Essential Parameters for Wastewater Monitoring in Paper Mills

Wastewater from the paper industry is a significant environmental concern due to its high volume and complex composition. Effective monitoring is the cornerstone of pollution control, regulatory compliance, and sustainable operation. This article outlines the essential parameters that must be routinely tested in pulp and paper mill effluent to assess its characteristics, treatment efficiency, and environmental impact。

Interpretation and Industry Context

Understanding the relationships between these parameters is crucial. A low BOD?/COD ratio (typically 0.1-0.4 in pulp mill wastewater) suggests a high content of non-biodegradable, recalcitrant organics like lignin, necessitating advanced chemical or physical treatment. As seen in a study of a recycled paper mill in India, untreated effluent can show high COD (1120-1160 mg/L) and BOD (200-210 mg/L) levels, which are significantly reduced by proper biological treatment. Furthermore, the volume of wastewater generated is substantial, ranging from 75 to 275 cubic meters per ton of product, emphasizing the scale of the treatment challenge.

Compliance, Treatment, and Future Outlook

Monitoring is directly linked to regulatory compliance. Official environmental monitoring reports, such as those from Chaozhou City, China, routinely check parameters like COD, BOD, TSS, pH, color, TN, TP, and ammonia at mill discharge points against national standards. Treatment technologies are evaluated based on their removal efficiency for these key parameters. For instance, constructed wetlands can achieve COD removal efficiencies of 54-58% and significant color reduction, while integrated membrane systems (like continuous membrane filtration and reverse osmosis) can produce effluent with COD as low as 2 mg/L, suitable for process reuse. The future of the industry lies in cleaner production strategies that reduce water consumption and pollution at the source, supported by rigorous and continuous wastewater parameter monitoring.

In conclusion, a comprehensive and well-defined wastewater monitoring program is non-negotiable for the modern paper industry. Tracking the suite of physical, chemical, and toxicological parameters detailed above enables mills to protect aquatic ecosystems, adhere to evolving regulations, optimize treatment processes, and move towards a closed-loop, sustainable operation.