Coagulation Basins Research Articles

CFD와 실증실험 적용을 통한 최적혼화 방법 도출 및 수리구조개선으로 정수장 혼화방법 개선

The existing mixing basin is comprised of 16 basins and each basin has different inflow flux and input chemical flow rate. Therefore, the mixing efficiency of the existing mixing basin was very lower due the inappropriate distribution channel and the nonuniform flow pattern, In this study, in order to investigate the flow pattern and the mixing efficiency, there were simulated the flow patten, the flow stability, and the mixing pattern by using the CFD analysis and experiment for the previous model and the advanced model. As a result of the numerical calculation, CFD results confirm that the weir height is increased to 0.2m from the existing model to obtain the most optimal flow. Because the head water level was more than 0.7m, which showed sufficient mixing strength. Also, in the verification test, the zeta potential, the flow current, the cohesive floc size, and the filtration time were compared with mechanical mixing, showing superiority in all items. By replacing the existing mechanical mixing with a head water level, reducing the number of used mixing basin from 16 to 2, and improving the weir drop height, the length from the mixing basin to the coagulation basin could be reduced by approximately 30m and the flocculation efficiency was improved.

Effect of Addition of Monosodium Glutamate (MSG) on Coagulation Basin to Characteristics of Cellulose Acetate Membranes

The aim of recearch is study the effect of MSG in coagulation basin on cellulose acetat membranes properties. It was preparated by phase inversion technique. As the result showed that the higher the concentration of MSG in coagulation basin, which is character of membrane permeability coefficients and lower water flux. Dextran rejection of 11, 40, 100-200, and 500 kDa increased. The morphology analysis has shown that sub layer membranes structure with 2% MSG addition more uniform than 0,5% MSG addition.Keywords: cellulose acetat, phase inversion, MSG, coagulation basin

Ozonation-based advanced oxidation for pre-treatment of water with residuals of anti-inflammatory medication

The study is about pre-treatment of water by O3-based AOPs as O3/UV, O3/ultrasound (O3/US), O3/H2O2, O3/UV/US and O3/US/FeSO4 to remove residuals of anti-inflammatory pharmaceuticals and to propose a simple modification to an existing drinking water treatment plant (WTP) containing a pre-ozonation unit. Experiments were run in ultrapure and raw water (collected from the aeration tank of the WTP) spiked with 30μM Diclofenac-Na (DCF)-the model compound to represent anti-inflammatory medication. The results showed that the most effective test processes were O3/US/UV and O3/US/Fe2+ (at 2–8mgL−1 O3, 861kHz US, 254nm UV irradiation) that were significantly more effective than ozonation alone or other combinations. The outcome was attributed to the synergy of excess mass transfer and OH radical formation rates, and the presence of additional reaction routes and species. As such, 10-min pre-treatment of pure water by O3/UV/US and O3/US/Fe2+ provided nearly 90% DCF conversion; 26% and 46% mineralization, respectively. The efficiency of the processes for conversion in raw water was slightly lower, but that of mineralization was appreciably higher (55% and 58%, respectively) to be attributed to the synergy of combinations causing the interaction of excited NOM fragments with the intermediate products of DCF, followed by oxidative degradation of all to yield CO2. Coagulation/flocculation of the pretreated streams (of raw water) with alum and without chemicals respectively provided DCF-free water and about 65% DOC mineralization. Hence, integration of the existing water treatment facility with either of the above processes is an excellent option to destroy anti-inflammatory pharmaceutical residues such as DCF and to provide appreciable DOC elimination, thus reducing the likelihood of THM formation in the distribution system. An additional benefit offered by the second process using a ferrous salt was that it allowed for a chemical-free coagulation basin.

Impact of carboxylic acid ultrafiltration recycle streams on coagulation

This research identified unintended consequences of integrating ultrafiltration and its required ancillary cleaning systems within conventional surface water treatment facilities. Carboxylic acids, used in ultrafiltration membrane chemically enhanced backwashes, were demonstrated to interfere with ferric chloride and alum coagulation if recycled into coagulation basins at sufficient acid to coagulant (A/C) molar ratios. Tricarboxylic citric acid and monocarboxylic acetic acid were shown to interfere with conventional coagulation process performance. Significant changes in settled water turbidity, true colour and metal concentrations were observed in jar tests designed to simulate full-scale water treatment plant operations. A threshold A/C molar ratio for coagulation interference was identified for three surface waters in the United States based on sedimentation basin performance goals established by the US Environmental Protection Agency. Citric acid interfered with coagulation at A/C molar ratios as low as 0.028; whereas acetic acid negatively influenced coagulation at A/C molar ratios in excess of 18.0.

Extraction and Characterization of Organic Matter from Surface Waters (Reservoir of Keddara in Algeria)

The combined XAD-8 and XAD-4 resin procedure for isolating dissolved organic solutes from Keddara reservoir in Algeria was found to isolate 65 % of total organic carbon (TOC). Of the 45 % of solute adsorbed onto XAD-8 resin, 34 % was in the form of fulvic acids, and 11% humic acids. Approximately 19 % of the hydrophilic solutes were adsorbed onto XAD-4 resin. Characterization experiments have shown that the three isolated fractions have a low apparent molecular weight investigated by ultrafiltration and fluorescence and low aromaticity as shown by the results of UV-absorbance, the formation potential of total organic halogens (reactivity with chlorine) and the polyhydroxyaromatic (PHA) determined by pyrolysis gas chromatography/mass spectrometry (GC/MS) which show that the isolated fractions are aliphatic as well as aromatic. The low molecular weight and the low aromaticity compared with literature data are due to coagulation and sedimentation of NOM with high molecular weight, which occur naturally in the reservoir. The Keddara reservoir, with low hydraulic loading area and long detention times receiving water with low NOM and high in hardness can be expected to be very effective coagulation and sedimentation basins.

Disposal of Wastes From Filter Plants and Coagulation Basins

plain sedimentation; (b) calcium carbonate and magnesium hydroxide resulting from the addition of lime for partial softening or for conditioning prior to coagulation; (c) hydroxides of iron and aluminum, if iron and aluminum compounds are used as coagulants or if iron compounds are present in the raw water; (d) carbon or adsorptive clay, if these materials are applied in basins; (e) plankton; and (f) organic matter. 4. From filters: (a) very fine clayey particles remaining in the water after sedimentation; (b) hydroxides of iron and aluminum; (c) iron oxide, when iron removal is effected by aeration prior to filtration; (d) activated carbon, when this material is applied; (e) plankton and algae, when these are present in the water; and (f) organic matter.

Care and Calibration of Recording Instruments

RECORDS of a filtration plant are very important as they are open to public inspection and may have to be produced in court when necessity demands. This is particularly true of public utilities, which are required by law to publish annual reports not only of their finances but of their operation as well. Most plants are equipped with enough meters and gages to enable them to check the results and by a process of elimination find the meter or sets of meters that are in error. For instance, Milwaukee meters its raw, wash and filtered water, and takes elevations of clear-water reservoirs and coagulation basins with continuously recording gages. By addition or subtraction, using the input and outtake method, it is possible to account for all the raw water pumped daily until it leaves the plant. This check holds for the water purification plant alone and is dependent on tight valves and absence of leakage. An additional continuous check of the quantity of water is provided by the high-lift stations, which take water from the clear wells and pump it into the distribution system. The accuracy of this check is also dependent on tunnel leakage from the plant to the pumping stations and on the permissible error in their meters. By applying these checks daily and recording and analyzing the results, slowly developing discrepancies can be discerned, and through a process of elimination the finger of suspicion can be pointed at the meters that need care and calibration, long, before any damage is done to the records or to the instruments. When there is an abrupt change, such as occurs if an instrument needs repair, the operator on shift usually picks up the failure immediately. The gradual deviations are, however, much harder to detect, but may nevertheless accumulate so that sizable errors are recorded unless

Effects of Temperature on Rate of Floc Formation

IS common knowledge among operators of water treatment plants of the rapid filter type that the coagulated water going to the filters is usually less well prepared for the filters in winter than in summer. The settled effluent from the basins contains more and finer floe and more color in winter; and more coagulant is usually required to produce a satisfactory filter effluent. These difficulties are usually ascribed to the low temperature of the water in winter, and more specifically to the effect of the temperature on coagulation. The coagulation (or flocculation) process per se is the mechanism by which small colloidal or suspended particles coalesce and form larger particles. To be of value in water or sewage treatment, this process must continue until the particles are large enough to settle and filter effectively. The function of the mixing chamber or flocculator is to form the floe, but flocculation nevertheless continues slowly after the water reaches the settling basin. The primary function of the settling basin, which in many plants is still referred to as the coagulation basin, is not coagulation but settling. The complete process of conditioning water for filters is twofold therefore, consisting of both coagulation and settling. The effect of temperature on the settling process is well known. For particles settling within the range of validity of Stokes' law (and this includes nearly all particles, except grit, dealt with in primary settling), the velocity of settling varies inversely as the viscosity of the water: Hence, other things being the same, a longer settling period is required in winter, when the water viscosity is high, than in summer, to produce the same quality of settled water. For example, at 35°F. the settling period must be 73 per cent longer than

At Hackensack Water Company, New Jersey

causes such as decaying organic matter, in the manifold forms in which this occurs, and those odors and tastes that enter the supply through pollution. In the second class we find odor troubles arising from decomposing sludge in settling and coagulation basins and from stagnation in dead ends or other parts of distributing systems where circulation is poor and excessive oxygen depletion takes place. Recent work seems to indicate that electrolysis from stray currents may constitute another source of odors and tastes developing in distributing mains, service pipes and meters. In any discussion of odor troubles it is well to point out that such difficulties are likely to be more pronounced in hot water systems employing storage tanks than in the cold water directly from the mains. This is particularly true where the odor producing substance is one of the volatile hydrocarbons of the benzene ring series. Furthermore, there must be a high degree of removal of such substances from water as small amounts, hardly detectable in the cold supply, become concentrated in the upper portions of hot water boilers. As the hot water is drawn off intermittently the first portions contain a high concentration of the contaminating substance. The diversity in character and treatment of water supplies throughout the country is so great that odor and taste control becomes, in considerable degree, a matter for local solution. In that large group of water systems comprising the surface supplies, with treatment plants, there are common problems however which are being successfully overcome by one or more of the several agents now available for odor elimination. Introduction of the latest of these substances activated carbon several years ago focussed attention upon the whole subject of odor control in water supplies as a matter not to be side-stepped but to be attacked vigorously. Successful application of this material in preventing odors from decomposing sludge in coagulating basins has made it possible to eliminate one of the most

Mechanical Agitators for the Knoxville Water Works

Knoxville, Tennessee, placed its new water works plant in operation September 1, 1927. It comprises an intake, pumping station and filter plant and coagulation basins. In addition to the plant, two concrete reservoirs were added to the system, having capacities of 1 and 10 million gallons respectively. Large feeder mains were also laid to strengthen the distribution system. The source of water supply is the Tennessee River and the intake is located about 3 miles down-stream from the junction of the French Broad and Holston Rivers.

Appellate Division Affirms Typhoid Fever Damage Awards Against Albany, N. Y.

Journal AWWAVolume 20, Issue 5 p. 671-673 Article Appellate Division Affirms Typhoid Fever Damage Awards Against Albany, N. Y. Charles R. Cox, Charles R. CoxAssistant Sanitarian, Division of Sanitation, State Department of Health, Albany, N. Y.Search for more papers by this author Charles R. Cox, Charles R. CoxAssistant Sanitarian, Division of Sanitation, State Department of Health, Albany, N. Y.Search for more papers by this author First published: 01 November 1928 https://doi.org/10.1002/j.1551-8833.1928.tb13678.x AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume20, Issue5November 1928Pages 671-673 RelatedInformation

Important Problems of Filter Plant Operation

Problems of plant operation are so numerous and varied in character as to prohibit a discussion of them all within the scope of a single paper. It will be necessary to confine ourselves to the more important problems and to these only briefly. Problems of plant operation originate as a result of conditions and influences not alone within the plant itself, but also as a result of conditions and factors at the source of supply. Topographical and geological features of the watershed, together with influences contributed by sewage and industrial wastes, affect the character and nature of a water in producing varying amounts and degrees of turbidity, color, odors, taste, alkalinity, carbon dioxide, bacteria, organic matter and microorganisms, all of which influence methods of treatment and subsequent plant problems. The variation in the character and nature of a water as a result of these influences produces a plant problem of great importance, namely, the accurate control of chemicals and basin treatment, important in their bearing on operating costs and quality of plant effluent. Chemical control may be defined as the determination of the proper minimum amounts and proportions of chemicals to meet the fluctuating character and quantity of water passing through the plant to secure complete reaction between chemical and water with maximum efficiency of coagulation and subsequent basin treatment, and the elimination of objectionable and undesirable qualities in the plant effluents. Proper chemical control to secure maximum efficiency and results in treatment necessitates as a first requisite that means be provided for the accurate determination of the quantity of water passing through the plant. Various means have been developed from time to time to meet this demand. The more commonly used is the

Aeration of Water at Fort Worth, Texas

Fort Worth derives its municipal water supply from Lake Worth. This lake was formed by building a dam on the West Fork of the Trinity River, about 6 miles west of the city The lake is about 14 miles long and has a very irregular shore line It covers about 5430 acres, and has a drainage area of about 1865 square miles. The capacity of this impounded lake to spillway level is about 15,000,000,000 gallons. The dam is about 3200 feet long, of which 700 feet is concrete spillway. The earthen portion of the dam is built of clay and sandy loam laid up in one foot horizontal layers, well wetted and rolled. The concrete spillway is designed to carry ten feet of overflow. The dam is 59 feet high and 85 feet thick at the bottom, resting on solid rock. Water is taken from the lake through a concrete tower with screens at about 12 feet below spillway level. A 48-inch line of reinforced concrete pipe extends for 13,600 feet toward the filter plant. At this point the line is reduced to 36-inch and has a valve placed in it. The remaining 18,800 feet of this line continuing to the filter plant is in rather bad condition from leaks and for this reason the valve is throttled, and the entire available static head from the lake to the filter plant is never developed. At the filter plant the water first passes a valve then through a 30by 13-inch Venturi meter, to the aeration basin, the dosing channel mixing basin, coagulation basins, rapid sand filters and finally storage reservoirs. The lake was finished in 1914. The supply line to the filter plant was not placed in service until 1916, as it was not completed until then. In 1913 a 5 million gallon rapid sand filter plant was completed, but had to use water from the Clear Fork of the Trinity River mixed with water from artesian wells until water was available from Lake Worth. There was considerable complaint from taste and odor, and when it became necessary in 1918 to enlarge