4.5 Design of Sedimentation tanks 4.5.2 Flocculent Sedimentation ( type 2 and 3): The design procedure for sedimentation tanks of type 2 and 3 are the same as type 1. tank. Determine the following: V W P G G = velocity gradient, sec-1 W = power imparted per unit volume of basin, N-m/s-m3 P = power imparted, N-m/s s ft. = 40 2 10 100 s ft. ft. 7.48 P gallons gallon P =0.427lbf s = 0.58 watts 1.355818 =0.427 P lbf watts s lbf s CIVL 1112 Water Treatment - Coagulation and Flocculation 6/7 RAPID MIXING DESIGN Design parameters for rapid-mix units are mixing time t and velocity gradient G. The velocity gradient is a measure of the relative velocity of two particles of fluid and the distance between. In some cases, the use of a coagulant or flocculant is sufficient to form settleable and floating floccules. Flocculation Compute the power requirements for a 100 gallon tank mixing water at a velocity gradient of 40 fps/ft: 2 3 5 2 ft. lb. •The mixture is slowly stirred to induce particles to clump together into “flocs.” •The water is then moved into a quiet sedimentation basin to settle out the In the coagulation process, chemicals are added which will It can be manufactured with different diameters, 800 to 3000 mm. - Two baffles were chosen … as adsorption , flocculation, electro-coagulation and flotation (Zouboulis, et al., 2000). This article provides an overview of the processes and looks at the latest thinking. 2. Figure 1 depicts the coagulation process in the resident tank by the diagonal lines. An operator cannot just set a dose and “hope” everything works out. Material for this article was largely taken from reference 1. 544 9 Coagulation and Flocculation the coagulation and flocculation processes. Coagulation and flocculation are often used in combination. Design of Rapid, Key Difference – Coagulation vs Flocculation in Water Treatment Water treatment is an important aspect which involves many different steps. Basic principle of flocculation: The flocculation step can only operate on a water/wastewater where the particles are already destabilized. Materials & Methods: This study is an applied-experimental study. Coagulation and flocculation processes are used to separate the suspended solids portion from the water. Detention times for flocculation = 20 to 60 minutes; Shape of the tank = Circular or rectangular; Depth of the tank = 3 to 4.5m; Total area of paddles = 10 to 25% of the vertical cross-sectional area of the tank; Velocity gradient, G = 20 to 75 / s 1.2.1. Design criteria for Mechanical flocculator are furnished below. The rapid mixing and flocculation tank together bring about aggregation and comprises the coagulation process. Although upflow units may provide more efficient sedimentation than horizontal designs, many upflow clarifiers compromise on the rapid and slow mix sequences. The currents can be beneficial in that they promote flocculation of the particles. Exit to the sedimentation tank entrance channel Design Considerations •The length of the flocculator channels matches the length of the sedimentation tank •Width of the flocculation channel? The aim of coagulation is to destabilise a colloidal solution, so that polluting matter can bunch together to form floccules. That is why Premium is specific for flocculation. The results confi rmed that the method used to design certain parameters of the tank are fairly accurate. There are four main mechanisms for coagulation: double layer compression, adsorption and charge neutralization, sweep flocculation, and inter-particle bridging. efficiency of coagulation and flocculation process along with chemical sequestration in the removal of organic and inorganic pollutants from automotive industry sewage. Most galvano companies generate wastewater containing metal ions. Some of the water current problems can be reduced by the proper design of the tank… Design a procedure to determine the proper flocculant dose. Flocculation Removal of TSS by flocculation Agglomeration of destabilised particles to a large size particles known as flocs , can be effectively removed by sedimentation or flotation. _____ •Material limitations (polycarbonate or concrete) •Vary to optimize flocculation … Consider the following in your design: 1. This design is aimed to prevent the fluid coming out from one blade to immediately meet the second blade. However, water currents also tend to distribute the floc unevenly throughout the tank; as a result, it does not settle out at an even rate. tank. Academia.edu is a platform for academics to share research papers. This method has a preference in the primary purification processes mainly due to the ease WATER TREATMENT PROCESSES – COAGULATION AND FLOCCULATION LEARNING OBJECTIVES • Analyse the chemistry of coagulation … Optimum retention time in pilot unit is equal to 2.5 h compared to 3.5 h for conventional chemical treatment. In case of tapered flocculation, which is often a preferred option in efficient and energy-saving flocculation process, G values can be set as follows: 100 sec-1 in 1st tank. You should have at least 4 different samples that can range in dose from 0 mL to 5 mL of alum solution. Coagulation and flocculation are an essential part of drinking water treatment as well as wastewater treatment. Flocculation … 50 -60 sec-1 in 2nd tank. A. Coagulation uses salts such as aluminum sulfate (alum) or ferrous of ferric (iron) salts, which bond to the suspended particles, making them less stable in suspension, i.e., more likely to settle out. A combined unit in which process of coagulation, flocculation and sedimentation, has been designed and operated utilizing hydraulic mixing. •Minimum? The purpose of coagulation and flocculation is to remove particulate impurities, especially non-settleable solids and colour from the water being treated. Coagulation in Water Treatment Salts of Al(III) and Fe(III) are commonly used as coagulants in water and wastewater treatment. A common use of coagulation and flocculation for wastewater treatment is in the galvanic industry. When a salt of Al(III) and Fe(III) is added to water, it dissociates to yield trivalent ions, which hydrate to form aquometal complexes Al(H 2 O) 6 3+ and Fe(H 2 O) 6 3+ . Flocculation. Non-settleable particles in water are removed by the use of coagulating chemicals. The theoretical mean hydraulic detention time of the tank will be 1 minute. The design flow for a water treatment plant (WTP) is 1 MGD (3.8x103 m3/d). Since water treatment is a very sensitive and important process it requires the presence of both physical and chemical processes. Coagulation Removal of TSS by coagulation Removal of TSS, (total suspended solids) from waste water. Specific topics include (1) the role of coagulation and flocculation processes in water treatment, (2) sta-bility of particles in water, (3) coagulation theory, (4) coagulation practice, (5) coagulation of dissolved and organic constituents, (6) flocculation - The length of the tank was chosen as 1 m and the corresponding depth to provide a volume of 5.70 m3 was determined to be 3.00 m. The depth was checked to be between 1.1-1.6 times the width of the tank, as per normal design standards. Use the Flocculation and Sedimentation Protocol in your design. Typical detention time is 1 hour. Flocculation is the step where destabilized colloidal particles (or the particles formed during the coagulation step) are assembled into aggregates. View Design of Coagulation Rapid Mixing System(1).pdf from AA 1Design of Coagulation & Flocculation Processes Rapid Mixing System Draft Lecture Notes Contents Prelim. Coagulation-Flocculation •In conventional coagulation-flocculation-sedimentation, a coagulant is added to the source water to create an attraction among the suspended particles. 3. The cost of coagulant and size of the plant are important factors to be considered in the design of a clariflocculator; Coagulation and flocculation play a very important role in any water treatment plant. Coagulation, Flocculation, Sedimentation 1. Coagulation / flocculation is a widely-used process in the primary purification of water and in industrial wastewater treatment. The difference is mainly in the overflow rate (v 0) .The following table gives the design criteria of these two types. Water quality can change frequently and operators must ensure they are on top of changing conditions. The coagulation and flocculation process requires a great amount of attention to detail along the way. Destabilization of colloids by addition of chemicals. A jar test simulates the coagulation and flocculation processes Fill the jars with raw water sample (500 or 1000 mL) – usually 6 jars Adjust pH of the jars while mixing using H 2 SO 4 or NaOH/lime (pH: 5.0; 5.5; 6.0; 6.5; 7.0; 7.5) Add same dose of the selected coagulant (alum or iron) to each jar Therefore, it is perfect when managing very delicate applications, where the fluid needs to be handled very gently and carefully. By the use of coagulation and flocculation these ions can be precipitated and settled in a sedimentation tank or … 20-30 sec-1 in 3rd tank Design Considerations of Flocculation: View 3 Coag+Flocc 1.pdf from CIVE 4407 at Carleton University. It is the logical step following coagulation. The gentle mixing is usually done mechanically although hydraulic mixing is sometimes required. Homework #6. Coagulation and flocculation are essential processes in various disciplines. Coagulation and Flocculation Cost NCF 4.8 or 5 units Project 1 – Treatment Cost The total yearly cost of the coagulation and flocculation system for 20 MGD is: $25,000 5 CF year Cost 7 9.462×10-5 kg 2 10 gal 365 days $0.25 gal day year kg Coagulation and Flocculation Cost $297,691 Project 1 – Treatment Cost Sedimentation System Cost When coagulants are added, the stabilised colloidal system of water is disturbed and the coagulant forms primary flocculation particles. 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