• Current Research on Agriculture and Life Sciences
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• v.17
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• pp.45-52
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• 1999

This study was conducted to evaluate the effects of microbial inoculation on sewage sludge composting. The number and species of microorganisms in sewage sludge sampled on February were higher than those sampled on August. The composting of sewage sludge is inhibited by the polyacrylamide cation, which was used as a coagulant and known to repress the growth of microorganisms. The growth of all microorganisms was inhibited by the addition of the polyacrylamide cation at a concentration of more than 0.8%. The species and viable counts of microorganisms were observed to increase during composting sewage sludge by inoculation of the effective microorganisms and addition of the pine tree sawdust as a bulking agent, compared with those without inoculation. A variety of organisms in compost(sewage sludge plus sawdust) were observed after composting for 30 days, such as Fragilaria sp., Proales sp., Vorticella sp., Schizothrix sp., Anabaena sp., Zoothaminium sp., Epstylis sp., Arcella sp., Balantidium sp., Actinophrys sp., Synedra sp., Euglypha sp., Ulothrix sp., Anacystis sp., and Clostium sp.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.32 no.1
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• pp.44-52
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• 2014

The purpose of this study is to investigate the tendency of the research on the traditional scenery architecture based on the old literature for the last 10 years and to suggest direction of the research on the traditional scenery through utilization of the old literature. For the tendency analysis of the research on the traditional scenery, I investigated and analyzed researches published in the Journal of the Korean Institute of Traditional Landscape Architecture between 2002 and 2012, and reviewed the utilization of the old literature about research on the traditional scenery. The number of the research papers through the old literature was two or three a year by 2009, but has increased to more than eight from 2010. The utilization tendency of the old literature was mostly to use the Korean translations or to use a collection of an individual's works after partially translating. As some of the researches were carried out only through translations even when they used the original, historical evidence on the translation of the original was insufficient. I can suggest the direction of the research on the traditional scenery by the results as follows: it is necessary to present both translation and the original and to specify the source of translation, for the efficient understanding and verification of the original. Professional translation of landscape architecture and scenery also seems to be necessary for the records of the current state. For the analysis of the old literature, as the analysis of the traditional scenery both through poetry and records facilitates assumption of the location of landscape by the abundant data, it seems to be necessary to approach research, using poetry and prose complementarily, after preparing foundation of research based on the records.

• Journal of Korean Society on Water Environment
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• v.32 no.1
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• pp.30-35
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• 2016

Urban areas generate large amounts of stormwater and non-point source (NPS) pollutants during rainfall events. These are caused by various land use runoffs, vehicular and human activities and increased impervious cover. The increased runoff and NPS pollutants cause water quality deterioration in the receiving waters and adversely affect the aqua-ecosystem. These environmental impacts could be reduced through the application of low impact development (LID) techniques. In Korea, more than 80% of the total rainfall occurs in summer and most of these were 10 mm or less. Therefore, if the LIDs developed were able to cope with rainfall of 10 mm and below, NPS management could be efficiently conducted. This research was performed to determine the effect of varying amounts of rainfall on the performance capability of an established infiltration and filtration facility (IF facility) that can be applied to Korea's common rainfall ranges. The IF facility area was 1.75% of the catchment area, however the facility treated more than 40% and 60% runoff volume and pollutant reduction respectively for a 10 mm rainfall. Lastly, higher volume and pollutant reduction could be attained when the LID area was at least 2% of the entire catchment.

• Journal of Korea Water Resources Association
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• v.41 no.4
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• pp.433-444
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• 2008

In recent, the integrated water resources management should consider not only existing management objects such as water supply, power generation, and instream flows but also new management objects such as water quantity, water quality, and water habitats which management system is large and complex. Moreover, integrated basin plan or operation are needed for solving conflicts problems between basins and between water usages and to maximize water resources usages. To increase use of optimization method for actual operation and apply various objects, a reservoir operation rule was developed and the KModSim's hydrologic states for integrated water resources management were tested in this study. The simulation results show that the developed operation rules applied in hydrologic states good represent the actual storages of both the Yongdam and the Daecheong Reservoirs so, it is possible to improve the water allocation method usually used in the basin management and manage the integrated basin water resources if new operating rules are applied in optimized programming.

• Journal of Korea Water Resources Association
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• v.43 no.7
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• pp.609-623
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• 2010

In this paper the feedback loop mechanisms that are inherent in the management of water supply systems were identified based on the system dynamics modeling methodology. As a result, a system dynamics (SD) computer simulation model that can be used to aid efficient management of water supply systems was developed. The developed SD model can be used to predict operating conditions of water supply systems including the effects of pipe maintenance on the entire system. The developed model is consisted of water supply, pipe maintenance and water supply business finance model. The operation and maintenance data from a study water supply system were used to verify the model and to predict the past and future operating conditions of the system. The policy leverage that greatly affects the operating condition was evaluated by the sensitivity analyses for the operational indices due to changes in the exogenous variables. It was found that while the pipe maintenance related exogenous variables had great effects on the leakage and conditions of pipes, they did not have great effects on the major operational indices such as revenue water ratio. It is considered that the social costs due to leaks and pipe breaks and the corresponding mechanism of propagation of the costs must be modeled to better evaluate the effects of pipe maintenance on the operational conditions of water supply systems.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.2
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• pp.200-205
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• 2011

This study was conducted to find the physico-chemical properties and the amino acid content of the pigs hoof hydrolysate, keratin protein and to investigate its fertilizer effect on the growth of crops. The keratin proteins such as pigs hoof were alkali-hydrolyzed to produce the hydrolysates. The chemical properties of the hydrolysate of pigs hoof was 6~7 of pH and $10{\sim}15dS\;m^{-1}$ of EC. Total amino acid contents released from the pigs hoof were 10.18%, respectively. The pot experiment was carried out for the cultivation of lettuce. The treatment design of these pot cultivation was composed of Control (compost + NPK), PHH-0.5, PHH-1.0, PHH-2.0 (${\times}2,000$ ; 1,000 ; 500 diluted solution of pig hoof hydrolysate). After lettuce cultivation, the pH values in all treatment soils were decreased than those in initial soils, and the exchangeable cation value was higher than that of control. In all PHH treatments, lettuce growth was better in the leaf length by 6~16% and the leaf width by 4~15% than in control. Therefore, the PHH solutions manufactured by hydrolysis process had plenty of amino acids, and among them PHH had the most abundant nutrients and amino acids with highest growth and yield effect on lettuce.

• Journal of Korea Water Resources Association
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• v.53 no.2
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• pp.89-96
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• 2020

Water management agencies under the Ministry of Environment produce and accumulate qualified basic data for major rivers. However, the integrated management of the river water has been weak since the artificial water circulation process, such as the intaking and drainage of agricultural water, has not been examined in the basin, which includes many agricultural land. In this study, a study was conducted on how the power usage method (operating time method) based on the running time can be applied and improved among indirect flow rate measurement methods used to investigate flow rates collected by the riverside for agricultural water purposes, and thus the resultant data of high reliability can be obtained at low cost. The operation time method is suitable for small-scale water pumping stations where it is difficult to secure real-time power supply data. The reliability of the data was verified through the correlation analysis with the actual flow rate, and it was found that the flow rate calculated by the operation time method reflecting the level of the stream to which the inlet of the pumping station is connected can be reasonably matched with the actual flow rate. In addition, it was confirmed that the investment cost at the time of initial installation of the facility was highly efficient by generating qualified flow data at low cost through comparison with direct flow rate measurement methods. If flow data is secured by applying the operation time method to large and small water farms located along the riverside, it is expected that more quantitative and integrated stream water management will be possible.

• Membrane Journal
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• v.20 no.2
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• pp.97-105
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• 2010

This study was to evaluate the performance of the Double stage Pore controllable fiber (DP) filter system as the pre-treatment of the RO membrane. The evaluation for the pre-treatment filter was performed through the indirect method, SDI (Silt Density Index) measurement of the filtrate. This study was done during Jan. 3 of 2009 to Dec. 3 of 2009 at OO Water Treatment Plant that was suppling industrial water to plants, and the raw water was contaminated lake water and it was fed to the system after clarification with coagulation. The average turbidity of the feed water and that of the filtrate was 0.79 NTU (0.28~4.01 NTU), and 0.16 NTU (0.04~0.50) respectively. And so the average turbidity removal efficiency was 77%. The filtrate flow rate and the backwash water flow rate was about 230 $m^3$/day and about 8.7 $m^3$/day respectively, and so the backwash rate was 3.8%. The data for some samples were obtained after a few days storage, and it caused the higher turbidity and SDI15 as the storage time was increased. But average SDI value of the filtrate was 3.6 (2.26~5.00) which was lower than minimum value required by the RO membrane manufacturer as the RO feed water to guarantee the life time of the RO membrane. So, the DP filter system was enough for the application as the pre-treatment of the RO membrane.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05a
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• pp.111-114
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• 2010

With the rise of green technology, the environmental question causes people’s attention more and more, based on objective of the sustainable development, the green risk has already begun to appear. In the paper the definition of the green risk of construction project is given, it analyzes and identifies the green risk of construction project from three aspects, based on BIM, the relation with green risk was found. Though the relation, the management of green risk was analyzed and we may take some measures to reduce the unnecessary risk and waste.

• KDI Journal of Economic Policy
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• v.12 no.4
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• pp.97-111
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• 1990

This paper examines the effect of redistributive inheritance tax on income distribution and social welfare. The model used here is the Overlapping-Generations Model consisting of individuals with different bequest motives where the lifetime income distribution in each cohort is determined endogeneously by the dynamic bequest process. It is shown that the introduction of redistributive inheritance tax can improve the vertical equity in the sense that the increase in tax rate reduces the coefficient of variations of intra-cohort income distribution in steady-state. However, it is also shown that, the effect on social welfare, when measured by Benthamite SWF, is uncertain in general. The numerical simulations show that, in spite of its equity-enhancing effect, the tax increase can actually lower the steady-state social welfare within the plausible range of parametric values, through the long-run output effect as well as the deadweight welfare loss incurred by tax distortion. Hence, the problem of equity-efficiency trade-off can arise in this case. However, if both the market interest rate and the elasticity of marginal utility in individual's preference function are sufficiently high, it is shown to be possible that the steady-state social welfare is enhanced by the introduction of inheritance tax.