Anaerobic wastewater treatment has become a technology of growing importance, especially for concentrated paper wastewater. Economic advantages such as a much smaller energy required and a much lower sludge production explain this progress. Generation of methane gas that is converted easily into energy source (heat/power) resulting in lower and attractive paybacks on investment has resulted in anaerobic wastewater treatment process as a preferred choice of mature and reliable technology.

However, the design of a new anaerobic treatment plant has to be carefully considered. Every wastewater is different and not every wastewater is suitable for anaerobic treatment. Especially the choice of the reactor type is very important and it has a major influence on the performance of the wastewater treatment plant. Typical references in this industry are Visy Paper Mill in Australia and Caxton Paper Mill in New Zealand.

Paper mill sludge can be dried in the Hydrogone® or incine­rated in the HELIOSOLIDS^® fluidized bed reactor.