Developing a multipoint titration method with a variable dose implementation for anaerobic digestion monitoring.

Area of Science:

• Analytical Chemistry
• Environmental Science

Background:

• Acid-base titration is a key method for metabolite determination in anaerobic digestion.
• Existing methods can be limited by speed, data quality, and complexity in handling polyprotic acids.

Purpose of the Study:

• To develop and validate a practical, at-line compatible multipoint titration method for anaerobic digester metabolites.
• To introduce a novel control algorithm for variable titrant dosage to improve titration efficiency and accuracy.

Main Methods:

• Implementation of an at-line compatible multipoint titration system.
• Development of a non-linear PI-controller like algorithm for adaptive titrant dosing.
• Mathematical analysis of polyprotic acid simplification and ionic strength effects.
• Presentation of a matrix-based model for concentration estimation.

Main Results:

• Achieved linear correlation > 0.999 for acetate and phosphate with high accuracy (slopes 0.98-1.00).
• Demonstrated superior performance of the novel controller over traditional linear controllers.
• Showcased method insensitivity to overlapping buffer capacity curves.

Conclusions:

• The developed multipoint titration method offers enhanced speed and data quality for metabolite determination.
• The novel control algorithm provides accurate and efficient titrant dosing without prior sample information.
• This method is robust and suitable for complex samples, including those with overlapping buffer capacities.