have been used in the past for distillery wastewater treatment. [1] Agglomeration (except in polymer science) The process is basically a combination of destabilisation (charge neutralisation) and transport (physical entrainment) (Amirtharajah, 1990). Clipping is a handy way to collect important slides you want to go back to later. However, a downside of metal hydroxide precipitate sweep-floc is that they add to the overall sludge volume that must be treated and removed. Al3+ + 3 ... particles come close to each other to produce larger visible flocs. KASHIF SHABBIR Coagulation and flocculation processes are used to facilitate the elimination of suspended solids and colloids by gathering these together to form floc. But the phenomena are also well-known from everyday life – especially coagulation. Fall 2017 Methods of Flocculation. 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. Mechanical flocculators can be installed both horizontally and vertically. Water supply system - Water supply system - Coagulation and flocculation: Suspended particles cannot be removed completely by plain settling. Flocculants are used in water treatment processes to improve the … • The best floc size is 0.1 to 3 mm. Thus, pH must be controlled to establish optimum conditions for coagulation. In coagulation, the forces responsible for keeping the particles apart after they contact, are reduced. When added to water, inorganic coagulants form aluminum or iron precipitates. Jar Testing Apparatus Coagulation and Floculation - Free download as Powerpoint ... enmesh the colloids in a “sweep floc”. Particles were presumed to be swept into a mesh of coagulant precipitate at coagulant dosages that are typically used in … Sweep floc occurs when coagulant is added past the point of solubility, creating insoluble “flocs” that aggregate. When the mechanism is sweep floc or entrapment, longer detention times on the order of 1 to 30 seconds may be appropriate. When the mechanism is charge neutralization, the detention time needed may be one second or less. 4. Sometime high molecular weight polymers are also added known as coagulant aids. Dated: 8th October, 2017 Overview of the Process Image of floc … this blog include Treatment process and Equipment for … They help in binding and strengthen the floc … After flash mix, the water heads to the flocculation basins to allow floc particles to gather in size. Looks like you’ve clipped this slide to already. 1. 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. Department of Environmental Engineering Also we get stoichiometry of coagulation. 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. Coagulation and flocculation are an essential part of drinking water treatment as well as wastewater treatment. It is found that fractal dimension is lower for sweep-floc coagulation where larger and more irregular aggregates are produced. Shown Above: The flash mix portion is also known as coagulation. The jar testing apparatus consists of six paddles which stir the contents of six 1 liter containers. 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 One container acts as a control while the operating conditions can be varied among the remaining five containers. Roll No. This is the key difference between coagulation and flocculation. The basis for this domain is not only the kinetics of coagulation reactions but also … Thus, we can understand the process of coagulation and flocculation with the help of examples derived from water treatment techniques. dosages may approach those of the sweep floc range, probably dont get sweep floc because much of the coagulant is used by the colloids. The time needed to achieve efficient coagulation varies depending on the coagulation mechanism involved. 1 See our Privacy Policy and User Agreement for details. 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. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. These help to clean the water by absorbing impurities in the water as they fall. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. This is the most popular mode of coagulation used in both wastewater and Because of this, the sedimentation step is usually preceded by a chemical process known as coagulation. 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. This article provides an overview of the processes and looks at the latest thinking. Precipitation of amorphous metal hydroxide is necessary for sweep-floc coagulation. In this scenario its almost impossible to overdose. NED University of Engineering & Technology. Sedimentation, flotation and/or filtration systems are then used to separate the floc (see the section sedimentation, filtration, as well as flocculators – settlin… The action differs fromprecipitation in that, prior to flocculation, colloids are merely suspended in a liquid and not actually dissolved in a solution. This process is known as the “sweep-floc” mechanism. coagulation, flocculation, sedimentation, water treatment Educational Standards ... sweep flocculation, and inter-particle bridging. Other particles in the water are swept up into the coagulant flocs and are removed during sedimentation. Disinfection for killing bacteria viruses and other pathogens. Typically aluminum or iron salts are used. It potentially results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair. This information can be recompiled into the following chart . 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. 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. Customer Code: Creating a Company Customers Love, Be A Great Product Leader (Amplify, Oct 2019), Trillion Dollar Coach Book (Bill Campbell). This is known as ‘sweep-floc’ coagulation (Packham, 1965). Larger floc settle and filter easier than small pin-point or carry-over floc. Coagulation in Water Treatment 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. Coagulation is achieved by neutralizing the particles and thus, the repelling force between the particles is greatly reduced. What is a Colloidal Suspension – Definition, Properties, Process. APIdays Paris 2019 - Innovation @ scale, APIs as Digital Factories' New Machi... No public clipboards found for this slide. Floc point, also known as Freon floc point, is used to measure the performance and consistency of refrigeration oils. As early as 2000 BC the Egyptians used al… Physico Chemical Processes (EN 525) Examples of inorganic coagulants are as below: Aluminum Sulfate (Alum) – One of the most commonly used water treatment chemicals in the world. Larger floc does not settle as well and is more subject to breakup in the flocculation basin. • The floc will then settle out in the sedimentation basin, with remaining floc being removed in the filter. 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. Coagulant aids, also known as polyelectrolytes - which improves coagulation and for more robust floc formation 5. Destabilization using Al(III) and Fe(III) Salts Treatment Process to produce water that is free of chemicals and microorganisms, and is aesthetically pleasing. 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. What is a Coagulation Sedimentation for solids separation 6. However, the SFmechanism has also its CN property moreover than its well-known weighting characteristic. From the numerous reviews of the fundamental theory and mechanisms of coagulation, Submitted to: Dr. Atif Mustafa If you continue browsing the site, you agree to the use of cookies on this website. You can change your ad preferences anytime. See our User Agreement and Privacy Policy. 1. Since the beginning, the objective of water treatment has not changed i.e. Filtration to remove particles 7. Coagulation, also known as clotting, is the process by which blood changes from a liquid to a gel, forming a blood clot. Coagulation and flocculation are well-known techniques within wastewater treatment. AND 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. : EN 18 / 2017 - 18 Jar Test Procedure, Destabilization using Al(III) and Fe(III) Salts. Coagulation can … Jar Test ... occur between any size particles. 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. Higher reductions in MS2 bacteriophage concentrations were obtained by aluminum … 59 (No Transcript) 60 We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. 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. Dissolved organic can be removed by adsorption on aluminum precipitation (Benschoten, 1990). Associate Professor The coagulation/flocculation (C/F) processes are mainly due to charge neutralisation (CN) and sweepflocculation (SF) mechanisms. They are typically used for treatment of wastewater containing colloids (suspended particles) and metal ions. Abstract and Figures The coagulation/flocculation (C/F) processes are mainly due to charge neutralisation (CN) and sweep flocculation (SF) mechanisms. The jar test is a common laboratory procedure used to determine the optimum operating conditions for water or wastewater treatment. Now customize the name of a clipboard to store your clips. After employing the flocculation process, the coagulated particles form a large agglomeration, which is also known as floc. neutralization or coagulation of colloidal particles in the presence of Al (OH) 3 is termed as enmeshment or sweep floc. However, the SF … Also known as Sweep Floc. 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. 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. COAGULATION Smaller floc also may not settle. Zone 4 coagulation, also known as sweep floc, was used for these experiments. A rpm gage at the top-center of the device allows for the uniform control of the mixing speed in all of the containers. Colloid Entrapment Occurs when large dosages of coagulant are added which precipitate as hydrous metal oxides. Material for this article was largely taken from reference1.Coagulation and flocculation are essential processes in various disciplines. In potable water treatment, clarification of water using coagulating agents has been practiced from ancient times. FLOCCULATION For this reason, fluid shear is the primary mechanism of floc formation, making the mechanical mixing of the water important in flocculation. 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). 2. The chemicals are added together and the process occurs within seconds. Flocculation takes out suspended colloids. Large, heavy particles settle out readily, but smaller and lighter particles settle very slowly or in some cases do not settle at all. 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