PURPOSES : Over the years, the concentration of fine dust is gradually increasing, thereby aggravating the seriousness of the situation. Accordingly, this study intends to install a clean road system using low impact development (LID) techniques on the roadside in order to reduce the scattering of dust on roads effectively. This system stores rainwater collected through gutters in rainy weather and sprays water onto the pavement surface to reduce the scattering of road dust. METHODS : The developed clean road system consists of a water tank, controller, rain detection sensor, and solar cell. Based on this, a test-bed construction was used to evaluate its applicability. By applying the developed system, actual applicability was evaluated through total suspended solid (TSS) test and fine dust measurement. TSS test was conducted to measure the reduction rate of scattering dust on the road owing to the water injected by the clean road system. A spray nozzle was used for the TSS test, and a nebulization nozzle was used for the measurement of fine dust. In order to increase the reliability of the test, three measurements were taken each, for normal road as well as unfavorable conditions road that reproduced the construction site. RESULTS : In this study, fine dust concentration measurement and TSS test were conducted to evaluate the practical applicability of the developed clean road system. From the TSS test, it was found that for both general roads and roads depicting bad conditions, the TSS value after the first spray was the highest, and the value after the second spray was sharply reduced, such that most of the re-dispersed dust was washed out after the first spray, and similar TSS value results were obtained after the third spray. Based on this result, the result of fine dust measurement showed similar fine dust reduction effect of 9%-15.9% regardless of the concentration of fine dust in the atmosphere. These results indicate that the concentration of fine dust in the atmosphere does not significantly affect of the degree of reduction in fine dust. CONCLUSIONS : In this study, a clean road system for reducing fine dust on the road was developed and its applicability was evaluated. In a future study, we intend to check the performance of the drainage pavement through performance evaluation of water permeability coefficient test and performance test in the form of drainage pavement. Through this, we intend to evaluate the applicability of the clean road system to which drainage pavement is applied. Moreover, we will develop a clean road system that applies drainage packaging, and analyzes the degree of fine dust reduction according to the spray angle, spray amount, and spray time of the clean road system in order to study the spray system with the optimum amount of fine dust reduction. In addition, in order to reduce fine dust in the winter, when fine dust is mainly generated, it is planned to install heating wires in spray pipes where freezing is expected. Lastly, the black ice prevention effect will be analyzed by mixing a certain amount of sodium chloride when spraying water.

This study evaluated the ecotoxicological properties of livestock waste water treated by a LID (Low Impact Development) system, using a mixture of bio-reeds and bio-ceramics as suitable bed media for a subsequent treatment process of a livestock wastewater treatment plant. The relationship between the pollutant reduction rate and the ecotoxicity was analyzed with the effluents from the inlet pilot plant, with vegetated swale and wetlands and the batch type of an infiltration trench. Each pilot plant consisted of a bio process using bio-reeds and bioceramics as bed media, as well as a general process using general reeds and a bed as a control group. The results indicated that, after applying the HRT 24 hour LID method, the ecotoxicity was considerably lowered and the batch type pilot plant was shown to be effective for toxicity reduction. The LID method is expected to be effective for water quality management, considering ecotoxicity by not only as a nonpoint source pollution abatement facility but also, as a subsequent treatment process linked with a livestock manure purification facility. It is necessary to take the LID technic optimization study further to apply it as a subsequent process for livestock wastewater treatment.

Recently, Low Impact Development (LID) technology has been developed and used to collect, infiltrate, filter and confine runoff in order to enhance the storm water quality and to preserve the natural water cycle. In this study, two technologies were employed in order to treat runoff from an impervious surface such as a paved road and a parking lot. The infiltration trench which was constructed to manage stormwater runoff from a paved road abates and temporarily holds stormwater runoff and removes sediments and attached pollutants within the sub-surface structure prior to infiltration into the subsoils. On the other hand, the tree box filter which incorporates trees and other gardening plants to regulate and treat runoff drains the stormwater from a parking lot. The infiltration trench and tree box filter represent only 1% of the catchment area that they drain. This research was conducted to evaluate the hydrologic and water quality effects of the infiltration trench and tree box filter after LID. Storm event monitoring was conducted for the infiltration trench from May 2009 to August 2014 with a total of 38 storm events and 24 storm events in the tree box filter from July 2010 to July 2014. Hydrologic (i.e., total rainfall, antecedent dry day (ADD), runoff volume, etc.) and water quality (i.e. particulates, nutrients, organics, and heavy metals) parameters were analyzed before and after LID. The major findings of this study are as follows: The runoff before LID was discharged directly to the sewers and could lead to local flooding of transport systems and pollution to receiving waters during intense storm events. But, after LID the runoff was partially reduced for atleast 50% on the two (2) urban landuses. Furthermore, the pollutant concentration before LID was observed to be at high concentrations. However, it was reduced to an approximate of 60% after LID. With the combined processes of infiltration, filtration, retention and evapotranspiration that were provided by the infiltration trench and tree box filter, the runoff was partially reduced and a significant decrease in pollutant concentration has been observed. The results and findings of this study will help facilitate the LID for further application.

본 연구는 도로의 Low Impact Development(LID) 시설에서 노면유출수의 저류와 토양내의 중금속 축적을 모니터링하였다. 경기도 A시에 위치한 시설로 기존가로수 하향식재와 나무화분 여과상자의 가로수 형태가 있으며, 식생 저류조 형태의 식생플랜트와 식생체류장치로 총 4개의 시설에 대하여 모니터링을 실시하였다. 강우에 실시된 4회의 모니터링에서 시설로 유입된 누적 강우유출수는 0.07~0.77 m3의 범위로 나타났으며, 가로수 형태 시설의 강우 유출수에 대한 시설 유입율은 평균 14.9%였다. 식생 저류조 형태의 경우 평균 4.6%의 유입율로 강우 유출수에 대한 저류능력을 나타내었다. 토양 의 중금속은 표층으로부터 10 cm의 토사를 채취하여 농도변화를 계절(여름, 가을, 겨울)에 따라 모니터링하였다. 타이어의 마모에 의해 발생하는 카드뮴(Cd)의 경우 식생플랜트 시설의 초기 기저농도 0.0014 mg/kg에서 겨울에는 0.0304 mg/kg으로 증가하였다. 나무화분 여과상자에서는 납(Pb)이 0.0263 mg/kg에서 0.0606 mg/kg으로 축적된 것을 확인하였다. 이러한 LID시설의 유량 저류는 도심의 불투수층에서 발생하는 강우 유출수가 하천으로 유입되어 유발되는 홍수 및 수해에 대한 방재 효과와 시설 내 중금속 저감을 기대 할 수 있는 것으로 나타났다.