Jan D Allen

US Patent:

8313921, Nov 20, 2012

Filed:

Dec 10, 2003

Appl. No.:

10/732162

Inventors:

Tom Kraemer - Duvall WA, US
Charles Kemper - Wilsonville OR, US
Jan Allen - Shoreline WA, US

Assignee:

CH2M Hill, Inc. - Englewood CO

International Classification:

C12M 1/00
C05F 11/08

US Classification:

435 29, 4352901, 4352904, 71 9, 71 10, 4051295, 40512957, 40512985, 40512995

Abstract:

A method of biodegrading municipal solid waste includes providing a quantity of municipal solid waste and promoting anaerobic digestion in the quantity of municipal solid waste by methanogenic organisms to produce methane. The methane production is monitored and when it is determined that production of methane from the quantity of municipal solid waste has subsided, aerobic digestion of the quantity of municipal solid waste is promoted. A gas collection system in operative association with the quantity of organic waste collects biogas and the biogas is monitored and the rate of gas collection is adjusted as necessary to maximize methane collection. A leachate collection system collects leachate from the quantity of municipal solid waste and circulates the leachate back to the quantity of organic waste during the anaerobic digestion and aerobic digestion steps. The leachate is preferably supplemented with liquid as necessary to maintain the moisture content of the quantity of municipal solid waste at at least the field capacity of the municipal solid waste. The leachate collection and distribution system may further be used for balancing pH or varying the nitrogen, phosphorous, potassium, calcium, magnesium, chlorine, sulfur, iron, copper, manganese, zinc, molybdenum, nickel or vanadium content of the municipal solid waste during biodegradation.