SAZ ENVIRO Secondary Circular Clarifiers are specifically engineered to produce high-quality effluent with minimal organic material and suspended solids, suitable for either direct environmental discharge or further treatment. These clarifiers are vital in the secondary stage of wastewater treatment, effectively separating biological floc and colloidal solids formed during the biological treatment process. With a range of customizable features, SAZ ENVIRO ensures optimal separation and sedimentation, delivering superior effluent quality.

Secondary Clarifier Influent and Functionality

Typically, the influent to a secondary circular clarifier is a mixture of water and microorganisms, referred to as mixed liquor, from an aeration tank. This mixture incorporates the activated sludge process, where microorganisms consume and break down organic material. After this biological degradation, the secondary clarifier separates these microorganisms and any remaining solids from the water.

SAZ ENVIRO provides advanced inlet designs for improved sedimentation. A central Energy Dissipating Inlet (EDI) can be utilized to ensure that the influent is evenly distributed throughout the clarifier, minimizing turbulence and enhancing the settling process. In some applications, SAZ ENVIRO can design a peripheral feed system that distributes the influent around the perimeter of the tank, which further aids in settling activated sludge. Both options are tailored to the influent characteristics and customer requirements to ensure optimal clarifier performance.

In addition, SAZ ENVIRO can incorporate mechanical flocculation and chemical coagulants to improve the recombination of suspended solids that may have broken apart during transport from the aeration basin. An enlarged flocculation zone can be custom-designed to provide increased residence time for suspended solids, promoting the formation of larger, more settleable flocs. This ensures that the clarifier achieves superior separation efficiency, particularly when treating mixed liquor suspended solids (MLSS).

Drives and Sludge Collection Mechanisms

The sludge collection system in an SAZ ENVIRO Secondary Circular Clarifier is a critical element that ensures continuous removal of settled solids. Typically, a radial tube header with orifices and manifolds is employed. This system uses hydraulic suction to remove settled solids from the tank floor and return them to the head of the activated sludge process (Return Activated Sludge or RAS) or send them to further solid waste treatment (Waste Activated Sludge or WAS).

SAZ ENVIRO engineers carefully design the suction header system, paying close attention to header geometry, orifice placement, and orifice sizing to maintain constant velocities and uniform sludge removal throughout the clarifier. Proper design of these components is essential to prevent uneven sludge accumulation and to ensure efficient solids handling.

In some cases, an alternative riser pipe mechanism may be employed. Similar to suction headers, the riser pipe system uses hydraulic suction to draw settled sludge from the clarifier. The design of the riser pipe system is also carefully engineered to maintain even sludge collection and prevent hydraulic imbalances.

For applications that require more robust sludge management, SAZ ENVIRO offers spiral scrapers or standard scraping mechanisms. These mechanisms continuously sweep the bottom of the clarifier, pushing sludge toward the central collection point. This mechanical action ensures that sludge is regularly removed, preventing buildup and maintaining the performance of the clarifier.

SAZ ENVIRO’s drive systems are designed for durability and longevity. The company offers both cast iron worm gear and fabricated steel precision gear drive assemblies, which are selected based on the specific application requirements. These drive assemblies ensure that the clarifier operates reliably over its long service life, even in harsh environments.

Skimming and Scum Removal Systems

The skimming system in the secondary circular clarifier plays a vital role in removing floating materials such as oils, grease, and other debris. SAZ ENVIRO provides several skimming solutions based on the application’s specific needs. A traditional skimming arm with a scum beach and sludge box is typically used to push floating matter toward the periphery of the tank, where it is collected and removed.

Alternatively, SAZ ENVIRO can furnish a full-radius scum trough or a ducking skimmer system. These advanced skimming systems are designed to maximize scum removal, particularly in applications with high floating material loads. The skimming mechanisms are further enhanced by the 3-axis pivoting scum wiper blade, which ensures continuous contact with the scum beach. This design significantly improves the efficiency of scum removal, ensuring that floating material is effectively collected and removed from the clarifier.

For applications with higher scum loads, anti-rotational scum baffles can be installed to prevent floating materials from drifting back into the effluent stream, ensuring that only clean water is discharged from the clarifier.

Clarifier Effluent and Discharge

The effluent from an SAZ ENVIRO Secondary Circular Clarifier is of high quality, with minimal levels of suspended solids and organic material. This clarified effluent is suitable for direct environmental discharge or further treatment in a tertiary system. To ensure that no floating material contaminates the effluent, SAZ ENVIRO installs scum baffles that prevent debris from reaching the effluent launder.

A properly sized V-notch weir ensures uniform laminar flow throughout the clarifier, further improving the quality of the discharged effluent. SAZ ENVIRO offers weirs, baffles, and launders in a variety of construction materials, including stainless steel, Fiber Reinforced Plastic (FRP), aluminum, and galvanized steel, allowing customers to choose materials best suited to their wastewater characteristics.

To further optimize the sedimentation process, SAZ ENVIRO can integrate Stamford (density current) baffles into the clarifier design. These baffles help control density currents within the clarifier, improving overall sedimentation and ensuring that the effluent quality meets the highest standards. Additionally, launder covers can be installed to protect the effluent from external contamination, providing an extra layer of assurance in sensitive applications.

SAZ ENVIRO offers evaluation services to assess existing clarifiers, providing recommendations for design improvements to maximize performance and effluent quality. By customizing each clarifier to the specific operational needs, SAZ ENVIRO ensures long-term reliability and efficiency.

Key Features of SAZ ENVIRO Secondary Circular Clarifiers:

• Energy Dissipating Inlet (EDI) or peripheral feed system for optimal flow distribution and settling
• Mechanical flocculation and chemical treatment options for improved floc formation
• Hydraulic suction sludge removal systems with radial tube headers or riser pipes
• Durable drive systems with cast iron worm gear or fabricated steel precision gear assemblies
• Advanced skimming systems including full-radius troughs and 3-axis pivoting scum wipers
• Scum baffles, V-notch weirs, and Stamford baffles for improved effluent quality

In conclusion, SAZ ENVIRO Secondary Circular Clarifiers are designed to ensure superior separation of biological solids, producing high-quality effluent while maintaining long-term reliability and operational efficiency. These clarifiers are engineered to handle the demands of industrial and municipal wastewater treatment processes, delivering optimal results for secondary treatment.