In such plants subsequent immobilisation of biomass resulted in
- Efficient and stable nitrification even at 10-13°C,
- Doubling of removal rates
- Lower excess sludge production and
- Lower outlet COD ( 45 to 65 mg/L at 1,4-1,8 kgCOD/m³x day)
First tests using LEVAPOR had been started in the early 90-ies,by filling 100 L LEVAPOR into a specially constructed cage, fitted with a membrane aerator and installed into an existing small anaerobic plant fpr 4 inhabitants.