A modified method for COD determination of solid waste, using a commercial COD kit and an adapted disposable weighing...

Area of Science:

• Environmental Science
• Analytical Chemistry
• Waste Management

Background:

• Chemical oxygen demand (COD) is crucial for monitoring waste, especially in anaerobic digestion.
• Existing COD methods often require dilution, posing challenges for solid waste analysis.
• Dry anaerobic digestion processes require precise COD monitoring for efficient operation.

Purpose of the Study:

• To develop and validate an adapted method for determining COD in solid waste (total solids >15%).
• To enable accurate COD measurement without sample dilution for solid waste streams.
• To support the monitoring and design of dry anaerobic digestion systems.

Main Methods:

• Utilized commercial COD tubes and a homemade weighing support for solid sample transfer.
• Adapted the standard COD determination protocol to accommodate high solid content samples.
• Validated the method using potassium hydrogen phthalate and glucose standards, and various solid waste types (cellulose, cattle manure, straw, mixed substrate).

Main Results:

• The adapted method demonstrated excellent repeatability with established standards.
• A slight underestimation of theoretical COD (approx. 5%) was observed, attributed to the weighing support and measurement uncertainties.
• The method successfully determined COD in diverse solid waste samples within the 1-8 mgCOD range.

Conclusions:

• The developed method provides a reliable and practical approach for COD determination in solid waste.
• This technique is suitable for routine monitoring and process design in dry anaerobic digestion.
• The adaptation overcomes limitations of traditional methods for high-solids waste analysis.