HYBRID™ – The two-stage activated sludge process for nitrogen removal

The HYBRID™ process is based on the conventional two-stage activated sludge process. However the activated sludges of both stages are not separated, but advantageously mixed through two innovative hybrid sludge cycles. The process was jointly developed by WABAG and the Vienna University of Technology .

The main advantages are:

Process stability:
The first process stage provides optimum load compensation, which even in the case of low wastewater temperatures secures the denitrification capacity of the second stage. This is an especially important advantage when dealing with industrial effluents or seasonal peak loads.

Economies over conventional single-stage plants:
The Hybrid process facilitates a considerable reduction in the tank volume required. Design comparisons for various plants have shown that in terms of total volume, approximately 30% can be saved.

Key Features
 Innovative HYBRID-sludge cycles:
o combined activated sludge in both stages,
o nitrification and denitrification in both stages
 Flexible way of operation:
o single stage / two stage,
o optimum adaptation facilities
 Advantages regarding operation costs
 Protection against toxic impacts due to two stage treatment
 Better hygenisation
 Ideal for plant extension:
o high flexibility regarding the layout
o cost-effective possibilities of integrating existing tanks