• Journal of Korean Society of Water and Wastewater
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• v.18 no.3
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• pp.377-384
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• 2004

In the present study, a feasibility of an advanced oxidation process using UV/Hydrogen peroxide($H_2O_2$) system equipped with a medium pressure lamp for secondary effluent reclamation was investigated. Initial concentration of $H_2O_2$ and pH were changed to determine the optimum operation condition for the system. The removal efficiency of color was than 80% with 14.3mg/L of initial $H_2O_2$ and 5 minute of contact time in the UV/$H_2O_2$ system. The color removal was analyzed using first-order reaction equation. The dependence of rate constant (k) on initial $H_2O_2$ represented the rational relationship with maximum value. Residual $H_2O_2$ caused increase of effluent COD, since analyzing agent, dichromate, reacted with $H_2O_2$ in the sample. Therefore, excess initial concentration of $H_2O_2$ would significantly affect effluent COD measurement. At pH variation experiment, both residual $H_2O_2$ and color showed peak in the neutral pH range with the same pattern. Effect of $H_2O_2$ dose also enhanced color removal but raised residual $H_2O_2$ problem in the continuous operation UV system. In conclusion, these results indicated that medium pressure UV/$H_2O_2$ system could be used to control color in the secondary effluent for reclamation and reuse.

• Journal of Environmental Science International
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• v.8 no.1
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• pp.107-113
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• 1999

A new biological nutrient removal system combining $A^2/O$ process with fixed film was developed in this work and the characteristics of denitrification were especially investigated in the combined fixed film reactor(CFFR). Media was added in the anaerobic, anoxic and aerobic reactors, respectively. Tests were made to establish the effluent level of $NO_x-N$, COD, DO and nitrite effects on $NO_x-N$ removal in the CFFR by decreasing hydraulic retention time (HRT) from 10.0 to 3.5 hours and by increasing internal recycle ratio form 0% to 200%. The influent was synthesized to levels similar to the average influent of municipal wastewater treatment plants in Korea. SARAN media with a porosity of 96.3% was packed 40% / 130% / 25% based on its reactor volume, respectively. It was found that COD rarely limited dentrification in the anoxic reactor because of high $C/NO_x/-N$ ratio in the anoxic reactor, while DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent inhibited denitrification in the anoxic reactor. It was proved that the critical points of DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent were 0.15mg/L and 10%, respectively. As the internal recycle ratio increased, DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent increased. Especially, at the condition of internal recycle ratio, 200%, DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent exceeded the critical points of 0.15mg/L and 10%, respectively. Then, denitrification efficiency considerably decreased. Consequently, it was represented that the control of DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent can assure effective denitrification.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.1
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• pp.57-64
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• 2019

We investigated influence of connected influent on the treatability of a wastewater treatment plant (WWTP), recently accepting effluent from a sludge carbonization facility. Based upon the pollutant loading rates (kg/d) of each connected influent, food waste leachate and livestock wastewater contributed to high BOD and COD loadings, while sludge carbonization facility effluent certainly contributed to T-N and $NH_3-N$ loadings. The nitrification rate in aerobic tank decreased to 55% with the carbonization facility effluent entering to the WWTP, while it was 89% with no carbonization facility effluent entering. The sludge carbonization facility effluent may need to be pretreated to reduce T-N and $NH_3-N$ loadings before entering to the WWTP for further treatment.

• Journal of Korean Society on Water Environment
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• v.37 no.3
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• pp.190-203
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• 2021

Water quality, benthic macroinvertebrate communities, and other factors were investigated to explore the effects of the effluent discharge from a sewage treatment plant into Jwagwang stream in Busan in 2019. During the study period, the flow rate of this stream was in the range of 10,400 m³/day to 52,200 m³/day except for the discharge of about 24,000 m³/day of the effluent. After discharge, the flow velocity increased by about 65% and the water depth increased by about 40%. At sites downstream of the discharge point, BOD, COD, TOC, T-N, T-P, and other water quality values were worse than those of the upstream sites. The periphytic algal chlorophyll-a concentrations in the natural substrata were higher than those of the upstream sites, especially in May and August. However, at sites downstream of the discharge point, the individual numbers of Annelida were decreased and individual numbers of the insecta of arthropoda were increased. Also, species numbers and the diversity and dominance indexes were improved in the sites downstream of the discharge point. The functional feeding groups (FFGs) of collector-filterers were increased and the habitat orientation groups (HOGs) of sprawlers, burrowers, and clingers were especially increased at the sites with additional reclaimed wastewater effluent flow. Regardless of the effluent discharge, BMI, an indicator of ecological stream health using benthic macroinvertebrate species, did not show large gaps between the study points. Although the water quality of the sites downstream of the discharge point was much worse than those upstream, their ecosystem soundness was better than those of the upstream sites from an ecological perspective.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.2
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• pp.165-172
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• 2010

Treated sewage could enable growth by providing key nutrients or seeding the sediments with enterococci strains that can grow in the environment. This study is to test the hypothesis that the flux of bacteria into the water column is rate-limited by the transfer of bacteria across the sediment/water interface. Two conceptual models are derived for the transfer of bacteria to the water column from the sediment/water interface: convective diffusion of isolated bacteria and resuspension of particle-associated bacteria. The model predictions are directly tested together with field measurements of bacteria and sediment in an effluent-dominated stream where high concentrations of enterococci in this stream originate primarily from growth of the bacteria in stream sediments. The results reveal that high concentrations of enterococci in this stream are transported primarily by resuspension of particle-associated bacteria accumulated at the sediment/water interface, either in the form of bacterial aggregates or in the form of inorganic particles.

• Journal of Applied Biological Chemistry
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• v.53 no.4
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• pp.232-238
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• 2010

In order to investigate the treatment efficiency of pollutants in free water surface constructed wetlands (FWS CWs) with lotus (Nelumbo nucifera) cultivation pond, the experiment was consisted of two sites (site I and II) in Lake Juam, Korea. The sites were configured a lotus cultivation pond (with fertilizer application) - a dropwort bed - a reed bed for site I, and a lotus cultivation pond (without fertilizer application) - a dropwort bed - a reed bed for site II. Removal rate of COD in site I and II were 13.3% and 26.0%, respectively. Removal rate of total nitrogen (TN) was 29.7% for site I, and 36.3% for site II. Removal rate of total phosphorus (TP) in site I and II were 36.0% and 36.5%, respectively. COD, TN and TP in effluent from site I (with fertilizer) was higher than that in site II (without fertilizer), showing that COD, TN and TP in effluent were strongly influenced by fertilizer addition. Therefore, in order to satisfy established water-quality standards, the amount of fertilizer used in lotus cultivation showed be evaluated.

• Journal of Korean Port Research
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• v.14 no.3
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• pp.361-371
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• 2000

A demand of marine outfall system has been much increased for the effective disposal of the wastewater due to population and industrial development at the coastal areas. The outfall system discharges primary or secondary treated effluent into the coastline, or at the deep water, or between these two. The discharge is carried out by constructing a pipeline on the sea bed with a diffuser or with a tunnel, risers and appropriate. The effluent, which has a density similar to that of fresh water, rises to the sea surface forming plume or jet, together with entraining the surrounding salt water and becomes very dilute. Thus there have been growing interests about plume behaviour around the outfall system. Plume or jet discharged from single-port or multi-port diffuser might cause certain impacts on coastal environment. Near field mixing characteristics of discharged water field using CORMIX model have been studied for effective outfall design various conditions on ambient current, depth, flow rate, effluent concentration, diffuser specification, port specification etc.. This kind of analysis is necessary to deal with water quality problems caused by the ocean discharge. The analyzed result was applied to the Pusan Jungang effluent outfall system plan.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.5
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• pp.537-546
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• 2005

This study was carried out to evaluate EPS and SMP variation of sludge and effluent in nitrification and denitrification process with zeolite addition, a possible reduction of effluent DOC by URC(Ultra Rapid Coagulation) process. As a biological wastewater treatment result, EPS formation of both aeration and anoxic sludges are not affect by SRT variation. However, EPS concentration of sludges is higher in aeration tank than in anoxic tank by 6~8 mg EPS/ g VSS. Linear relationship between SMP to DOC indicates that SMP of bulk solution contributes to most of the biological treatment effluent DOC. DOC and turbidity removal efficiency was more improved with URC process than in a conventional coagulation. For pretreatment of UF filtration DOC removal was advanced by URC process than only UF filtration.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.1
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• pp.3-7
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• 2005

In the present study a feasibility of a novel filtration process using synthetic for secondary effluent reclamation was investigated. Polyurethane was chosen as a filter medium among tested three media. Compressibility and up-flow velocity were changed to determine the optimum operation for the system. An equation was introduced to express the relationship between the removal efficiency and up-flow velocity. In pilot study, the synthetic medium filtration with compression showed very stable effluent quality without clogging trouble, though the system operated with 3 times higher filtration rate and much longer backwashing interval than conventional systems.

• Environmental Engineering Research
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• v.20 no.1
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• pp.99-104
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• 2015

The purpose of this study is to evaluate the performance of forward osmosis (FO) system for harvesting microalgae cultivated in secondary sewage effluent. Microalgae species used in this study were chlorella sp. ADE4. The drawing agents used for forward osmosis system were seawater and concentrate of sea water reverse osmosis (SWRO) system. Chlorella sp. ADE4 cultured in secondary sewage effluent illustrated moderate efficiency in removal of total nitrogen (TN) (68%) and superior performance in total phosphorus (TP) removal (99%). Comparison of seawater and SWRO concentrate as drawing agent were made in FO membrane separation of the microalgae. The result from this study depicts that SWRO concentrate is strong drawing agent in FO membrane system providing an average dewatering rate of $4.8L/(m^2{\cdot}hr)$ compared to seawater with average dewatering of $2.9L/(m^2{\cdot}hr)$. Results obtained from this study indicated that FO system could be viable option for harvesting the microalgae for further biodiesel production. SWRO concentrate as a drawing agent could be very important finding in field of membrane technology for disposal of SWRO concentrate.