TOC Monitoring Upstream of Paper Mill Wastewater Treatment Facility Using Online TOC Analyzer

Importance of Continuous TOC Monitoring in Wastewater Treatment

Continuous online measurement of total organic carbon (TOC) offers critical insight into pollutant loads entering activated sludge processes. In paper mill wastewater systems characterized by fluctuating organic content and biological fouling risk, real-time monitoring enables stable plant operation, accident prevention and regulatory compliance.

Objectives and Study Overview

The case study evaluated the performance of Shimadzu’s TOC-4200 analyzer for high-frequency upstream monitoring of paper mill effluent. Key goals included demonstrating continuous TOC measurement under challenging sample conditions and establishing the correlation between TOC and biological oxygen demand (BOD) to support process control.

Methodology and Instrumentation

Sample from a paper mill activated sludge influent was drawn continuously at ~5 L/min into the TOC-4200 with a single stream suspended solid sampling unit. Measurement conditions were:

• Catalyst: standard oxidative catalyst
• Calibration: one-point using 1 000 mg C/L potassium hydrogen phthalate
• Measurement interval: 10 min
• Dilution: automated 10-fold for both standards and samples
• Backwashing: dilute HCl rinse to minimize fouling and carryover

Main Results and Discussion

TOC values measured over a 10-day period captured pollution spikes corresponding to process load changes and production shutdowns. Simultaneous BOD tests on collected samples yielded a strong linear correlation (R=0.96) between TOC and BOD in treated effluent. This confirms TOC as a reliable surrogate for biological load assessment and early warning of process upsets.

Benefits and Practical Applications

• Robust and low-maintenance operation under high solids loading
• Automated sample pretreatment reduces line blocking and biofilm formation
• High-frequency data supports real-time process control and load management
• Versatile deployment for influent/effluent monitoring, cooling and boiler water, wash water, and advanced treatment streams

Future Trends and Potential Uses

Integration of online TOC analyzers with digital platforms and IoT-enabled networks will facilitate predictive maintenance and advanced process optimization. Expanding multi-parameter sensing (e.g. nitrogen, phosphorus) and coupling with machine learning algorithms can further enhance wastewater analytics and environmental compliance strategies.

Conclusion

The Shimadzu TOC-4200 delivered continuous, accurate TOC monitoring in challenging paper mill wastewater, demonstrating strong agreement with BOD and providing a reliable tool for operational stability and pollution load control.

References

• Shimadzu Corporation. TOC Monitoring Upstream of Paper Mill Wastewater Treatment Facility Using Online TOC Analyzer. Application News No. O53, First Edition Feb. 2015.