LONG TERM PROCESS CON­TROL FOR BIO­GAS PLANTS – THE IMPOR­TANCE OF BICAR­BON­ATE PARAMETER

For effi­cient bio­gas pro­duc­tion, sludge bac­te­ria require a pH in the range of about 6.5 to 8. A sta­bi­liza­tion of the pH in this area is main­ly achieved ( 85) by the bicar­bon­ate (= buffer sub­stance) released in large quan­ti­ties dur­ing anaer­o­bic degradation.>

Process dis­tur­bances reg­u­lar­ly lead to increased lev­els of free fat­ty acids (FFA) or decreas­ing bicar­bon­ate lev­els, as the acids con­sume bicar­bon­ate. How­ev­er, the buffer­ing effect of the bicar­bon­ate hard­ly reduces the pH at first.

Only when the dis­tur­bance lasts for a long time and the stock of bicar­bon­ate is large­ly exhaust­ed, it comes to a rapid drop in pH and sub­se­quent­ly to a reduc­tion or in extreme cas­es to a fail­ure of bio­gas production.

ADVAN­TAGES OF A PROCESS CON­TROL WITH THE BICAR­BON­ATE TESTER

• In con­trast to an exclu­sive pH val­ue check, process faults are detect­ed much ear­li­er – leav­ing more time to avoid eco­nom­ic losses
• Very sim­ple operation
• Results after 5 minutes!
• Data is easy to interpret
• Mea­sur­ing tech­nol­o­gy does not require calibration
• Very low con­sump­tion costs
• Robust, long term proven mea­sure­ment technology