good information abt coagulation and alum dosage . Feed water pH should be adjusted to the appropriate range prior to coagulant addition. The slaking of quick lime should be done carefully, ‘as the success of the water treatment depends to great extend on this process. pollution Reduction of COD. 1937 . Thank you for the info. Turbidity removal efficiency was slightly decreased by increasing alum concentration from 40 to 50 mg/L, e.g. really helpful for science fair project. The required alkalinity may be naturally present in the water or it has to be added through dosage of lime, Ca(0H)2 or sodium carbonate, Na2CO3 (also called soda ash). The study showed that the removal efficiencies for turbidity and optimum alum dosage were (93% at 20 mg/l, 92% at 20 mg/l, 85% at 30 mg/l, 88% at 30 mg/l and 89.3% at 30 mg/l) respectively. The effect of various operating variables like coagulant dose, pH, and reaction time were measured. Flocs formed from alum at low temperatures settle very slowly, whereas flocs formed from polyaluminium coagulants tend to settle equally well at low and at normal water temperatures, 6. The slaking requires 15 – 30 minutes under optimum conditions. Reverse Osmosis This lowering of natural alkalinity is desirable in most cases as the pH range for coagulation of turbid waters being 5.7 – 8.0. only 10 mg/l (as CaCO3) of the natural alkalinity with the alum. water desalination plz include it. 3 0 obj /Type /Page I propose the use of natural coagulant flocculation such as chitosan which are environmental friendly, not toxic like these chemicals. send me more important notes on water and waste water, Good information but I want Comparison between FeCl3 & Non Ferric Alum, really this topic helps me to undestaning pre water treatement plant of thermal power plant Hydrated lime, also known as calcium hydroxide, is a white powder formed when quicklime is slaked in water. /StructParents 40 5 0 obj Coagulant aid is an inorganic material, when used along with main coagulant, improves or accelerates the process of coagulation and flocculation by producing quick forming, dense and rapid-settling flocs. /Resources 13 0 R The dosage of Aluminum Sulfate applied for each experiment started at 10 mg/L, with an increase of 0.5 mg/L between each sample. If my company doing the waste water treatment plant for the mining slurry treatment, how much should i use for the 150m3/hr flow & 300m3/hr. (does it become landfill? Have a great day always! /MediaBox [0 0 595.3200073242 841.9199829102] Coagulation will be affected by changes in the water’s pH, salt content, alkalinity, turbidity, and temperature. However starting from the experiment number 9, corresponding to 340 NTU, it was necessary to increase the dosage because this was insufficient for that Play media. the real goal would be to reduce chloride discharge … Thanks! water supply INTRODUCTION. Coagulation: It is the process of addition of a chemical to de-stabilize a… reverse osmosis system The particles of coagulant aids may become negatively charged making them subject to attraction by positively charged aluminium ions. dose for alum was 7 mg/l and for polymer was 0.004 mg/l. In other words, results showed that alum dosage range for good coagulation was almost wide in this study. Get 1:1 help now from expert Civil Engineering tutors An analysis of the type of rapid mixing necessary in specific regions of the stability diagram suggests that it is possible to tailor the design of the rapid‐mix operation to the predominant mode of alum coagulation. The alkalinity ratio of pure calcium oxide (CaO) to pure calcium hydroxide [Ca(OH)2] is 1 : 1.32. good notes on coagulation. This variety of precipitates may be soluble or insoluble, depending on the coagulant dose I-2]. Compare to Alum, PACl and ACH (aluminium chlorohydrate) work extremely well at low raw water temperatures. /Tabs /S thanks for that information but I wonder how practically determining the strength of alum or in other wards how to measure the Al2O3 content in alum. Also PAC was efficient over a wider pH range (3-11) compared to Alum. )y�����O��VU_({�� ����ߪ���ɳ���[��.>E�]�F��: endobj Complete clarification of the waste water << For example, alum reacts to form aluminium-hydroxide floc, Al(OH)3, a gelatinous precipitate. What dosage of lime is required, in addition to 10 mg/l of natural alkalinity, to react with the alum dosage? Coagulant aids, are generally used to reduce flocculation time and when the raw water turbidity is very low. good flocculation may not be possible with alum in some waters. water plant Disinfection Plot a graph with alum dosage along x-axis and turbidity along y-axis. And because ATS 835 is completely soluble, it will hardly increase solids due to the coagulant. groundwater Reagents required: Alum solution (1 ml containing 10 mg of alum) chemical treatment Thus, pH must be controlled to establish optimum conditions for coagulation. water treatment plant /Rotate 0 The pH range of the water may be the single most important factor in proper coagulation. water shortage /Group 18 0 R Effect of pH and coagulant dosage on concentration of orange OGR after coagulation; a - 0.5 mg Al/mg dye, b - 1 mg Al/mg dye, c - 1.5 mg Al/mg dye, d - 2 mg Al/mg dye, e - 3 mg Al/mg dye. Formation of easy to remove sludge /Type /Page Drinking Water A higher than the optimum dose of coagulant thus results in less turbidity removal. Very informative site about the topic. 1. /CropBox [0 0 595.3200073242 841.9199829102] The amount of alum required to treat a flow of 1 MGD(million gallon /day) 2. /Rotate 0 /Tabs /S /Count 5 /StructParents 43 Coagulant aids when added increase the density to slow-settling flocs and toughness to the flocs so that they will not break up during the mixing and settling processes. Which type of chemical i used to neutralize the water, kindly also describe the chemical with process. water conservation so informative in waste water treatment and its components.. Hello, congratulations for the site. THANKS FOR THE INFORMATION. Coagulation should be carried out within this optimum zone using alkalis and acids for correction of pH where necessary. Post-filtration pH adjustment may be necessary to optimize corrosion control and comply with other … 123 mL/min The optimum liquid alum dose from the jar tests is 10 mg/L. The coagulation efficiency of alum remained almost constant within the dosage range of 10 to 40 mg/L at pH range of 4-8 (Fig. No need dosage equipment Keywords: alum dosage, coagulation, jar test, turbidity, and water treatment. These properties are largely determined by coagulant type, dose, pH and mixing intensity [4, 51. /Contents 11 0 R Quicklime or calcium oxide (CaO) may be used to provide artificial alkalinity to water when necessary. /CropBox [0 0 595.3200073242 841.9199829102] In water, the cation and the anion come apart and can interact with other charged particles in the water. When the issue of the coagulant dosage is solved, the optimum pH range for coagulation is also a undergoing topic. It is therefore necessary to agitate the contents of the tank continuously to maintain a uniform suspension. Alum coagulation profiles of the three source waters were also compared. watertreatment Fig. 3. These lower pH values mean that there are more positively charged particles loose in the water to react with the negatively charged colloids. ATS 835 is a great replacement for alum because it does an amazing job, but with a much, much smaller dose. Through RSM optimization, the optimum dose for alum was 7 mg/l and for polymer was 0.004 mg/l. http://www.thewatertreatments.com/waste-water-treatment-filtration-purify-sepration-sewage/coagulation-types, yes , this important , notices about Alum , so which is better Alum or Polymer ? sea desalination /CropBox [0 0 595.3200073242 841.9199829102] x��=�nG���/��� 0�]���`���L�eO�$���M���)R! The mechanism of both alum and FeCl 3 coagulation was controlled by pH, coagulant dosage and colloid concentrations . The treated water should be corrected with the addition of carbon dioxide. Maintaining the optimum alum dose is critical for maximizing turbidity removal through the clarifiers, especially during spring runoff … 1 0 obj These anti-coagulants are often used to ease blood clots to prevent artery blockage. coagulant performance. 8. As!’l result, all three factors influence the amount of coagulants which must be used to remove the turbidity in the water. Through RSM optimization, the optimum dose for alum was 7 mg/l and for polymer was 0.004 mg/l. Advantage of Flocculation in powder form alum coagulation based on the hydrolysis equilibria of AI(II1). A raw water supply is treated with an alum dosage of 25 mg/L. How does Silicate effects in coagulation? endobj While Process Controller read a value of 5 mg/L for the alum dose, the pump was not spinning and thus not pumping the amount indicated by Process Controller. In this study water samples were collected locally from different sources e.g. 7 0 obj is it re used?) The study was initialized by testing the efficiency of the coagulants in removal of turbidity. The optimum pH range varies depending on the coagulants used, but is usually between 5 and 7. Add same dose of the selected coagulant (alum or iron) to each jar (Coagulant dose: 5 or 10 mg/L) Jar Test. The alum/polymer combinations were first screened to determine which polymers worked best with our waste and with the alum. To calculate the dose of a coagulant or other chemical in mg/L, you will need to know its % w/w strength and specific gravity. The effects of a coagulant can be reversed by the use of an anti-coagulant. Coagulant doses are often approximated, resulting in poor quality effluent from secondary settling tanks. When dissolved in water, alum dissociates and the multivalent aluminum ions (Al3+) form various species that have an average positive charge. acidic and basic aluminum salts, PACl, ACH or alum, together with sodium aluminate. One of the commonest coagulants used is alum (Al 2 (SO 4) 3.14H 2 O). /Tabs /S Coagulation and Flocculation 37 Dose (mg/L) 7. To provide artificial alkalinity to water so as to have effective coagulation quick lime or hydrated lime are added to water. Pls I want urgent response. 1,5,6] have stated that coagula- The pH of the leachate that we treat is between 6.5 and 8. Optimum pH for the coagulation operation obtained through traditional methods and RSM was 7.6. The ferric hydroxide floc does not redissolve at high pH values. Water Conditioner Then, the effect of an electrochemical process using aluminum electrodes was studied. after acidifying the raw water to pH = 6. /Filter /FlateDecode In order to determine the optimum pH, first the initial dosage of coagulant was determined using 200 m1 of sample. Failure to operate within the optimum pH zone, may be a waste of coagulants and may be reflected in the lowered quality of the plant effluent. a little details on reactions between the substances would help a lot….. How to remove sodium silicate from waste water ? (Yukselen and Gregory 2004 ). I WILL BE MUCH HAPPY IF YOU KINDLY MAIL ME ALL THE WATER TREATMENT PROCESS.THANK YOU. At pH values above 7, the removal performance of aluminum-based coagulants drops markedly. /MediaBox [0 0 595.3200073242 841.9199829102] 11 Jar Test set-up Rapid mix each jar at 100 to 150 rpm for 1 minute. I desire to know more on the type of flocculants that can be used for sewage water (suck-away). Accepta 8302 is used for the treatment of potable water as well as process water, and sewage and industrial effluents. 2 0 obj In pH range from 6.0 to 7.0 it was observed diminished the effectiveness of coagulation; the decrease was the most in … With aluminum sulfate, optimum coagulation efficiency and minimum floc solubility normally occur at pH 6.0 to 7.0. Alkalinity is the capacity of the water to neutralize acids, based on the water’s content of carbonate, bicarbonate, hydroxide, borate, silicate, and phosphate. Some interesting graphics that help develop an understanding of how the treatment actually works. endobj Alum and Ferric Chloride reacts with natural alkalinity in water as follows: Al 2 (SO 4 ) 3 .14H 2 O + 6 HCO 3- 2 Al(OH) 3 (s) + 6CO 2 +14 H 2 O + 3 SO 4 2- Aim: To determine the optimum dosage of coagulant to remove small or charged particles present inside water by using "Alum" as coagulant. Reduction of the treatment costs Dosages are generally established on the basis of bench-scale tests and occasionally by full-scale tests, especially if polymers are used. /Tabs /S Results showed that coagulation process could remove turbidity effectively using Alum and Ferric chloride tested within (50-100 mg/L) dose range. Water with a high alkalinity is preferred for coagulation since it tends to have more positively charged ions to interact with the negatively charged colloids. /Type /Page Normally the optimum coagulant dose obtained by jar test, but this test is time-consuming, costly, and not effective for real time change in water quality. filtration maintenance potable Depending on the type of coagulant used, the dosage will vary. Inorganic coagulants generally require a higher dose than polymeric coagulants. Some illustration required, better if on my e-mail. Among the tested dyes the best coagulation results, both in the case of acidic medium (pH value 3) and neutral, were obtained for turquoise DG (Fig. Should the alkalinity be >50 mgL-1 then, in general, there will be sufficient present to drive most coagulation reactions. The floc formed with ferric coagulants is heavier than alum floc. The amount of natural alkalinity required to react with the alum added in terms of CaCO3 It is especially useful for clear water with very low turbidity that does not coagulate well with usual processes. Ac0ually i thought this website given elaborate information for water treatment coagulation and sewage water treatments.Thanks for that info. The dosage of alum, which represents least turbidity, gives Optimum Coagulant Dosage (O.C.D.). endobj /Parent 2 0 R /MediaBox [0 0 595.3200073242 841.9199829102] In theory, if you have the proper coagulant dose and a complete mixing of the chemical has occurred, the SCM will read "0.0". I should say that i have already tried reducing the pH with sulfuric acid to pH 5.00-5.20. in jar tests carried out the as the dose is increased the turbidity increases. /Contents 8 0 R ?����`��5u8~ϋ�n�]��l������D�d&Iu���� -?l���Ml�Y�#������l���&�hZ|����i�=2zpŝ��&����]�{��j3 #�^r�Za�%��3�Ã��S_֮wG��>Mě�c͋41�4�s:��2�f��ß�6�)�z��鬣E��'Ʊ[���d��f���h����n���x���k��>��'w��mf�Sf�F��53^�"��Z�U���-m��� �:��`�),��r����w����|u��B^���Re�4���A�*@j���Rג�C�~����}�{�']-��F��h�� �;��&. Limitations. Thanks..this help me a lot for doing my waste water treatment thesis.. May i know that is activated sludge can substitute alum or nt ? >> /Type /Page Within the plant, mixing effects and coagulant effects will influence the coagulation/ flocculation process. /Type /Catalog I require a final water UV @254nm transmitance of greater than 85%. Nearly all coagulant aids are very expensive, so care must be taken to use the proper amount of these chemicals. disinfectant The final turbidity, pH after coagulation and residual aluminium recorded were all within acceptable limits. /Type /Pages Corrosion Because of the consumption of alkalinity, CO2 is produced during coagulation. %PDF-1.4 Coagulation is an important phenomenon in the clotting of blood. aluminum/iron humates rather than coagulation. However, if the coagulant dosage has to be higher (by a factor of two) than the raw water alkalinity it may be necessary add some alkalinity What is Flocculation. Water Treatment << It’s important to refer to the technical data sheets of the product. Typical coagulant dosage ranges from 0.5 to 20 ppm. Determine the setting on the liquid alum chemical feeder in gallons per day (gpd) when the flow is 3.0 Mgal/d. stream One of the important contributors to the formation of flocs is the chemical coagulant aluminum sulfate (Alum). 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Mg/L for a plant treating a flow of 7 MGD with an alum feed rate of 340 lb/day //www.thewatertreatments.com/waste-water-treatment-filtration-purify-sepration-sewage/coagulation-types.