• Journal of environmental and Sanitary engineering
• /
• v.8 no.2
• /
• pp.99-108
• /
• 1993

It is well known that we should take 2L of drinking water per day to maintain our health. The drinking water quality is becoming worse owing to sewage discharge and industrial wastewater. Surface water is polluted by various kinds of contaminants and ground water were known as clean and unpolluted water, but through recent many reports the ground waters are also contaminated by waste disposal and intrusion of organic and bacterial movement. This research was undertaken to make a water index of water contamination by referringcations cations and anions. NH$_{4}$, Fe, Mn, and Pb are chosen as cations and $NO_3$, Cl, and $SO_4$ ions are chosen as anions to make a index, and the following water index was made as the contamination index. (Fe+Mn+Pb)/0.7+$(NH_4+NO_3+Cl+SO_4)$/10.5<6.0 By using ton Chromatography the cations and anions are rapidly analyzed and plotting the analyzed data to the equation, we can easily get the degree of contaminations by avoiding analysis of over 37 water parameters in several days. Of course this index of water contamination is not perfect and detail one, but in case of emergent case or to know the overall trends of contamination, it is convenient to use this index. Among the tested 5 kinds of samples the ground water showed contamination index of 6.87. Authors used the already published healthy index and tasty index and differentiated their degrees in detail.

• Journal of Korean Society on Water Environment
• /
• v.24 no.3
• /
• pp.328-332
• /
• 2008

This research was about T-N removal efficiency of oxic reactor in which fixed media submerged from Membrane BNR(An+Ax+Ox) process. This experiment was implemented by using fixed media and changing DO concentration in the oxic reactor. Nitrification efficiencies of all modes were more than 98%. When no media was in the oxic reactor, T-N removal efficiency was only 47.4%, while it were shown from 60.3% to 67.4% with packed media, which indicated improved efficiency of 27~42%. The removal efficiencies of TCOD and BOD were more than 89%, 98% respectively, which could satisfy the guideline of advanced sewage reclamation by Department of Environment. When DO concentration in the packed oxic-media tank was 0.5~1.0 mg/L, T-N removal efficiency was low, which resulted from insufficient nitrification in the oxic reactor. Therefore, DO concentration of bulk solution needs to be kept more than 1.0 mg/L to induce higher nitrification efficiency in the reactor in which media was submerged. Also, the selection of DO concentration is important to prevent media from being clogged.

• Journal of Environmental Science International
• /
• v.13 no.6
• /
• pp.561-570
• /
• 2004

This study was carried out to survey the pollution of nonylphenol (NP) in surface sediments around Gwangyang bay and Yeosu sound. NP was suspected chemicals as endocrine disruption. Gwangyang bay is located on the mid south coast of Korea. It is a semi-closed bay which Yeosu petrochemical industrial complex, POSCO (Pohang Steel Company) and Gwangyang container harbor are there. The surface sediments were collected at 15 stations with gravity corer at October, 1999, February, May and August, 2000. Also, the stream and intertidal sediment were collected at 5 sites at August, 2000. Concentrations of NP in surface sediments were in the range of 6.89 to 202.70 ng/g dry wt.. Seasonal range (mean value) of NP is 13.98 to 30.48 (23.46) ng/g dry wt. at October, 10.35 to 54.91 (28.10) ng/g dry wt. at February, 29.05 to 202.70 (82.32) ng/g dry wt. at May and 6.98 to 83.40 (25.37) ng/g dry wt. at August. NP was seasonally fluctuated, and the highest mean value and range was detected at May, 2000. NP was highly distributed in the inner part of Gwangyang bay than Yeosu sound. Concentrations of NP in stream and intertidal sediments showed the highest value in downstream near Yeosu petrochemical industrial complex and Yondung stream. It suggests that the source of NP is industrial wastewater and municipal sewage.

• Proceedings of the IEEK Conference
• /
• 2001.10a
• /
• pp.443-447
• /
• 2001

A laboratory-scale electrodewatering system for enhancing conventional filter pressure dewatering by an electric field has been developed to decrease the water content of sludge generated in the wastewater treatment. It consists of a piston-typed filter press, a power supply and data acquisition system. The offset of electrodewatering is investigated as a function of applied pressure, applied voltage, sludge type and filtration time. Also the optimal conditions for maximizing the dewatering efficiency in the eletrodewatering system are investigated. Electric field strength and mechanical pressure are in the range of from 0 to 120 V/cm and from 98.1 to 392.4 kPa. The dewatering rates increased with increasing electric strength. These experiments produced a final sludge cake with water content of 60 wt% using electrodewatering technology, compared with a 80 wt% using pressure filtration alone. The conventional filtration system using the electrodewatering shows the potential to be effective method for improving dewatering Sludge.

• Proceedings of the Korea Society of Environmental Biology Conference
• /
• 2004.05a
• /
• pp.26-26
• /
• 2004

This study was conducted to evaluate the characteristics of dissolved orgamc matters based on their origins. The dissolved organic carbon(DOC) represents an index for dissolved organic matter and basically regarded as a source of organic pollution. The monthly variations and vertical profiles of dissolved organic carbon(DOC) in Kumoh reservoir were surveyed from May 2001 to April 2002. In addition, other areas such as river, reservoir, sewage and industrial wastewater were also surveyed in summer 2001. Kumoh reservoir was divided with depth into three layers .: epilimnion, metalimnion and hypolimnion. The proportion of total DOC(T-DOC) was classified by labile DOC(L-DOC) and refractory DOC(R-DOC) on the basis of long-term incubation. DOC of freshwater and Kumoh reservoir was ranged to be 1.6~4.1 mgC/L and 2.1~4.0 mgC/L, respectively. L-DOC accounted for 3~30% of DOC from watershed. Therefore, refractory dissolved organic carbon(R-DOC) was major component of DOC in the watershed. The decomposition rate(k) ranged from 0.008 $d^{-1}$ to 0.083 $d^{-1}$ in Kumoh reservoir. The highest decomposition rate(k) was observed at River Hoein III freshwater. Therefore, modified total organic carbon analyzer is needed to be applied for effective management of dissolved organic matter.

• Journal of Korean Society on Water Environment
• /
• v.25 no.6
• /
• pp.872-878
• /
• 2009

Advanced Phase Isolation Ditch (APID) process was studied to develop economic retrofitting technology, for the plants where retrofitting of common activated sludge process is required. In this study, to develop and apply the modified intermittently aeration mode as process control conditions for treating municipal wastewater, a demonstration plant was installed and operated in the existing sewage treatment plant of P city. During this study, the average effluent $BOD_5$, SS, T-N, and T-P concentrations were 6.3, 4.5, 10.0, and 1.3 mg/L. The modified mode decreased the nitrification capability more than the conventional mode in the application period. Nitrate in the anaerobic condition can have a negative effect on biological phosphorus removal. In the decreasing nitrate levels, the modified mode increased the biological ability of removal phosphorus more than the conventional mode in this study. Therefore, newly developed APID process with modified intermittent aeration mode can be one of the useful processes for stable organic matter and nutrients removal.

• Journal of Korean Society on Water Environment
• /
• v.23 no.1
• /
• pp.97-102
• /
• 2007

The present investigation deals to achieve an accurate determination of the phosphorous present in the wastewater samples using the membrane reactor. The study may enable to quantify the dissolved (DP) and adsorbed phosphorous (AP), also the adsorbed phosphorous categorically identified as inorganic coupled phosphorous (DRP) and organic coupled phosphorous (NRP). Moreover, the study has been conducted separately in anaerobic and aerobic chamber. The results obtained showed that dissolved phosphorous only can occur in anaerobic chamber with ca. 25%. The study conducted for adsorbed phosphorous showed that the DRP has the percent composition in anaerobic and aerobic chamber respectively 33% and 40% i.e., 7% more in aerobic chamber. The similar values obtained for NRP was found to be 42% and 60% i.e., 18% more in aerobic chamber. On the other hand while comparing the results for NRP and DRP, it has to be noted that NRP has 9% and 20% more percent composition than DRP respectively in anaerobic and aerobic chamber. Further, the adsorbed phase showed the species Al-P, Fe-P in the aerobic chamber with the quotient of 7.73 mg/g TS (total solid) whereas in the anaerobic chamber it showed the species Fe-P and $Fe(OH)_3$-P with the 7.16 mg/g TS.

• Journal of Korean Society on Water Environment
• /
• v.23 no.1
• /
• pp.155-160
• /
• 2007

Constructed wetland has been widely used for the treatment of sewage, stormwater runoff, industrial wastewater, agricultural runoff, acid mine drainage and landfill leachate. For the removal of nitrogen and phosphorus, uptake by plants and adsorption to media material are the major processes, and, therefore, the selection of media with specific adsorption capacity is the critical factor for the optimal design of wetland along with the selection of appropriate plant species. In this study, two media materials (loess bead and mixed media) possessing different adsorption characteristics for ammonium and phosphate were selected, and their adsorption characteristics were evaluated. In addition, the performance of subsurface-flow wetland systems employing these media was evaluated in both batch and continuous flow systems. With LB medium, beter phosphorus removal was observed, while better ammonia removal was obtained with MM medium. In addition, enhanced removal efficiencies were observed in the wetland systems employing both media and aquatic plants, mainly due to the better environment for microbial growth. As a result, appropriate selection or combination of media with respect to the inflow water quality maybe important factors for the successful design and operation of wetland systems.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.11a
• /
• pp.175.1-175.1
• /
• 2011

A rotating activated bacillus contactor (RABC) process with a series of aerobic reactors was tested in pilot scale to treat digested liquid from an anaerobic digester treating swine wastewater and sewage sludge. The influent (digested liquid) for the RABC process showed C/N ratios less than 2 as a typical feature of effluent from anaerobic digesters. The pilot process, which consists of three 3 RABC reactors, four aerobic tanks and a sedimentation tank, was operated for 210 days with a hydraulic retention time of 20 days without pH and temperature control. Since the Bacillus-enriched aerobic reactors shows high efficiencies of nitrogen removal at low DO levels less than 1.0 mg/L, they were operated at reduced aeration intensities. With relatively low concentrations of organics in comparison with nitrogen concentrations, the RABC process tested in this study showed stable and high nitrogen and organics removal efficiencies over 80%. The nitrogen removal process tested in this study was proven to be an effective and operation-cost saving (lower aeration) method to remove nitrogen without adding external carbon sources to meet the optimum C/N ratio.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.1174-1178
• /
• 2007

본 연구는 다양한 공법으로 설치 운영되고 있는 고도처리시설에 대한 처리효율 및 운영현황을 조사하여 고도처리공법 선정시 활용할 수 있는 기초자료를 제공하고, 각 공법별 현장적용 및 운영상 문제점을 파악하여 하수처리시설 운영의 효율성을 도모하기 위한 목적으로 실시하였다. 6개월 이상 운영 중인 하수종말처리시설 145개소를 대상으로 일반적 현황을 분석하고 실제 현장조사는 고도처리시설 37개소의 현장조사표를 중심으로 실시하였다. 고도처리 공법은 $A_2O$계열, SBR계열이 대부분을 차지하였으며 대규모처리장은 $A_2O$계열, 소규모처리장은 SBR계열이 주로 적용되었으며 대규모 하수처리시설일수록 유입수질의 농도 및 처리효율이 높고 톤당 시설설치비용과 유지관리비용이 적었다. 현장조사 결과, 첫째, 하수처리시설의 유입문제로 시설용량대비 하수유입량이 초과되거나 50%미만인 시설이 10개소로 조사되었다. 이에 따라 하수관거의 조속한 정비 및 인구감소에 따른 대책수립, 효율적인 운영을 위한 하수처리시설 증설 및 계열 축소운전이 필요하였다. 둘째, 각 처리공법별로 몇몇 문제점이 있어 공법사의 문제점 보완, 운영기술전수 및 원활한 A/S가 필요한 것으로 나타났다. 셋째, 운영관리자가 수시로 현상을 파악하고 주의하여 운전해야 하는 것으로 나타났다.