The jar test is a common laboratory procedure used to determine the optimum operating conditions for water or wastewater treatment. 2.1.1 Coagulation and Flocculation Coagulation, a process of agglomerating colloidal particles, using chemicals such as aluminum sulfate, ferrous sulfate, ferric chloride, aluminum chloride, etc. This information can be recompiled into the following chart . ENMESHMENT IN A PRECIPITATE (Sweep-Floc Coagulation) When a metal salt is added to water in concentration sufficiently high Precipitates of metal hydroxides (e.g., Al (OH)3, Fe (OH)3 with form Colloidal particles can be enmeshed (entrapped) in the precipitates and settle with them 33. In coagulation, the forces responsible for keeping the particles apart after they contact, are reduced. Flocculation brings the de-established colloidal particles together and they form large aggregates. The downstream processing of rhamnolipid using synergistic action of sweep-floc coagulation and acidification also puts forward an efficient cost effective strategy with only 2 % loss, an important aspect to be considered in the current industrial market scenario, with market price of rhamnolipid biosurfactants (90 % purity) ranging between 3253$ (Sigma-Aldrich) - 700$ (Natsurfact)/kg. In contrast, in flocculation, the de-stabilization is brought about by physical techniques such as mixing of the solution, and also sometimes by the addition of polymers. See our User Agreement and Privacy Policy. Thus, we can understand the process of coagulation and flocculation with the help of examples derived from water treatment techniques. What is a Coagulation Jar Test Procedure, Destabilization using Al(III) and Fe(III) Salts. The results presented here provide insight to jar test data and help explain why better settling often is observed in practice for sweep-floc coagulation as compared to floc produced by a charge-neutralization mechanism. For this reason, fluid shear is the primary mechanism of floc formation, making the mechanical mixing of the water important in flocculation. This process is known as the ‘sweep-floc’ mechanism. But the phenomena are also well-known from everyday life – especially coagulation. After flash mix, the water heads to the flocculation basins to allow floc particles to gather in size. Sedimentation, flotation and/or filtration systems are then used to separate the floc (see the section sedimentation, filtration, as well as flocculators – settlin… You can change your ad preferences anytime. Flocculants, or flocculating agents (also known as flocking agents), are chemicals that promote flocculation by causing colloids and other suspended particles in liquids to aggregate, forming a floc. Typically aluminum or iron salts are used. The second explanation was called sweep flocculation and was the catch all explanation that was used to describe observations that didn’t fit the charge neutralization explanation. dosages may approach those of the sweep floc range, probably dont get sweep floc because much of the coagulant is used by the colloids. Water supply system - Water supply system - Coagulation and flocculation: Suspended particles cannot be removed completely by plain settling. Destabilization using Al(III) and Fe(III) Salts Customer Code: Creating a Company Customers Love, Be A Great Product Leader (Amplify, Oct 2019), Trillion Dollar Coach Book (Bill Campbell). When the mechanism is charge neutralization, the detention time needed may be one second or less. If you continue browsing the site, you agree to the use of cookies on this website. Floc point, also known as Freon floc point, is used to measure the performance and consistency of refrigeration oils. It potentially results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair. Dated: 8th October, 2017 When the mechanism is sweep floc or entrapment, longer detention times on the order of 1 to 30 seconds may be appropriate. Coagulation, also known as clotting, is the process by which blood changes from a liquid to a gel, forming a blood clot. What is a Colloidal Suspension – Definition, Properties, Process. Since the beginning, the objective of water treatment has not changed i.e. This method allows adjustments in pH, variations in coagulant or polymer dose, alternating mixing speeds, or testing of different coagulant or polymer types, on a small scale in order to predict the functioning of a large scale treatment operation. However, the SFmechanism has also its CN property moreover than its well-known weighting characteristic. Colloid Entrapment Occurs when large dosages of coagulant are added which precipitate as hydrous metal oxides. As early as 2000 BC the Egyptians used al… Bench-scale experiments were performed to evaluate virus control by an integrated electrochemical–microfiltration (MF) process from turbid (15 NTU) surface water containing moderate amounts of dissolved organic carbon (DOC, 5 mg C/L) and calcium hardness (50 mg/L as CaCO3). Associate Professor Water treatment process is the process in which water from various sources is treated to a water quality or standard that meets its intended use. Because of this, the sedimentation step is usually preceded by a chemical process known as coagulation. Methods of Flocculation. Physico Chemical Processes (EN 525) A rpm gage at the top-center of the device allows for the uniform control of the mixing speed in all of the containers. FLOCCULATION Higher reductions in MS2 bacteriophage concentrations were obtained by aluminum … Other particles in the water are swept up into the coagulant flocs and are removed during sedimentation. 4. The jar testing apparatus consists of six paddles which stir the contents of six 1 liter containers. A … coagulation, flocculation, sedimentation, water treatment Educational Standards ... sweep flocculation, and inter-particle bridging. Particles were presumed to be swept into a mesh of coagulant precipitate at coagulant dosages that are typically used in … Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. 1. Precipitation of amorphous metal hydroxide is necessary for sweep-floc coagulation. [1] Agglomeration (except in polymer science) However, the SF … Examples of inorganic coagulants are as below: Aluminum Sulfate (Alum) – One of the most commonly used water treatment chemicals in the world. In this scenario its almost impossible to overdose. Sometime high molecular weight polymers are also added known as coagulant aids. Shown Above: The flash mix portion is also known as coagulation. This article provides an overview of the processes and looks at the latest thinking. We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. Al3+ + 3 ... particles come close to each other to produce larger visible flocs. Large, heavy particles settle out readily, but smaller and lighter particles settle very slowly or in some cases do not settle at all. One container acts as a control while the operating conditions can be varied among the remaining five containers. Coagulation and flocculation processes are used to facilitate the elimination of suspended solids and colloids by gathering these together to form floc. In potable water treatment, clarification of water using coagulating agents has been practiced from ancient times. Jar Testing Apparatus Coagulation and flocculation are well-known techniques within wastewater treatment. Disinfection for killing bacteria viruses and other pathogens. The process is basically a combination of destabilisation (charge neutralisation) and transport (physical entrainment) (Amirtharajah, 1990). APIdays Paris 2019 - Innovation @ scale, APIs as Digital Factories' New Machi... No public clipboards found for this slide. They help in binding and strengthen the floc … suspension and settled along with the sinking iron or aluminium. Jar Test Larger floc settle and filter easier than small pin-point or carry-over floc. Now customize the name of a clipboard to store your clips. Sedimentation for solids separation 6. Flocculation, in the field of chemistry, is a process wherein colloids come out ofsuspension in the form of floc or flake; either spontaneously or due to the addition of aclarifying agent. Thus, pH must be controlled to establish optimum conditions for coagulation. AND See our Privacy Policy and User Agreement for details. Also we get stoichiometry of coagulation. Treatment Process to produce water that is free of chemicals and microorganisms, and is aesthetically pleasing. Abstract and Figures The coagulation/flocculation (C/F) processes are mainly due to charge neutralisation (CN) and sweep flocculation (SF) mechanisms. From the numerous reviews of the fundamental theory and mechanisms of coagulation, Roll No. 2. However, a downside of metal hydroxide precipitate sweep-floc is that they add to the overall sludge volume that must be treated and removed. Dissolved organic can be removed by adsorption on aluminum precipitation (Benschoten, 1990). Flocculation takes out suspended colloids. Overview of the Process Image of floc … The sweep flocs can be described as large aggregates of Al (OH)3/Fe (OH)3 that are formed when Al/Fe salt is added to water. The chemicals are added together and the process occurs within seconds. neutralization or coagulation of colloidal particles in the presence of Al (OH) 3 is termed as enmeshment or sweep floc. It is found that fractal dimension is lower for sweep-floc coagulation where larger and more irregular aggregates are produced. However, this can add to the overall sludge volume that must be treated and removed, so it’s not the right choice in every scenario. 1 Coagulation and flocculation are an essential part of drinking water treatment as well as wastewater treatment. Smaller floc also may not settle. Clipping is a handy way to collect important slides you want to go back to later. this blog include Treatment process and Equipment for … • The floc will then settle out in the sedimentation basin, with remaining floc being removed in the filter. Both these techniques are employed in the treatment of water. These help to clean the water by absorbing impurities in the water as they fall. Filtration to remove particles 7. Material for this article was largely taken from reference1.Coagulation and flocculation are essential processes in various disciplines. : EN 18 / 2017 - 18 Submitted to: Dr. Atif Mustafa They are typically used for treatment of wastewater containing colloids (suspended particles) and metal ions. When added to water, inorganic coagulants form aluminum or iron precipitates. The solubility of Al (OH) 3 (s) and Fe (OH) 3 (s) is minimal at a particular pH and increases as the pH increases or decreases from that value. Mechanical flocculators can be installed both horizontally and vertically. This is the key difference between coagulation and flocculation. Coagulation and Floculation - Free download as Powerpoint ... enmesh the colloids in a “sweep floc”. Flocculants are used in water treatment processes to improve the … If you continue browsing the site, you agree to the use of cookies on this website. • The best floc size is 0.1 to 3 mm. Coagulation in Water Treatment 3) ENMESHMENT IN A PRECIPITATE (Sweep-FlocCoagulation) When a metal salt (e.gAl2(SO 4)3or FeCl3) is added to water in precipitatatesof metal hydroxides [e.g., Al(OH) , Coagulation& Flocculation: Destabilization of Colloids concentrations sufficiently high 3 Fe(OH)3] willform colloidalparticlescan be enmeshed (entrapped) in the precipitatesandsettle Coagulant aids, also known as polyelectrolytes - which improves coagulation and for more robust floc formation 5. NED University of Engineering & Technology. KASHIF SHABBIR Sweep floc occurs when coagulant is added past the point of solubility, creating insoluble “flocs” that aggregate. Flocculation (in polymer science): When a sol is colloidally unstable (I.e., the rate of aggregation is not negligible) then the formation of aggregates is called flocculation or coagulation. After employing the flocculation process, the coagulated particles form a large agglomeration, which is also known as floc. The action differs fromprecipitation in that, prior to flocculation, colloids are merely suspended in a liquid and not actually dissolved in a solution. This is the most popular mode of coagulation used in both wastewater and Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Also known as Sweep Floc. Department of Environmental Engineering The coagulation/flocculation (C/F) processes are mainly due to charge neutralisation (CN) and sweepflocculation (SF) mechanisms. ... occur between any size particles. Coagulation can … The time needed to achieve efficient coagulation varies depending on the coagulation mechanism involved. The basis for this domain is not only the kinetics of coagulation reactions but also … diagram the area defined as optimum sweep coagulation is the area for best settling floc, and is defined by the major parameters of alum dose of 20-60 mg/l and a pH of 7.0 to 8.0. 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