Research and development of the BAS™ process

Many ciliates in a biofilm sample from a BAS™ process.

Biofilm + activated sludge

The word BAS is made up from the words biofilm and activated sludge. It is our designation for a two-step process consisting of an optimized symbiosis between a MBBR™ biofilm process and an activated sludge process.

Development

The present development of the BAS™ process is optimization for different types of wastewaters. Parameters studied are:

  • Optimal retention time and load in the respective stages
  • Filling degree of the suspended carriers
  • Optimal degradation in the respective stages
  • Nutrient dosage

The nutrient dosage actually has its own chapter since nutrient limited BAS is a special concept AnoxKaldnes has developed in order to reduce the sludge production. Using effluents from the production of bleached Kraft and newspaper (recycled fibers) the sludge production has been reduced by 50%, from 0.3 to 0.1-0.15 ton sludge per ton reduced COD. At present, nutrient limited BAS™ is being tested on other types of pulp and paper wastewater and other industrial wastewater.