Major Process Components: Equalization, Sequencing Batch Reactor (SBR), Sludge Digestion, Filtration, PLC control panel.
Napier-Reid Services: Process Design, Instrumentation & Control Design, Electro-mechanical
Supplies, Installation and Commissioning Support, Operator's Training
Scope of Supply:
Equalization Tank: Submersible Sewage Transfer Pumps.
SBR Tanks (Steel), Decanter Assembly - Napier-Reid UD-500, Fine Bubble Aeration Systems, Submersible Waste Sludge Pumps, Fittings, and Valves with electrical actuators.
Effluent Tank (Steel), Submersible Effluent Transfer Pumps
Sludge Digestion Tank (Steel) with Fine Bubble Aeration System.
Blower Assemblies for SBR and Sludge Digestion Tanks including Motors and Accessories.
Continuous Backwash Sand Filters including Filter Tank (Steel), Air Lift Pump, Filter Internals, Media, Compressed Air System with Control Panel.
Alum and Polymer Feed Systems: Day Tanks, Metering Pumps, Valves and Tubings.
UV Disinfection System consisting of UV Modules, Stainless Steel Channels, Weir, UV Intensity Monitoring, Cleaning Racks.
Instrumentation & Control:
Control Panel Complete with PLC, Main Disconnect, Fusing, Relays with bases, Wiring Terminals, Operator Interface Panel, PLC and Operator Int-erface Programming.
Float Level Switch, Dissolved Oxygen and Suspended Solids Monitoring System.
Ultrasonic Level Sensors.
Distinguished Features: Napier-Reid�s Bio-Batch� SBR including Decanter Assembly - Napier-Reid UD-500, High Quality Effluent, Smaller Footprints. High Strength Wastewater Treatment.
- Process Description
Equalization tank receive wastewater from the North and South Service Centers that is pumped to Sequencing Batch Reactor (SBR) secondary treatment.
SBR is an aerobic biological system comprising a batch reactor for eliminating pollutants i.e. BOD, COD, TSS, nitrogen and phosphorous. Bio-Batch® is the SBR designed by Napier-Reid. It is a true interrupted batch feed process, in which, continuous inflow is accommodated through an alternating fill and draw by feeding two or more reactors. A unique feature of the Bio-Batch® is that there is no return activated sludge (RAS) or secondary clarifier required for solids separation because both aeration and settling occurs in the same reactor. A portion of the sludge is removed from the reactor at a predetermined interval in each cycle to maintain a constant and calculated inventory of activated sludge solids.
The Bio-Batch® process is a sequence of five steps; fill / aerate, settle, decant, idle / fill, carried out in a 4 hour cycle.
Fill / Aerate: Screened and de-gritted raw wastewater is mixed and aerated to satisfy the design oxygen demand. In this step, BOD removal and nitrification takes place. To increase biological performance and eliminate the conditions encouraging filamentous bacteria proliferations, the inlet end of the reactor has a selector zone.
Settling: Following aeration, the air is shut off and flow is diverted to other reactor(s). A tranquil condition is created in the main aeration zone for efficient sludge settling. During this period anoxic/anaerobic conditions are created for denitrification and biological phosphorous removal.
Decant: After settling, the clarified supernatant water is decanted through swing type or telescopic type decanter for further processing to meet the discharge standards.
Fill / Idle: At reduced loadings an idle sequence can be introduced and added to the treatment cycle. When the system is designed for nutrient removal, idle time can also be used during the aeration sequence to create an anoxic/anaerobic condition for denitrification and biological phosphorus removal.
SBR effluent after the addition of Alum and Polymer for assistance in Phosphorus and suspended solids respectively undergoes filtration for polishing and then passes through UV system for disinfection. The waste sludge is conveyed to aerobic sludge digesters for further stabilization.
BOD5: 600 mg/L
NH3-N: 80 mg/L
TP: 10 mg/L
Specified Treated Effluent
BOD5: <10 mg/L
TSS: <15 mg/L
July to October:
<2 mg/L (Summer)
November to June:
<4 mg/L (Winter)