operational area | usage

  • Reservoirs, tanks, weirs or dams as part of municipal networks or industrial plants
  • Incorporated as storage, allowing a controlled discharge of wastewater to the subsequent sewage system or wastewater treatment plant during flooding

Technology | Process

The purpose of drainage networks is to contain and safely transport wastewater, and to permit excess rainwater from being removed from the sewage system. This in effect reduces the volume of mixed rain and wastewater being treated as well as the process engineering costs.

Storm water retention systems should take up large volume of mixed rain and wastewater during flooding, and later discharge it in a controlled way.

An effective process engineering solution must ensure controlled inflow and discharge of the stormwater, as well as automated cleaning of the tank/reservoir.

Normal dry-weather flow in a pipeline, sewer or main collector passes through a flow-dividing structure.

Sewers can be maintained by manually flushing them, or through the use of flushing vehicles. A mechanical or electromechanical throttle valve at the flow-dividing structure can automatically adjust the discharge level to a specified amount.

During a flood, substantial quantities of combined rain water, wastewater and detached deposits from the upstream sewage network are carried to the flow-riding structure.

There, excess water is contained, floating debris are removed and the overflow adequately managed. In addition, mechanical or electromechanical overflow flap valves, floating scum-boards, automatic disc filters or fine-screens can be used to remove floating debris.

An overflow tank in combination with carefully selected gates or electromechanical valves should be incorporated as a buffer system to protect the storm-water reservoir downstream from overloading.

The stormwater tank takes up the designated amount of mixed rain/wastewater and mechanically regulates the controlled discharge.

After the stormwater reservoir has been fully drained, process controlled jet cleaners, flushing flaps or flushing tipping buckets, are used for automatic flushing of the bottom of the tank.

The exact type of automatic cleaning to be used is dependet on:

  • Local conditions such as gradient, whether the sump is more readily flushable, whether the residual waste is to be pumped, and/or any additonal operator requirements.
  • wks group provides consulting support regarding advantages or limitations of recommended equipment, its installation, commissioning and maintenance.

Process Engineering Components

  • Pumping stations
  • Cleaning equipment for retaining coarse material, such as disc filter system for fine bar screens
  • Scumboards for retaining floating material
  • Flap valves and weirs for water level control
  • Flushing equipment (surge flushing) such as flushing tipping buckets or flushing flaps
  • Flow control systems such as flow restrictors and discharge controllers
  • Control system for fully automatic operation
  • Optional integration in the process control system


  • Fully integrated to ensure optimum functionality and reduced investment and operating costs
  • Significant increase in functional safety and reliability in comparison to standalone solutions
  • Modifiable range of technical equipment adaptable to specific conditions
  • Fully-automatic operation with individually tuned control systems
  • Flushing equipment (flushing tipping bucket) does not depend on external energy sources and requires relatively low volumes of water for flushing
  • Easy operation and maintenance
  • The system and its components are well suited for retrofitting or upgrade