- Bar Screen or Septic Tank (Optional): Preliminary Treatment, such as a bar screen, in-
line grinder or Septic Tank, is typically provided to accept raw sewage from the building
services to intercept and remove rags, plastics and debris which would impair the process
or clog the pumps. Restaurant or other special wastewater should have additional grease
traps or preliminary treatment as appropriate.
- Influent Batch Equalization (EQ) Tank: Effluent from Preliminary Treatment
discharges into the Influent EQ Tank. The Influent EQ Tank stores the wastewater until
the volume of one batch is reached. The Influent EQ Tank is aerated intermittently to
maintain sufficient dissolved oxygen to prevent the generation of odours and the settling
of solids.
- Influent Pumps: The wastewater is pumped from the Batch EQ Tank to the SBR Tank.
Influent Pumps are controlled by the PLC and a water level input from a float or pressure
transducer in the Influent Tank.
- SBR Tanks: Upon completion of the Filling Stage, the Influent Pump shuts off and the
Reaction Stage begins. The SBR Tank is aerated by diffusers mounted near the bottom of
the tank, and supplied by an air blower in the control building. During this stage the
microorganisms in the SBR mix with the wastewater and, through biological activity,
break down and consume the organics and nutrients in the wastewater. After the
Reaction Stage is completed, the blower is either turned off or redirected to aerate another
SBR Tank. Suspended solids in the SBR are allowed to settle in the Settling Stage.
- Aeration System: Aeration of the Influent EQ and Sludge Tanks is accomplished by
coarse bubble diffusers for maintenance-free effective mixing and oxygen transfer.
Aeration of the SBR Tanks is accomplished by fine bubble diffusers with superior oxygen
transfer capacity. Blowers are typically regenerative type for low energy consumption
and low noise generation.
- Decant Pumps: Decanting of the SBR Tanks can be by pumping or by gravity. Depending on the configuration, the Decant System would consist of either Decant Pumps or Decant Valves (actuated pinch valves). Following the Settling Stage, the PLC signals the decant mechanism to start decanting. The Decant Pump turns on or the Decant Valve opens to transfer the process effluent to the next stage of treatment such as filtration, disinfection, effluent storage (if reuse is proposed), or outfall.
- Sludge Pumps: The population of microorganisms will increase over time. In order to
maintain an optimum population, some of the settled sludge must be removed from the
SBR Tanks. A Sludge Pump is provide in each SBR Tank to transfer some of the settled
sludge into the Sludge Tank.
- Sludge Management System: The Sludge Tank has an overflow at the normal operating
water level which leads to the Influent EQ Tank. This maintains the level of this tank full
under normal operating conditions. As the waste sludge is pumped into the Sludge Tank,
this displaces the same volume of supernatant into the Influent EQ Tank. The Sludge
Tank is aerated intermittently by diffusers which are supplied by an air blower in the
control building. Accumulated sludge should be pumped out of the Sludge Tank on a
regular basis. By observation of the sludge blanket level with a "Sludge Judge" or a
Secchi disk, the operator would arrange for the removal of the settled sludge as required.
- Tanks (FRP Option) : Heavy duty fiberglass vessels are typically supplied. The vessels
have internal baffles to separate the various functions. Tanks are complete with access
hatches for operation and maintenance.
- Tanks (Concrete Option): Tanks are constructed of reinforced concrete including a top
slab with access hatches for maintenance. Tanks are to be watertight including sealing
around pipe penetrations. The top slab of the tanks may serve as the floor of the control
building. This arrangement has been incorporated successfully in three of our SBR
facilities. ABL prepares dimensional drawings for structural design of the tanks by
others.
- Disinfection System (Optional): If disinfection is required, the plant can be equipped
with either sodium hypochlorite or ultraviolet disinfection. The disinfection system is
sized to suit the discharge rate of the plant.
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