Coagulation means to curdle; it basically refers to a chemical process in which the destabilization of non- settleable particles takes place. However, they can be commonly adopted for de-stabilizing any suspension system. trailer The three most common coagulants used in water treatment are Aluminum Sulfate (Alum), Ferric Sulfate, and Ferric Chloride. This gets very confusing as “alkaline water” has become a more widely popularized marketing term. Remember, if the chlorine solution is not 100 percent available chlorine you are going to need more to dose properly! 0000009281 00000 n During coagulation, coagulant is added to clump the particles together. Once the waste particles have clumped together using coagulation, flocculating agents in wastewater treatment are used to remove the clumps. The influencing factors of oil wastewater treatment by coagulation/flocculation have also been summarized in-depth, like dosage, pH, etc. The particles are then more easily removed in the sedimentation and filtration process. Mechanical mixers require the greatest amount of energy because they require an electrical source to achieve mixing. The coagulation-flocculation process can be used as a preliminary or intermediary step between other water or wastewater treatment processes like filtration and sedimentation. However, the appearance of synthetic polymers(very long macromolecules that tend to be adsorbed over microfloc and, therefore, to connect them together) has led to major developments in flocculation performance, creating larger floc that has greater shear resistance. Thus, in terms of water treatment, both can be differentiated easily. One way an operator can achieve this is through jar testing. * Start the equation as you normally would. The process of flocculation is achieved by controlling the rate of impacts between particles as they gain size. The most common primary coagulant is ___________. The coagulation-flocculation processes facilitate the removal of SS and colloidal particles. Have questions or comments? Flocculation: The process of agglomeration of the destabilized particles to such a size that separation by sedimentation and filtration is possible. The plant output is 2,500,000 gallons a day. Coagulation and flocculation separates the dissolved and suspended particles from the water by application of chemicals. How many pounds of Ferric Chloride does the plant use in a day? 0 Flocculation and sedimentation are technological processes used by Veolia Water Technologies South Africa (Veolia) within water treatment cycles to make water safe to drink or for water reuse.Flocculation and sedimentation cannot occur without coagulation, and some of Veolia’s patented Hydrex® water treatment chemicals are used to facilitate all of these processes. If the floc is not formed properly, then operators cannot effectively remove pathogens from the treated water. The chemicals are added together and the process occurs within seconds. Since you are adding a solution of chlorine that is not 100 percent an extra step is needed to solve the problem. 0000001159 00000 n As early as 2000 BC the Egyptians used alm… Coagulation and flocculation water treatment chemicals are used to remove iron, suspended solids, organic color, and hardness from influent water. Flocculation and coagulation is a chemical cleaning treatment for the waste water generally undertaken before the sedimentation process thus aiding in enhancing the process to remove particles from the water. x�b```b``y������� ̀ �@1V����9����ٲ(׳T� B%#��B-�ש�ɤ8���j��0'�]Rࠕ�B{���m��r�d��us1�kY�c~����L Coagulation is the neutralization of the electronic charge on suspended particles. 0000003529 00000 n * This sample problem is pretty simple. A treatment plant uses 300 lbs of alum a day. If there is a problem with floc formation, what would you consider changing? endstream endobj 276 0 obj <>/Size 253/Type/XRef>>stream November 30, 2012 by admin 2 Comments. 0000014191 00000 n 0000014541 00000 n This manual on Coagulation, Flocculation & Clarification sets out the general principles and practices which should be followed in the production of drinking water, Manual on the general principles and practices which should be followed in the production of drinking water Coagulation is a process of making colloidal matter dispersed/suspended in a liquid to join in a coherent mass. Coagulation. Insoluble is something that will not dissolve. ��W�(B�+�̒+��A�J�"(J��V��+|�jUh���|�2$T�n���TQ�5�{]fɽB|��^QrAB��O)Ȩ)C�� Coagulation and flocculation process in water treatment. Unless otherwise noted, LibreTexts content is licensed by CC BY-NC-SA 3.0. The efficiency of water treatment plants is determined by the combined effluent turbidity reading. Coagulation is defined as. 0000003221 00000 n Coagulation and flocculation constitute the backbone processes in most water and advanced wastewater treatment plants. As noted earlier the coagulation process is completed within a matter of seconds. Proper water quality tests must be performed by operators to promote the proper addition of coagulant chemicals. What was the dose rate? Mixing can be achieved by utilizing hydraulic mixers, mechanical mixing, diffusers, or pumped blenders. Finally, pumps can be used to push coagulant into water flow. For more information contact us at info@libretexts.org or check out our status page at https://status.libretexts.org. There are three steps: 1. Note: If the number is smaller than the original number, you multiplied instead of dividing. ��2X\\*P� i4w �8���bi��*����'�[��`�B1�t?���5���,�la6|������������0�Aj���3p�0��,��?�f��t��U��&�� � ��9� This step is called flocculation. The dry alum dosage rate is 15 mg/L. The physical removal of pathogens is accomplished in several steps. This process, known as flocculation, therefore requires slow mixing and a prolonged retention time. The first two steps include the processes of coagulation and flocculation. In wastewater treatment these clarification aids help with the removal of other contaminants such as oil, phosphate and heavy metals. This process is much longer than coagulation lasting roughly 15-45 minutes. This is a laboratory procedure that finds the best coagulant dose based on water quality conditions. The floc will gain in size during the second step of flocculation. Correct application of coagulation and flocculation depends upon these factors. There is no widespread standard for choosing a polymer. Coagulation and flocculation are an essential part of drinking water treatment as well as wastewater treatment. The flash mix process only lasts several seconds as the coagulant rapidly mixes and reacts with the raw untreated water. Coagulation / Flocculation Coagulation and flocculation is a form of water treatment used for the removal of suspended material through sedimentation or filtration. Flocculation is a physical process in which the fine solids produced by coagulation are brought together into … 0000015069 00000 n An operator cannot just set a dose and “hope” everything works out. It’s used in the first stage of solids-liquids separation: settling, flotation or filtration. What is Coagulation and Flocculation? Coagulation and flocculation Suspended particles cannot be removed completely by plain settling. 0000001599 00000 n Coagulation, flocculation and agglutination are terms that usually cause confusion. The coagulation and flocculation process requires a great amount of attention to detail along the way. Primary coagulant aids used in the treatment process are ___________. 2.First of all, the coagulants can neutralize negative charges of oil particles and reduce the electrostatic repulsion of the electric double-layer. and accordingly will see improvements in treatment such as: One of the most important calculations an operator will use is the “Pounds Formula.” The pounds formula can be used to solve water math problems including milligrams per liter to pounds per day, feed rate, chlorine dosage, percent strength, and dilution calculations. The mechanical wheel can be used to solve a chemical dosage problem by plugging in the given information and then multiplying or dividing as indicated to determine the solution. Coagulation and flocculation 14.1 Introduction Coagulation and flocculation provide the water treat-ment process by which finely divided suspended and colloidal matter in the water is made to agglomerate and form flocs. The aim of coagulation is to destabilise a colloidal solution, so that polluting matter can bunch together to form floccules. Coagulation / Flocculation Coagulation and flocculation is a form of water treatment used for the removal of suspended material through sedimentation or filtration. Flocculation, in physical chemistry, separation of solid particles from a liquid to form loose aggregations or soft flakes. Enhanced coagulation occurs at a lower pH. Coagulation and Flocculation are designed to: - remove infectious agents - remove toxic compounds - remove precursors to the formation of disinfection byproducts - make water palatable. In wastewater treatment these clarification aids help with the removal of other contaminants such as oil, phosphate and heavy metals. On the other hand, flocculation means to form flocs. Diffusers apply uniform flow during the coagulation process but may require many adjustments after flow changes. Coagulation. In industrial processes, flocculation may be a Coagulation-flocculation is a chemical water treatment technique typically applied prior to sedimentation and filtration (e.g. Because of this, the sedimentation step is usually preceded by a chemical process known as coagulation. Plug the numbers into the equation and multiply to get your answer. first process in drinking water treatment, coagulation, is to destabilize the particles and allow them the potential to collide and stick together. The colloidal surfaces are negative thus positively charged metal salts are used as primary coagulants. Coagulation, flocculation and agglutination are terms that usually cause confusion. They can also be referred to as nonstable solids. Every single water source has a different chemistry and jar tests must be performed to see what polymer works best with the specific source water. Flocculation goes hand in hand with coagulation in wastewater treatment. NOM - = natural organic matter - particulate and dissolved organic mater W+���!ޡ��P��Z��|EP�|�u�p�&E�B����U��{��*/E��*P�+wQ(}A{*?�J�� Coagulation is a process to neutralize charges and then to Coagulation and flocculation are used to separate the suspended solids portion from the water. The equation used to calculate detention time, if the flow is in gallons per minute, is: Important things to consider when choosing a polymer: Like many processes in water treatment, the theory of coagulation is very complex. xref The chlorine dose is 3.0 mg/L. startxref 0.785 × 100ft × 100ft × 30ft × 7.48 Gal/ft3 = 1,761,540 gallons, Feed Rate = 50 × 1.76 × 8.34 = 733.92 pounds/day. Sweep flocculation is the primary Chemistry of Coagulation and Flocculation; The chemistry of coagulation and flocculation is primarily based on electricity. 0000003258 00000 n EX: A water treatment operator must super chlorinate a 650,000-gallon tank at 50 ppm. 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