What is secondary clarifier?
The secondary clarifier can be described as a circular basin where effluent from the activated sludge process is held. The biomass of microorganisms settles to the bottom in the form of activated sludge. After settling over a period of time, this biomass of microorganisms is returned to the first aeration tank.
Why is it called the secondary clarifier?
Settling tanks, called secondary clarifiers, follow the trickling filters. These clarifiers remove microbes that are washed off the rocks by the flow of wastewater. Two or more trickling filters may be connected in series, and sewage can be recirculated in order to increase treatment efficiencies.
What does a secondary clarifier remove?
Sedimentation tanks called secondary clarifiers remove flocs of biological growth created in some methods of secondary treatment including activated sludge, trickling filters and rotating biological contactors.
What is the main purpose of a secondary clarifier?
Gravity sedimentation occurs in basins frequently called clarifiers. Secondary clarifiers are used to remove the settlable suspended solids created in biological treatment processes such as the activated sludge and trickling filter process.
Why is a secondary clarifier needed after an aeration tank?
The function of the secondary clarifier is to separate the activated sludge solids from the mixed liquor. These solids represent the colloidal and dissolved solids that were originally present in the wastewater. Some sludge is being removed continuously to be used as returned sludge in the aeration tanks.
What is the primary function of a secondary clarifier?
The secondary clarifiers have two key functions: clarification of the biologically treated wastewater; and thickening and storage of the sludge from the biological treatment process.
How secondary treatment is carried out?
Secondary treatment is the removal of biodegradable organic matter (in solution or suspension) from sewage or similar kinds of wastewater. This is achieved with physical phase separation to remove settleable solids followed by a biological process to remove dissolved and suspended organic compounds.
What is the purpose of bubbling air in aeration tank during the treatment of sewage?
Compressed air is bubbled through the watery waste in the aeration tank to provide oxygen to activate aerobic bacteria and make them grow rapidly in this water so they can break down wastes in microscopic level in wastewater treatment’s aeration tank.
What is the function of secondary clarifier?
secondary clarifiers is to separate biological floc from the treated liquid waste stream. Secondary clarifiers are most often discussed in conjunction with suspended growth biological wastewater treatment systems.
Why is secondary clarifier important?
The function of the secondary clarifier is to separate the activated sludge solids from the mixed liquor. These solids represent the colloidal and dissolved solids that were originally present in the wastewater. The cycle of sludge removal from the secondary tanks is much more important than with primary tanks.
What does secondary clarifier do?
A secondary clarifier is a tank that is used to remove biological matter that a primary clarifier will not address. As such, this equipment plays a crucial role in the wastewater treatment process.
What is a primary clarifier?
Primary Clarifiers. The purpose of a primary clarifier is to create a relatively quiescent area where solids with a higher specific gravity than liquid will tend to settle and those with a lower specific gravity will tend to rise.
How does a clarifier work?
The clarifier works by permitting the heavier and larger particles to settle to the bottom of the clarifier. The particles then form a bottom layer of sludge requiring regular removal and disposal. Clarified water then proceeds through several more steps before being sent for storage and use.