• 한국농공학회지
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• 제44권5호
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• pp.96-105
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• 2002

As an useful water purification system for non-point source pollution in rural watersheds, interests in constructed wetlands are growing at home and abroad. It is well known that constructed wetlands are easily installed, no special managemental needs, and more flexible at fluctuating influent loads. They have a capacity for purification against nutrient materials such as phosphorus and nitrogen causing eutrophication of lentic water bodies. The Constructed Wetland Design Model (CWDM), developed through this study is consisted mainly of Database System, Runoff-discharge Prediction Submodel, Water Quality Prediction Submodel, and Area Assessment Submodel. The Database System includes data of watershed, discharge, water quality, pollution source, and design factors for the constructed wetland. It supplies data when predicting water quality and calculating the required areas of constructed wetlands. For the assessment of design flow, the GWLF (Generalized Watershed Loading Function) is used, and for water quality prediction in streams estimating influent pollutant load, Water Quality Prediction Submodel, that is a submodel of DSS-WQMRA model developed by previous works is amended. The calculation of the required areas of constructed wetlands is achieved using effluent target concentrations and area calculation equations that developed from the monitoring results in the United States. The CWDM is applied to Bokha watershed to appraise its application by assessing design flow and predicting water quality. Its application is performed through two calculations: one is to achieve each target effluent concentrations of BOD, SS, T-N and T-P, the other is to achieve overall target effluent concentrations. To prove the validity of the model, a comparison of unit removal rates between the calculated one from this study and the monitoring result from existing wetlands in Korea, Japan and United States was made. As a result, the CWDM could be very useful design tool for the constructed wetland in rural watersheds and for the non-point source pollution management.

• 한국물환경학회지
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• 제26권2호
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• pp.191-199
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• 2010

Introduction of Technology-Based Effluent Limitations (TBELs) concepts into Korea requires extensive and through analyses on the expected pollutants reduction effects and the cost factor for the industry side. In addition, the TEBLs should be optimized for the regulatory environments of Korea and be applied in a progressive manner to minimize the undesirable effects. It is also necessary to assess the contribution of each industrial categories's to the pollution of natural water bodies to find the priority of TEBLs application. For these purposes, the pollution loads of various industrial categories were analyzed using risk assessment indicator based on Toxic Weighting Factors (TWFs). First, the TWFs were calculated for the pollutants regulated using the method adopted by USEPA. And the effluent characteristics of the eighty two categories of industry in Korea were investigated. Although the analytical data on the wastewater from different industrial categories are relatively limited, the results from two previous studies were used. The first study, conducted by the National Institute of Environmental Research in 2001~2004, investigated the wastewater characteristics from 255 industrial sources covering the major 20 industrial categories. The second study includes more recent analytical data for the wastewater from 500 industrial sources, covering all the 82 industrial categories. In the result of the pollution loads analyses, the category of 'Synthetic and Chemical manufacture' was found to show the highest raw pollution load. On the other hand the category of 'Ion & Steel manufacture' was found to show the highest effluent pollution loads, which can be considered as the real impacts on natural water streams. The top five categories occupied 62.2% of the total effluent pollution loads. Through the analyses, the relative importances of each industrial categories and the priorities of TEBL-based pollution reduction were determined.

• 한국환경복원기술학회지
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• 제17권5호
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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 Engineering Research
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• 제21권3호
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• pp.276-283
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• 2016

The goal of this study was to evaluate the effect of effluents from conventional activated sludge (CAS) and biological nutrient removal (BNR) processes on algal bloom in receiving waters. We made multiple effluent sampling from one CAS and two BNR facilities, characterized their effluents, and conducted bioassay using river and ocean water. The bioassay results showed that CAS effluents brought similar productivity in both river and ocean water, while BNR effluents were more reactive and productive in ocean water. Unexpectedly, nitrogen-based biomass yields in ocean water were up to six times larger for BNR effluents than CAS effluent. These results indicated that nitrogen in BNR effluents, although its total concentration is lower than that of CAS effluent, is more reactive and productive in ocean water. The ocean water bioassay further revealed that effluents of BNR and CAS led to considerably different phytoplankton community, indicating that different characteristics of effluents could also result in different types of algal bloom in receiving waters. The present study suggests that effects of upgrading CAS to BNR processes on algal bloom in receiving waters, especially in estuary and ocean, should be further examined.

• 한국물환경학회지
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• 제39권5호
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• pp.390-395
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• 2023

The feasibility of applying the shortcut nitrogen removal process to treat livestock wastewater on individual farms was examined, and appropriate operating parameters were established. As a result,, it was determined that the nitrification reaction was carried out under 550 mg/L of ammonium nitrogen concentration, but it was less effective under conditions of high ammonia concentration. Consequently, it was confirmed that a partial injection of inflow water was necessary to minimize the effects of ammonia toxicity. Following the sequential batch reactor (SBR) operation results, it was difficult to achieve the effluent quality standard without an external carbon source. Also, selection of the appropriate hydraulic retention time was critical for the optimal SBR operation. Following the livestock farm application, with external carbon source injecting, the total nitrogen concentration in the effluent was 85.1 mg/L. This result revealed that the standard could be accomplished through a single treatment on individual livestock farms. The ratio of nitrite nitrogen to ammonia nitrogen in the effluent was verified to be suitable for implementing the anammox process with a 10 days of hydraulic retention time. This study demonstrated the potential applicability of process in the future. However, in order to apply to livestock farms, managing variations in wastewater load across individual farms and addressing reduced nitrogen oxidation efficiency during the winter season are crucial.

• 상하수도학회지
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• 제25권3호
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• pp.335-342
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• 2011

Secondary effluent contains particle compounds which are comprised of microorganisms that occurs membrane fouling when the water is reused. This study evaluates the characteristics of membrane fouling of secondary effluent reuse. Effects of chemical backwashing are analyzed to reduce membrane fouling by regular chemical backwashing. As the result, major membrane foulants are verified EPS materials which include protein and polysaccharide that cause biofilm cake layer on the membrane. Also, sodium hypochlorite is applied to chemical backwashing. The backwashing improves recover rate when injected chemical concentration is increased and chemical backwashing cycle is amplified. Chemical backwashing cycle affects more than injected chemical concentration yet idle time does not noticeably influence on reducing membrane fouling.

• 한국물환경학회지
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• 제28권3호
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• pp.467-472
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• 2012

In this study, water quality and acute toxicity using Daphnia magna were analyzed to investigate the eco-toxicological substances identified as statistical analysis and propose a management plan for the effluent of Banwol industrial complex, Ansan, Gyeonggi-do. Cu, Zn, F, Mn concentrations in the effluent far exceeded the US standards to protect the aquatic ecosystem and eco-toxicity values were 5 ~ 22 TU. However, concentrations of heavy metals significantly decreased after Ansan public wastewater treatment plant operating a biological treatment and toxicity values were 0 TU. Zn, Cr, F and Cu in the effluent showed very strong and strong positive correlations with eco-toxicity values, respectively. Regression analysis resulted in an equation between toxicity and Zn, TU = $4.884{\times}Zn$ (mg/L) -0.391 showing Zn concentration should be managed less than 0.285 mg/L to keep the eco-toxicity (TU) less than 1.

• 한국물환경학회지
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• 제22권1호
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• pp.145-149
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• 2006

Textile and pigment wastewater samples collected from an industrial complex showed toxic effect on Daphnia magna. For textile wastewater, 48 h acute toxicity of effluent was not detected while toxic unit (TU) of influent was 1.79. The toxicity of influent was completely disappeared by gamma-ray treatment at 10 kGy or by suspended solids (SS) removal. In case of pigment wastewater, both influent and effluent were toxic to D. magna though the effluent satisfied current water quality standards. Gamma-ray treatment had little effect on the toxicity reduction of pigment wastewater since the toxicity was mainly caused by metal ions, in particular, Cr(VI). This work suggests the bioassay technique for monitoring adverse effects of wastewater should be introduced, and also shows the usefulness of gamma-rays as an advanced treatment technique for textile wastewater.

• Asian-Australasian Journal of Animal Sciences
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• 제17권8호
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• pp.1168-1176
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• 2004

Intensive animal industries create large volumes of nutrient rich effluent, which, if untreated, has the potential for substantial environmental degradation. Aquatic plants in aerobic lagoon systems have the potential to achieve inexpensive and efficient remediation of effluent, and to recover valuable nutrients that would otherwise be lost. Members of the family Lemnaceae (duckweeds) are widely used in lagoon systems, but despite their widespread use in the cleansing of sewage, only limited research has been conducted into their growth in highly eutrophic media, and little has been done to systematically distinguish between different types of media. This study examined the growth characteristics of duckweed in abattoir effluent, and explored possible ways of ameliorating the inhibitory factors to growth on this medium. A series of pot trials was conducted to test the tolerance of duckweed to abattoir effluent partially remediated by a sojourn in anaerobic fermentation ponds, both in its unmodified form, and after the addition of acid to manipulate pH, and the addition of bentonite. Unmodified abattoir effluent was highly toxic to duckweed, although duckweed remained viable and grew sub optimally in media with total ammonia nitrogen (TAN) concentrations of up to 100 mg/l. Duckweed also grew vigorously in effluent diluted 1:4 v/v, containing 56 mg TAN/L and also modified by addition of acid to decrease pH to 7 and by adding bentonite (0.5%).

• 한국물환경학회지
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• 제16권4호
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• pp.533-539
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• 2000

A bench-scale reactor using SBR process was experimented with an synthetic wastewater. The main purpose of this investigation was to evaluate applicability in the field and process removal efficiencies in terms of BOD and T-P and its corresponding kinetic parameters. Removal rate of phosphorus was 77% in terms of total phosphorus. Effluent concentrations were $9.8mg/{\ell}$ BOD and $1.1mg/{\ell}$ T-P. Effluent quality was maintained consistently stable by controlling decant volume and operating cycles. The efficiency for phosphorus removal was increased due to decrease in BOD-SS loading value in the range of $0.25{\leq}$aeration time ratio${\leq}0.52$.