Dewatering Training 07 May 2025

Date: 2025 05-May 07

ALFA LAVAL training
www.alfalaval.com
Dewatering belt press

• Modular design of the "G3"
• No requirement for flocculation mixer
• No electric motor for polymer distribution
• High pressure 12 roller design

Vocabulary

• "Chicane" (plows)
• Flingers
• BFP

Models:

• Ashbrook Klampress
• Winkle Press (we have this one) - vertical section
• Gravity belt thickener ("Aquabelt")
• KPZ

Zones:

1. Gravity zone
2. low pressure zone
3. high pressure zone

Maintenance requirements:

• Daily cleaning
• Lift ploughs
• Turn the wheel daily on the wash box, lock to lock, to clean the nozzles. Uncleaned streaks on the belt indicate a clogged nozzle. It has brushes inside when are engaged and moved by turning the handle.
• Check hydraulic fluids
• Check E-stops

Weekly maintenance

• Lubricate tensioner
• Lubricate bearings
• Lubricate rack and pinion gears

Annual

• Change belt drive gear reducer oil
• Change hydraulic unit oil

Belt cleaning

• pH neutral basic cleaner

Inspection:

• Even loading of feed.
• Inspect wear of chicanes/ploughs, ensure they are turning the sludge mass
• Ensure edge restrainer seals are contracting the belt. Replace or adjust seals as needed.
• Ensure scraper / doctor blades are functioning - replace as required.
  • Upper and lower scraper blades are meant to rub the belt to remove sludge from the belt.
• Ensure belt wash system is cleaning
• Inspect wash box seals
• Inspect the dewatering belt - replace broken belt seam wires
• Max pressure 500 PSI, or even 300 PSI
• Ensure flingers are in place on the bearings
• Ensure the steering system is functional
• Adjust polymer feed rate until flocculation is correct
• Adjust belt speed and tension
  • Range of belt speed is defined in percentage, from 0 to 100 %

Auto tensioning hydraulic system
SmartPressTM Belt Alignment System
Automated hydraulic guidance control
AS-H Belt Press G3 Belt Alignment - Where is the paddle and the cylinder? For the automatic hydraulic adjustment.

Dewatering zones

• Radial (low) pressure dewatering wedge zone (we have a vertical wedge zone)
• Full-pressure dewatering zone - pressure is increased as sludge passes through 8 to 12 rollers

Nozzles in the wash box - washes the belt before it starts again.

Static mixer

• The lower you put the paddle, the more backpressure and retention time for mixing, to achieve uniform floc. You can go too high energy (disintegrated floc) and too low (large and non-uniform flocculation).
• Adjust retention time between 15 and 45 seconds by changing the pipe routing

Process variables

• Sludge feed rate
• Polymer feed rate and concentration
• Mixing energy (hydraulic pressure)
• Belt speed
• Ramp angle
  Make 5% adjustment and wait 10 to 15 minutes to see changes.

Questions:

• Is auto adjustment onboard in PLC, firmware, etc, or is it in the PLC in control room?

Startup:

• 3-minute pre-wet