Mercer resumes effluent discharge at Rosenthal mill as swimming ban lifted
Mercer International has resumed discharging treated wastewater from its Rosenthal pulp mill in Germany into the Saale, after water samples showed pollutant levels back to normal and the Saale-Orla district lifted its precautionary swimming ban on the southern Bleiloch Reservoir. Discharge had been halted in early October, with effluent held in on-site buffer basins, after discolouration and dead fish were found near the outfall following a four-week maintenance period. The company says it is preparing to resume cellulose production; the substances involved have not been identified.
Why this mattersThe all-clear lets Rosenthal move back toward pulp production after an early-October discharge halt, though the substances behind the fish kill remain unidentified.
- Mercer says it resumed discharging treated effluent at the Rosenthal mill on 3 October 2026 after water samples showed pollutant levels back to normal
- The Saale-Orla district authority lifted its precautionary swimming ban in the southern Bleiloch Reservoir following the test results
- Discolouration and dead fish were detected near the discharge point in early October 2026, after a four-week maintenance period
- Wastewater was held in on-site buffer basins during the investigation
- The specific contaminants have not been identified; the mill is preparing to resume cellulose production