• Title/Summary/Keyword: Urban Sewage

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Variations of Secchi Depth in Coastal Water, Masan Bay in Korea (마산만의 투명도 변동)

  • 염말구;정연수
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.39 no.1
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    • pp.44-49
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    • 2003
  • Masan Bay is one of the most heavily polluted bay in Korea owing to the large industrial complex and urban area. Water transparency, Secchi depth in meter, was observed 33 times totally at four sites during 1995 through 2002 and analysed statistically. The range was 0.2∼7.2m, mean 204m, and variation coefficient 60% in totally. Roughly speaking, monthly mean showed lower value April or July than other months. Seasonal mean showed lower in spring or summer than other seasons. Yearly mean was lowest in '95 and '98 during 7 years. Each sampling site showed a different patterns by the monthly, seasonal or yearly transparencies. Inner bay area, S1 site, showed lowest transparency and highest variation coefficient owing to the streamlets and urban area. And it was supposed that one of the important factor affecting different transparency distribution of most seaward site, S4 site, among four sites in the Masan Bay may be the underwater effluents of urban sewage water treated.

An Ecological Restoration of Treatment Wetland and Urban Upper Stream for Reusing Sewage Treatment Water - In the case of Sustainable Structured Wetland Biotop System at Upper Part of Jaemin Stream in Gongju-si, Korea - (하수처리수의 재이용을 위한 처리습지 및 도시 상류하천 생태환경복원 - 공주시 제민천 생태적수질정화비오톱을 중심으로 -)

  • Byeon, Chan-Woo
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.17 no.5
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    • pp.65-77
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    • 2014
  • The ecosystem of Jaemin stream, flowing into the center of Gongju-si, had been damaged by low water quality and lack of water quantity of the steam. However, after applying the SSB (Sustainable Structured wetland Biotop) system to the flood plain and the upstream of Jaemin stream, the efficiency of ecological water purification and ecological restoration are as follows. Through the constant maintenance and monitoring from year 2009 to year 2013 after restorative design and construction the average influent concentration of BOD5 was 4.2 mg/L, and the average effluent concentration was 1.8 mg/L, reaching ecological water purification rate of 57%. As for the T-N, the average influent concentration was 9.983 mg/L, and the average effluent concentration was 6.303 mg/L, showing the rate of 37%. For the T-P, the average influent concentration was 0.198 mg/L, and the average effluent concentration was 0.098 mg/L, being the rate of 51%. The vegetation of Jaemin stream monitored for 2 years after the restoration was composed of 51 species in 28 families which show high ratio of planted native species. As for the animals in the site, 5 species in 3 families of reptiles and amphibians, 34 species of 23 families of birds, and 3 species in 2 families of mammals were monitored, indicating that the bio-diversity of the site has improved, as well.

Environmental Characteristics and Nature-friendly Planning Strategies for an Urban Stream - The Case of Chuncheon's Gongji Stream - (도시하천의 환경특성과 친자연적 계획전략 - 춘천시 공지천을 대상으로 -)

  • Jo Hyun-Kil;Ahn Tae-Won
    • Journal of the Korean Institute of Landscape Architecture
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    • v.34 no.3 s.116
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    • pp.1-11
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    • 2006
  • This study analyzed characteristics of natural and human environments in Chuncheon's Gongji stream, and suggested nature-friendly planning strategies for self-purification of water quality, biodiversity improvement and conservative waterfront recreation. The environmental analysis included streambed structures, floodplain soils, water quality, vegetation, wildlife, and human facilities. Natural colonization of vegetation for the middle section of the study stream was obstructed by a straightened concrete revetment of baseflow channel, and vehicle movement and concrete parking lots across the floodplain. These human disturbances also deteriorated the naturalness of the stream landscape and limited habitation of bird species. However, natural sedimented wetlands in half of the channel width for the lower section of the stream contributed to a desirable vegetational landscape and greater bird occurrence. Based on BOD measurements, water quality of the stream fell under class $II{\sim}III$ of the stream water-quality standard, but it was worse around sewage outlets due to incomplete sewage collection especially during the dry season. Dominant fish species included typical inhabitants of good water-quality streams that are tolerant of adverse habitat changes. Nature-friendly planning strategies were established based on analysis of the environmental characteristics. They focused on not merely spatial zoning and layout divided into four zones - preservation, partial preservation, conservation and use -, but close-to-nature channel revetment techniques, natural water-purification facilities, biotope diversification, and water-friendly recreation and circulation. Strategies pursued both renewal of stream naturalness and hydraulic stability of streamflow by minimizing transformation of natural channel micro-topography and biotope, and by reflecting natural traces of streambed structures such as revetment scour and sedimentation.

Municipal wastewater reclamation for non-potable use using hollow- fiber membranes

  • Waghmare, Sujata;Masid, Smita;Rao, A. Prakash;Roy, Paramita;Reddy, A.V.R.;Nandy, T.;Rao, N.N.
    • Membrane and Water Treatment
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    • v.1 no.3
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    • pp.207-214
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    • 2010
  • Approximately 80% of water used in urban areas reappears as municipal wastewater (MWW). Reclamation of MWW is an attractive proposition under the present scenario of water stressed cities in India. In this paper, we attempted to reclaim MWW using lab-scale hollow- fiber (HF) membrane modules for possible reuse in non-potable applications. Experiments were conducted to evaluate the efficiency of virgin HF ($M_1$) and modified HF ($M_2$) modules. The $M_2$ module consists of HF modified with a skin layer formed through interfacial polymerization of m-phenylenediamine with trimesoyl chloride (MPD-TMC). The molecular weight cut-off (MWCO) of $M_1$ was 44000 g/mol and that of $M_2$ 10000 -14000 g/mol on the basis of rejection of polyethylene glycol. The combination of $M_1$ and $M_2$ modules was able to reduce concentrations of most of the pollutants in sewage and improved the treated water quality to the acceptable limits for non potable reuse applications. It is found that about 98-99% of the initial flux is recovered by the backwashing process, which was approximately two times in a month when operated continuously.

A Study on Taehwa River Red Tide Solution through Stream Flow (유수소통을 통한 태화강 적조해결 방안 연구)

  • Cho, Hong-Je;Yoon, Sung-Kyu
    • Journal of Wetlands Research
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    • v.13 no.2
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    • pp.363-375
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    • 2011
  • Recently, Water quiality of urban river largely have gotten better by virtue of sewer pipe laying and sewage treatment plants construction. or the various contaminants which is flowed in into river have generated underwater ecosystem disturbance and red tide by lack of sewage and waste water disposal facilities. With tidal river, taehwa river of ulsan metropolitan city has large river width and gradual stream bed gradient at the dry and storage period. Moreover, the flow is paralyzed due to the bridge pier protection work, consist of the mat foundation which is about 1.2km from two bridge and the contaminant is accumulated. it is caused by of the red tide generated from the several years or it activates. In this study, When flow area is largest by changing independent footing of bridge pier of two bridges and using RMA2 model, we hydraulically analyzed a variable breadth of velocity and discharge. Consequently, flow rate increased the maximum 103%, discharge was exposed to increase the maximum 61%. Directly this cannot extinguish the red tide but suppresses the red tide occurrence or can reduce. And it is determined to prevent the depositioning of the contaminant and can control fundamentally the red tide occurrence cause.

Groundwater and Surface Water Hydrology in the Lake Rotorua Catchment, New Zealand, and Community Involvement with Lake Water Quality Restoration

  • White, Paul A.;Hong, Timothy;Zemansky, Gil;McIntosh, John;Gordon, Dougall;Dell, Paul
    • Proceedings of the Korea Water Resources Association Conference
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    • 2007.05a
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    • pp.8-14
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    • 2007
  • Water quality in Lake Rotorua, New Zealand, deteriorated since the 1960s because of excessive phytoplankton growths due principally to increasing nitrogen and phosphorus in the lake waters. Nutrient concentrations in eight of the nine major streams feeding Lake Rotorua have increased since 1965. The groundwater system has a key role in the hydrology of the Lake Rotorua catchment and the groundwater system is probably the control on the time delay between intensification of agricultural land use and response of surface water quality. All major, and many minor streams, in the catchment are fed by springs. Two lithological units are most important to groundwater flow in the Lake Rotorua catchment: Mamaku Ignimbrite, erupted in about 200,000 years ago and Huka Formation sediments which filled the caldera left by the Mamaku Ignimbrite eruption. Rainfall recharge to groundwater in the groundwater catchment of Lake Rotorua is estimated as approximately 17300 L/s. A calibrated steady-state groundwater flow model estimates that approximately 11100 L/s of this flow discharges into streams and then into the lake and the balance travels directly to Lake Rotorua as groundwater discharge through the lake bed. Land use has impacted on groundwater quality. Median Total Nitrogen (TN) values for shallow groundwater sites are highest for the dairy land use (5.965 mg/L). Median TN values are also relatively high for shallow sites with urban-road and cropping land uses (4.710 and 3.620 mg/L, respectively). Median TN values for all other uses are in the 1.4 to 1.5 mg/L range. Policy development for Lake Rotorua includes defining regional policies on water and land management and setting an action plan for Lake Rotorua restoration. Aims in the action plan include: definition of the current nutrient budget for Lake Rotorua, identification of nutrient reduction targets and identification of actions to achieve targets. Current actions to restore Lake Rotorua water quality include: treatment of Tikitere geothermal nitrogen inputs to Lake Rotorua, upgrade of Rotorua City sewage plant, new sewage reticulation and alum dosing in selected streams to remove phosphorus.

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Examining Synchronous Fluorescence Spectra of Dissolved Organic Matter for River BOD Prediction (하천수 BOD 예측을 위한 용존 자연유기물질의 synchronous 형광 스펙트럼 분석)

  • Hur, Jin;Park, Min-Hye
    • Journal of Korean Society on Water Environment
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    • v.23 no.2
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    • pp.236-243
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    • 2007
  • Fluorescence measurements of dissolved organic matter (DOM) have the superior advantages over other analysis tools for the applications to water quality management due to their rapid analysis. It is known that protein-like fluorescence characteristics are well corelated with microbial activities and biodegradable organic matter. In this study, potential biochemical oxygen demand (BOD) predictor were explored using the fluorescence peak intensities and/or the integrated fluorescence intensities derived from synchronous fluorescence spectra and the first derivative spectra of river samples. A preliminary study was conducted using a mixture of a river and a treated sewage to test the feasibility of the approach. It was demonstrated that the better BOD predictor can be derived from synchronous fluorescence spectra and the derivatives when the difference between the emission and the excitation wavelengths (${\Delta}{\gamma}$) was large. The efficacy of several selected fluorescence parameters was rivers in Seoul. The fluorescence parameters exhibited relatively good correlation coefficients with the BOD values, ranging from 0.59 to 0.90. Two parameters were suggested to be the optimum BOD predictors, which were a fluorescence peak at a wavelength of 283 nm from the synchronous spectrum at the ${\Delta}{\gamma}$ value of 75 nm, and the integrated fluorescence intensity of the first derivatives of the spectra at the wavelength range between 245 nm and 280 nm. Each BOD predictor showed the correlation coefficients of 0.89 and 0.90, respectively. It is expected that the results of this study will provide important information to develop a real-time efficient sensor for river BOD in the future.

Contamination Assessment of Surface Sediments in Urban Rivers, Busan (부산지역 도시하천 표층 퇴적물 오염도 평가에 관한 연구)

  • Kwag, Jin-Suk;Son, Jung-Won;Kim, Chu-In;Song, Bok-Joo
    • Journal of Korean Society on Water Environment
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    • v.37 no.4
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    • pp.296-305
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    • 2021
  • This work investigated heavy metal pollution in surface sediments of rivers in Busan, Korea. Surface sediments were analyzed in order to conduct contamination assessment of organic matter, nutrients, and heavy metal concentrations. Contamination assessment of heavy metals was conducted using geoaccumulation index (Igeo), pollution load index (PLI), and potential ecological risk index (RI). Accumulation of organic matter and nutrients were affected by water discharged from sewage treatment plant. The concentrations of organic matter and nutrients were found to be greater in points which were close to the sewage treatment plant more than points furthest. The concentrations of Pb, Zn, Cu, Cd, Hg, As, Cr, and Ni were found to be greater in surface sediment more than in the background. The mean concentrations of heavy metals were in the order of Zn (323.5 mg/kg) > Cu (70.5 mg/kg) > Pb (39.8 mg/kg) > Cr (33.4 mg/kg) > Ni (13.5 mg/kg) > As (9.4 mg/kg) > Cd (0.84 mg/kg) > Hg (0.092 mg/kg). The result of geoaccumulation indices indicated that Hg > Cr > Cu > Ni > Zn > As > Pb > Cd were found in order of severe contamination by heavy metals. From PLI and RI analysis, it was evident that the Suyeonggang 2 was the most contaminated river.

Evaluating and Improving Urban Resilience to Climate Change in Local Government: Focused on Suwon (기초지자체 기후변화 대응을 위한 도시회복력 평가 및 증진방안: 수원시를 대상으로)

  • Kim, Eunyoung;Jung, Kyungmin;Song, Wonkyong
    • Journal of Environmental Impact Assessment
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    • v.27 no.4
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    • pp.335-344
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    • 2018
  • As the damage caused by the abnormal climate due to climate change is increasing, the interest in resilience is increasing as a countermeasure to this. In this study, the resilience of Suwon city was examined and the plan to improve the resilience were derived against climate impacts such as drought, heatwave, and heavy rain. Urban resilience is divided into social resilience (e.g. vulnerable groups, access to health services, and training of human resources), economic resilience (e.g. housing stability, employment stability, income equality, and economic diversity), urban infrastructure resilience (e.g.residential vulnerability, capacity to accommodate victims, and sewage systems), and ecological resilience (e.g. protection resources, sustainability, and risk exposure). The study evaluated the urban resilience according to the selected indicators in local level. In this study, the planning elements to increase the resilience in the urban dimension were derived and suggested the applicability. To be a resilient city, the concept and value of resilience should be included in urban policy and planning. It is critical to monitor and evaluate the process made by the actions in order to continuously adjust the plans.

A study on simplification of SWMM for prime time of urban flood forecasting -a case study of Daerim basin- (도시홍수예보 골든타임확보를 위한 SWMM유출모형 단순화 연구 -대림배수분구를 중심으로-)

  • Lee, Jung-Hwan;Kim, Min-Seok;Yuk, Gi-Moon;Moon, Young-Il
    • Journal of Korea Water Resources Association
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    • v.51 no.1
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    • pp.81-88
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    • 2018
  • The rainfall-runoff model made of sewer networks in the urban area is vast and complex, making it unsuitable for real-time urban flood forecasting. Therefore, the rainfall-runoff model is constructed and simplified using the sewer network of Daerim baisn. The network simplification process was composed of 5 steps based on cumulative drainage area and all parameters of SWMM were calculated using weighted area. Also, in order to estimate the optimal simplification range of the sewage network, runoff and flood analysis was carried out by 5 simplification ranges. As a result, the number of nodes, conduits and the simulation time were constantly reduced to 50~90% according to the simplification ranges. The runoff results of simplified models show the same result before the simplification. In the 2D flood analysis, as the simplification range increases by cumulative drainage area, the number of overflow nodes significantly decreased and the positions were changed, but similar flooding pattern was appeared. However, in the case of more than 6 ha cumulative drainage area, some inundation areas could not be occurred because of deleted nodes from upstream. As a result of comparing flood area and flood depth, it was analyzed that the flood result based on simplification range of 1 ha cumulative drainage area is most similar to the analysis result before simplification. It is expected that this study can be used as reliable data suitable for real-time urban flood forecasting by simplifying sewer network considering SWMM parameters.