Biological wastewater treatment

Complete wastewater treatment plants

GTWE offers complete treatment plants for industrial and common wastewater. Biological process technology is combined with chemical and physical treatment to achieve optimal cleaning results.

Principle of operation

The effect of the biological wastewater treatment is based on the metabolism of microorganisms. They use the organic wastewater components as well as oxygen for energy production and their own multiplying. By that pollutants are transformed to biomass (sludge) which is separated from the treated water in a downstream physical treatment step and later on disposed.

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Different methods

Basically there are two different methods for biological wastewater treatment: fixed-bed reactors and activated sludge. Both methods have their specific advantages and disadvantages.

Based on the characteristics of your case of application our team will recommend you the best solution.

Fixed-bed reactors

The water cleaning microorganisms are as a biofilm fixed on a surface (lava rocks, plastic chips, etc.). Fixed-bed reactors may require artificial aeration (submerged fixed-bed reactor) or may not (trickling filter).

Activated sludge

The microorganisms are in constant suspension in the wastewater to be cleaned. The provision of oxygen for the bacteria is effected by means of artificial aeration at the bottom of the activated sludge tank. The air bubbles should be as small as possible. The separation of suspensed sludge and cleaned water normally is effected by means of sedimentation.

Alternatives to activated sludge systems

Trickling filters consist of a fixed bed of media (e.g. lava rocks, plastic chips, etc.) on which a biofilm exists. The wastewater flows downwards being in constant contact with the biofilm and oxygen from the surrounding air.

Such a trickling filter has several benefits:

  • High energy efficiency
  • Stable process
  • Simple process technology (very easy sludge separation)
  • Cascadic plant design possible
  • Special, highly adapted bacteria remain in the system constantly (degradation of rare and persistent pollutants)

Especially in warm regions (e.g. Central America) such trickling filters may present a good alternative to activated sludge systems.

There are special versions of these trickling filters which have additional advantages, among them adaptions developed and exclusively offered by GTWE. Feel free to contact us about the different technologies.