• Journal of Korean Society on Water Environment
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• v.28 no.5
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• pp.729-742
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• 2012

Recently, to using chemical coagulation process for T-P removal in STP effluent as tertiary treatment process is generalized in the country. The importance of analysis technique to save the treatment & maintenance cost during coagulation process is becoming more increased each day. Thus, it is necessary for the analysis technique during coagulation process to be presented well the characteristic of coagulation in field apply. There are a few analysis techniques such as Jar Test, zeta potential analysis and streaming current detecting techniques. But there are difficult to apply in field immediately due to long test time and difficult analysis techniques. And using PDA technique, it is reviewed applicability of the techniques as field index on pilot plant of P-CAP system The P-CAP system is composed of an in-line static mixer, a Flocculation Tank and the CAP reactor with 2 stage weir for effluent. Pre-test is performed to fix the mixing velocity in the Flocculation Tank using the PDA equipment and it fixed with 30RPM. Also, Jar Test is performed to select optimum dose of each coagulant for each T-P concentration level of influent. Result of continuous test on pilot plant of P-CAP system, the FSI in the Flocculation Tank is increased consistently by increasing each dosing concentration of coagulant such as LAS and PAC in the low level influent T-P concentration comparatively. It is considered that formed Al-hydroxide complexes for dosed coagulant are caused FSI variation. Furthermore, it seems that FSI value in the high level influent T-P concentration appeared lower than the opposite influent condition relatively because it is formed simultaneously Al-hydroxide complexes as solid type and Al-phosphorus complexes as soluble type. Thus, relation of FSI by PDA technique and T-P removal of final effluent on pilot plant of P-CAP system are very limited for the kind of coagulant and the characteristics of influent. And it though that FSI value by PDA technique with analyzing of turbidity in Flocculation Tank will be used restrictedly on field as the relative field-index.

• Korean Journal of Environmental Agriculture
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• v.20 no.3
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• pp.135-142
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• 2001

Compostable household wastes(mainly food wastes), after waste papers and cardboard being removed, were daily fed into small bins and mixed thoroughly while the air was supplied into the bin. Three small bins were employed: in case I, only recycled compost was composted, after being once fed at the beginning of composting, in case II, compostable household wastes(less than 50 mm) torn roughly by the hands with recycled compost, and in case III, compostable household wastes(less than 2 mm) ground by a kitchen mixer for vegetables with recycled compost. The straight-line was maintained between the wet or the dry residual mass of composting mixture versus composting time date(the coefficient of determination $R^2{\geq}0.98$ for the wet and $R^2{\geq}0.90$ for the dry). The decomposition rate of each composted material was estimated during composting. The total weight reduction rate after 30 days was 67.86% and 66.14% for case II and III, respectively. For case II, the daily weight reduction 6.82% and the daily decomposition rate 8.81% with the composting mixture, but the daily weight reduction rate was 56.43% and the daily decomposition rate 19.26% with only compostable household wastes. For case III, the daily reduction rate was 6.93% and the daily decomposition rate 7.70% with the composting mixture, but the daily weight reduction rate was 53.30% and the daily decomposition rate 22.95% with only compostable household wastes. The physicochemical characteristics of composting mixture did not show much difference between case II and III as was expected.

• Journal of Wetlands Research
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• v.15 no.1
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• pp.1-8
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• 2013

A pilot scale coagulation system, which has a function of physicochemical treatment, was developed to treat Combined sewer overflows(CSOs). This coagulation system requires evaluation of optimum design factors whether it has reflected those of lab scale system, moreover, the pilot scale system can be evaluated differently according to the characteristics of influent CSOs even though it has reflected lab scale's design factors. We conducted an experiment using lab scale system that could treat $1m^3$ of CSOs in a day, and also pilot-scale system with $100m^3/day$ CSOs flowed into the Cheongju sewage treatment plant. Therefore the aim of this study is to evaluate a hydraulic similarity between the design factors of pilot scale and those of lab scale coagulation system, and to evaluate feasibility of the coagulation system for the CSOs treatment with optimum operation conditions. From the result of pilot-test, we drew the optimum operation factors of in line mixer and flocculator having similarities with those of lab scale system as well as the optimum coagulant dose. Finally we confirmed that the coagulation system has feasibility to treat the CSOs with high removal efficiency.