The HydroThane STP^®UASB (Upflow Anaerobic Sludge Blanket) process is the most commonly applied anaerobic technology for the biological treatment of industrial effluents. The first UASB pilot plant was installed at a beet sugar refinery in The Netherlands (CSM Suiker) in the 1970's. Thereafter, a large number of full scale UASB plants were installed throughout The Netherlands at sugar refineries, potato starch processing plants and other food industries as well as at paper recycle plants. Nowadays the UASB process is a proven and worldwide accepted process in and for different types of effluent streams.

Characteristics of HydroThane STP^® UASB are:
- Maximum process stability because of its controlled external
   re-circulation flow and is not depending on the influent COD/flow
- Due to the complete overpressure design of the UASB process
   a (bio)gas holder is not required
- Phase separators are constructed completely of PP,
   so no corrosion possibilities
- Phase separators are based on the mammoth stream principle
- No complex internals (like tilted plates) or rotating equipment
    inside the reactor (no maintenance, no clogging at all within the reactor)
- Loading rates of the UASB reactor are typically in the range
   of 5 - 1 5 kg COD/m³.day.