Showing papers in "Journal of Korean Society of Water and Wastewater in 2008"

Evaluation of Coagulants Dispersion in Pump Diffusion Mixer for Water Treatment

Abstract: The objectives of this research were to evaluate the pressurized/the main inlet water flowrate ratio which have been used as the most important parameter for operating the pump diffusion mixer until now, to suggest the alternative operating parameter and the relating criteria if the flowrate ratio was not inadequate. For the objectives of this research, computational fluid dynamics (CFD) simulation was conducted for 21 cases of flowrate ratio in full-scaled pump diffusion mixer. From the results of CFD simulation, the local velocity gradient values were calculated in each case in order to analyze the simulation results in more detail. For verifying CFD simulation, wet test was conducted. The wet test was to measure the factual coagulant dispersion distribution at a distance of 5.4m from deflector. From both results of CFD simulation and wet test, flowrate ratio was inadequate as operating parameter or criteria, on the other hand the pressurized/the main inlet velocity ratio(dimensionless) was useful in predicting the performance of pump diffusion mixer. Also, the injected coagulant could be dispersed evenly in overall cross section on the condition that pressurized/the main inlet velocity ratio(dimensionless) is over at least 20.

Comparative Analysis of QUAL2E. QUAL2K and CAP Steady State Water Quality Modeling Results in Downstream Areas of the Geum River, Korea

Abstract: Major factors affecting water quality in rivers are transportation, input of pollutant loads and kinetic transformation of pollutants. Government level decision makings on water quality management are based on steady state water quality modeling. However, it is more than often that a such steady state assumption is far from real situations in rivers. Therefore, it is unavoidable to have modeling errors in water quality modeling especially for steady state modeling for longer period of time. Authors attempted to identify sources of errors in results of steady state models and thus tried to find out ways to minimize those errors. Three water quality models, QUAL2E (Brown et al., 1983), QUAL2K (Chapra et al., 2006) and CAP (Seo and Lee, 2000) were applied to the lower stream of the Geum River in this study. In general, BOD5 and COD tend to underestimate observed data while TN and TP showed relatively smaller errors. QUAL2E model provided best calibration results for BOD5 and TP and QUAL2K model showed best calibration results for TN. Since these errors are only relative values, it was difficult to conclude which model is better performing in certain situations. The most probable reasons for errors in water quality modeling are; 1) inappropriate consideration on flow characteristics, 2) lack of information on incoming pollutant load and 3) inappropriate location of sampling for water quality analysis.

The removal of Nitrate-nitrogen from ground water by electrodialysis

Abstract: In this study, the effects of applied voltage, solution pH and coexistence of other ions such as sulfate ion (SO42-) and chlorideion (Cl-) were investigated on the removal of nitrate-nitrogen (NO3--N) from ground water by electrodialysis. The examinedoperating conditions were evaluated for optimizing the removal efficiency of NO3--N. Real ground water samples taken from arural area of Yongin city and artificial ones with components similar to the real ground water were tested for the study, whichcontained NO3--N concentration of 17mg/L that exceeds current drinking water quality standard of 10 mg/L. The increase in theremoval rate of NO3--N was observed as the applied voltage increased from 5V to 30V, while no significant increase in theremoval rate appeared at the applied voltage beyond 20V during a given operating time. The removal rate appeared to getlower at both acidic and basic condition, compared to neutral pH. Coexistence of of SO42-and Cl-demanded much longeroperating time to achieve a given removal rate or to meet a certain level of treated water concentration. When nitrate ion wascombined with SO42-and Cl-, the removal rate was reduced by 4.29% and 10.83%, respectively.

An Experimental Study for Drainage Capacity Increment at Surcharged Square Manholes

Abstract: Urban sewer systems are designed to operate in open-channel flow regime and energy loss at square manholes are usually not significant. However, the energy loss at surcharged manholes is considered as one of the major causes of inundation in urban area. Therefore, it is necessary to analyze the head loss associated with manholes, especially in surcharged flow. Hydraulic experimental apparatus which can be changed the manhole inner profile(CASEⅠ,Ⅱ,Ⅲ, and Ⅳ) and the invert types(CASE A, B, C) were installed for this study. The experimental discharge was 16l/sec. As the ratio of b/D(manhole width/inflow pipe diameter) increases, head loss coefficient increases due to strong horizontal swirl motion. The head loss coefficients for CASEⅠ, Ⅱ, Ⅲ, and Ⅳ were 0.46, 0.38, 0.28 and 0.37, respectively. Side covers increase considerably drainage capacity at surcharged square manhole when the ratio of d/D(side cover diameter/inflow pipe diameter) was 1.0. The head loss coefficients for CASE A, B, and C were 0.45, 0.37, and 0.30, respectively. Accordingly, U-invert is the most effective for energy loss reduction at surcharged square manhole. This head loss coefficients could be available to evaluate the urban sewer system with surcharged flow.

Analysis of relationship between daily inflow rate fluctuation and surface wave transfer velocity in water treatment processes

Abstract: The fluctuation of inlet flow to a water treatment plant makes a serious problem that it can change the outlet flow-rate from each process abruptly, and ultimately occur the detachment of the attached particles inside each unit process. Also, since it takes very short time for the surface wave occurred from the fluctuation of inlet flow to reach the latter processes, it is impossible for operators to cope with that stably. Therefore this study was conducted to suggest the methodology for accurately predicting the travel time of surface wave occurred from the fluctuation of inlet flow to reach the latter process. Through the experiment, which was carried out for the full-scale water treatment plants (capacity : 2,000m3/d), it could be confirmed that the flow rate fluctuation from equalization tank produce the surface wave. And the wave transfer velocity is a function of the hydraulic radius and the length of each open type tanks which are comprised in the latter processes.

Characteristics of Non-point Pollutant Discharge from Upper Watershed of Seomjin Dam during Rainy Season

Abstract: This study was carried out to investigate the characteristics of the pollutant discharge from non-point source and to estimate the unit loads of the pollutant discharge from the upper watershed of Seomjin Dam during rainy season The upper watershed of Seomjin Dam is located in the middle of Jeonbuk province is formed two tributaries mainly A sub-branch stream of those tributaries is Imsil stream of which flow rate is about 13% of the main stream of Seomjin reservoir normallyOn the basis of measurement result in this study, the water quality of Imsil stream was fluctuated much highly than the main stream and the quantity of measured pollutant discharge was higher than the value calculated with the proportion of flow rate during dry season On the contrary, during rainy season the mean values of flow rate and water quality were higher than the quartile according to the statistical analysis That means rainfall influenced strongly on the water quality of the upper watershed of Seomjin reservoir Among the several criteria of water quality, SS discharge was most sensitive to the flow rate variation of stream, which was fluctuated in proportion of rainfall, basicallyIt was evaluated the event mean concentration (EMC) of non-point source pollutants depending on rainfall events as well Though the pollutant discharge unit of Imsil stream was lower than the main stream of Seomjin reservoir, the EMC value of Imsil stream was higher than the main stream of Seomjin reservoir

Corrosion Control in Water Distribution System using Lime and Carbon Dioxide(I) - Determination of Optimum Operational Conditions in Lime Adding Process

Abstract: The pH & alkalinity adjustment method by lime and carbon dioxide(CO2) for corrosion control in water distribution system was investigated to determine the optimum operational condition in lime adding process in water treatment plant(WTP). The mixing time at dissolution tank and sedimentation time at saturator for maintaining optimal turbidity condition of lime supernatant were 60∼75 minutes and 75∼95 minutes, respectively. There was no difference according to CO2 adding methods such as CO2 saturated water or CO2 gas. But, CO2 saturated water could be convenience at WTP in terms of pH control and quantitative dosing. To minimize generation of calcium carbonate products, the short time interval between adding of lime and CO2 is most important. The lime should be added below 32 mg/L for preventing pH rising and generation of calcium carbonate products at the heating condition

Evaluation of the qualities of rainwater collected from the top of vinyl house : A Case Study in Jeju Island

Abstract: Recently there has been a great deal of interest in promotion of the utilization of rainwater. In this paper, we comparedqualities of the rainwater collected from the top of vinyl houses to those of precipitated rainwater itself in Jeju Island. The pH ofthe collected rainwater was acidic and lower than the precipitated one. As a storm progresses, the pH of the collected watergradually increases. Ranges of EC of the precipitated and collected rainwater were 1-118 and 1-475 μS/cm. Most of Cl andturbidity values of the collected rainwater were less than 20 mg/L and 20 NTU, while those of the precipitated rainwater wereless than 10 mg/L and 5 NTU. Differences in qualities between precipitated and collected rainwater indicate that qualities of thecollected rainwater should be changed by the first flush effects, and imply that long term continuous monitoring for thequalities of collected rainwater is essential to quantify the first flush phenomenon more accurately.

Distribution of average rainfall event-depth for overflow risk-based design of detention storage basin

Abstract: This study collected the latest 30-year (1976~2005) continuous rainfall data hourly recorded at 61 meterological observatories in Korea, and the continuous rainfall data was divided into individual rainfall events. In addition, distribution charts of average rainfall event-depth were created to facilitate the application to the overflow risk-based design of detention storage basin. This study shows that 4 hour is appropriate for SST (storm separation time) to separate individual rainfall events from the continuous rainfall data, and the one-parameter exponential distribution is suitable for the frequency distribution of rainfall event depths for the domestic rainfall data. The analysis of the domestic rainfall data using SST of 4 hour showed that the individual rainfall event was 1380 to 2031 times, the average rainfall event-depth was 19.1 to 32.4mm, and ranged between 0.877 and 0.926. Distribution charts of average rainfall event-depth were created for 4hour and 6 hour of SST, respectively. The inland Gyeongsangbuk-do, Western coastal area and inland of Jeollabuk-do had relatively lower average rainfall event-depth, whereas Southern coastal area, such as Namhae, Yeosu, and Jeju-do had relatively higher average rainfall event-depth.

Corrosion Control in Water Distribution System using Lime and Carbon Dioxide(II) - Evaluation on the Characteristics of Corrosion as a Function of Pipe Material

Abstract: The pH & alkalinity adjustment method by lime and carbon dioxide(CO2) for corrosion control in water distribution system was investigated to evaluate the corrosion characteristics of metal pipes, such as galvanized iron, copper, stainless steel, and carbon steel. When the pH in sand filtered and ozone+GAC treated water was increased with lime and CO2 from 7.5 to 8.0, the concentration of residual chlorine decreased at higher pH and longer reaction time; the concentration of trihalomethane increased. The corrosion rate of coupons with corrosion control using lime and carbon dioxide was showed much smaller than those without corrosion control using pilot-scale simulated distribution system. The galvanized iron was corroded much faster than carbon steel, copper, and stainless steel. Especially, copper and stainless steel coupons were hardly corroded. The galvanized iron and carbon steel coupons with corrosion control were produced the corrosion products less than those without corrosion control by the results of environmental scanning electron microscope(ESEM) and energy dispersive x-ray spectroscopy(EDS) analyses. The galvanized iron coupon with pH and alkalinity adjustment by lime and carbon dioxide was detected about 30 percent of zinc, when the carbon steel was detected about 30 percent of calcium by calcium carbonate products formation. For the results of X-ray diffraction(XRD) analysis, the goethite(α-FeOOH) was identified as primary corrosion product of galvanized iron without corrosion control, while the Zinc oxide(ZnO) was found on corrosion products of galvanized iron coupon with corrosion control as the results of EDS analysis. However, the carbon steel corrosion products regardless of corrosion control were composed predominantly of maghemite(γ-Fe2O3) and hematite(α-Fe2O3).

Reliability Analysis for Probability of Pipe Breakage in Water Distribution System

Abstract: Water pipes are supposed to deliver the predetermined demand safely to a certain point in water distribution system. However, pipe burst or crack can be happened due to so many reasons such as the water hammer, natural pipe ageing, external impact force, soil condition, and various environments of pipe installation. In the present study, the reliability model which can calculate the probability of pipe breakage was developed regarding unsteady effect such as water hammer. For the reliability model, reliability function was formulated by Barlow formula. AFDA method was applied to calculate the probability of pipe breakage. It was found that the statistical distribution for internal pressure among the random variables of reliability function has a good agreement with the Gumbel distribution after unsteady analysis was performed. Using the present model, the probability of pipe breakage was quantitatively calculated according to random variables such as the pipe diameter, thickness, allowable stress, and internal pressure. Furthermore, it was found that unsteady effect significantly increases the probability of pipe breakage. If this reliability model is used for the design of water distribution system, safe and economical design can be accomplished. And it also can be effectively used for the management and maintenance of water distribution system.

Evaluation of influent changing effect on the STP performance using Dr. Wastewater

Abstract: Sewer Rehabilitation Project (SRP) is planed, designed and constructed to perform its intended performance as sewerage delivery systems. Recently, a subject of performance evaluation methodology development for SRP has become a great deal of concern among researchers in Korea. From the view point of Sewage Treatment Plant (STP), however, the estimation of improvement efficiency for SRP is in lack of reliability due to the fact that affections for the treatment efficiency and operating condition are not reflected on SRP design and construction. In this study, statistical methodology was used in the analysis of data, which are taken during 1,186 days (1st Jan. 2005 - 31th Mar. 2008) from the influent, effluent and operating conditions of full-scale STP(25,000m3/d). Then the effect of SRP on the influent characteristics and operating conditions changing was compared and evaluated. Results from the statistical evaluation show that SRP causes characteristic changes in influent and exerts a significant effect especially on the performance of STP.

Search Method for Optimal Valve Setting and Location to Reduce Leakage in Water Distribution Networks

Abstract: The reduction of leakage is a major issue of the South Korea water industry The inclusion of pressure dependent leakage terms in network analysis allows the application of optimization techniques to identify the most effective means of reducing water leakage in distribution networks This paper proposes a method to find optimal setting and location of control valve for reducing leakage efficiently The proposed search method differs from previous methods for addressing optimal valve location problem and improves the GA simulation time with guaranteeing for getting the global optimal solution The strength of this method has been demonstrated by means of case studies This allows the procedure of optimization to be more robust and computational efficient

Patents Review on the Seawater Desalination Plant and Technology Using Reverse Osmosis Membrane Process

Abstract: Many reports have warned of insufficient water supply in most countries in future and prospected providing safe and clean water become more difficult by lack of access to sustainable drinking water resources. Several facts and figures explained the impact by natural climate change and human activity results in the water scarcity and deterioration. Among many scientific solutions, the seawater desalination using a reverse osmosis membrane, so called SWRO (Seawater Reverse Osmosis) process, has been recognized as one of the most promising alternatives because of its stability and efficiency in producing large amount of drinking water from seawater through desalination by membrane filtration. Recently, in Korea, numerous researches are conducted to develop more productive and cost effective SWRO process for its wide implementation. The objective of this paper is to review the patents concerning SWRO technologies involving the plant engineering, maintenance including pretreatment of seawater and fouling control, module design, and mechanical units development for energy saving. The patents in Korea, U.S., Japan, Europe, and PCT were intensively researched and analyzed to provide the state of the art as well as leading edge technology on SWRO. This information can hopefully suggest meaningful guidelines on future research and development.

Evaluation of Flow Characteristics within In-Line Mixer for Water Treatment using CFD Technique

Abstract: The modified in-line mixer which was suggested in this study for small water treatment facilities was evaluated on the performance of coagulation. For the objectives of this research, computational fluid dynamics(CFD) simulation was applied for analysis of flow characteristics within the modified in-line mixer. For verifying the results of CFD simulation, wet tests for the pilot plant were conducted. The wet test was to measure the actual coagulant dispersion distribution on the overall cross-section at a distance of 5.5D from the chemical injection point. From the results of CFD simulation and wet test, it was shown that the coagulant dispersion within the modified in-line mixer was occurred more uniformly than within the existing PDM(Pump diffusion Mixer). The results have confirmed the modified in-line mixer had several advantages compared with the existing PDM in terms of dispersion efficiency.

A study on the headloss of filter media for treatment of Road Runoff

Abstract: Stormwater runoff from urban road area as non-point source has a tendency of including lots of pollutants at initial rain period. Recently, there are several cases of having installed treatment facilities for reducing pollution discharge from the impervious cover in urban area to prevent watershed environment from getting worse. The filtration type among non-point source treatment systems has been known as one of the most efficient system for treatment of non-point source pollutants. Therefore, various kinds of filter media such as expanded polypropylene(EPP), granular activated carbon, zeolite, perlite, illite, sand, gravel has been developed. This study was conducted to verify performance and hydraulic characteristics of filter media as measures for non-point source. The experiment was carried out to evaluate applicability and variation of 4 kind of most popular filter media(EPP, GAC, Zeolite, Perlite) in headloss with elapsed time and influent flow rate and to obtain data base that could be used to establish management plan for road runoff treatment. In experiment by tap water, it showed that EPP and perlite those are floatable materials showed stable operating performance and lower headloss than the others. The removal efficiency was high over than 95% and stable for EPP in experiment for road runoff. Headloss and removal efficiency with elapsed time for GAC and zeolite was highly unstable.

Hydraulics and water quality characteristics of flushing in distribution pipes

Abstract: This study was conducted to optimize a unidirectional flushing program in distribution pipes by analysis of water pressure, velocity, quality, and other parameters during flushing. As a result, correlation coefficient between flushed pipe length and the flushing duration was obtained R2 = 0.83 and the equation YTime = 0.0571XPipe length ＋ 4.7648 for 10 pipes. The averaged flushing velocity in the pipes, 1.1 m/s, was enough to remove loose deposits on the inner wall of the pipes. 3 of 92 water samples taken during flushing met the National Drinking Water Quality Standard for Fe and Mn, but not for Al. Turbidity less than 1 NTU is suggested for the appropriate criteria to finish flushing in pipes. The coefficient of determination (R2) between turbidity and TSS was 0.95 and the equation was induced as YTSS = 1.2068XTurbidity. The amount of removed deposits could be estimated from the turbidity data of discharged water in field because turbidity and TSS in the discharged water is highly correlated.

An analyze of oversea desalination plant order result

Abstract: A population growth and industry advances are increasing the demand for water while improving the quality of life. By turning seawater into freshwater it is an alternative for the water shortage problem.The study analyzes the orders and makes suggestions on the outlook of an enterprise that can supply desalination plants both inside and outside the country. It compares the production capacity of enterprises in the desalination industry who deal with the thermal and RO methods. We compare 7 enterprises in the thermal method which includes Doosan Heavy Industries, and the top 10 enterprises in the RO method which includes General Electric Corp. Now that the markets in the Middle East have opened and markets in other regions are gradually growing, demand for water will grow especially in developing countries that are in the process of industrialization. Also, the market share of thermal method desalination has been falling, gradually, because too much energy is spent during the process. On the other hand, the market share of the RO method will rise from 37% in 2005 to 57% in 2015. Recently, the desalination market shows that changing from thermal method to RO method is the trend in the Middle East. Growth and demand in other regions are growing at the same pace as the Middle East. Due to this trend, if the RO system, which is highly effective and uses less energy, were to be continuously developed it would be possible to supply water using sea water and would be a viable alternative water resource.

Cost Evaluation for the Decision of Advanced Treatment Processes

Abstract: Since 1989, Advanced drinking water treatment processes began to build in Korea, especially the water treatment plants around the Nak-dong river stream due to sequential pollutant accidents. Moreover, Advanced drinking water treatment processes, ozone and GAC, are again to be built in water treatment plants around Han-river stream to control taste and odor, micro pollutants. However, there are still a lot of discussion to decide the processes to apply for advanced treatment. Thus there are still need to understand clearly on the cost evaluation of each advanced treatment processes. The cost evaluation was accomplished based on the data of six water treatment plants which are currently being either operating or constructing. Exceptionally, PAC(Powdered Activated Carbon) process was evaluated with cost estimation from construction company. The capital cost per unit volume of ozone process was significantly decreased as the treatment capacity increased. The capital cost was in the order of GAC, ozone and GAC. The operation cost decreased in the order of PAC, GAC and ozone. The total cost considering present value shows that ozone process covers 84% of ozone and GAC process for 30,000 m3/d capacity while it covers less than 35% for over 140 thousands m3/d capacity. Comparing GAC only, and ozone/GAC process, ozone/GAC process is more cost effective for high capacity water treatment plant.

Transient Analysis of Pipeline System Considering Unsteady Friction Models

Abstract: This research compared several unsteady friction models for transient analysis of pipeline system. Unsteady friction is an important factor for accurate simulation of hydraulic transient. Steady friction, quasi-steady friction, Zielke's model and two versions of Brunone model were compared with measurement data of identical pipeline conditions. This study showed that the existing simple steady friction model can be useful for the safer design of pipeline system due to its overestimation of waterhammer, but introduction of more elaborate models are required for advanced analysis such as inverse transient analysis of friction or leakage and the preliminary analysis of water quality prediction of water distribution system.

Characteristics of Coagulants Distribution by the Pumping Rate in Pump Diffusion Mixer

Abstract: This research was conducted to investigate the coagulant dispersion distribution in the selected full-scale pump diffusion mixers(PDM), and to evaluate their performance through wet test experimentally The wet tests was to measure the factual zeta-potential all over the cross section at a distance of 45D(D=1,200mm) from deflector in the selected PDMs on various conditions of the pressurized/the main water inlet flow-rate ratios From the wet tests, in the case that the pressurized / the main water inlet flow rate ratio was less than 2%, the injected coagulant was distributed unevenly and dispersed locally On the other hand, in the case of 4% the coagulant dispersion distribution was relatively even Also, in the case of over 8%, comparing with any other condition, the injected coagulant was dispersed most equitably all over cross section

Settling Characteristics of Water Treatment Plant Sludges by Pretreatment Methods

Abstract: It is necessary to investigate methods for improvement by diagnosing sludge settling characteristics on inflow of slurry to thickener. The results of the settling tests are correlated to determine zone settling velocities at the various sludge solids concentrations. Conditioning of WTP residuals is generally done by either chemical or physical treatment. The settling test was conducted with 1m columns dosing polymer to WTP residuals at various solids concentration. The estimated results for dosing to WTP residuals for a sludge of 2,100~ 16,012 mg/L solids concentration were the zone settling velocities of 48.38 ~ 6.8 m/day, supernatant solid concentration of 3.2 ~ 19 mg/L and solid flux of 101.6 ~ 317.61 kg/㎡․day. The values for non-polymer treatment were the zone settling velocities of 28.37 ~ 0.12 m/day, supernatent solid concentration of 8.5 ~ 108 mg/L and solid flux of 59.58 ~ 1.92 kg/㎡․day. The limiting solid flux value by Yoshioka methods was 4.0 kg TS /㎥․day for Non-polymer and 228.0 kg TS /㎥․day for dosing polymer. These results are to indicate a possibility of improvement on the thickening characteristics and the quality of supernatant as increasing the settling velocities by dosing polymer to WTP residuals.

Prediction Models to Control Pro-chlorination in Water Treatment Plant

Abstract: Prediction models for post-chlorination require complicated information of reaction time, chlorine dosage considering flow rate as well as environmental conditions such as turbidity, temperature and pH In order to operate post-chlorination process effectively, the correlations between inlet and outlet of clear well were investigated to develop prediction models of chlorine dosages in post-chlorination process Correlations of environmental conditions including turbidity and chlorine dosage were investigated to predict residual chlorine at the outlet of clear well A linear regression model and autoregressive model were developed to apply for the post-chlorination which take place time delay due to detention in clear well tank The results from autoregressive model show the correlationship of 0915～0995 Consequently, the autoregressive model developed in this study would be applicable for real time control for post chlorination process As a result, the autoregressive model for post chlorination which take place time delay and have multi parameters to control system would contribute to water treatment automation system by applying the process control algorithm

Long Term Evaluation of UF Membrane process using River-bed Water

Abstract: Membrane system has been increasingly considered as a safe and cost-effective water treatment process especially in case of small scale water works. This research is a basis of membrane application in water works through a long period test with obtaining operation skills and evaluation of water quality and cost competitiveness. For the research, the UF membrane system was installed in small water treatment plant that uses river-bed water as raw water. The system was consisted of 2 stage membrane and operated in constant flow mode (Flux: 1.5, 1.0, 0.9, 0.6). In each different flux condition, TMP trends were showed better results at lower flux condition. And through the high flux condition test, it is certified that membrane system could deal with breakdown of one stage. Water quality of permeate was satisfied the water quality standards especially turbidity. To know what mainly causes fouling on membrane, the test by membrane with several cleaning agents and EDX analysis have done in lab. Through the tests, ferrous concentration in raw water, backwashing water and membrane surface etc. was high and it causes fouling inside and outside of membrane. So acid cleaning using organic acid such as oxalic acid is necessary in Chemical in Place (CIP). At the economical aspect the electrical cost of membrane system is higher than that of slow sand filtration but labor cost can be reduced by automation. However, the use of labor should be determined considering effectiveness and stability of operation. Because during the operation, there are several breakdown such as electrical shock by lightning, water drop in summer, etc.

Advanced Wastewater Treatment using Sludge Solubilization by the Cavitation and PGA addition

Abstract: Some pretreatment methods have been proposed to enhance the biodegradability and to shorten the hydrolysis reaction time. By means of efficient pretreatment the suspended solids (SS) can be made of better accessible for the anaerobic bacteria. There are several ways how this can be accomplished, which include biological, mechanical, thermal, and chemical methods. For the sludge solubilization using the cavitation phenomenon, we have tried to develop a pretreatment process consisted of a reactor and pumps. The objectives of this study were to develop a advanced wastewater treatment consisted of IABR and the cavitation with PGA. The most effective removal for organic matter and nutrients were occured when both cavitation pretreatment and γ-PGA were applied at the IABR process. Only small portion of γ-PGA at a rate of 1.38mg/L, was enough to improve sedimentation ability, SS removal efficiencies, and sludge volume reduction. After the sludge solubilization by the cavitation, SCOD increased to 193% and SS decreased to 36%. The removal ratio of BOD is 94.5%, T-N removal ratio is 85.5% and T-P removal ratio was 84.9%. The combination process of the IABR with the cavitation and PGA addition seems to be very effective alternative wastewater treatment process.

Analysis of Domestic Water Consumption Characteristics for Water Usage Purpose

Abstract: Throughout the analysis of field data from water distribution system, valid parameters were determined that can be included in the water service and design plan. This study investigates water consumption patterns to understand the variation of water-demand structures utilizing the pattern analysis of domestic purpose water. Water use data were collected by a public water resources management firm in Korea, Kwater, for 140 houses monitored during three years. Flow meters were installed at the faucet for drinking water, the shower booth, the laundry machine, bathroom sink, toilet, and garden faucet. Data was filtered using multiple physically meaningful criteria to improve analysis credibility. MannKendall and Spearman’s Rho tests were used to carry out the analysis. Distinct factors of water consumption patterns can be determined for both increasing and decreasing trends of water use. Throughout the data analysis, the characterization of terms was classified and analyzed by the condition of the location of water-demand. Analysis of this data provide a physical basis for the parameter configuration of a reasonable design for a domestic waterdemand prediction model.

Evaluation of Granular Activated Carbon Process Focusing on Molar mass and size distribution of DOM

Abstract: The primary objective of this study was to evaluate the variation of the molecular size distribution by granular activated carbon (GAC) adsorption. GAC adsorption was assessed by using the rapid small-scale column test (RSSCT) and high-performance size-exclusion chromatography (HPSEC) was used to analyze the molecular size distribution (MSD) in the effluent of GAC column. RSSCT study suggested that GAC adsorption exhibited excellent interrelationship between dissolved organic carbon (DOC) breakthrough and MSD as function of bed volumes passed. After GAC treatment, the nonadsorbable fraction which was about 25percents of influent DOC corresponded to the hydrophilic (HPI) natural organic carbon (NOM) of NOM fractions and was composed entirely of

역세 배출수 처리를 위한 관형막의 전량여과 운전 적용에 대한 연구

Abstract: Many other countries have investigated the new backwash water treatment process to save the existing water resource. There are various methods for reusing backwash water, but the membrane system has received the most interest for its efficiency. The objective of this study was to certify the application of membrane filtration system for the backwash water treatment. The experiment equipment was composed of Lab scale tubular membrane filtration system. Generally, cross-flow operation mode is used in the tubular membrane system but cross-flow operation mode demands high electric cost mainly for the pump energy. So to cut off electric cost, dead-end operation mode was used in this experiment. Filtration and bleed operation cycle was used in this membrane system. Backwash water was concentrated during the filtration process and when backwash water reached our target suspended solid concentration, it was discharged from this system. For efficient operation of filtration and bleed, mathematical matrix was drawn up and with this matrix we could simulate various sets of filtration and bleed time.

Assesment of Powdered Activated Carbon Effect on PAC+MF Hybrid Membrane Process

Abstract: This study aims at an assessment of the effectiveness of taste & odor removal and transmembrane pressure changes in a pilot membrane plant(500m3/day) by adding PAC to MF process, and at providing a basis for applying it to the advanced water treatment process. The transmembrane pressure showed, in low turbidity of raw water, a tendency to decrease when PAC was injected at the Flux of 1, 1.5㎥/㎡ㆍd, while it increased in high Flux(1.5㎥/㎡ㆍd) in high turbidity of raw water. in addtion, it is shown that the fouling could be reduced more when PAC is injected together with appropriate amount of coagulant, than when PAC is solely injected. Taste & Odor-causing 2-MIB may not be detected in membrane filtered water, if the amount of PAC injection is increased in accordance with the increasing concentration of 2-MIB. Hence, PAC injection, as a pre-treatment process in MF membrane filtering, is supposed to be a suitable process for reducing fouling as well as for improvement effectiveness of taste & odor treatment.