As more biogas plants include prepackaged material in their feed stocks, contamination of the anaerobically digested sludge with plastics can be a significant hurdle to using land application for disposal. For example, in Great Britain all plastic particles larger than 12 mm (0.5 inches) must be removed from the biomass after the fermentation process. Recently a British biogas plant whose feedstock includes corn and food waste turned to Boerger to solve their plastics issue using the Bioselect RC 40.

The Bioselect is a solids/liquid separator that includes Boerger BLUEline rotary lobe pumps for feeding the unit, as well as discharge of the filtrate. To optimize performance of the skid Boerger also provides the controls for the supplied equipment including an intuitive and easy-to-use touch screen HMI.

For the British plant Boerger was able to accommodate several project-specific requirements including ATEX (explosion proof) compliant electric motors and mounting the entire package on a mobile base frame. The mobile base frame allows the skid to be easily moved around the site to maximize the equipment’s usage.

During the anaerobic digestion process the food waste, corn, and biomass are fermented into renewable natural gas and a fluid waste stream. The Bioselect was chosen to remove all particles larger than 12mm, including plastics, from the fluid waste. After several months in operation the Bioselect has outperformed expectations by removing all plastic particles larger than 1 mm while achieving a high solids content in the dewatered solids. The filtrate is then able to be land applied for disposal.

Börger Control Technology

• Stainless steel control cabinet
• 4” touch display with schematic display
• Display: capacity, current consumption, pressures, messages
• Operating modes: automatic (continuous and time-controlled), manual, external control via mobile communication
• Manual switches: emergency stop / start-stop command
• Indicator lamps: operation / fault / automatic
• VFDs adjust pump flow rates to optimize separator performance
• Temperature controller with heater and filter ventilator

Advantages of this Bioselect RC 40

• Compact, ready-to-connect unit, on a mobile base frame “from a single source” by Börger
• Separation of all plastic particles > 1 mm (0.039 inches)
• High capacity
• Control technology coordinates the operation of all components
• Low life-cycle costs thanks to energy-efficient and low-wear operation
• Optimal adjustments to changing composition of the influent stream
• Compact, space-saving design
• Easy installation and integration into the production process