• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.3
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• pp.124-132
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• 2009

The optimal type and discharging position of ocean outfall of wastewater have been determined by hydrodynamic modeling, near-field dilution modeling, and far-field dispersion modeling. Tide and tidal currents have been simulated by a finite element hydrodynamic model showing good agreements with field observations. Based on the hydrodynamic simulation results candidates of ocean outfall position were preliminary determined. Submerged single port and submerged multi-port diffuser were selected as discharging system alternatives and finally designed by considering tide, tidal currents and water depth. Initial dilution of wastewater discharged from the designed ports has been estimated by CORMIX system. A 2-dimensional random-walk dispersion model has been employed to simulate far-field dispersion of discharged wastewater.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.17 no.3
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• pp.166-177
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• 2005

This study developed the jet integral model to analyze the behavior of the wastewater discharge in the near field using the fourth order Runge-Kutta method in order to numerically solve the problems of six ordinary differential equations and six unknowns. This jet integral model used the entrainment hypothesis and the manipulation of sonle shape constant. This study also conducted the hydraulic experiments fnr single horizontal buoyant Jet using LIF through the calibration procedure. The results calculated by the previous models, CORMIX 1 and VISJET, and the proposed jet integral model were compared to the hydraulic experimental results. The centerline trajectories predicted by the proposed model were in good agreements with the experimental results in the transition region whereas the trajectories calculated by the VISJET model agreed well with the measured data in the momentum and buoyancy-dominated regions. The centerline dilution calculated by the proposed model agreed generally with the measured dilution in the intial and transition regions while the centerline dilution predicted by the CORMIX 1 was in good agreements with the experimental results in the momentum and buoyancy-dominated regions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.243-252
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• 1999

Recently several research groups using CORMIX, approved by EPA, have been working on the hydrodynamic mixing processes due to the ocean discharges. It provides a useful tool for analyzing near field mixing characteristics through the outfall system. This paper applies CORMIX 1 & 2 to the Pusan Jungang Effluent Outfall System, which is planned to be in the Gamchun harbour and will be completed in 2011. This model output shows the trajectoral variation of dilution and concentration for three cases of outfall system. Dilution differences have been simulated and found the highest dilution condition under the different displacement of outfall system. On the basis of these outputs it will be proposed the optimum outfall system type and location. This approach might contribute on protecting the serious water quality problem due to the ocean discharge.

• Journal of the Korean Society for Marine Environment & Energy
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• v.2 no.2
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• pp.60-69
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• 1999

In this paper, we have obtained the initial and near-field dilution rates of wastewaters discharged from the ocean outfall of Masan-Changwon municipal wastewater treatment plant from both of field measurements and CORMIX model simulations. In the summer of 1998, water temperature and salinity profiles was measured at 16 stations in the vicinity of the Masan outfall and the dilution rates were analyzed by salinity deficit method. The transport of the wastefields and their initial dilution rates were calculated by CORMIX model using field data as model input. Both of observed and predicted results are shown In very low dilutions with the range of 32～48 from the field data analysis and 29～43 from the model prediction, respectively. This indicates that the water quality in the Masan outfall area can be worsening due to the low dilution rates of diswastewaters, especially, when the ambient currents are very weak in a neap tide and ambient water density is highly stratified in summer.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.12 no.2
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• pp.53-69
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• 2000

For the case of the capacity increase of Masan-Changwon wastewater treatment plant, the changes of near-field dilution rates due to the increased discharges into Masan Bay from the submerged multipart-diffuser were predicted by using CORMIX model. As the increase of wastewater discharges from currently 280,000 m3f day to 720,000 m3fday by 2011, the dilution rates become much lower than the present rates. To enhance the reduced dilution rates, the engineering design changes of diffuser length and alignment were considered as an optimal engineering option. According to the results of the model simulations for these changes, the dilution rates were increased in the strong ambient current of spring tide, but they were not affected by these changes in the weak current of neap tide in Masan Bay. From the analysis of oceanographic survey data, new outfalls sites have been searched. A promising outfalls site is selected and proposed on the basis of maximum obtainable dilution rates predicted by the model simulations.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.1
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• pp.35-44
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• 2000

The winter case of the near-field dilution at the Masan outfalls has been studied by field measurements and CORMIX model simulations. Dilution rates of the wastewater discharge in winter were obtained by a salinity deficit method using the field data observed in the neap tidal period of February, 1999. The observed dilution rates in winter season were found to be very high in the range of 90～130 due to the isopycnal mixing of ambient density compared with the summer range of 30～40 under weak neap tidal currents. The results of CORMIX model simulations also show that the winter dilution rates under a weak ambient current(Ua=6.0ms/s) were increased by 3-fold of the summer dilution rates. However, the difference between two seasons becomes small by 30% under a strong current(Ua=15.5cm/s). This result indicates that the dilution and hydrodynamic mixing process of the effluents are more influenced by ambient crossflow condition than by ambient density stratification at the outfalls site.

• Ocean and Polar Research
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• v.22 no.1
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• pp.45-56
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• 2000

Hydrodynamic mixing characteristics of submerged effluent discharges into Masan Bay were investigated by both field observations and numerical model simulations. CORMIX model, a length-scale mixing model, was adopted to obtain the near-field dilution and wastefield characteristics of the effluent discharges into Masan Bay. Model predictions of the near-field dilution rates were in a good agreement with field observations in summer and winter seasons. Seasonal variations in the dilution rates showed that the highest dilution rate was obtained in winter while the lowest dilution rate was in summer. As the effluent discharges are increased with the treatment capacity expansion to be completed by 2011, the dilution rates are expected to be much reduced and the near-field stability of the wastefields will become unstable due to the increased effluent discharges.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.934-935
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• 2005

• 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 Korea Water Resources Association
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• v.31 no.5
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• pp.613-620
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• 1998

Field and laboratory studies of the near field behavior of the San Francisco ocean outfall were reported. The data sets cover broad ranges of discharge conditions and oceanic conditions, and are associated with a typical type of outfall discharges with multiport diffusers. The laboratory data sets were obtained in density-stratified towing tanks to replicate the field tests. Model studies of wastefield behavior using these data sets were predicted by the mathematical models UM, UDKHDEN, RSB, and CORMIX2 for minimum dilution, the height to top of wastefield, and wastefield thickness. In this paper, the results are discussed and compared measurements with mathematical model predictions. The hydraulic model studies reproduced the major features observed in the field. It also afforded considerable insight into the mechanics of mixing of multiport risers which could have been obtained neither from the field test nor the mathematical models.