Decanting Weir
Description
The AquaDecanter-R rotary decanter is one of the most successful and reliable products in the range of wastewater treatment equipment available from Aquatec Maxcon Pty Ltd.
During the settlement period of an intermittent aeration wastewater treatment process, activated sludge settles to the tank bottom, leaving clear treated supernatant on the top. The treated supernatant can be removed effectively with minimal carry-over of solids by the decanter without disturbing the sludge blanket at the bottom of the tank.
Design
The rotary decanter consists of a decant trough, weir, floating scum buffer, carrier pipes, rotary collection pipe, submersible support bearings, and drive mechanism.
In operation, the drive mechanism extends and retracts a drive shaft which actuates an eccentric link arm that rotates the trough up or down in an arc into the supernatant. The trough, carrier and collection pipes are supported at both ends by submersible bearings. The bearings are secured inside bearing housings, which are bolted to concrete plinths. The supernatant discharge rate can be controlled over the weir by variable speed control to maintain optimum flow. The floating scum baffles prevents scum from approaching the weir.
The decanter drive mechanism consists of an electric motor, gearbox, jack mechanism and screwed drive shaft. The drive is typically fitted with internally actuated position indicators that allow drive limits to be set for BWL, top park position and over limit safety stops. Optionally position transponders can also be fitted. The drive mechanism is normally installed at the end of the tank.
Design Advantages
- The decanting flow rate can be controlled and varied by adjustment of the drive speed.
- Decanting depth and park positions can be controlled through limit switch adjustment.
- During the aeration phase, the decanter trough is parked above the water level and prevents scum and floating objects from entering the trough.
- The screw jack and drive system is mounted above the water for ease of maintenance.
- The floating scum baffle prevents scum and floating objects from entering the decant trough during the decanting phase.
- All underwater bearings are self-lubricated and corrosion resistant.
- AquaDecanter-R rotary decanter can be made of stainless steel material or galvanised steel to suit customer requirements.
Technical
- Standard decanter trough lengths are available from 3m to 15m.
- Decant depth ranges up to 2m.
- For higher flow requirements a multiple decanter arrangements can be used.
- The decanter is normally installed on the opposite end of the tank to the inlet.
- The weir loading index depends on the flow requirement, tank depth, treatment process and other factors. For general applications, the weir loading index is 25 to 40 litres per second for each linear metre of weir.
Other Decanting Equipment
Aquatec Maxcon can also provide different kinds of decanters to suit customer requirements.
These include:
- the Tilted Plate Weir Decanter suitable for decanting depths up to 0.5m. This decanter must be installed on a concrete discharge channel.
- the Double Trough Vertical Decanter suitable for reactor tanks with central fixed bridges, with decanting depths up to 1.5m.
Applications
- Sequential Batch Reactors (SBR)
- Intermittent Decant Aeration Lagoons (IDAL) &
- Intermittent Decant Extended Aeration (IDEA) Processes
Services
- Setting and/or re-setting of internal limit switches
- Ongoing service maintenance
- Spare parts and parts refurbishment
Aquatec Maxcon has established and maintains a dedicated service department for scheduled maintainence and breakdown services.
