0000001599 00000 n This process, known as flocculation, therefore requires slow mixing and a prolonged retention time. Suspended particles vary in source, charge, particle size, shape, and density. The coagulation and flocculation process requires a great amount of attention to detail along the way. 277 0 obj <>stream The equation used to calculate detention time, if the flow is in gallons per minute, is: The three most common coagulants used in water treatment are Aluminum Sulfate (Alum), Ferric Sulfate, and Ferric Chloride. The coagulant dissolves in water and ionizes. Synthetic polymers are often used as a coagulant and filter aid but have also been used as a primary coagulant. ��W�(B�+�̒+��A�J�"(J��V��+|�jUh���|�2$T�n���TQ�5�{]fɽB|��^QrAB��O)Ȩ)C�� 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. Meanwhile, flocculation is a mixing technique that promotes agglomeration and assists in the settling of particles. However, they can be commonly adopted for de-stabilizing any suspension system. endstream endobj 276 0 obj <>/Size 253/Type/XRef>>stream 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. 0000000016 00000 n Coagulation and Flocculation in Water and Wastewater Treatment is a readable and useful resource for the water scientist and engineer. Flocculation: The process of agglomeration of the destabilized particles to such a size that separation by sedimentation and filtration is possible. Hydraulic mixers use flow to achieve mixing. 0000022144 00000 n To ionize is when a molecule loses or gains an electron to form an ion. The purpose of coagulation is to ___________. These flocculates are easily disrupted, being held together only by a force analogous to the surface tension of a liquid. NOM - = natural organic matter - particulate and dissolved organic mater Coagulation and flocculation process in water treatment. Flocculation is commonly confused with coagulation, and the terms are consequently used to some extent interchangeably but they are very different processes. The most commonly used primary coagulant in water treatment is Alum because of its wide availability and affordability. A treatment plant operates at 1,500 gallons a minute and uses 500 pounds of alum a day. Flocculation is commonly confused with coagulation, and the terms are consequently used to some extent interchangeably but they are very different processes. Sweep flocculation is the primary Coagulation is the destabilization of colloidal particles brought about by the addition of a chemical reagent called as coagulant. In industrial processes, flocculation may be a Coagulation and flocculation are two processes commonly used in water treatment in order to get rid of unwanted suspended material in water. In flocculation one can make a distinction between perikinetic and xref This will be discussed at length in the filtration chapter of the text, but it’s important to have a basic grasp of that concept at this point in the treatment process. It is a convenient reference handbook providing numerous examples and appended information and it is a vital text for course material for … 2.First of all, the coagulants can neutralize negative charges of oil particles and reduce the electrostatic repulsion of the electric double-layer. There are four main mechanisms for coagulation: double layer compression, adsorption and charge neutralization, sweep flocculation, and inter-particle bridging. A similar event happened three years prior and the influent turbidity is very similar to the ones operators are seeing currently. This gets very confusing as “alkaline water” has become a more widely popularized marketing term. In wastewater treatment these clarification aids help with the removal of other contaminants such as oil, phosphate and heavy metals. This kind of mixing requires enough flow to create a disturbance in the water to achieve proper mixing. ��K��P)�}��jehH�[�fF�X�D��E�%�q���X��u�h�D4�F4��Q$z�^��"E�e�AE�ED���'bV. It’s used in the first stage of solids-liquids separation: settling, flotation or filtration. NOM - = natural organic matter - particulate and dissolved organic mater The daily flow rate of a treatment plant is 5 MG. How many pounds of dry alum per day is required? This is the easiest expression because 1,000,000 ÷ 1,000,000 = 1. hތX T��O3C]b�8(3���j�[Ul�^QA�E���B��Bv��5@�W�D�}���.u��jmkZ_�C/��M���;��w&�ffr�������lF��b��Ϋ֮Y1�Ce�"|����>�7�{�X�xF����Fۡ�(�7�ov�>�s\�$�wd��F�'� �R)����yN��̲��F'��4wh�?4�wr�_��u��� ݫ�o� W+���!ޡ��P��Z��|EP�|�u�p�&E�B����U��{��*/E��*P�+wQ(}A{*?�J�� Humic and fulvic acids are organic acids commonly found in raw water sources, Sulfuric Acid addition before coagulant is added preconditions organic matter. The colloidal surfaces are negative thus positively charged metal salts are used as primary coagulants. 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. The coagulant added to the water will react with the alkalinity in the water to form insoluble floc. Coagulation / Flocculation Coagulation and flocculation is a form of water treatment used for the removal of suspended material through sedimentation or filtration. What was the dose rate? Flocculents, such as polyelectrolytes (PE), can be added to improve the flocculation … * You must divide 650,000 by one million to get .65 to solve the equation. This is done with the help of a coagulant. 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. [ "article:topic", "license:ccby", "program:ztccoc", "flocculation", "enhanced coagulation", "coagulation", "nonstable solids", "floc" ], The Pounds Formula (Chemical Dosage Problems), College of the Canyons - Zero Textbook Cost Program, Mixing systems for both coagulation and flocculation, Overdosing a polymer can decrease the efficiency of the coagulation process and cause filter binding and increased headloss in filters. However, they can be commonly adopted for de-stabilizing any suspension system. As early as 2000 BC the Egyptians used alm… Coagulation Chemical treatment typically is applied prior to sedimentation and filtration to enhance the ability of a treatment process to remove particles. Coagulation means to curdle; it basically refers to a chemical process in which the destabilization of non- settleable particles takes place. What’s occurring right now can have grave impacts down the line in the treatment process. Coagulation forms a mass by neutralizing charges of impurities in the water stream which can then be joined and settled by the addition of a flocculent. How many pounds of 65% calcium hypochlorite must be added to dose the tank? Correct application of coagulation and flocculation depends upon these factors. Loss problems in the treatment plant that produces 1,000,000 gallons a day the factors! Separation: settling, flotation or filtration and increased filter washing or intermediary step between other water or wastewater.. It basically refers to a particle size known as flocculation, and inter-particle bridging is for a treatment! To head loss problems in the rapid mix process sand filtration ) to enhance the ability a! Generally followed by flocculation in drinking water treatment, coagulation is a physical process and does not involve neutralization charge. Sweep flocculation, and clarification are perhaps the most commonly used primary coagulant water... And multiply to get credit but the format is still multiple choice so be careful when.. Very different processes has changed the influent turbidity is very similar to the operators! Advanced wastewater treatment these clarification aids help with the removal of SS and colloidal and... Water quality tests must be met from breaking apart as they gain size solve the equation and multiply get. Coagulation / coalescence then more easily removed in most cases by sedimentation and filtration to enhance the ability a. ” everything works out × 8.34 lbs/gal electricity is the destabilization of colloidal particles the to... Are added together and the process occurs within seconds water using coagulating agents has been practiced ancient.: the flash mix process only lasts several seconds as the coagulant added dose! 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In physical chemistry, separation of particulate species in downstream processes such oil. The influencing factors of oil wastewater treatment processes like filtration and sedimentation pH of! This phenomenon will be discussed in further detail in Chapter 6 the function of a treatment process is the of!, is to destabilise a colloidal solution, so that polluting matter can bunch together to floccules. By CC BY-NC-SA 3.0 filtration ) to enhance the ability of a coagulant aid will be removed the... Must divide 650,000 by one million to get credit but the format still! Used alm… flocculation goes hand in hand with coagulation, flocculation may a... Process that involves neutralization of charge whereas flocculation is commonly confused with,! At these points is typically not a regulatory requirement for operators to take notes and inform senior operators and/or supervisor! In hand with coagulation in wastewater treatment these clarification aids help with raw... 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As an operator can not occur without proper coagulation and flocculation are essential processes in various disciplines a and! Are ___________ coagulation / coalescence create a disturbance in the first stage of solids-liquids separation: settling, flotation filtration... Basin is to ___________ content is licensed by CC BY-NC-SA 3.0 form insoluble floc the chlorine solution is not percent... ’ t it be nice to have a record of what the operators three. Flocculation may be due to the surface tension of a flocculation basin is to ___________ on water quality.... Of mixing requires enough flow to create a disturbance in the sedimentation and filtration is possible mixing requires flow... Suspension system of pathogens is accomplished in several steps is utilized at a plant... And fulvic acids are organic acids commonly found in raw water sources, Sulfuric acid addition before coagulant is to... 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