Franz Kevin F. Geronimo

Flood reduction analysis on watershed of LID design demonstration district using SWMM5

ABSTRACT Urban development is the primary cause of the expansion of impervious areas. Urbanization reduces infiltration of rainwater, increases runoff volume, and finally has an effect on the hydrological cycle and urban environment. To solve these problems, Low Impact Development (LID) methods have been used to restore the natural hydrology of predevelopment sites using site design techniques such as infiltration, evaporation, and retention. SWMM5 has been developed as a model to analyze the hydrologic impacts of LID facilities. This study performed hydrologic analysis and evaluated the flood reduction effect of the Jangjae Stream watershed by the design of LID facilities of the rainwater management demonstration district of AsanTangjung New Town (Korea). LID facilities in this study were comprised of infiltration trench, rain barrel, vegetation swale, etc. SWMM5 was calibrated using rainfall data of the 7th and the 14th of July, 2011 and was verified using rainfall data of the 10th and the 11th of Augus...

Treatment of suspended solids and heavy metals from urban stormwater runoff by a tree box filter

Particulates, inorganic and toxic constituents are the most common pollutants associated with urban stormwater runoff. Heavy metals such as chromium, nickel, copper, zinc, cadmium and lead are found to be in high concentration on paved roads or parking lots due to vehicle emissions. In order to control the rapid increase of pollutant loads in stormwater runoff, the Korean Ministry of Environment proposed the utilization of low impact developments. One of these was the application of tree box filters that act as a bioretention treatment system which executes filtration and sorption processes. In this study, a tree box filter located adjacent to an impervious parking lot was developed to treat suspended solids and heavy metal concentrations from urban stormwater runoff. In total, 11 storm events were monitored from July 2010 to August 2012. The results showed that the tree box filter was highly effective in removing particulates (up to 95%) and heavy metals (at least 70%) from the urban stormwater runoff. Furthermore, the tree box filter was capable of reducing the volume runoff by 40% at a hydraulic loading rate of 1 m/day and below.

Evaluation of a hybrid constructed wetland system for treating urban stormwater runoff

AbstractThis study developed hybrid constructed wetlands (CWs) for treatment of urban stormwater runoff pollutants. Hybrid CWs applied at narrow sections in urban areas are typically small and modular in type. Several treatment mechanisms were occurring in the hybrid system to treat high level of pollutant mass loading from urban stormwater runoff. A small scale hybrid CW comprised of a sedimentation tank, free water surface (FWS) CW, and horizontal sub-surface flow (HSSF) CW, was studied. A total of 10 test runs were simulated in the hybrid CW since July 2011–November 2012. Based on the results, almost 51–78% reduction in pollutants such as TSS, COD, TN, TP, and total heavy metals (Fe, Cu, and Zn) was achieved after passing the first and second units of the hybrid CW (i.e. sedimentation tank and FWS CW). Finally, additional 9–25% reduction of these pollutants was obtained as they went through the HSSF CW. Using normalized pollutant concentration with respect to the facility length, the appropriate size o...

Fate and removal of nutrients in bioretention systems

AbstractPhosphorus and nitrogen in different forms are the primary concern in surface water bodies nowadays since it causes eutrophication. A bioretention system, an example of green stormwater infrastructures reduces nutrients through biological processes such as plant uptake and microbial conversion of nitrogen known as bioremediation. In this study, the performance of two types of bioretention system in managing nutrients from urban stormwater runoff was investigated. Total phosphorus (TP) was reduced by 85% up to 86% in both bioretention types while total nitrogen (TN) was reduced by 49 and 55% in type A and type B bioretention, respectively. Among the plants species used in the study, Rhododendron indicum Linnaeus was identified as the most appropriate plant that should be used in bioretention systems considering factors such as number of flower per plants, plant decay rate, cost of plant, number of plant per reactor, and TN and TP uptake by plants. Based on the results, 25–32% of TN and 47–59% of th...

Treatment of parking lot runoff by a tree box filter

ABSTRACT Nonpoint source pollutants were usually transported by stormwater runoff, especially in highly urbanized areas. For this reason, studies on stormwater management have been one of the major focuses of the Ministry of Environment of Korea at present. Application of tree box filter, an example of stormwater best management practice, is highly considered in Korea due to its minimal space requirements, applicability in landscaping and good pollutant-removal efficiency. This study investigated the efficiency of a tree box filter in reducing both the pollutant and volume of stormwater runoff generated from a parking lot. This study also identified the relationship between pollutant and volume reduction and the effects of varying amount of rainfall to the overall volume reduction efficiency of the system. The study proved the capability of the tree box filter in improving stormwater runoff quality that was more efficient in total suspended solids (TSS) and soluble heavy metals discharging only 9 and 30% ...

Investigation on the effectiveness of pretreatment in stormwater management technologies

The effectiveness of presettling basins as component of stormwater best management practice (BMP) technologies was investigated. Storm event monitoring and sediment collection were conducted from May 2009 to November 2012 on the presettling basins of the three BMP technologies designed to capture and treat stormwater runoff from highly impervious roads and parking lots. Data on captured runoff and sediment, total suspended solids (TSS) loadings, rainfall and runoff rate, sediment accumulation rate, as well as particle distribution and pollutant concentrations of sediment were gathered and analyzed along with the physical design characteristics of the presettling basins such as surface area and storage volume. Regression models were generated to determine significant relationships between design parameters. Results revealed that the storage volume ratio (ratio of storage volume of presettling basin to BMP) was an important parameter in designing the presettling basin of the BMP. For practicality, optimizing the design of the presettling basin means that the storage volume ratio should be determined based on the desired captured amount of runoff and sediment from runoff to limit the frequency of maintenance caused by the accumulation of sediment. It was recommended that pretreatment of runoff should be employed when the site in which the BMP is to be sited has high TSS loading and runoff rate, and is subjected to high intensity rainfall.

Transport of nonpoint source pollutants and stormwater runoff in a hybrid rain garden system

본 연구는 도시 강우유출수 처리를 위한 하이브리드 빗물정원 시스템을 개발하고자 수행되었으며, Pilot scale 모니터 링을 통하여 시스템 내의 서로 다른 구성요소간의 효율을 검증하였다. 유입수는 국내·외 도로강우유출수의 농도를 고 려한 인공강우유출수를 이용하여 수행하였다. 모니터링 결과 하이브리드 빗물정원은 시설 내 저류 80%, 지하수의 침 투 15%로 유입수의 약 95% 저감되는 것으로 나타났다. 이는 ST의 저류 및 PB와 IT의 침투 기작이 물순환 효과에 기 여한 것으로 판단된다. 또한 오염물질 저감효율을 산정한 결과, TSS의 경우 평균 87%으로 나타났으며, 유기물은 76%, 영양염류는 46%, 중금속은 56%으로 나타났다. 이는 PB와 IT에 포함된 여재의 여과, 침투 및 식생과 토양의 생물학적 흡수 기작 영향에 의해 나타난 결과로 판단된다. 이러한 연구 결과는 향후 빗물정원의 효율을 향상시키기 위 한 시설의 개선 및 설계방안으로 활용 가능할 것으로 평가된다.

Performance comparison of two hybrid stormwater treatment systems having different filter media configuration

ABSTRACT Stormwater best management practices (BMPs) commonly employ only one function that is sometimes insufficient to achieve its necessary efficiency. The method of integrating several functions of BMP technologies and incorporating them in one treatment system is referred to as hybrid BMP. This study developed, investigated, and compared the efficiency of two laboratory-scale hybrid BMP in reducing stormwater pollutants and runoff volume. The laboratory-scale hybrid BMPs developed were composed of treatment tanks arranged in series referred to as infiltration, storage or retention and final tanks that have different media configuration. Based on the results, both hybrid types were effectual in pollutant removal and flow volume reduction since both hybrid types significantly reduced the inflow volume and all pollutants including total suspended solids, chemical oxygen demand and total metals (p < 0.05). Hybrid type A was more advantageous for designs considering greater volume for groundwater recharge...

Implications of CaCl2 application to plants in LID facilities

Low impact development (LID) technologies mimic the natural water cycle through the physico-chemical and biological interactions of plants, filter media and soil, and microorganisms, thereby reducing the release of pollutants. In LID facilities, plants carry out photosynthesis, facilitate microbial growth, and uptake pollutants contained in stormwater runoff. However, de-icers (CaCl2) used to melt snow during winter slow the growth of plants and even increase plant mortality. In addition, de-icers change the soil structure, causing changes in soil content and affecting the growth of plants and microorganisms. Therefore, this study examined the effects of CaCl2 on the resistance of plants, the removal efficiency of non-point source pollutants, and water circulation. The mortality rate of the tree and shrubs caused by CaCl2 was found to be in the order of Rhododendron indicum > Spiraea prunifolia var. simpliciflora > Metasequoia glyptostroboides. For herbaceous plants, mortality rate was in the order of Pratia pedunculata > Aquilegia japonica > Tagetes erecta > Sedum makinoi aurea > Hosta longipes > Dianthus chinensis > Acorus gramineus > Liriope platyphylla. In addition, it was found that the amount of chlorophyll decreases with high concentrations of CaCl2. The findings of this research will be useful for plant selection considering CaCl2 concentrations applied to paved areas during the winter.

Impacts of nonpoint source pollutants on microbial community in rain gardens

Low-impact development (LID) techniques are being applied to reduce non-point source (NPS) pollution which are generated from various land uses. Cost-effective LID design requires consideration of influent runoff properties as well as physical and ecological pollutant-removing mechanisms. However, current LID technology design has failed to reflect the different properties of influent water from various land uses, and the biological design factors in LID facilities causing low efficiency and difficulties in maintenance. This study was conducted to identify biological design factors by analyzing the impact of the pollutants included in influent runoff and physical environment on microbial growth in rain garden facilities applied to different land uses. The results showed that the non-point source pollutant loadings were about 1.5-3 times higher in the runoff from parking lots, which are frequently visited by automobiles than in roof runoff. Type of soil, chemical species, and chemical composition were assessed as internal environmental factors having significant impact on the phylum and the count of microorganisms in the facilities. The growth of Cyanobacteria, Streptophyta, Chlorophyta, Bacillariophyta, and Xanthophyceae was good when there was appropriate water content in the soil, light, and sandy soil. Based on these results, the future design of rain garden facilities should be performed by considering a microorganism appropriate to the properties of the influent pollutants, determining appropriate water content, nutrient content and soil type, and choosing plants that contribute to microbial growth.