Measurements of assimilable organic carbon (AOC) in high saline conditions using P17

Mun, Eunjeong,Lee, Sangyoup,Kim, Inhyuk,Kwon, Boksoon,Park, Heedueng,Hong, Seungkwan IWA Publishing 2013 WATER SCIENCE AND TECHNOLOGY -WATER SUPPLY- Vol.13 No.2

sion='1.0' encoding='utf-8'?><!DOCTYPE article PUBLIC '-//NLM//DTD Journal Publishing DTD v2.3 20070202//EN' 'journalpublishing.dtd'><article article-type='research-article' xmlns:xlink='http://www.w3.org/1999/xlink'><front><journal-meta><journal-id journal-id-type='pmc'>ws</journal-id><journal-id journal-id-type='pubmed'>WS</journal-id><journal-id journal-id-type='publisher'>Water Science & Technology: Water Supply</journal-id><issn pub-type='ppub'>1606-9749</issn><publisher><publisher-name>IWA Publishing</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type='doi'>10.2166/ws.2013.019</article-id><article-id pub-id-type='other'>jWSTWS.v13.i2.pg265</article-id><article-categories><subj-group><subject>Research Article</subject></subj-group></article-categories><title-group><article-title>Measurements of assimilable organic carbon (AOC) in high saline conditions using P17</article-title></title-group><contrib-group><contrib contrib-type='author' rid='aff1'><name><surname>Mun</surname><given-names>Eunjeong</given-names></name><xref ref-type='aff' rid='aff1'></xref></contrib><contrib contrib-type='author' rid='aff1'><name><surname>Lee</surname><given-names>Sangyoup</given-names></name><xref ref-type='aff' rid='aff1'></xref></contrib><contrib contrib-type='author' rid='aff1'><name><surname>Kim</surname><given-names>Inhyuk</given-names></name><xref ref-type='aff' rid='aff1'></xref></contrib><contrib contrib-type='author' rid='aff2'><name><surname>Kwon</surname><given-names>Boksoon</given-names></name><xref ref-type='aff' rid='aff2'></xref></contrib><contrib contrib-type='author' rid='aff1'><name><surname>Park</surname><given-names>Heedueng</given-names></name><xref ref-type='aff' rid='aff1'></xref></contrib><contrib contrib-type='author' rid='aff1'><name><surname>Hong</surname><given-names>Seungkwan</given-names></name><xref ref-type='aff' rid='aff1'></xref></contrib><aff id='aff1'>School of Civil, Environmental & Architectural Engineering, Korea University, 1, 5-ga, Anam-Dong, Sungbuk-Gu, Seoul, 136-713, Korea E-mail: <email>skhong21@korea.ac.kr</email></aff><aff id='aff2'>Environment G. Emerging Tech, Center/SAIT Samsung Electronics, Korea</aff></contrib-group><volume>13</volume><issue>2</issue><fpage>265</fpage><lpage>272</lpage><history><date date-type='received'><day>30</day><month>4</month><year>2012</year></date><date date-type='accepted'><day>6</day><month>9</month><year>2012</year></date></history><permissions><copyright-statement>© IWA Publishing 2013</copyright-statement><copyright-year>2013</copyright-year></permissions><abstract ><P>Biofouling caused by the deposition or growth of microorganisms on the membrane surface is one of the major concerns in nanofiltration (NF) and reverse osmosis (RO) processes. Assimilable organic carbon (AOC) has been a useful index to assess the growth potential of bacteria. In the case of drinking water, the AOC assay method has been widely applied to estimate growth or regrowth potential of bacteria in distribution and storage systems. However, studies on AOC measurement for high salinity water samples such as brackish water and seawater are rather scarce. The objective of this research is to investigate the influence of water salinity on the conventional AOC assay method. AOC samples with different salt concentrations were prepared by varying NaCl concentration from 0 to 35,000 mg/L, while the acetate concentration was held at 100 μg/L. The number of cells produced in water samples was measured by the heterotrophic plate count (HPC) method using R2A agar. The result showed that the cell production of <I>Pseudomonas fluorescens</I> strain P17 and <I>Spirillum</I> strain NOX decreased with increasing salinity. Especially, the growth of <I>Spirillum</I> strain NOX was noticeably influenced by water salinity. To further observe the relation between acetate concentration and cell production in high salinity water, organic-free saline water

Nitrifying biocathode enables effective electricity generation and sustainable wastewater treatment with microbial fuel cell

Tran, Hung-Thuan,Kim, Dae-Hee,Oh, Se-Jin,Rasool, Kashif,Park, Doo-Hyun,Zhang, Rui-Hong,Ahn, Dae-Hee IWA Publishing 2009 Water Science & Technology Vol.59 No.9

<P>Simultaneous organics removal and nitrification using a novel nitrifying biocathode microbial fuel cell (MFC) reactor were investigated in this study. Remarkably, the introduction of nitrifying biomass into the cathode chamber caused higher voltage outputs than that of MFC operated with the abiotic cathode. Results showed the maximum power density increased 18% when cathode was run under the biotic condition and fed by nitrifying medium with alkalinity/NH4+-N ratio of 8 (26 against 22 mW/m2). The voltage output was not differentiated when NH4+-N concentration was increased from 50 to 100 mg/L under such alkalinity/NH4+-N ratio. However, interestingly, the cell voltage rose significantly when the alkalinity/NH4+-N ratio was decreased to 6. Consequently, the maximum power density increased 68% in compared with the abiotic cathode MFC (37 against 22 mW/m2). Polarization curves demonstrated that both activation and concentration losses were lowered during the period of nitrifying biocathode operation. Ammonium was totally nitrified and mostly converted to nitrate in all cases of the biotic cathode conditions. High COD removal efficiency (98%) was achieved. In light of the results presented here, the application of nitrifying biocathode is not only able to integrate the nitrogen and carbon removal but also to enhance the power generation in MFC system. Our system can be suggested to open up a new feasible way for upgrading and retrofitting the existing wastewater treatment plant by the use of MFC-based technologies.</P>

Statistical assessment for spatio-temporal water quality in Angkor, Cambodia

Ki, Seo Jin,Kang, Joo-Hyon,Lee, Young Geun,Lee, Yun Seok,Sthiannopkao, Suthipong,Kim, Joon Ha IWA Publishing 2009 Water Science & Technology Vol.59 No.11

<P>Comprehensive water quality monitoring was conducted to assess the water quality conditions and to determine the impact of urban infrastructure on ambient water quality in Angkor, Cambodia. During this study, surface water, groundwater, and sediment samples were collected for two distinctive seasons in 2006-2007 at 58 monitoring sites along and near the Siem Reap River, in Tole Sap Lake (TSL), and West Baray, the primary water resources in this region. To assess the seasonal and spatial variability of 27 water quality parameters, multivariate analysis of variance, hierarchical cluster analysis, and the Kruskal-Wallis test were conducted using the obtained data. Differences and relationships between the surface water and groundwater were also investigated using t-test and correlation analysis, respectively. The results of these tests showed that the bacterial indicators need special attention as the urban infrastructure of the downtown area caused increased levels of these bacterial indicators in both surface water and groundwater. However, for most parameters, though surface water showed strong seasonal variations, groundwater presented relatively stable conditions between seasons (p&gt;0.05) with site-specific geochemical conditions. Sediment quality illustrated that pollution levels of 10 trace metals were the highest in TSL because of its unique characteristic (river with backward flow), but did not reflect any potential enrichment from urban development. Overall, the results reveal that while the urban infrastructure in this region has not significantly affected most of the water quality parameters, bacteria and coliphages are still a main concern due to their contributions in widespread waterborne diseases. Thus, careful mitigation plans for reducing each pollutant source are needed in the Angkor area.</P>

Toxicity of artificial runoff fostered with dry deposition particulates from industrial, commercial, and highway area in Gwangju, Korea

Chung, N. T.,Ra, J. S.,Park, K.,Kim, D. W.,Kim, S. D. IWA Publishing 2009 Water Science & Technology Vol.59 No.11

<P>The adverse effects of rainwater and artificial urban runoff (an imitation of urban runoff during rainfall event) were investigated using a battery of bioassays employing three test species. Urban dusts were collected at three representative sites; commercial, industrial and highway areas. The water quality parameters of rainwater and artificial runoff revealed low hardness (23.4 ∼ 34.2 mg·L−1 as CaCO3) and alkalinity (7.0 ∼ 34.2 mg·L−1 as CaCO3). High toxicities were observed in the bioassays for the artificial runoffs. The average toxic units for D. magna, S. capricornutum, and O. latipes were 1.26(±0.84), 1.34(±1.10) and 2.05(±1.08), respectively. Of these species, O. latipes revealed significantly higher toxicity compared to D. magna and S. capricornutum (p&lt;0.05). Embryo lesions were observed with 6.25% treatments, and these significantly increased at 12.5% treatments (p&lt;0.05). The EC50 values for each artificial runoff were 22.5, 22.6 and 25.4% for commercial, industrial and highway areas, respectively. With 12.5% treatment, significant delays in hatching times were observed (p&lt;0.05); all embryos tested did not hatched at 100% treatment. Similarly, a significant decrease in hatching success was observed at every sampling point from 25% treatment (p&lt;0.05). The adverse effects of artificial runoff on the three test species suggests that urban surface runoff can cause significant impairment in aquatic ecosystems.</P>

Effects of ozone in treating drinking water by DAF system

Lee, Byoung-Ho,Song, Won-Chul,Ha, Jong-Gyu,Yang, Hyeon-Ju,Kim, Young-Suk IWA Publishing 2009 WATER SCIENCE AND TECHNOLOGY -WATER SUPPLY- Vol.9 No.3

<P>The Dissolved Air Flotation (DAF) process is very effective in removing low density floc particles for drinking water treatment. It is especially well known in removing turbidity and algae by flotation process. The micro-bubbles in the DAF process pick up small flocs, thereby turbidity materials and floated algae are removed efficiently. When air is substituted by ozone in the DAF process, the removal rates of water quality parameters are highly enhanced including turbidity and algae. The turbidity removal rate is enhanced by 1.1% while the removal rate of THMFP is increased by 11.7%. Other parameters such as TOC, and microbial agents are also removed greatly by using ozone instead of air in DAF system.</P>

Unit soil loss rate from various construction sites during a storm

Maniquiz, Marla C.,Lee, Soyoung,Lee, Eunju,Kong, Dong-Soo,Kim, Lee-Hyung IWA Publishing 2009 Water Science & Technology Vol.59 No.11

<P>The Korean Ministry of Environment (MOE) opts to establish an ordinance having a standard specifying an allowable soil loss rate applicable to construction projects. The predicted amount of soil loss from a construction site exceeding the standard can be used to calculate the percent reduction necessary to comply with the ordinance. This research was conducted to provide a basis to establish a standard by investigating the unit soil loss rates in the three phases of development: pre-construction, active construction and post construction based from 1,036 Environmental Impact Assessment (EIA) reports within the six-year period (2000-2005). Based on the findings, several factors affect the magnitude of soil loss rates particularly storm characteristics, site slope, soil type, location from rivers, as well as the type of construction activity. In general, the unit soil loss rates during the active construction phase are extremely higher in comparison to undisturbed areas; in magnitude of 7 to 80 times larger in urban areas and 18 to 585 times in rural areas. Only between 20 to 40 percent of the soil loss rates was contributed at pre- and post- construction phases indicating that the active construction phase is the most important phase to control.</P>

A new methodology for determining dispersion coefficient using ordinary and partial differential transport equations

Cho, Kyung Hwa,Lee, Seungwon,Ham, Young Sik,Hwang, Jin Hwan,Cha, Sung Min,Park, Yongeun,Kim, Joon Ha IWA Publishing 2009 Water Science & Technology Vol.59 No.11

<P>The present study proposes a methodology for determining the effective dispersion coefficient based on the field measurements performed in Gwangju (GJ) Creek in South Korea which is environmentally degraded by the artificial interferences such as weirs and culverts. Many previous works determining the dispersion coefficient were limited in application due to the complexity and artificial interferences in natural stream. Therefore, the sequential combination of N-Tank-In-Series (NTIS) model and Advection-Dispersion-Reaction (ADR) model was proposed for evaluating dispersion process in complex stream channel in this study. The series of water quality data were intensively monitored in the field to determine the effective dispersion coefficient of E. coli in rainy day. As a result, the suggested methodology reasonably estimates the dispersion coefficient for GJ Creek with 1.25 m2/s. Also, the sequential combined method provided Number of tank-Velocity-Dispersion coefficient (NVD) curves for convenient evaluation of dispersion coefficient of other rivers or streams. Comparing the previous studies, the present methodology is quite general and simple for determining the effective dispersion coefficients which are applicable for other rivers and streams.</P>

Evaluation of pollutants removal efficiency to achieve successful urban river restoration

Cha, Sung Min,Ham, Young Sik,Ki, Seo Jin,Lee, Seung Won,Cho, Kyung Hwa,Park, Yongeun,Kim, Joon Ha IWA Publishing 2009 Water Science & Technology Vol.59 No.11

<P>Greater efforts to provide alternative scenarios are key to successful urban stream restoration planning. In this study, we discuss two different aspects of water quality management schemes, biodegradation and human health, which are incorporated in the restoration project of original, pristine condition of urban stream at the Gwangju (GJ) Stream, Korea. For this study, monthly monitoring of biochemical oxygen demand (BOD5) and fecal indicator bacteria (FIB) data were obtained from 2003 to 2008 and for 2008, respectively, and these were evaluated to explore pollutant magnitude and variation with respect to space and time window. Ideal scenarios to reduce target pollutants were determined based on their seasonal characteristics and correlations between the concentrations at a water intake and discharge point, where we suggested an increase of environmental flow and wetland as pollutants reduction drawing for BOD5 and FIB, respectively. The scenarios were separately examined by the Qual2E model and hypothetically (but planned) constructed wetland, respectively. The results revealed that while controlling of the water quality at the intake point guaranteed the lower pollution level of BOD5 in the GJ Stream, a wetland constructed at the discharge point may be a promising strategy to mitigate mass loads of FIB. Overall, this study suggests that a combination of the two can be plausible scenarios not only to support sustainable urban water resources management, but to enhance a quality of urban stream restoration assignment.</P>

A systematic approach to data-driven modeling and soft sensing in a full-scale plant

Kim, M. H.,Kim, Y. S.,Prabu, A. A.,Yoo, C. K. IWA Publishing 2009 Water Science & Technology Vol.60 No.2

<P>The well-known mathematical modeling and neural networks (NNs) methods have limitations to incorporate the key process characteristics at the wastewater treatment plants (WWTPs) which are complex, non-stationary, temporal correlation, and nonlinear systems. In this study, a systematic methodology of NNs modeling which can be efficiently included in the key modeling information of the WWTPs is performed by selecting the temporal effect of the hydraulics based on multi-way principal components analysis (MPCA). The proposed method is applied for modeling wastewater quality of a full-scale plant, which is a Daewoo nutrient removal (DNR) process. Through the experimental results in a full-scale plant, the efficiency of the proposed method is evaluated and the prediction capability is highly improved by the inclusion of the hydraulics term due to the optimized structure of neural networks.</P>

Effect of ultrasonic treatment on swine wastewater solubilization

Lee, Y. H.,Kim, S.-M.,Na, S.,So, K.-H.,Nam, J.-J. IWA Publishing 2009 Water Science & Technology Vol.59 No.3

<P>In order to accelerate hydrolysis known to be the rate-limiting step of the overall digestion process for swine wastewater, an ultrasonic treatment process was tested for the solubilization of the swine wastewater. The effectiveness of ultrasonic solubilization of the swine wastewater under various operational conditions was compared by means of an increment of soluble organics in the treated swine wastewater and the hydrolysis rate constant. Ultrasonic treatment resulted in the high degree of solubilization of particulate organics in the swine wastewater and the degree of solubilization increased with increasing supplied energy. The highest extent of an increment of SCOD concentration and SCOD/TCOD ratio at the end of the operation time of 60 min was 109.7 and 117.5%, respectively, under 120 W power output and 20oC operating temperature conditions. The observed highest hydrolysis rate constant described by pseudo-first order rate constant was 2.94 h−1 under the same conditions. Based on the estimated activation energy from modeling using the Arrhenius equation, ultrasonic solubilization of the swine wastewater under higher supplied energy conditions was more dependent on the operating temperature, which was consistent with the experimentally obtained results. Based on the investigation into the effect of gas type and gas delivery methods for ultrasonic solubilization of the swine wastewater, oxygen gas bubbling through the liquid showed the highest degree of an increment of soluble organics possibly attributed to the influent of oxygen in an increase of radicals during the sonolysis.</P>