What it is?

The Aquasuite Crystalactor Controller is the process controller tailored to making the operation of Crystalactor installations robust, efficient and easy. The Crystalactor Controller is integrated with the plants PLC/SCADA and ensures optimal master control of the chemical dosing, carrier dosing, crystal discharge and flow control of the installation. The controller is PC-based and meets the international ISA-88 standard for batch control.

Why it is important?

The Crystalactor Controller recognises and manages all processes resulting in optimal settings for the process control.

Furthermore the Crystalactor Controller offers large flexibility for future extensions or upgrades.

In addition, the controller enables logging of process parameters. These parameters are converted into smart process performance information (the so-called Blue Reports), providing detailed insights into process fundamentals and kinetics. This way the Crystalactor Controller is an important instrument in plant performance evaluation enabling extensive optimization and early-warnings.

Above that, the Crystalactor Controller is designed to facilitate remote control.

How does it work?

The Crystalactor Controller basically performs the following functions:

  • Controlling the discharge of pellets and dosing of carrier materials
  • Controlling the dosing of chemicals
  • Controlling the fluidized bed level and -flows
  • Visualization

The controller functions

Controlling the discharge of pellets and dosing of carrier materials

Crystalactor Controller provides the Operator with the entire automated process of controlling the discharge of pellets that have grown inside of the Crystalactor reactors. The Controller also initiates the dosing of new carrier material. By doing this in the optimal way, the Crystalactor Controller ensures that the pellet bed is maintained in the best condition to enable efficient crystallization. For this purpose, the Crystalactor Controller uses a soft-sensor to estimate the average pellet diameter very accurately under a wide range of operational conditions.

Controlling the dosing of chemicals

Crystalactor Controller calculates the dosing set-point of the chemical that creates the supersaturation inside the Crystalactor reactors. Based on recent data, the Crystalactor Controller derives the optimal supersaturation condition of the water, in which the crystallization takes place efficiently. By doing this, chemical consumption for dosing and neutralization is minimized.

Controlling the fluidized bed level and -flows

The Controller monitors and controls all flows of the Crystalactor installation, and determines the optimal feed flow, circulation flow and by-pass flow (if any) of all reactors. This control ensures stable operations of the Crystalactor installation and maintains the set point levels in the reactors.


Crystalactor Controller generates clear web based visualization pages. These pages are easily integrated in your SCADA or operator control panel and can also be remotely accessed.

Support packages

After the start-up of a Crystalactor installation Royal HaskoningDHV offers three levels of operational support: Bronze, Silver and Gold.

Award-winning smart controls leads to low operational expenditures

The Crystalactor is provided with a Smart Controller, which is a unique advanced control system that predicts and controls the crystallization processes. The added-value of the controller is based on more than 10 years of (award winning) modelling of the fundamental processes and hydrodynamics within fluidized bed crystallizers. The controller has been developed in close collaboration with the Delft University of Technology and Amsterdam Water Works.

We deliver an Advanced Control for pellet softening based on soft-sensoring, through model-based, adaptive control on changes in water characteristics and temperature.


  • Reduced chemical consumption
  • Improved process robustness
  • Easy operation and reduction in spend hours of operators
  • Optimized process performance (less carry-over lower turbidity) leads to significantly lower operational costs for back-washing of downstream carry-over filters.