Audit and monitoring of the thermophilic anaerobic digester for solid waste treatment

Walkers Crisps is the Pepsico Group’s potato chip production unit. It started a thermophilic anaerobic digester with a capacity of approximately 4,500 m³ in early 2016 to recycle organic solid waste (potato chips, peelings, starch) by cogeneration. There were a number of start-up issues resulting in reduced digestion efficiency and partial treatment of available solid waste which impacted cogeneration performance and reliability.



Audit, large-scale monitoring, and process optimization
  • Facility audit and optimization program;
  • Evaluation of the technical database and calculation and interpretation of the most important operational parameters;
  • Calculation of energy balance of the digester and the cogeneration unit;
  • Assistance in monitoring full-scale results while evaluating the optimization program and adjusting it if necessary;
  • Preparation of audit and monitoring reports.

Laboratory research

  • Characterization of digestate to complete the database: analyses, microscopic examination of composition, methanogenic activity tests;
  • Characterization of biogas composition;
  • Characterization of the methanogenic bacterial association by microscopic examination;
  • Distinction between methanogenic, hydrogenotrophic, and acetoclastic bacteria;
  • Measurement of methanogenic activity: laboratory batch test.