The use of settlers (sedimentation tanks) in water filtration

Settlers are extremely important elements in the water purification process, both in industry and in households. Their main task is to remove suspended solid particles from liquids, which contributes to improving its quality and preventing damage to equipment and installations. In this article, we will discuss what settlers are, list their various types, and indicate methods of their application in water filtration processes. Additionally, we will take a look at newtechnologies and trends in this field that may influence the future of water purification.

What are settlers?

Settlers, also known as sedimentation tanks, are mechanical devices in the form of tanks used for the separation of suspended solid particles from water by utilizing the force of gravity. They operate on the principle of solid particles settling at the bottom of the settler due to a decrease in the flow velocity of the water. They can be used independently or as part oflarger water purification systems, such as treatment plants or sewage systems.

Types of settlers/decanting tanks

Putrefactive settlers

Putrefactive settlers, also known as primary settlers or fermentation settlers, are tanks used in wastewater treatment processes. Their main purpose is to break down organic substances contained in wastewater through the process of anaerobic fermentation.

Septic tanks operate similarly to traditional settlers, but differ in that the process occurs under anaerobic conditions, which promotes the decomposition of organic matter by anaerobic bacteria. As a result of this action, the amount of organic pollutants is reduced, allowing for further wastewater treatment in biological processes.

It's worth remembering: In septic tanks, the mixture of wastewater is retainedfor a certain period, which allows the fermentation process to begin.

In the anaerobic settlers, the mixture of wastewater is retained for a certain period, which allows the fermentation process to begin. During this process, anaerobic microorganisms break down the organic matter contained in the wastewater, leading to the production of gas, mainly methane and carbon dioxide.

Lamella settlers

Lamella settlers are a more advancedof settlers that use special lamella plates to increase the settling surface area and improve the efficiency of the separation process. By using flannel plates, they are able to achieve higher degrees of water purification with lower energy consumption. They are used, among other things, for the separation of sand, clay, or CaCO3 after the carbonation of drinking water.

Gravity settlers

Gravity settlers are the most commonly used typesettlers in the industry and in sewage systems. They operate on the principle of using gravity to separate solid particles from water. Gravity settlers can be used both vertically and horizontally, depending on the specific conditions and requirements of the water treatment process. They are basic equipment used to separate easily settling suspensions from wastewater with a density greater than 1g/cm³.

Radial settlers

Radial settlers utilize centrifugal force to separate the solid phase from the liquid. They are characterized by a design in which the mixture is introduced near the axis of rotation and then undergoes rotational motion, resulting in the separation of solid particles from the liquid.

In radial settlers, the mixture enters the settler in a radial direction and is then distributed along the edge of the rotor. The centrifugal force generated by its rotation causesthe separation of solid particles that settle at the bottom, while the clean liquid is discharged outside.

Methods of using settlers in water filtration

Municipal waterworks

Settlers are commonly used in municipal waterworks to purify water from preliminary reservoirs before water processing. In this case, they are used to remove larger solid particles, which contributes to improvingdrinking water quality for residents of the agglomeration.

Industry

In industry, sedimentation tanks are used to purify water used in production processes, e.g., in the food, chemical, or pharmaceutical industries. In many sectors, they are used to remove contaminants before further water processing.

Wastewater treatment

Sedimentation tanks are key elements inwastewater treatment processes. They are used to separate suspended solids from water before further processing and treatment. The most popular types of settlers used in wastewater treatment plants include:

It is worth remembering: The most commonly used settlers are anaerobic, lamellar, gravitational, and radial settlers.

• Imhoff settler – a device used for separationa separator of liquids from sludge, consisting of two chambers: an upper chamber where solid particles settle, and a lower chamber from which the purified water is discharged.
• Dorra Settler – a technologically advanced separator used for the separation of liquids from sludge, which utilizes special flushing systems for more effective separation of the solid phase from the liquid. It enables the removal of both large and fine solid particles.

New technologies of settlers

In recent years, the development of technologies related to settlers has accelerated, which has impacted their efficiency and application. Innovative solutions have been introduced, such as settlers with an automatic monitoring system that allows for real-time control of the purification process and water quality. Additionally, modern materials used in the construction of settlers increase their resistance to pollutants andcorrosion, which translates to a longer lifespan of the devices. In the future, further development in automation and integration with water management systems can be expected, which may significantly improve the efficiency of purification processes.

Settlers/clarifiers – summary

Clarifiers (also known as settlers) are an essential element of water purification processes both in industry and in households. Thanks to various types and by using their application methods, it is possible to effectively remove suspended solids from water, which contributes to improving water quality and preventing damage to devices and water supply installations.