abstract |
Wastewater is continuously disinfected by combining the wastewater with sufficient acid to reduce the pH of the wastewater to less than about 4 and with sufficient SO 2 that the wastewater has a selected free SO 2 content of at least 5 mg/liter. The combined SO 2 /wastewater is maintained at the selected free SO 2 content for at least about 5 minutes. The wastewater can be treated by dissolving SO 2 into a first portion of the wastewater and combining the first portion with SO 2 dissolved therein with a second portion of the wastewater stream. SO 2 can be stripped from the wastewater, and the stripped SO 2 can be recycled. |