Unit: 5

Design criteria and design of Clari flocculator : 

Design criteria for Clari flocculators include the following:

Flocculation Efficiency: The ability of the Clari flocculator to form large, heavy particles (flocs) from smaller, lighter particles. This is typically measured by the size and density of the flocs formed, as well as the settling rate of the flocs. 

Flow Rate: The amount of water that the Clari flocculator can handle per unit of time. This is typically measured in cubic meters per second (m3/s) and should be consistent with the flow rate of the treatment process.

Mixing Time: The amount of time required for the flocculent to fully mix with the water. This should be as short as possible to minimize the residence time and ensure efficient treatment.

Size and type of Clari flocculator: The size and type of Clari flocculator should be chosen based on the flow rate and the treatment process. Clari flocculators can be of different types such as in-line Clari flocculators, static Clari flocculators, and mechanical Clari flocculators.

Materials: The materials used to construct the Clari flocculator should be corrosion-resistant and able to withstand the chemicals used in the treatment process.

Maintenance: The ease of cleaning and maintaining the Clari flocculator. This includes factors such as the design of the Clari flocculator, the materials used to construct it, and the ability to easily access and remove debris.

Cost: The initial and ongoing costs associated with the Clari flocculator, including purchase price, installation costs, and maintenance costs.

Safety: The design should include safety features such as emergency shut-off valves, to minimize the risk of accidents.

Compliance with regulatory requirements: The design should comply with the relevant regulatory requirements, such as safety and environmental regulations.

Energy consumption: The Clari flocculator should be designed to minimize energy consumption, and maximize the flocculation efficiency.

The design of a Clari flocculator typically involves determining the appropriate type and size of Clari flocculator, as well as the materials and features that will be used to achieve efficient flocculation. 

The Clari flocculator is usually placed after the rapid mixer, where it forms large, heavy particles (flocs) from smaller, lighter particles by slow mixing of water and flocculent. 

The design should also consider the location of the Clari flocculator, it should be placed in an area where it is easy to access and maintain, and where the water flow is not too fast, so that debris can be easily removed. 

Clari flocculator is a specific type of flocculator which uses a combination of flocculation and clarification process to remove suspended particles, algae, and other impurities from water. 

Design criteria and Design of Primary Sedimentation Tank : 

Design criteria for primary sedimentation tanks (PSTs) include the following:

Sedimentation Efficiency: The ability of the PST to remove suspended solids from the water. This is typically measured by the percentage of solids removed and the settling rate of the solids.

Flow Rate: The amount of water that the PST can handle per unit of time. This is typically measured in cubic meters per second (m3/s) and should be consistent with the flow rate of the treatment process. 

Detention Time: The amount of time that the water remains in the PST. This should be sufficient to allow the solids to settle and be removed, but not so long that the water becomes stagnant.

Size and shape: The size and shape of the PST should be determined by the flow rate, the type of solids to be removed, and the available space. PSTs can be circular, rectangular or any other shape that suits the site location.

Materials: The materials used to construct the PST should be corrosion-resistant and able to withstand the weight of the solids.

Maintenance: The ease of cleaning and maintaining the PST. This includes factors such as the design of the PST, the materials used to construct it, and the ability to easily access and remove the settled solids.

Cost: The initial and ongoing costs associated with the PST, including purchase price, installation costs, and maintenance costs.

Safety: The design should include safety features such as emergency shut-off valves, to minimize the risk of accidents.

Compliance with regulatory requirements: The design should comply with the relevant regulatory requirements, such as safety and environmental regulations.

Energy consumption: The PST should be designed to minimize energy consumption, and maximize the sedimentation efficiency.

Design criteria and design of Tube Settlers : 

Tube settlers are used in the treatment of wastewater and are typically installed in the clarification stage of a treatment plant. The design criteria for tube settlers include: 

High surface area to volume ratio: This is important to maximize the settling of particles from the wastewater.

Low Headloss: To minimize the energy required to pump water through the tube settlers, the headloss should be kept as low as possible.

Durability: Tube settlers should be made of materials that are resistant to corrosion and abrasion, and can withstand the harsh conditions of wastewater treatment.

The design of tube settlers typically consists of parallel tubes that are inclined at an angle and arranged in a stacked configuration. 

The tubes are usually made of PVC or HDPE and are typically around 4 inches in diameter and 10-15 feet long. 

The inclined angle of the tubes allows particles to settle to the bottom of the tubes and be removed from the water. 

The stacked configuration increases the surface area available for settling, and also allows for easy removal of the settled particles.