Self-Flushing Anaerobic Digester System

A digester system comprising:

• a primary digester tank containing a primary feed material portion defining a primary feed material level;
• a secondary digester tank containing a secondary feed material portion defining a secondary feed material level;
• a first conduit connected between the primary digester tank and the secondary digester tank to define a primary tank lower opening within the primary digester tank and a secondary digester tank lower opening within the secondary digester tank, where the primary digester tank lower opening is below the primary feed material level and the secondary digester tank lower opening is below the secondary feed material level;
• a second conduit connected between the primary digester tank and the secondary digester tank to define a primary tank upper opening within the primary digester tank and a secondary digester tank upper opening within the secondary digester tank, where the primary digester tank upper opening is above the primary feed material level and the secondary digester tank upper opening is above the secondary feed material level;
• a flow control valve configured to allow or prevent flow of fluid through the first conduit;
• a pump is operatively connected to the secondary digester tank and a separator;
• wherein
• when the flow control valve is configured to allow flow of fluid through the first conduit, a portion of the primary feed material portion flows at a first flow rate from the primary digester tank to the secondary digester tank to form the secondary feed material portion;
• the pump is configured to transfer at least a portion of the secondary feed material portion from the secondary digester tank to the separator at a second flow rate;
• the first flow rate is greater than the second flow rate;
• and
• the separator separates the secondary feed material portion pumped from the secondary digester tank into liquid and solid components.

An anaerobic digesting method comprising the steps of:

• providing a primary digester tank;
• arranging a primary feed material portion defining a primary feed material level within the primary digester tank;
• providing a secondary digester tank;
• connecting a first conduit between the primary digester tank and the secondary digester tank to define a primary tank upper opening within the primary digester tank and a secondary digester tank upper opening within the secondary digester tank such that the primary digester tank upper opening is below the primary feed material level and the secondary digester tank upper opening is below the secondary feed material level;
• configuring a flow control valve to allow or prevent flow of fluid through the first conduit;
• configuring the flow control valve to allow flow of fluid through the first conduit such that a portion of the primary feed material portion flows at a first flow rate from the primary digester tank to the secondary digester tank to form a secondary feed material portion;
• and
• transferring at least a portion of the secondary feed material portion from the secondary digester tank at a second flow rate, where the first flow rate is greater than the second flow rate.