• Journal of Korean Society of Water and Wastewater
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• v.19 no.1
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• pp.92-97
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• 2005

This research is to investigate the effect of the dual coagulant using inorganic coagulants($AICl3{\cdot}6H2O$) and polymer on the coagulant process. Jar-test was conducted by using Kaolin injected raw water. PDA(Photometric Dispersion Analyzer) equipment in order to analyze the size of the particles and the characteristics of the shapes. The change in the rate of sample ores' residual deposited after coagulants were also compared. According to the result derived from this experiment, the concentration of inorganic coagulant reduced 50% and the residual was lower by using dual coagulants compared to using single coagulant. However the dual coagulant required sufficient mixing time, and affected particle characteristics, with the effect of the injection order of coagulants, the simultaneous injection of inorganic coagulant and polymer showed the most effective in the particle removal.

• Journal of Korean Society on Water Environment
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• v.30 no.3
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• pp.311-318
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• 2014

The purpose of this study is to investigate the effect of various types of coagulant on dewaterability and settleability of sewage sludge for the application of dewatering process. Cationic organic coagulants and inorganic coagulants of the aluminium base were used; PAC (Poly Aluminium chloride, $Al_2O_3$ 17%) and C-210P (0.2%). After Jar test, PAC 26 mg/L and 0.2% C-210P 55 mg/L was decided as the optimum concentration of the coagulant according to zeta potential measurement. pH, alkalinity and viscosity were measured in all experiments and the data on sedimentation characteristics is analyzed by SDI, SVI sedimentation rate and solid flux. The SRF(Specific Resistance of Filtration) experiment was conducted with the result of single and dual injection system as the dewaterability experiment. As a result, the organic coagulant making large floc has good characteristics of sedimentation and agglutination. Also, it is observed that the organic coagulants injection has a better dewaterability efficiency of coagulants under the condition of the lowest SRF value, followed by dual and inorganic coagulants injection.

• Journal of Korean Society of Water and Wastewater
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• v.14 no.3
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• pp.260-270
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• 2000

The objective of this study is to evaluate the effect of filter aids in the dual-media rapid filtration. Paper-filter tests were conducted to determine the proper dosages of coagulant and filter aid, and pilot plant tests using two dual-media filter columns were performed for a variety of filtration rates. Using a filter aid (non-ionic polymer), the maximum feasible filtration rate is 480m/day, while turbidity is less than 0.3 NTU and filter run-time is about 70 hours. It is possible to increase the filtration rate up to 360 m/day for keeping the turbidity less than 0.1 NTU. Turbidity increases for the filtration rate greater than 360m/day. In general, the quality of filtered water with a filter aid is stable, while the filter maintains a sufficient filter run-time for a maximum allowable head loss. Particularly, the initial breakthrough can be effectively controlled. The use of a filter aid may be one of the methods applicable if the turbidity of filtered water is required to be improved or if the filter breakthrough limits filter run-time.

• Journal of Korean Society of Water and Wastewater
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• v.37 no.6
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• pp.447-456
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• 2023

Risk assessment on Jeju Special Self-Governing Province(JSSGP)'s water supply facilities and establishment of adaptation measures for climate crisis factors were implemented. JSSGP's vulnerability to the climate crisis was high in the order of drought, heat wave, heavy rain and strong wind. As a drought adaptation measure, policies of water saving and revenue water ratio improvement were considered. As for the heat wave adaptation measure, the introduction of an advanced water treatment process was suggested in response to the increase of algae cell number which resulting in taste and odor problem. As for heavy rain adaptation measures, the installation and operation of automatic coagulant injection devices for water purification plants that take turbid surface water were proposed. As a measure to adapt to strong winds, stabilization of power supply such as installation of dual power line was proposed in preparation for power outages. It is expected that water facilities will be able to supply high-quality tap water to customers even under extreme climate conditions without interruption through risk assessment for climate crisis factors and active implementation of adaptation measures.