• 112% increase in biogas yield per kg of COD removed
  • 86% increase in biogas production overall
  • Enhanced COD removal in the anaerobic system
  • Reduction of floating grease build-up in the anaerobic treatment unit


The plant had an anaerobic internal circulation (IC) reactor that converted starchy wastewater to biogas. The plant operators wanted to increase COD degradation in the IC and increase biogas production for additional cost savings.


The facility produces French fries and potato flake used in a variety of food products. It uses a multi-stage wastewater treatment process which includes both anaerobic and aerobic treatment units to treat 2,800 m3/day (0.74 MGD) of starchy wastewater (4,000 mg/L COD). The IC is the source of biogas production. The biogas generated in the IC is utilized as fuel for the boiler system. The customer and Novozymes teamed up to trial BG MaxTM to demonstrate its ability to improve biogas production and lower treatment costs.


Over a 90-day period, BG Max resulted in an 86% increase in biogas production. The enhanced conversion of organic compounds to biogas was evident by a 112% increase in biogas yield from 0.34 to 0.72 m3/kg (5.5 to 11.6 ft3/lb.) COD removed. This also contributed to decreased loading to the aerobic system, thereby reducing the energy demand. An additional side benefit of this application was a reduction in floating grease build-up in the anaerobic system.

Without BG Max With BG Max
Biogas production (m3/day) 2,389 4,435
Biogas yield (m3/kg COD)
0.34 0.72
COD removal (%) 38 53

Table 1. Productivity diagram



Fig. 1. Biogas production and COD removal increased with the use of Novozymes BG Max™ 3000.



Fig. 2. Biogas yield increased 112% during the different trial stages.


The addition of BG MaxTM to the anaerobic treatment system of a potato processor increased biogas production and improved treatment efficiency. This resulted in:

  • Offset natural gas purchases
  • Decreased energy demand
  • Lowered overall cost of treatment
  • Improved sustainability