Anaerobic Digestion Process Monitoring Device and Method Thereof

A method for the quantification of compounds in an anaerobic digestion process for monitoring a substantially constant anaerobic digestion process, the method comprising:

• a. extracting a liquid sample from an anaerobic digester and introducing the liquid sample into a selectively sealable sample chamber such that a sample chamber gas head-space remains near a top portion of the sample chamber;
• b. adding a desired amount of an acid to the liquid sample so as to produce a liquid sample and acid combination;
• c. agitating the liquid sample and acid combination so as to decrease the pH of the liquid to about 4.4 or less and produce carbon dioxide gas therefrom wherein at least a portion of the carbon dioxide gas is released into the sample chamber gas head-space;
• d. determining a first gas pressure in the sample chamber gas head-space so as to determine a concentration of buffering inorganic carbon compounds in the liquid sample therefrom;
• e. heating and agitating the sample so as to cause the release of organic acids into sample chamber gas head-space;
• f. collecting and removing at least a portion of the organic acids from the sample chamber gas head-space and analyzing the concentration of the organic acids in the portion collected from the sample chamber gas head-space so as to determine the concentration of organic acids in the liquid sample therefrom;
• and
• g. determining a ratio of the concentration of organic acids in the sample to the concentration of the buffering inorganic carbon compounds in the liquid sample so as to provide an indication of the health of the anaerobic digestion process.

A computer-readable medium having statements and instructions stored thereon for implementation by a processor of an anaerobic digestion process monitoring device operatively coupled to an anaerobic digestion system, the statements and instructions for operating components of the system to provide a substantially real-time quantification of compounds in an anaerobic digestion process of the system for identifying a health of the anaerobic digestion process by automatically:

• a. combining a liquid sample from the system and a predetermined amount of an acid into a sealable sample chamber so that a gas head-space remains in the sample chamber;
• b. agitating the liquid sample and the acid combination while monitoring a pH thereof;
• c. determining a gas pressure in the sample chamber gas head-space upon the pH reaching about 4.4 or less;
• d. determining a concentration of buffering inorganic carbon compounds in the liquid sample as a function of the gas pressure;
• e. heating and further agitating the combination;
• f. determining a concentration of organic acids released to the sample chamber gas head-space;
• g. determining a concentration of organic acids in the liquid sample as a function of the determined concentration of organic acids released to the sample chamber gas head-space;
• h. determining a ratio of the concentration of organic acids in the liquid sample to the concentration of buffering inorganic carbon compounds in the liquid sample for use as an indication of the health of the anaerobic digestion process.

A computer-readable medium having statements and instructions stored therein for implementation by a processor of an anaerobic digestion process monitoring device operatively coupled to an anaerobic digestion system, the statements and instructions to provide a substantially real-time quantification of compounds in an anaerobic digestion process of the system for identifying a health of the anaerobic digestion process by automatically:

• a. monitoring pH of a liquid sample from the system when combined and agitated with a predetermined amount of acid within a sealed sample chamber;
• b. determining a gas pressure formed in a sealed sample chamber gas head-space upon pH reaching about 4.4 or less;
• c. determining a concentration of buffering inorganic carbon compounds in the liquid sample as a function of the gas pressure;
• d. determining a concentration of organic acids released to the sample chamber gas head-space upon further agitation and heating of the combination;
• e. determining a concentration of organic acids in the liquid sample as a function of the determined concentration of organic acids released to the sample chamber gas head-space;
• f. determining a ratio of the concentration of organic acids in the liquid sample to the concentration of buffering inorganic carbon compounds in the liquid sample for use as an indication of the health of the anaerobic digestion process.