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ISO9001 Wastewater Treatment Plant Equipment Manufacturer
Eliminating suspended solids from fluids is essential for many wastewater treatment processes. Plants often use clarifiers for this purpose. Clarifiers are settling tanks, so they are also frequently referred to as settlers. In addition, the devices are sometimes used for thickening - in this case, they are called thickeners.
Clarifiers usually have a built-in mechanism that continuously removes solids deposited by sedimentation. The concentrated impurities discharged from the bottom of the storage tank are called sludge, and the particles floating on the surface of the liquid are called scum.
Inclined plate settler is one of the most commonly used clarifiers. This blog will introduce this kind of clarifier comprehensively. After reading this blog, you will know better about the working principles, applications, and advantages of inclined plates settlers.
Inclined plate settler (IPS), also known as lamella clarifier, is a settler designed to remove particles from a liquid. They often replace conventional sedimentation tanks for primary water treatment. They are used in industrial water treatment. Unlike traditional clarifiers, they use a series of inclined plates.
An inclined plate settler or a lamella clarifier uses inclined plate for sedimentation process and solids separation. These inclined plates provide a large effective settlement area with a small footprint. That’s one of the advantages of inclined plates settlers we will talk about in details in the later section.
A typical design consists of a series of inclined plates inside the container. The liquid flow enters from the top of the container and flows down through the feed channel below the inclined plate. The liquid then flows upwards in the clarifier between the inclined plates. During this time, the solids settled on the plate and eventually fell to the bottom of the container. At the bottom of the container, a funnel or funnel collects these particles as sludge. Sludge can be discharged continuously or intermittently. Above the inclined plate, all particles have settled, creating a clear liquid which is discharged by the weir plate into the outlet channel. The clarified liquid leaves the system in the form of an outlet stream.
The inclined plate settler is ideal for applications involving fine-grained solids with varying loads. In some industrial sites, such devices are more common than traditional clarifiers because of their smaller footprint and lower overall cost. These devices are also often favoured by transformation and renovation projects.
A special application of lamella clarifier is to allow liquids to enter certain filters during the pretreatment stage. In fact, inclined plate settlers are considered to be one of the best choices for pretreatment of membrane filters. Their all-steel design means that part of the sloping plate is peeled off and carried into the filter with little chance, especially compared to a tube settler made of plastic or a large concrete body traditional clarifier. In addition, the inclined plate settler can better maintain the liquid quality required for membrane filters than other designs.
Among advantages of inclined plate settlers, a key point is that they can produce a larger effective settlement area by using inclined plates than other clarification systems. This improves the operating conditions of the clarifier in a number of ways. The device is more compact and usually requires only 60-75% of the area of the clarifier to operate without inclined plates. Therefore, a lamella clarifier system is preferred when considering the site footprint limitation. The reduced required area allows the clarifier to be located inside, avoiding the common blockage problems faced by outdoor equipment due to the accumulation of blown debris. For some applications, this is a great advantage. Operating in an enclosed space also provides better control of operating temperature and pressure as well as overall operating conditions. The inclined plates mean that the overflow rate of lamella clarifiers is two to four times that of conventional clarifiers - allowing a larger inlet water flow rate, making the clarification process more time-saving.
Another key advantage of inclined plate settlers is that they have a simple design without any moving parts. As a result, these devices are much less prone to mechanical failure compared to other clarifiers, which makes operation safer and more reliable. In addition, these devices typically do not require the use of chemicals for clarification and solids separation. Therefore, they can be used as pretreatment for fine filtration processes.
Even though inclined plate settler can overcome many problems encountered by using more conventional clarifiers, they do have some disadvantages. The lamella clarifier can not handle most raw liquid combinations, which require some pretreatment (e.g., fine screening) to eliminate materials that may decrease separation efficiency. In addition, the layout of lamella clarifiers creates additional turbulence as the liquid moves from the feed to the corner of the inclined plates. The area of increased turbulence coincides with the sludge collection point, and the flowing liquid will cause the solids to re-suspend while diluting the sludge. This leads to the need for further processing to remove excess moisture from the sludge. The inlet and outlet of the clarifier should be designed so that the flow is evenly distributed.
Regular maintenance is required because the sludge will run down the swash plate, making them dirty. Regular cleaning helps prevent uneven flow distribution and reduces process efficiency. Tightly packed plates make cleaning difficult. However, a movable and independently supported plate can be installed. There are many proprietary swash plate clarifier designs. Sloping plates can be based on round, hexagonal or rectangular tubes. As a rough guide, the board spacing is usually about 50 mm and the board length is 1-2.5 m. The minimum plate spacing is approximately 10 °. The 45 ° to 70 ° pitch allows self-cleaning. Smaller pitches require cleaning with backwash fluid flow.
Nothing is perfect. The inclined plates settler maybe not the best clarifier in some terms. However, we can not ignore the advantages of inclined plates settlers that give to some specific applications, such as cost reduction, floor space savings and performance advantages.
That’s our guide to inclined plates settlers. We, Jinwantong, has been dedicated to lamella clarifier for years. If interested in this kind of clarifier, please contact us and will provide you with the best device and solution.