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Effect of coagulation conditions on ultrafiltration for wastewater effluent
Maeng, Sung Kyu,Timmes, Thomas C.,Kim, Hyun-Chul Techno-Press 2017 Membrane Water Treatment Vol.8 No.2
Low-pressure membrane filtration is increasingly used for tertiary treatment of wastewater effluent organic matter (EfOM), mainly comprising organic base/neutral compounds. In-line coagulation with underdosing, charge neutralization, and sweep floc conditions prior to ultrafiltration (UF) was studied to determine removals of the EfOM components and consequent reduction of fouling using polyethersulfone membranes. Coagulation and UF substantially reduced fouling for all coagulation conditions while removing from 7 to 38% of EfOM organic acids. From 7 to 16% of EfOM organic base/neutrals were removed at neutral pH but there was no significant removal for slightly acid coagulation conditions even though fouling was substantially reduced. Sweep floc produced the lowest resistance to filtration but may be inappropriate for in-line use due to the large added volume of solids. Charge-neutralization resulted in poor recovery of the initial flux with hydraulic cleaning. Under-dosing paralleled sweep floc in reducing hydraulic resistance to filtration (for sub-critical flux) and the initial flux was also easily recovered with hydraulic cleaning. Hydrophobic and hydrophilic base/neutrals were identified on the fouled membranes but as previously reported the extent of fouling was not correlated with accumulation of organic base/neutrals.
Maeng, Sung Kyu,Timmes, Thomas C.,Kim, Hyun-Chul Informa UK (TaylorFrancis) 2017 Environmental technology Vol.38 No.20
<P>Two different quaternary amine polymers were examined as primary coagulants for the removal of natural organic matter (NOM) and concurrent production of flocs favorable for downstream membrane separation. The primary issue explored was the relationship between various coagulation conditions on the floc characteristics and the subsequent performance of microfiltration when filtering coagulated NOM. The size distribution and morphological properties of flocs formed through the coagulation of NOM were characterized and the effects of polymer type and dose on these characteristics were also examined. Coagulation of NOM using polydiallyldimethyl-ammonium chloride (pDADMAC) produced looser and less settleable flocs compared to dosing the equivalent amount of epichlorohydrin/dimethylamine (epi/DMA). This was associated with the formation of a relatively denser cake layer on the top of the membrane for the filtration of NOM coagulated with epi/DMA. The charge neutralization coagulation condition with the polymers removed almost all of the fouling tendency that had occurred when filtering raw NOM. The median diameter and the fractal dimension of the flocs produced increased as the zeta potential approached zero, which resulted in the formation of a cake layer that was easily removed from the surface of the membrane.</P>
Maeng, Sung Kyu,You, Song Hee,Nam, Joo-Youn,Ryu, Hodon,Timmes, Thomas C.,Kim, Hyun-Chul Elsevier 2018 Water research Vol.134 No.-
<P><B>Abstract</B></P> <P>This study achieves a better operational simplicity for the phycoremediation of reverse osmosis (RO) concentrate using <I>Scenedesmus quadricauda</I> microalgae. Under continuous illumination with CO<SUB>2</SUB> supplementation, algal growth in the RO concentrate resulted in a conversion of polymeric organic matter (a mixture of humic substances and polysaccharides) to biodegradable fractions and their prompt removal along with inorganic nutrients (NO<SUB>3</SUB> <SUP>−</SUP> and PO<SUB>4</SUB> <SUP>3−</SUP>). The algal-induced degradation of humic-like substances which are typically refractory to microbial decomposition was demonstrated in an indirect manner. In this study, we also investigated the effects of algal treatment on the growth of <I>Escherichia coli</I> and removal of trace organic compounds (TOrCs) from the RO concentrate. Our results indicate that algal treatment of the RO concentrate using aeration with 10% (v/v) CO<SUB>2</SUB> under continuous illumination is highly feasible as a safe and inexpensive technology to remove non- or slowly-biodegradable organic matter, reduce enteric bacteria, and attenuate TOrCs in wastewater. However, the results should not be generalized, but critically discussed, due to limitations of using the synthetic RO concentrate in evaluating the performance of wastewater remediation with microalgae.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>S. quadricauda</I> is capable of utilizing carbonaceous organics under aerated conditions. </LI> <LI> Continuous light stimulated the microalga to improve the biodegradability of organics. </LI> <LI> <I>S. quadricauda</I> successfully removed colored refractory organics along with N & P. </LI> <LI> The algal treatment is also promising to reduce <I>E. coli</I> and trace organic chemicals. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Ji, Min-Kyu,Kim, Hyun-Chul,Sapireddy, Veer Raghavulu,Yun, Hyun-Shik,Abou-Shanab, Reda A I,Choi, Jaeyoung,Lee, Wontae,Timmes, Thomas C,Inamuddin,Jeon, Byong-Hun Springer International 2013 Applied microbiology and biotechnology Vol.97 No.6
<P>The feasibility of using a microalga Chlorella vulgaris YSW-04 was investigated for removal of nutrients from piggery wastewater effluent. The consequent lipid production by the microalga was also identified and quantitatively determined. The wastewater effluent was diluted to different concentrations ranging from 20 to 80 % of the original using either synthetic media or distilled water. The dilution effect on both lipid production and nutrient removal was evaluated, and growth rate of C. vulgaris was also monitored. Dilution of the wastewater effluent improved microalgal growth, lipid productivity, and nutrient removal. The growth rate of C. vulgaris was increased with decreased concentration of piggery wastewater in the culture media regardless of the diluent type. Lipid production was relatively higher when using synthetic media than using distilled water for dilution of wastewater. The composition of fatty acids accumulated in microalgal biomass was dependent upon both dilution ratio and diluent type. The microalga grown on a 20 % concentration of wastewater effluent diluted with distilled water was more promising for generating high-efficient biodiesel compared to the other culture conditions. The highest removal of inorganic nutrients was also achieved at the same dilution condition. Our results revealed the optimal pretreatment condition for the biodegradation of piggery wastewater with microalgae for subsequent production of high-efficient biodiesel.</P>
Hydraulic Force and Impeller Evaluation of a Centrifugal Heart Pump
Timms, D.L,Tan, A.C.C,Pearcy, M-J,Mcneil, K,Galbraith, A The Korean Society of Marine Engineering 2004 한국마린엔지니어링학회지 Vol.28 No.2
A rig was constructed to test the performance characteristics and compare the hydraulic forces exerted on a centrifugal type artificial heart impeller. A conventional shaft. seal and bearing system. while driven by a small electric motor. supported the impeller which was separated from the pump casing by a six degree of freedom force transducer (JR3 Ine). Radial (x. y) and axial (z) hydraulic forces were recorded and compared. At physiological operating conditions. the results indicate that the double entry/exit centrifugal pump encounters a smaller radial force and significantly reduced axial thrust. These experimental results are valuable in the design of a magnetic bearing system to suspend the impeller of a centrifugal artificial heart pump. This experimental technique may also be applied to evaluate the required capacity and predict the lifetime of contact bearings in marine pumps.
Derek A. Timm,Ashok Hospattankar,Joanne L. Slavin 한국식품영양과학회 2010 Journal of medicinal food Vol.13 No.4
Dietary fiber fermentation decreases luminal pH by the production of short-chain fatty acids (SCFAs). Additional proposed physiological benefits of fiber fermentation include decreased growth of pathogenic bacteria, increased mineral absorption, and serving as an energy source for the colon epithelium. This study examined three common fiber supplements—wheat dextrin (WD) (Benefiber®, Novartis Consumer Health Inc., Parsippany, NJ, USA), psyllium (PS) (Metamucil®, Procter & Gamble, Cincinnati, OH, USA), and inulin (Fiber Sure®, Procter & Gamble)—for pH, SCFAs, and gas production. An established in vitro fermentation model was used to simulate colonic fermentation at 0, 4, 8, 12, and 24 hours. At 24 hours, WD and inulin significantly decreased pH compared to PS. Inulin produced significantly more hydrogen and total gas. All treatments produced similar total SCFA concentrations at 24 hours; however, the rate of production was different. PS had a declining rate of SCFA production from 12 to 24 hours, whereas WD and inulin had a higher rate during that period. Fast-fermenting substrates may not provide as much SCFAs to the distal colon as slow-fermenting substrates. Differences in fermentation rate, gas production, and SCFA production observed for WD, PS, and inulin may affect their gastrointestinal tolerance and require further study.
( Hyung Joon Park ),( Tarmo Timm ),( Jae Bae Yeon ) 한국하천호수학회(구 한국육수학회) 2013 생태와 환경 Vol.46 No.4
Abstract Aquatic oligochaetes were investigated from a small amount of sediment sampled from the Jungnang Stream, an urban stream in Seoul, Korea, in November 2012. Sorted oligochaetes were observed under a light microscope in a drop of carbonated water, and then preserved in 70% ethanol. Some specimens were slide mounted using glycerin and Eupharal. As a result, the following 12 species were identified including 8 new Korean records, Bothrioneurum vejdoskyanum Stolc, Branchiodrilus hortensis (Stephenson), Chaetogaster cristalinus Vejdosky, Nais communis Piguet, Nais pardalis Piguet, Dero obtusa d`Udekem, Piguetiella denticulata Liang, and Haemonais waldvogeli Brescher and 4 additional known species, Limnodrilus hoffmeisteri Cleparede, Branchiura sowerbyi Beddard, Chaetogaster diastrophus (Gruithuisen), and Stylaria fossularis Leidy. This study shows how freshwater oligochaetes are diverse even in urban streams in Korea, if a proper sampling and examining method is employed.
Experimental Flow Visualisation of an Artificial Heart Pump
Tan, A.C.C.,Timms, D.L.,Pearcy, M.J.,McNeil, K.,Galbraith, A. The Korean Society of Marine Engineering 2004 한국마린엔지니어링학회지 Vol.28 No.2
Flow visualization techniques were employed to qualitatively visualize the flow patterns through a 400% scaled up centrifugal blood pump. The apparatus comprised of a scaled up centrifugal pump. high speed video camera. Argon Ion Laser Light Sheet and custom coded particle tracking software. Reynolds similarity laws are applied in order to reduce the rotational speed of the pump. The outlet (cutwater) region was identified as a site of high turbulence and thus a likely source of haemolysis. The region underneath the impeller was identified as a region of lower flow.