Nitrification/denitrification
| Company | Country |
|---|---|
| Caboolture | Australia |
 Highland Creek, City of Toronto, Ontario |
Canada |
| Vihti | Finland |
| Bergamo |
Italy |
| Dervio | Italy |
| Bekkelaget | Norway |
| Gardermoen |
Norway |
| Lillehammer |
Norway |
| Nordre Follo |
Norway |
| RA-2 | Norway |
| Steinsholt |
Norway |
| Bjuv | Sweden |
| Klagshamn |
Sweden |
| Knivsta | Sweden |
| Margretelund | Sweden |
| Nyköping | Sweden |
| Sjölunda |
Sweden |
| Strängnäs | Sweden |
| Visby | Sweden |
| Vänersborg | Sweden |
| Öckerö | Sweden |
| Fislisbach | Switzerland |
| Laufäcker, Baden | Switzerland |
| Braintree STW |
UK |
| Bury St. Edmunds | UK |
| Bury St. Edmunds II | UK |
| Great Dunmow STW | UK |
| Tuddenham | UK |
| South Adams County, Colorado |
USA |