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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Korean Society of Water and Wastewater
Journal Basic Information
Journal DOI :
The Korean Society of Water and Wastewater
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Volume & Issues
Volume 24, Issue 6 - Dec 2010
Volume 24, Issue 5 - Oct 2010
Volume 24, Issue 4 - Aug 2010
Volume 24, Issue 3 - Jun 2010
Volume 24, Issue 2 - Apr 2010
Volume 24, Issue 1 - Feb 2010
Selecting the target year
Effects of ballasting Agent (Microsand) on Physical Floc Characteristics
Ryu, Jae-Na ; Lim, Yoon-Dae ; Oh, Je-Ill ;
Journal of Korean Society of Water and Wastewater, volume 24, issue 5, 2010, Pages 485~493
Chemical coagulation destabilizes colloidal particles so that particles grow to larger flocs. Solid particles are then removed by solid-liquid separation after typical precipitation. Rapid precipitation enhances the separation by reducing the precipitation time with larger and denser particles. Conventionally, polyelectolyte compounds (polymers) function as a flocculant aid by introducing a interparticle binding, which increases the particle size and density. And more recent ballasted flocculation adds a ballasting agent (microsand) to form denser particles with its high-density(sp gr=2.65). The current research was to evaluate the manner in which ballasted flocs are formed under different injection timings of microsand and to recognize the effects on floc formation.
as a coagulant, anionic polymer for a flocculation aid and microsand were used for the floc formation. Floc size (diameter) was widely ranged with the highest mean value when microsand was injected between
and polymer. Mean floc density was larger when the floc formed smaller. Settling velocity increased with larger floc size, whilst not significantly affected by the timing of microsand injection. The additional slow mixing on floc formation increased floc size to some extent.
Estimation of background minimum night flows by metering water use in water distribution areas
Lee, Doo-Jin ; Kim, Do-Hwan ; Kim, Ju-Hwan ; Kim, Kyoung-Pil ;
Journal of Korean Society of Water and Wastewater, volume 24, issue 5, 2010, Pages 495~508
The aim of this study is to develop a quantified water loss Index to evaluate and manage leakage scientifically for the reduction of non-revenue water in water distribution systems. For the purpose, unavoidable background leakage suggested from UK water industry and IWA, and allowable water leakage in accord with the concept of allowable water loss are proposed by analyzing the inflow into two study water districts and the short-term water use of each customer in the districts. The study distribution areas are selected among the metered districts with good maintenance of leakage after improvement activities in Nonsan, medium sized city in Korea. Estimation models of allowable leakage are developed by metering and analyzing the minimum night flow at residential and commercial areas in the city. In the results of the investigation, it is estimated that background night flow in residential area was larger than that of commercial area where the types of business shows small water use characteristics. Meanwhile, night flow and background water loss on internal plumbing systems show great differences for each district which is influenced much by the water use characteristics and facilities scale. Based on metering water use data in various districts, leakage management criteria can be established under the consideration of domestic conditions in Korea by analyzing separated real water use and background leakage and it is possible to apply into presentation of optimal leakage level and reasonable time for working activities for leakage reduction.
Probability of performance failure of storm sewer according to accumulation of debris
Kwon, Hyuk-Jae ;
Journal of Korean Society of Water and Wastewater, volume 24, issue 5, 2010, Pages 509~517
Statistical distribution of annual maximum rainfall intensity of 18 cities in Korea was analyzed and applied to the reliability model which can calculate the probability of performance failure of storm sewer. After the analysis, it was found that distribution of annual maximum rainfall intensity of 18 cities in Korea is well matched with Gumbel distribution. Rational equation was used to estimate the load and Manning's equation was used to estimate the capacity in reliability function to calculate the probability of performance failure of storm sewer. Reliability analysis was performed by developed model applying to the real storm sewer. It was found that probability of performance failure is abruptly increased if the diameter is smaller than certain size. Therefore, cleaning the inside of storm sewer to maintain the original diameter can be one of the best ways to reduce the probability of performance failure. In the present study, probability of performance failure according to accumulation of debris in storm sewer was calculated. It was found that increasing the amount of debris seriously decrease the capacity of storm sewer and significantly increase the probability of performance failure.
Study on Methodology for Reducing Dead Zone Flow within Chlorine Contactor Installing Porous Baffles
Park, Hyun-Ho ; Park, No-Suk ; Cha, Min-Whan ; Kim, Sa-Dong ; Won, Chan-Hee ;
Journal of Korean Society of Water and Wastewater, volume 24, issue 5, 2010, Pages 519~525
From the results of tracer test for the existing chlorine contactor in Y water treatment plant,
/T were calculated as 130 min and 0.16, respectively. Therefore it required the modification schemes for improving hydraulic efficiency, surrogated by T10 and
/T, and disinfection performance. In this study, in order to reduce dead zone within contactor, the installation of porous baffles in the near of each corner was suggested and verified using transient CFD(Computational Fluid Dynamics) simulation technique and tracer tests on dynamic condition. From the results of simulation and tracer tests, it was revealed that porous baffles installed have been effective to reduce dead zone within contactor, and increase plug flow fraction.
Cause of Break-up and Flotation Characteristics for Sludge from DAF Process
Yoo, Young-Hoon ; Moon, Yong-Taik ; Kim, Seong-Jin ; Lee, Kwang-Joon ; Kwak, Dong-Heui ;
Journal of Korean Society of Water and Wastewater, volume 24, issue 5, 2010, Pages 527~536
Although the bubble-floc agglomerate floated and formed the float layer on the surface of the water in the DAF process, after inducing in the thickening tank a part of the bubble-floc agglomerate come up again to the surface and the other is settled at the bottom of the tank. The bubble-floc agglomerate divided into two group as the scum on the surface and the sludge of the bottom gives rise to operational troubles for the thickening process. In order to find out the cause of break-up and the effective thickening method for sludge from the DAF process, the composition of the bubble-floc agglomerate was investigated and a series of flotation experiments carried out. There was no difference of composition between the scum on the surface and the sludge of the bottom in the thickening tank. The coagulation was not effective to improve the trouble that the bubble-floc agglomerate divided into the scum and the sludge. It was estimated that for the bubble-floc agglomerate of thickening tank the trouble was caused by not the change or the difference of chemical composition but whether the bubble-floc agglomerate hold bubbles. Furthermore, for the effective thickening of sludge from the DAF process, it is required an additional flotation applied the AS ratio depending upon the solid concentration of sludge as the operation parameter.
Saturation curves for chemical coagulation of wastewater treatment
Ryu, Jae-Na ; Oh, Je-Ill ; Lee, Kyeoung-Jong ;
Journal of Korean Society of Water and Wastewater, volume 24, issue 5, 2010, Pages 537~548
Recently the Government has announced updated water quality standards for wastewater treatment effluent (become effective in 2012). That includes highly enforced regulations for T-P, BOD and COD, and a large budget, in particular for phosphorus removal, was set by the Ministry of environment. Chemical coagulation destabilizes colloidal particles so that particles grow to larger flocs, and solid particles are removed by solid-liquid separation. The efficiency of chemical coagulation depends on a various factors, including coagulant types and costs, construction and operation costs for the treatment facilities and so on. The proper selection should be based on the treatment efficiency of coagulants and underlying costs. The current research was to evaluate the treatment efficiencies of coagulants on a variety of wastewater influents and to develop saturation curves for several water quality parameters. Typical
were tested under a range of coagulant concentrations. The pollutant removal efficiencies of chemical treatment both for the
were especially high for T-P, followed by SS, BOD and COD. Correlation test also proved the highest relationship between SS and T-P.
Quantifying Inundation Analysis in Misari motorboat racing stadium using MOUSE
Hwang, Hwan-Kook ; Han, Sang-Jong ; Chong, Yon-Kyu ;
Journal of Korean Society of Water and Wastewater, volume 24, issue 5, 2010, Pages 549~560
Recently, heavy rainfalls due to the climate change in Korea have caused inundation problems in urban sewer networks. In july 2006, a flooding accident at Misari motorboat racing stadium near the Han river occurred due to the effect of record-breaking outflow discharge from Paldang-dam. The purpose of this study was to simulate and analyze the flooding accident at Misari stadium by MOUSE model. The results of simulation analysis indicated that the total flood volume was
. The effect of back water was 85.9% of the total volume which was caused by the manhole accident, and the effect of accumulated runoff was 14.1% of total volume which was caused by non-return valve shutdown. The simulation results of this MOUSE modeling that was linked to the boundary condition of the dynamic flows in the river by DWOPER model showed the potential of successful inundation analysis for sewer networks.
A Study of Biological Hydrolysis Efficiency for Methane Digestion with Municipal Solid Waste
Cheon, Ji-Hoon ; Hiroshi, Tsuno ;
Journal of Korean Society of Water and Wastewater, volume 24, issue 5, 2010, Pages 561~572
The efficiency of biological hydrolysis at
on municipal solid waste mixed with anaerobic digestion sludge was investigated in 100L batch reactors. The hydrolysis effect was observed within a day, when the hydrolysis reactor used for a pre-treatment reactor for methanogenesis, and the effect was observed during two days, When the reactor used for post-treatment reactor. For both configurations, methane production rate decreased, when hydrolysis was carried out more than a day. Gaseous ammonia in the hydrolysis reactors was successtully removed by the ammonia stripping system. Microbial diversity analysis on the hydrolysis reactors indicated dependency of microbial diversity on the configuration of the hydrolysis reactors. Carbohydrate and lactate degrading microbes dominated in the hydrolysis reactor, when the hydrolysis reactor used for a pre-treatment reactor for methanogenesis, while protein degrading microbes dominated in the post-treatment reactor.
Minimum Period of Data Collection for the Determination of Average Water Pressure in the Water Distribution Networks
Hyun, In-Hwaan ; DockKo, Seok ; Kim, Duck-Hyun ;
Journal of Korean Society of Water and Wastewater, volume 24, issue 5, 2010, Pages 573~580
Average pressure in a pipe network is one of critical factors to estimate the flow distribution and to calculate UARL (Unavoidable Annual Real Losses) value in ILI (Infrastructure Leakage Index). While its collection period and measuring location are essential to obtain average pressure, their standard method have not been established so far. In this study, proper method including its procedure for data collection period and measuring point for average pressure were suggested using non-exceedance probability concept in the water distribution network.
The Effects of pH and Dosages According to Qualities of Raw Waters and Basicity of Coagulants
Park, Noh-Back ; Lee, Bum ; Tian, Dong-Jie ; Lee, Young-Ju ; Jun, Hang-Bae ;
Journal of Korean Society of Water and Wastewater, volume 24, issue 5, 2010, Pages 581~593
The objectives of this study were to investigate the effects of raw water pH and basicity of coagulants on turbidity removal with several raw waters having different level of turbidity, alkalinity and pH. Raw waters were sampled from M, S and B water treatment plants(WTP) located at Miryang, Nakdong, Han river, respectively. Six coagulants which have different levels of basicity and aluminum contents were used for this evaluation. High basicity of the coagulant helped to properly control coagulation processes for treating turbid and low alkali raw water. It was difficult for operators to determine optimum coagulant dose for high basicity coagulants, since residual turbidity tended to decrease continuously as coagulant dose increased. Turbidity removal efficiencies with high basicity coagulants(E and F) were higher than the other coagulants at ambient pH for the M WTP. Turbidity removal efficiencies, however, at adjusted pH 7.0 showed similar among six coagulants. Residual turbidity kept low at excess dosages with high basicity coagulants. Optimum coagulant dosages at adjusted pH 7.0 showed higher than those at ambient pH in M WTP. On the contrary in B WTP, optimum coagulant dosage at ambient pH were higher than that at adjusted pH 7.0.
A Study on the Pretreatment Process for Sewage Reuse by Microfiltration Process
Kuk, Young-Long ; Joo, Jae-Young ; Bae, Yoon-Sun ; Lee, Hye-In ; Jung, In-Ho ; Park, Chul-Hwi ;
Journal of Korean Society of Water and Wastewater, volume 24, issue 5, 2010, Pages 595~601
It is evident that Korea will continue its battle with water shortage and alternative program are being taken into action. One of the main actions is reusing 1,800 tons of effluent of 357 sewage treatment plant located nationwide. Therefore this study supplemented ozone oxidation methods that would increase the efficiency of organic oxidation and coagulation. Through this method, fouling will be controled sufficiently by preventing membrane process in the system for advanced sewage treatment. In this study, ozone-coagulation-microfiltration membrane were used. The final removal efficiency of the pretreated water from the result of the ozone-coagulation were 50% of CODcr, 38% of TP and 11% of TOC respectively. Water quality treatment has decreased about 80% for TP. Ozone-coagulation-microfiltration membrane maintains the high flux while decreasing the number of organic matter and the membrane fouling, and reducing the TP. As a result, in order to reuse the water from the sewage, the ozone-coagulation-microfiltration membrane type must be considered in order to achieve the best efficiency.
Biodegradability Index Development Based on Aerobic Biodegradation, Anaerobic Biodegradation, and Toxicity Test
Yoo, Kyu-Seon ; Shin, Hang-Sik ;
Journal of Korean Society of Water and Wastewater, volume 24, issue 5, 2010, Pages 603~608
More than 8 millions of chemical have been used for human activities and lots of chemicals can not be degraded by microbial activities in this world. To show the biodegradability of a chemical, biodegradability index (B.I.) is suggested using aerobic biodegradability by
/COD, anaerobic biodegradability by methane potential (M.P.) and toxicity by the luminiscent bacteria. In this study, PVA (polyvinyl alcohol), HEC (hydroxy ethyl cellulose), 2,4,6-TCP (tri-chloro phenol) and 2,4-DCP (di-chloro phenol) are used for test chemicals. Though they show little toxicity, PAV and HEC have low B.I. because they are polymers having high molecular weight. That means that there are no bacteria that has enzyme to degrade polymer molecules. Also, anaerobic treatment is suggested better than aerobic treatment from B.I. 2,4,6-TCP and 2,4-DCP show high toxicity and have low B.I. Their low biodegradabilities seem to be originated from their toxicities. If B.I. is used in wastewater treatment, better treatment process can be suggested and finally it can lead our society to make more environment-friendly chemicals.
A Study on Characteristics of Water Content Changes of Wastewater Sludge Using Direct Current Electricity
Ahn, Jeong-Mo ; Song, Ji-Yun ; Joo, Jae-Young ; Bae, Yun-Sun ; Park, Chul-Hwi ;
Journal of Korean Society of Water and Wastewater, volume 24, issue 5, 2010, Pages 609~615
This study examined the change of water content in sludge using direct current electric equipment for decreasing the amount of sludge. The experiment showed that the average density of solids in the sludge treated by direct current before the centrifugal dewatering process was increased by 47.8%, when compared to those not treated by direct current. From the result of measuring the granularity of the sludge by the direct current treatment, that the average particle size of the sludge that was not exposed to the electric current was 52.36
, and more than 90% of the sludge was <94.29
in size. On the other hand, the average particle size of the sludge passed through the direct current was 28.67
, and more than 90% of the sludge was 52.46
. This means that the average particle size of the sludge treated by the direct current was 45.2% smaller, and the standard deviation of granularity was improved. Because of water that separated from sludge moves to the (+) pole, larger particles become smaller and fine particles combine together, resulting in the equalization of the particle size. On the sludge after the centrifugal dehydrator, the change of the water content by the direct current was measured. The results showed that the average density of the solids was increased by 44.2% compared.
Statistical Methods for the Use of Infiltration and Inflow as Performance Index in Sewer Rehabilitation Works
Kim, Hyung-Joon ; Park, Kyoo-Hong ;
Journal of Korean Society of Water and Wastewater, volume 24, issue 5, 2010, Pages 617~628
The operation performance of sewer rehabilitation projects conducted with Build-Transfer- Lease contract in Korea will be evaluated using the index of infiltration and inflow (I/I). Though I/I obtained at the fourth year should be initially evaluated based on the I/I values observed for the previous three years after the completion of sewer construction, the concrete methodology have not been proposed to rely on the so called 'performance evaluation committee'. This study suggests two statistical methodology to evaluate the I/I performance; the confidence interval method and the hypothesis-testing method. Assumed ten I/I values in each year for 20 years are used in this study. Two cases are analyzed and compared; case I to use as control data all I/I values for all years obtained before the evaluation year and case II to use I/I values for only 3 years before the evaluation year. As a result, case II tends to have relatively higher scores than case I, reflecting the low mean I/I values at the initial years.
Performance Evaluation of Lab-scale High Rate Coagulation System for CSOs Treatment
Gwon, Eun-Mi ; Oh, Seok-Jin ; Cho, Seong-Ju ; Lee, Seng-Chul ; Ha, Sung-Ryong ; Lim, Chea-Hoan ; Park, Ji-Hoon ; Kang, Seon-Hong ;
Journal of Korean Society of Water and Wastewater, volume 24, issue 5, 2010, Pages 629~639
To evaluate the performance of high rate coagulation system(HRCS) for CSOs treatment, fundamental function of lab scale HRCS has been tested by using the Jar tester and lab scale HRCS. The optimum pH dose by Streaming Current value was found in the range of 5.3~6.0 in Fe(III), and in the range of 5.8~6.6 in Al(III) and the optimum chemical dose were 0.44mM of
and 0.93mM of
. The removal efficiencies at optimum
dose were 75%(
), 97%(TP), 95%(SS) and 96%(turbidity), respectively. And the removal efficiency of particles with less than
of diameter was 70% and that of particles with higher than
of diameter was 90%. The optimum alum dose in lab scale HRCS was 150mg/L, and the treatment efficiency was the best with addition of 1.0mg/L polymer. The effect of Micro sand addition was not clear, because the depth of the sediment tank in lab scale HRCS was not long enough. But the HRT of this lab scale HRCS was able to be shorten less then 7 minutes by adding the micro sand. The surface loading rates with respect to using different chemicals were 0.43m/h with alum only, 5.78m/h with alum and polymer and 6.22m/h with alum, polymer and micro sand. As a result, HRCS using coagulant, polymer and micro sand developed in this study was evaluated to be very effective for CSOs treatment.