Analysis of Heavy Metals in Sewage Sludge and Sewage by ICPE-9820

Significance of the Topic

Environmental discharge of treated wastewater and reuse of sewage sludge require precise monitoring of toxic metals to protect ecosystems and comply with regulations. Accurate quantification of traceable elements forms the basis for safe recycling of sludge into cement, fertilizer and other materials.

Objectives and Overview

This study aims to demonstrate the capability of the Shimadzu ICPE-9820 ICP atomic emission spectrometer for simultaneous analysis of heavy metals in treated sewage and sewage sludge ash across a wide concentration range. Results are compared with ICP-MS for trace-level validation.

Methodology and Instrumentation

• Sample Preparation
  
  • Treated wastewater: Acid digestion with HNO3 and HClO4, heat until white fumes, internal standard Y addition, dilution to 10 mL with 1 mol/L HCl
  • Sewage sludge ash: Nitric acid digestion, heat treatment, addition of internal standard Y, dilution to 100 mL with 1 mol/L HCl
• Analytical Method
  
  • ICP-AES using internal standard calibration curve method
  • Simultaneous axial (AX) and radial (RD) viewing for broad concentration coverage
  • Comparison with Shimadzu ICPM-8500 ICP-MS for treated water trace elements

Main Results and Discussion

The system achieved blank levels below 0.1% of effluent standards even after high-concentration sample runs, demonstrating low memory effects. Calibration curves for elements such as Zn exhibited linearity (r>0.9999) across distinct ranges under axial and radial observation. Detection limits were under one-tenth of regulatory thresholds, and quantitative results for treated wastewater agreed closely with ICP-MS data.

Benefits and Practical Applications

• Single-instrument solution for trace to high concentration analysis reduces workflow complexity
• Automatic axial/radial switching accelerates data evaluation
• High sensitivity and accuracy support regulatory compliance for wastewater discharge and sludge reuse

Future Trends and Opportunities

• Integration with automated sampling and real-time monitoring for continuous process control
• Expansion to additional elements and speciation studies for comprehensive environmental assessment
• Coupling with data analytics platforms for predictive maintenance and trend analysis

Conclusion

The Shimadzu ICPE-9820 demonstrates robust performance in quantifying heavy metals from trace to high levels in sewage treatment matrices, providing a reliable tool for environmental monitoring and resource recycling initiatives.

Instrument Used

• ICP Atomic Emission Spectrometer Shimadzu ICPE-9820
• Radio frequency power 1.2 kW
• Plasma gas flowrate 10 L/min
• Auxiliary gas flowrate 0.6 L/min
• Carrier gas flowrate 0.7 L/min
• Nebulizer with cyclone misting chamber
• Mini torch with vertical orientation
• Observation modes axial and radial

References

1. Official Specifications Related to Typical Fertilizer Based on the Fertilizer Control Act Notification No. 284, Ministry of Agriculture, Forestry and Fisheries, 1986 (revised 2012)
2. Enforcement Regulations Regarding the Soil Contamination Countermeasures Law Ordinance No. 29, Ministry of the Environment, 2002
3. Ordinance on Test Method for Water Quality of Sewage Ordinance No. 1, Ministry of Health and Welfare/Ministry of Construction, 1962 (revised 2012)
4. Ordinance for Determination of Effluent Standards Prime Minister’s Office Ordinance No. 35, 1971 (revised 2013)
5. JIS K0102-2013 Industrial Wastewater Test Method