Analysis of hydrocyclone behaviors in the separation of particulates from highway rainfall runoff

Yu, Jianghua,Yi, Qitao,Kim, Youngchul,Tateda, Masafumi IWA Publishing 2010 Water Science & Technology Vol.62 No.3

<P>In this study, the separation behaviors of particles in highway rainfall runoff using a Ø7.5 cm hydrocyclone were examined. The volume fraction and the total suspended solids concentrations in the overflow and underflow from the hydrocyclone were analyzed. The results indicated that the overflow volume fraction increased with increasing operational pressure, but decreased with decreasing ratio of underflow outlet to inlet sizes (Du/Di), while the underflow volume fraction showed contrary behavior. The TSS concentration ratio between the overflow and inflow (TSSover/TSSin) decreased as a function of the operational pressure, while the corresponding ratio of underflow to inflow (TSSunder/TSSin) increased. There was no visible difference in the TSSover/TSSin ratio with increasing Du/Di ratio but the TSSunder/TSSin decreased sharply. The particle removal efficiency was affected mainly by the particle size. The hydrocyclone can work well using 1.6 m natural water head, and it is more space saving and more efficient in the separation of fine particles than the sedimentation method.</P>

Post-treatment schemes of the outflow from hydrocyclone treating paved-road stormwater runoff

Yu, Jianghua,Yu, Haixia,Chen, Yaoping,Cheng, Jing,Kim, Youngchul Informa UK (Taylor Francis) 2013 Desalination and water treatment Vol.51 No.19

Performance Evaluation and Modeling of Synthetic-Fiber Barrier in the Treatment of Turbid Water

Yu, Jianghua,Kim, Youngchul Wiley (John WileySons) 2013 Water environment research Vol.85 No.7

<P>A synthetic-fiber barrier for the removal of turbidity in water was developed and tested using a laboratory scale channel. The effects of hydraulics (flow rate and exchange rate); density current caused by temperature and turbidity difference; barrier conditions (thickness, number and shape); and particle size were analyzed. The experimental results indicated that removal efficiency was positively related to barrier thickness and number, was inversely related to the strength of the density current, and was also negatively affected by the flow rate and exchange rate. A wedged barrier was found to work better than a rectangular one when the same amount of fiber was used. Based on the experimental work, empirical models for the removal efficiency and barrier design were established using dimensionless groups. The modeling results indicated that the predicted values were consistent with the experimental work and the increases and decreases in the performance were suitably simulated.</P>

The seasonal characterization of highway particulate pollutants by size fraction

Yu, Jianghua,Yi, Qitao,Kim, Y. Informa UK (Taylor Francis) 2010 Desalination and Water Treatment Vol.19 No.1

수리동력학적 분리장치에 의한 고속 도로 강우유출수의 전처리 기술

우강화(Yu, Jianghua),이치타오(Yi, Qitao),김필주(Kim, Phil-Ju),여미미(Lu, Wei Wei),박성순(Park, Sung-Soon),김영철(Kim, Y.C.) 한국산학기술학회 2009 한국산학기술학회 학술대회 Vol.- No.-

고속도로 교량이나 성토지역 노면이 제공하는 자연적인 위치에너지(동력)를 활용하여 수리학적인 입자상 오염물질 분리장치를 실험실 조건에서 운전한 결과 운전압력 0.5기압(수두 5.6m) 이상에서 90% 이상의 제거효율을 보였다. D50는 약45μm이었는데 입자의 크기가 45 μm 보다 굵은 입자는 거의 대부분제거되지만 45 μm보다 작은 입자의 제거는 쉽지 않음을 시사해주고 있다. 이러한 입자를 제거하기 위한 후속장치가 필요하며 장치의 원활한 운전을 위해서 유지관리문제에 대한 치밀한 검토가 필요하다.

Variation of Flow and Filtration Mechanisms in an Infiltration Trench Treating Highway Stormwater Runoff

Heidi B. Guerra,Jianghua Yu,김영철 한국습지학회 2018 한국습지학회지 Vol.20 No.1

The particle filtration mechanisms in an infiltration trench should be varying due to the different hydraulic conditions during stormwater runoff. The understanding of these variations associated with different filtration mechanisms and their effect on the particle removal efficiency is of vital importance. Therefore, a LID (Low Impact Development) system comprising of an infiltration trench packed with gravel and woodchip was investigated during the monitoring of several independent rainfall events. A typical rainfall event was divided into separate regimes and their corresponding flow conditions as well as filtration mechanisms in the trench were analyzed. According to hydraulic conditions, it was found out that filtration changes between vertical and horizontal flows as well as between unsaturated, saturated, and partially-saturated flows. Particle separation efficiency was high (55-76%) and was mainly governed by physical straining during the unsaturated period. It was then enhanced by diffusion during the saturated period (75-95%). When the trench became partially saturated at the end of the rainfall event, the efficiency decreased which was believed to be due to the existence of a negatively charged air-water interface which limited the removal to positively charged particles.

Enhancement of the electro-Fenton degradation of organic contaminant by accelerating Fe3+/Fe2+ cycle using hydroxylamine

Dong Li,Tong Zheng,Jianghua Yu,Haiyang He,Wei Shi,Jun Ma 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.105 No.-

The Electro-Fenton process can generate reactive oxygen species capable of oxidizing refractory organiccontaminants. However, low regeneration efficiency of Fe2+ restricts its application. Herein, hydroxylamine(HA) was added into the Electro-Fenton (HA/Electro-Fenton) process to accelerate the transformationof Fe3+ to Fe2+. Using dimethyl phthalate (DMP) as target contaminant, the HA/Electro-Fenton systemalleviated the two-stage reaction process and accelerated the removal of DMP in the pH range of 2.0–6.0. With improving DMP concentration from 5 mg L-1 to 50 mg L-1, their degradation rate increased in theHA/Electro-Fenton system, while decreased in the Electro-Fenton system. The addition of HA had negligibleeffect on electro-generation of H2O2, but facilitate the redox cycle of Fe3+/Fe2+ and the generation ofhydroxyl radicals, thus improving the degradation of DMP. The final transformation products of HA wereN2, N2O, and NO3. The presence of PO4 3 improved DMP degradation, while Cl and organic matters inhibitedDMP removal in varying degrees. This study provided useful reference to solve the low efficiency ofFe3+/Fe2+ cycle and expand the pH application range in the Electro-Fenton process.

Particle Size Dependent Heavy Metals in Road Dusts from Maanshan City, China

Siping Niu,Xiaolong Song,Jianghua Yu,Xuan Wang,Jianjun Lian 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.5

In this study the road dusts (RDs) <1,000 μm from Maanshan City, China were characterized from the prospects of size fractionated pollution by heavy metals (HMs). Particulates with size <75 μm, 75 − 125 μm, 125 − 250 μm, 250 − 500 μm and 500 − 1,000 μm averagely accountedfor 35.7±11.7%, 14.6±11.0%, 25.3±12.5%, 11.6±8.8% and 12.8±12.9% of the total weight, respectively. This result implies the gravimetric percentage was overall declined with increasing granular size, following gamma distribution function (p < 0.001). It was observed that the highest contents of Zn, Ni, Pb and Cd occurred with the fine RDs <75 μm while Cu with these <125 μm, suggesting HMs preferred to be associated with the fine particulates. Cu, Zn, Ni, Pb, Cr and Cd were present in RDs with bulk contents of 68±30 mg/kg, 285±122 mg/kg, 23±16 mg/kg, 53±21 mg/kg, 432+297 mg/kg and 0.56±0.39 mg/kg, which resulted in geo-accumulation index (Igeo) values as -1.04, 2.35, -2.38, 0.38, 1.54 and 0.18, respectively. Hence, it can be concluded that the RDs had only been significantly polluted by Zn. Person correlation analysis suggests those HMs ubiquitously present in RDs had size-dependent sources.

섬모상 매트에 의한 저수지와 댐에서 탁수확산차단 기술의 개발

이치타오(Yi, Qitao),우강화(Yu, Jianghua),박성순(Park, Sung-Soon),김영철(Kim, Y.C.) 한국산학기술학회 2009 한국산학기술학회 학술대회 Vol.- No.-

This study presented a lab-scale apparatus for turbidity control in the lakes or reservoirs. Overall, the filamentous mat had a capture efficiency of 70∼90% compared with the control group. Generally, the capture efficiency decreased with improved input turbidity flux. However, the attachment and sedimentation were thought to be the main processes for turbidity water retention and removal. Thus, the increase of hydraulic detention time in the mat zone is very important to improve the capture efficiency of the turbidity water.

eDNA-based bioassessment of coastal sediments impacted by an oil spill

Xie, Yuwei,Zhang, Xiaowei,Yang, Jianghua,Kim, Seonjin,Hong, Seongjin,Giesy, John P.,Yim, Un Hyuk,Shim, Won Joon,Yu, Hongxia,Khim, Jong Seong Elsevier 2018 Environmental pollution Vol.238 No.-

<P><B>Abstract</B></P> <P>Oil spills offshore can cause long-term ecological effects on coastal marine ecosystems. Despite their important ecological roles in the cycling of energy and nutrients in food webs, effects on bacteria, protists or arthropods are often neglected. Environmental DNA (eDNA) metabarcoding was applied to characterize changes in the structure of micro- and macro-biota communities of surface sediments over a 7-year period since the occurrence of <I>Hebei Spirit</I> oil <I>spil</I>l on December 7, 2007. Alterations in diversities and structures of micro- and macro-biota were observed in the contaminated area where concentrations of polycyclic aromatic hydrocarbons were greater. Successions of bacterial, protists and metazoan communities revealed long-term ecological effects of residual oil. Residual oil dominated the largest cluster of the community-environment association network. Presence of bacterial families (<I>Aerococcaceae</I> and <I>Carnobacteriaceae</I>) and the protozoan family (<I>Platyophryidae</I>) might have conferred sensitivity of communities to oil pollution. Hydrocarbon-degrading bacterial families (<I>Anaerolinaceae</I>, <I>Desulfobacteraceae</I>, <I>Helicobacteraceae</I> and <I>Piscirickettsiaceae</I>) and algal family (<I>Araphid pennate</I>) were resistant to adverse effects of spilt oil. The protistan family (<I>Subulatomonas</I>) and arthropod families (<I>Folsomia</I>, <I>Sarcophagidae Opomyzoidea,</I> and <I>Anomura</I>) appeared to be positively associated with residual oil pollution. eDNA metabarcoding can provide a powerful tool for assessing effects of anthropogenic pollution, such as oil spills on sediment communities and its long-term trends in coastal marine environments.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Long-term ecological impact on coastal sediment community by an oil spill were accessed by eDNA metabarcoding. </LI> <LI> Residual oils altered the alpha-diversity, beta-diversity and compositions of multiple sedimentary communities. </LI> <LI> The largest cluster of the sedimentary community-environment association network was dominated by residual oils. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>