Digester and process for converting organic matter to methane and fertilizer

Claim 2

A digester for controlling the decomposition of organic matter to produce methane gas and a liquid fertilizer comprising: first, second and third slurry chambers disposed in tandem; a flexible chamber located above and covering said slurry chambers; a first passthrough tube connecting said first chamber to said second chamber and disposed to pass slurry from the central level portion of said first chamber to the lower level portion of said second chamber; a second passthrough tube connecting said second chamber to said third chamber and disposed to pass slurry from the lower level portion of said second chamber to the lower level portion of said third chamber; an input line connected for periodically feeding a load of raw slurry into the bottom of said first chamber; and an output line connected to the bottom of an upright pipe in said third chamber, the upper end of said upright pipe being the outlet port into which the slurry in the third chamber drains for feeding into the output line; whereby the periodical feeding of a load of raw slurry into said first chamber results in an equal volume of slurry being automatically transferred from each chamber to the next and into the output line; and wherein the size of the said first chamber is large enough to detain the volume of slurry received there in long enough to produce an acidified material and the size of said second chamber is large enough to detain the volume of slurry received therein from the first chamber long enough to generate methane gas which is collected in said fourth chamber.

Claim 3

A digester as defined in claim 1 including heating coils positioned about said second chamber for heating the slurry therein.

Claim 4

A digester as defined in claim 1 including a mix tank for preparing the slurry and having a connection to said input line, a recycle line having one end connected to the bottom of a flexible tube in said third chamber, and float means for supporting the upper end of said flexible tube adjacent the surface of the slurry in the third chamber, the other end of said recycle line connected to said mix tank.

Claim 5

The digester as defined in claim 1 including upper gas jets located on one side of the chambers and lower gas jets located on the opposite side of the chambers for circulating the slurry therein after the periodical feeding of a load of raw slurry into the bottom of the first chamber.

Claim 6

A digester as defined in claim 1 wherein said digester is formed of a flexible oblong bag having its lower half portion supported in a trench dug in the earth and a first and second divider, the lower half portion of the bag being separated by said first and second divider to form said first, second and third chambers, and the upper half portion of said bag forming said fourth chamber, and wherein said first passthrough tube is elbow shaped with its lower end extending through an opening in the bottom of said first divider and with its upper free end disposed on the central level portion of the first chamber, and wherein said second passthrough tube is straight and extends through an opening in the bottom of said second divider.

Claim 7

The digester as defined in claim 5 wherein said first divider has a weir formed on the upper end thereof.

Claim 8

The digester as defined in claim 5 including a gas outlet pipe flexibly connected to the upper half portion of said bag, said gas outlet pipe providing for feeding gas to a compressor.

Claim 9

The digester as defined in claim 5 including a compressor on-off control switch coupled to sense the expansion and contraction of the upper half portion of said bag.

Claim 10

The digester as defined in claim 5 wherein said bag and said first and second dividers are formed of a nylon reinforced synthetic rubber structural fabric.

Claim 11

A process for the producing of a methane gas and a liquid fertilizer from organic matter comprising the steps of: blending a slurry of organic waste matter containing aerobic and anaerobic bacteria in a mix tank providing a first, second and third chamber interconnected in tandem by passthrough tubes such that the central level portion of the first chamber is connected to the bottom level portion of the second chamber and the bottom level portion of the second chamber is connected to the bottom level portion of the third chamber, the size of the second chamber being larger than the size of either the first or third chambers; providing a flexible gas collecting chamber above and covering first, second and third chambers; initially filling said first, second and third chambers with slurry from said mix tank to the level of an output port provided by the upper end of an upright pipe in the third chamber; and periodically feeding a predetermined volume of slurry less than the volume of the first chamber from the mix tank into the bottom of the first chamber and automatically creating a movement of a like volume of the slurry from said first chamber to said second chamber, from said second chamber to said third chamber; and from said third chamber into the outlet port; wherein the size of said first chamber is large enough to detain the volume of slurry received therein from the mix tank long enough to react to aerobic bacteria and anaerobic bacteria to produce an acidified material and the size of said second chamber is large enough to detain the volume of slurry received therein from the first chamber long enough to further react to anaerobic bacteria to generate methane gas; whereby the digested slurry received in the third chamber from the second chamber and drained down said outlet port corresponds to liquid fertilizer and permitting the slurry in the second chamber to remain long enough to generate methane gas which is collected in said fourth chamber.

Claim 12

A process for the producing of a methane gas and a liquid fertilizer from organic matter comprising the steps of: blending a slurry of organic waste matter containing aerobic and anaerobic bacteria in a mix tank providing a first, second and third chamber interconnected in tandem by passthrough tubes such that the central level portion of the first chamber is connected to the bottom level portion of the second chamber and the bottom level portion of the second chamber is connected to the bottom level portion of the third chamber, the size of the second chamber being larger than the size of either the first or third chambers; providing a flexible gas collecting chamber above and covering first, second and third chambers; initially filling said first, second and third chambers with slurry from said mix tank to the level of an output port provided by the upper end of an upright pipe in the third chamber; and periodically feeding a predetermined volume of slurry less than the volume of the first chamber from the mix tank into the bottom of the first chamber and automatically creating a movement of a like volume of the slurry from said first chamber to said second chamber, from said second chamber to said third chamber; and from said third chamber into the outlet port; wherein the size of said first chamber is large enough to detain the volume of slurry received therein from the mix tank long enough to react to aerobic bacteria and anaerobic bacteria to produce an acidified material and the size of said second chamber is large enough to detain the volume of slurry received therein from the first chamber long enough to further react to anaerobic bacteria to generate methane gas; whereby the digested slurry received in the third chamber from the second chamber and drained down said outlet port corresponds to liquid fertilizer and permitting the slurry in the second chamber to remain long enough to generate methane gas which is collected in said fourth chamber.

Claim 13

The process of claim 10 including the step of agitating the slurry in said slurry chambers after the periodical feeding of the slurry from the mix tank into the first chamber.