@article{kang_mclaughlin_2020, title={Polyacrylamide and Chitosan Biopolymer for Flocculation and Turbidity Reduction in Soil Suspensions}, volume={28}, ISSN={["1572-8919"]}, DOI={10.1007/s10924-020-01682-2}, number={4}, journal={JOURNAL OF POLYMERS AND THE ENVIRONMENT}, author={Kang, Jihoon and McLaughlin, Richard A.}, year={2020}, month={Apr}, pages={1335–1343} }
 @article{kang_vetter_mclaughlin_2018, title={Chemical Treatment to Reduce Turbidity in Pumped Construction Site Water}, volume={144}, ISSN={["1943-7870"]}, DOI={10.1061/(ASCE)EE.1943-7870.0001498}, abstractNote={AbstractMany construction projects need to pump turbid water from borrow pits or other excavations into stilling basins or sediment filter bags prior to discharge. This study evaluated the effectiv...}, number={12}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING}, author={Kang, Jihoon and Vetter, Joshua W. and McLaughlin, Richard A.}, year={2018}, month={Dec} }
 @article{kang_king_mclaughlin_wiseman_2014, title={Flocculated sediment and runoff quality improvement by polyacrylamide}, volume={57}, DOI={10.13031/trans.57.10532}, abstractNote={<abstract> <bold><sc>Abstract.</sc></bold> Increasing regulations on construction site runoff requires improved sediment and erosion control practices, including the application of polyacrylamide (PAM) to enhance turbidity reduction. We evaluated water quality improvement and particle size distribution of suspended sediments affected by various types of passive PAM dosing under simulated stormwater flows. Three straw wattles were installed in a 7% sloped channel, and six different treatments were tested individually: (1) wattle with no jute netting and no PAM, (2) solid block PAM (BPAM) after the wattle + no jute netting, (3) granular PAM (GPAM) on wattles + no jute netting, (4) wattle + jute netting with no PAM, (5) wattle + jute netting where GPAM was applied to the wattle, and (6) wattle + jute netting where GPAM was applied to the jute netting. For each treatment, three repeated turbid stormwater flows were run in the channel, and water samples were collected from the entrance (influent) and exit (effluent) of the channel. There was no turbidity reduction with wattles and/or jute netting unless PAM was introduced to the channel system. The use of GPAM reduced effluent turbidity by 58% to 67% relative to influent, with the best treatment being GPAM on jute netting. The addition of jute netting to the GPAM + wattle treatment did not improve sediment reduction but did reduce turbidity. Applying GPAM to jute netting shifted the mean particle size from 24 to 211 μm and the 10th percentile from 1.6 to 66 μm, indicating the greatly increased particle size distribution of the flocculated sediment. This study emphasizes that the passive treatment of stormwater runoff using GPAM is a very effective method of flocculating sediments in turbid water.}, number={3}, journal={Transactions of the ASABE}, author={Kang, J. and King, S. E. and McLaughlin, R. A. and Wiseman, J. D.}, year={2014}, pages={861–867} }
 @article{kang_amoozegar_heitman_mclaughlin_2014, title={Granular and Dissolved Polyacrylamide Effects on Erosion and Runoff under Simulated Rainfall}, volume={43}, ISSN={["1537-2537"]}, DOI={10.2134/jeq2014.01.0022}, abstractNote={Polyacrylamide (PAM) has been demonstrated to reduce erosion under many conditions, but less is known about the effects of its application method on erosion and concentrations in the runoff water. A rainfall simulation study was conducted to evaluate the performance of an excelsior erosion control blanket (cover) and two PAM application methods. The treatments were (i) no cover + no PAM (control), (ii) cover + no PAM, (iii) cover + granular PAM (GPAM), and (iv) cover + dissolved PAM (DPAM) applied to soil packed in wooden runoff boxes. The GPAM or DPAM (500 mg L) was surface-applied at a rate of 30 kg ha 1 d before rainfall simulation. Rainfall was applied at 83 mm h for 50 min and then repeated for another 20 min after a 30-min rest period. Runoff samples were analyzed for volume, turbidity in nephelometric turbidity units (NTU), total suspended solids (TSS), sediment particle size distribution, and PAM concentration. The cover alone reduced turbidity and TSS in runoff by >60% compared with the control (2315 NTU, 2777 mg TSS L). The PAM further reduced turbidity and TSS by >30% regardless of the application method. The median particle diameter of eroded sediments for PAM treatments was seven to nine times that of the control (12.4 μm). Loss of applied PAM in the runoff water (not sediment) was 19% for the GPAM treatment but only 2% for the DPAM treatment. Both GPAM and DPAM were effective at improving groundcover performance, but DPAM resulted in much less PAM loss.}, number={6}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Kang, Jihoon and Amoozegar, Aziz and Heitman, Joshua L. and McLaughlin, Richard A.}, year={2014}, pages={1972–1979} }
 @article{kang_king_mclaughlin_2014, title={Impacts of flocculation on sediment basin performance and design}, volume={57}, DOI={10.13031/trans.57.10652}, abstractNote={Abstract. There is increasing interest in controlling turbidity in construction site runoff using chemical flocculant treatments. Since flocculated sediment is likely to behave much differently from untreated sediment, changes to current sediment basin designs may be appropriate. This study evaluated a system consisting of three fiber check dams in a lined ditch discharging to sediment basins that differed in their configuration. Three different basin configurations were tested with and without granular polyacrylamide (PAM) applied to the weir of each check dam: (1) standard basin with a 2:1 length to width (L/W) ratio, (2) horizontal basin with a 1:2 L/W ratio, and (3) standard basin with a rising floor toward the exit (spillway). All configurations included two porous baffles of jute/coir netting across the full width of the basin. For each treatment of PAM and basin configuration, sediment-laden stormwater flows (0.014 to 0.056 m 3 s -1 ) were introduced to the ditch for 29 min, and water samples were collected at the ditch entrance (influent), ditch exit, and basin exit. Regardless of PAM treatment, total suspended solids (TSS) concentrations were reduced by more than 55% at the ditch exit and by up to 90% at the basin exit relative to the influent (3,700 mg L -1 ). The 1:2 L/W basin reduced TSS more than either of the 2:1 L/W basins without flocculation, but there was no significant difference in TSS when sediment was treated with PAM. Turbidity at the ditch exit was similar to the influent (less than 10% difference) without flocculation but was greatly reduced (>66%) with flocculation. The PAM treatment lowered turbidity further (>88%) at the basin exit and was similar among all basin configurations. The particle size distribution of flocculated sediment was shifted into coarser fractions, enhancing settling in the basin. The estimation of basin surface area requirement based on the measured particle size suggested that basins receiving flocculated sediment could be reduced in surface area and altered in configuration while improving water quality for construction site discharges.}, number={4}, journal={Transactions of the ASABE}, author={Kang, J. and King, S. E. and McLaughlin, R. A.}, year={2014}, pages={1099–1107} }
 @article{kang_mccaleb_mclaughlin_2013, title={Check dam and polyacrylamide performance under simulated stormwater runoff}, volume={129}, ISSN={["1095-8630"]}, DOI={10.1016/j.jenvman.2013.08.023}, abstractNote={High levels of turbidity and fine suspended sediments are often found in stormwater discharges from construction sites even when best management practices (BMPs) for sediment control are in place. This study evaluated turbidity reduction by three check dam types: 1) rock check dam representing a standard BMP, 2) excelsior wattle representing a fiber check dam (FCD), and 3) rock check dam wrapped with excelsior erosion control blanket (rock + excelsior ECB) representing an alternative FCD. Three check dams (all same type) were installed in a lined, 24-m ditch on a 5–7% slope and three consecutive simulated stormwater flows were run in the ditch. Additional tests were performed by adding granular polyacrylamide (PAM) on the check dams in the same manner using two sediment sources differing in clay content. Without PAM treatment, significantly higher effluent turbidity (>900 nephelometric turbidity units (NTU)) exited the ditch with rock check dams than with excelsior wattles or rock + excelsior ECBs (<440 NTU). The extent of sediment deposition between the check dam types was in the order of excelsior wattle > rock + excelsior ECB > rock check dam, indicating better water pooling behind the wattle. The PAM treatment reduced turbidity substantially (>75% relative to no PAM treatment) for all check dam types and it was very effective in excelsior wattles (<57 NTU) and rock + excelsior ECBs (<90 NTU) even during the third storm event. This study demonstrates that the passive treatment of runoff with PAM on FCDs (or rock + excelsior ECB) in construction site ditches can be very effective for sediment retention and turbidity reduction.}, journal={JOURNAL OF ENVIRONMENTAL MANAGEMENT}, author={Kang, Jihoon and McCaleb, Melanie M. and McLaughlin, Richard A.}, year={2013}, month={Nov}, pages={593–598} }
 @article{chae_kang_2013, title={Estimating the energy independence of a municipal wastewater treatment plant incorporating green energy resources}, volume={75}, ISSN={["1879-2227"]}, DOI={10.1016/j.enconman.2013.08.028}, abstractNote={Increasing energy prices and concerns about global climate change highlight the need to improve energy independence in municipal wastewater treatment plants (WWTPs). This paper presents methodologies for estimating the energy independence of a municipal WWTP with a design capacity of 30,000 m3/d incorporating various green energy resources into the existing facilities, including different types of 100 kW photovoltaics, 10 kW small hydropower, and an effluent heat recovery system with a 25 refrigeration ton heat pump. It also provides guidance for the selection of appropriate renewable technologies or their combinations for specific WWTP applications to reach energy self-sufficiency goals. The results showed that annual energy production equal to 107 tons of oil equivalent could be expected when the proposed green energy resources are implemented in the WWTP. The energy independence, which was defined as the percent ratio of green energy production to energy consumption, was estimated to be a maximum of 6.5% and to vary with on-site energy consumption in the WWTP. Implementing green energy resources tailored to specific site conditions is necessary to improve the energy independence in WWTPs. Most of the applied technologies were economically viable primarily because of the financial support under the mandatory renewable portfolio standard in Korea.}, journal={ENERGY CONVERSION AND MANAGEMENT}, author={Chae, Kyu-Jung and Kang, Jihoon}, year={2013}, month={Nov}, pages={664–672} }
 @article{kang_sowers_duckworth_amoozegar_heitman_mclaughlin_2013, title={Turbidimetric Determination of Anionic Polyacrylamide in Low Carbon Soil Extracts}, volume={42}, ISSN={["1537-2537"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84887582502&partnerID=MN8TOARS}, DOI={10.2134/jeq2013.07.0279}, abstractNote={Concerns over runoff water quality from agricultural lands and construction sites have led to the development of improved erosion control practices, including application of polyacrylamide (PAM). We developed a quick and reliable method for quantifying PAM in soil extracts at low carbon content by using a turbidimetric reagent, Hyamine 1622. Three high-molecular weight anionic PAMs differing in charge density (7, 20, and 50 mol%) and five water matrices, deionized (DI) water and extracts from four different soils, were used to construct PAM calibration curves by reacting PAM solutions with hyamine and measuring turbidity development from the PAM-hyamine complex. The PAM calibration curve with DI water showed a strong linear relationship ( = 0.99), and the sensitivity (slope) of calibration curves increased with increasing PAM charge density with a detection limit of 0.4 to 0.9 mg L. Identical tests with soil extracts showed the sensitivity of the hyamine method was dependent on the properties of the soil extract, primarily organic carbon concentration. Although the method was effective in mineral soils, the highest charge density PAM yielded a more reliable linear relationship ( > 0.97) and lowest detection limit (0.3 to 1.2 mg L), compared with those of the lower charge density PAMs (0.7 to 23 mg L). Our results suggest that the hyamine test could be an efficient method for quantifying PAM in environmental soil water samples as long as the organic carbon in the sample is low, such as in subsurface soil material often exposed at construction sites.}, number={6}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Kang, Jihoon and Sowers, Tyler D. and Duckworth, Owen W. and Amoozegar, Aziz and Heitman, Joshua L. and McLaughlin, Richard A.}, year={2013}, pages={1902–1907} }
 @article{hashimoto_kang_matsuyama_saigusa_2012, title={Path Analysis of Phosphorus Retention Capacity in Allophanic and Non-allophanic Andisols}, volume={76}, ISSN={["1435-0661"]}, DOI={10.2136/sssaj2011.0196}, abstractNote={Andisols derived from volcanic ash minerals are characterized by a high P retention capacity (PRC). The PRC of soil is often correlated with various soil properties, and a simple correlation analysis alone may not necessarily explain the direct cause and effect relationships between soil properties and PRC values. The objectives of this study were to determine which soil properties best explain the variability in the PRC of allophanic and non-allophanic Andisols using path analysis. A total of 671 Japanese Andisols were used in this study. The PRC values were determined for allophanic and non-allophanic soil samples, along with pH, organic matter (OM) contents, acid ammonium oxalate extractable Al (Al ox ) and Fe (Fe ox ), and pyrophosphate-extractable Al (Al p ) and Fe (Fe p ). The PRC value of allophanic soils was correlated with Al ox (r = 0.72) and Fe ox (r = 0.56). Path analysis revealed, however, that Al ox was the single most important direct effect on PRC, and the correlation between PRC and Fe ox was mostly partitioned to an indirect effect through Al ox . According to path analysis on non-allophanic soils, Al p was the single most important causal factor in predicting PRC, and the correlation between Al ox and PRC (r = 0.77) was mostly partitioned to an indirect effect through Al p . The correlation between OM and PRC was attributable to organically bound Al in allophanic soils by the indirect effect of Al p on PRC through OM. Pyrophosphate extraction may be a better indicator than oxalate extraction for predicting PRC in non-allophanic Andisols.}, number={2}, journal={SOIL SCIENCE SOCIETY OF AMERICA JOURNAL}, author={Hashimoto, Yohey and Kang, Jihoon and Matsuyama, Nobuhiko and Saigusa, Masahiko}, year={2012}, month={Mar}, pages={441–448} }
 @article{kang_amoozegar_hesterberg_osmond_2011, title={Phosphorus leaching in a sandy soil as affected by organic and inorganic fertilizer sources}, volume={161}, ISSN={["0016-7061"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-79951581004&partnerID=MN8TOARS}, DOI={10.1016/j.geoderma.2010.12.019}, abstractNote={Long-term application of phosphorus (P) to soils as fertilizer or manure can increase the potential for P loss to ground and surface waters. Vertical P transport was investigated in a sandy soil material receiving seven different P fertilizer sources: poultry compost, poultry litter, triple superphosphate [Ca(H2PO4)2·H2O], dairy lagoon liquid, swine lagoon liquid, swine lagoon sludge, and dissolved potassium dihydrogen phosphate (KH2PO4). The P sources were surface-applied to soil columns (6.35-cm diameter, 10-cm long) at two rates equivalent to 75 and 150 kg total P ha−1, and columns were intermittently leached with deionized (DI) water. Column effluents were collected for up to 23 pore volumes and analyzed for dissolved reactive phosphorus (DRP) and dissolved organic carbon (DOC). In addition, a P retardation factor was determined for the soil from a P adsorption isotherm. Transport of P through soil columns receiving liquid P sources was simulated by a one-dimensional equilibrium convective–dispersive equation (CDE) based on water-extractable P (WEP) concentrations. Cumulative amounts of DRP leached were linearly related to the amounts of WEP in P source materials (r2 = 0.87***). The recovery of DRP in the column effluents relative to WEP in the applied materials was 126 ± 15% (mean ± standard error) for organic P sources and 66 ± 2% for inorganic P sources. The use of WEP in the CDE model underpredicted P transport in the columns amended with lagoon liquids compared with dissolved KH2PO4. Results indicated that leaching losses of P from land-applied manures exceed the amounts of WEP in source materials because of organic P mineralization and competitive sorption of DOC.}, number={3-4}, journal={GEODERMA}, author={Kang, Jihoon and Amoozegar, Aziz and Hesterberg, Dean and Osmond, Deanna L.}, year={2011}, month={Mar}, pages={194–201} }
 @article{kang_hesterberg_osmond_2009, title={Soil Organic Matter Effects on Phosphorus Sorption: A Path Analysis}, volume={73}, ISSN={["1435-0661"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-62549111344&partnerID=MN8TOARS}, DOI={10.2136/sssaj2008.0113}, abstractNote={While P sorption in mineral soils has been extensively studied, P sorption behavior in organic‐rich soils is less known. This study was conducted to determine the relationships between Langmuir P sorption maxima (Smax) and selected physicochemical properties of soils, with particular emphasis on organic matter (OM) content. The Smax values were determined for 72 soil samples from the North Carolina Coastal Plain, along with pH, clay and OM contents, oxalate‐extractable P (Pox), Al (Alox), and Fe (Feox), and Mehlich 3 extractable P (PM3), Al (AlM3), and Fe (FeM3). Path analysis was used to examine direct and indirect effects of soil properties on Smax In the oxalate path analysis, the direct effects of clay, Alox, and Feox on Smax were significant in the order Alox > clay > Feox (P < 0.05). The Smax was highly influenced by the indirect effect of Alox and Feox through OM content. A two‐piece segmented linear relationship existed between Smax and OM and the regression slope in soils with OM ≤ 49 g kg−1 was 10‐fold greater than that for soils with OM > 49 g kg−1 This finding suggested that noncrystalline or organically bound Al and Fe in the soils with OM > 49 g kg−1 is less effective for P sorption than in the soils with lower OM content. In the Mehlich 3 path analysis, the direct effects of clay, OM, and AlM3 on Smax were significant in the order AlM3 > OM > clay (P < 0.05) while the direct effect of FeM3 on Smax was not significant. Oxalate may be better suited than Mehlich 3 as an extractant for predicting P sorption capacity in the Coastal Plain soils.}, number={2}, journal={SOIL SCIENCE SOCIETY OF AMERICA JOURNAL}, author={Kang, Jihoon and Hesterberg, Dean and Osmond, Deanna L.}, year={2009}, pages={360–366} }