzed and the focus was made on BOD, COD, SS, IN, TP The fluctuations of influent such as BOD, COD, SS were extremely large and their standard deviations(st.dev) were more than 10 mg/L. but those of TN, TP were small; the st.dev was 6.6 mg/L for TN, 0.6 mg/L for TP, respectively. But, effluent concentration showed consistent pattern regardless of the influent fluctuations, the st.dev was ranged between 0.28 and 4.48 mg/L. Effluent distributional characteristics were as follows; BOD, COD were distributed normally, but SS, TN, and TP, log-normally; unsymmetric and skewed to the right. The coefficient of reliability(COR) based on the results of statistics of data was introduced to evaluate the process performance an4 to reflect the process performance to the process design. The coefficient of reliability relates the design value(the goal) with the standards and it can be used in operating treatment facilities under a certain reliability level and/or in evaluating the reliability of the treatment facilities on operation. Each treated water quality of effluent showed the half of water quality standards in the level of 50% percentile and all treatment plant was achieved 100% probability of water quality standards. It was concluded that the variability of the process performance should be reflected to the design procedure and the standards through the analysis based on the statistics and the probability.

• Journal of Life Science
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• v.12 no.6
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• pp.700-707
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• 2002

To study the characteristics of organic and nutrient removal by Bacillus species at high COD concentration of influent, three lab-scale batch reactors(R1, R2, R3), each of which has different substrate composition, were operated. More than 95% of $NH_4^+$-N and $COD_{cr}$, concentrations were removed under an aerobic condition, and their removal efficiencies were found to be 22.6 and 90.5%(R1), 23.9 and 65.8%(R2), 30.2 and 86.4%(R3), respectively. The removal efficiency of $NH_4^+$-N was high when an enough amount of $NO_3^{-}$-N was supplied, and that of $COD_{cr}$. was low when a high concentration of initial $NO_2^{-}$-N was added. The amount of carbon utilized in denitrification was a little. In all reactors,$NO_3^{-}$-N was removed under an anoxic condition, but in the R3 reactor, 10% of $NO_3^{-}$-N could be removed even undo, an aerobic condition. The removal efficiencies of TN and TP were 41.8 and 49.5%(R1), 40.1 and 35.8%(R2), 47.0 and 57.6%(R3), respectively. Alkalinities destructed under an aerobic condition for each reactor were 4.96, 5.41 and 3.93 mg/L (as $CaCO_3$) per each gram of $NH_4^+$-N oxidized, respectively, while 3.06, 3.17 and 2.60 mg/L (as $CaCO_3$) of alkalinities were produced for each gram of ,$NO_3^{-}$-N reduced to $N_2$. The SOUR were found to be 38.5, 52.7 and 42.0 mg $O_2$/g MLSS/hr, which indicated that Bacillus sp. had a higher cell activity than activated sludge. The OLR and sludge production were estimated to be 0.69 and 0.28(Rl), 0.77 and 0.20(R2), 0.61 kg COD/$m^3$/day and 0.25 kg MLSS/kg COD(R3), respectively. From the N-balance, the highest percentage(40.9%) of nitrogen lost to $N_2$ was obtained in the R3 reactor. From all the results, the possibility of aerobic denitrification Bacillus sp. has been shown and the B3 process seemed to have two advantages: a little amount of carbon was required in denitrification and not much amount of alkalinity was destructed under an aerobic condition.

• Membrane and Water Treatment
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• v.11 no.2
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• pp.123-130
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• 2020

Submerged Membrane bioreactor (SMBR) is one of the last techniques that allow a high quality of treated industrial effluents by coupling biological treatment and membrane separation. Thus, this research was an effort to evaluate performance of a SMBR treating a model textile wastewater (MTWW). Different SMBR operating parameters like mixed liquor suspended solids (MLSS) and Dissolved oxygen concentration, hydraulic retention time (HRT), and nutrients addition (N and P) have been investigated. MTWW (influent to the SMBR) was generated using the reactive azo-dye, Novacron blue FNG (100mg/L feed concentration). Results of MTWW treatment using SMBR under optimal operating conditions (MLSS, 4.2-13.3g/L; HRT, 4 days; pH, 6.9-7.2; conductivity, 400-900 μS/cm and temperature, 19.4-22.2 ℃) showed that COD and blue colour treatment performances are between 94-98% and 30-80%, respectively. It is concluded that SMBR can be used in large scale textile wastewater treatment plants to improve effluent quality in order to meet effluent discharge standards.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.2 no.1
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• pp.19-31
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• 1982

The purpose of the research is to investigate the applicability of the filter activated sludge process for the treatment of toxic phenolic wastewaters. The experiment for the research was carried out by continuously feeding synthetic phenol wastewater for four periods, and the results show that a synthetic fiber filter is an adequate material for filter activated sludge process when taking consideration of durability, SS removal efficiency and wastewater permeability. The permeability of the filter sharply decreases when the temperature of the reactor is below $10{\sim}15^{\circ}C$ for a long period. In filter activated sludge process, even under high volumetric loading conditions, high phenol removal efficiencies can be attained due to the high microbial sludge concentration in the reactor and consequently low F/M ratio. In this research, the effluent phenol concentration were checked to be below $0.1mg/{\ell}$ at the influent phenol concentrations of $63{\sim}468mg/{\ell}$. During the research very low microbial yield coefficients, 0.035~0.160 kg SS/kg COD removed, were observed and the temperature coefficient for aerobic sludge digestion was measured to be 1.021.