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US 11,851,355 B2Granted
Methods and systems for digesting biosolids and recovering phosphorus
OwnerRichard Pressley, Justin Wippo +1inventors
InventorsRichard Pressley, Justin Wippo, John H. Graham, Jr.
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Abstract
Processes and system are provided for digesting biosolids in a multistage digestion system. The processes and system are well suited for producing Class A biosolids and biogas containing a high content of methane. Methods and systems are also provided for recovery of phosphorus from wastewater and biosolids.
Claims19
A method for digesting biosolids and recovering phosphorus from the biosolids, the method comprising:
- hydrolyzing insoluble organic polymers in a sludge derived from wastewater in an acidic hydrolysis environment to produce hydrolyzed biosolids;
- fermenting the hydrolyzed biosolids in an anaerobic digestion environment to produce anaerobically digested biosolids;
- optionally digesting the anaerobically digested biosolids in a thermophilic aerobic digestion environment to produce thermophilically digested biosolids;
- digesting the anaerobically digested biosolids or the thermophilically digested biosolids in a mesophilic digestion environment to produce mesophilically digested biosolids;
- separating the mesophilically digested biosolids into a phosphorus-rich centrate and dewatered digested phosphorus-lean biosolids;
- and
- recovering a phosphorus-rich precipitate from the phosphorus-rich centrate.
4 more elements
A system for digesting biosolids and recovering phosphorus, the system comprising:
- an acidic hydrolysis reactor adapted to produce hydrolyzed biosolids;
- an anaerobic digestion reactor fluidly connected to the acidic hydrolysis reactor so as to receive the hydrolyzed biosolids, wherein the anaerobic digestion reactor is adapted for maintaining an anaerobic digestion environment to produce anaerobically digested biosolids;
- optionally a thermophilic aerobic digestion reactor fluidly connected to the anaerobic digestion reactor so as to receive the anaerobically digested biosolids, wherein the thermophilic aerobic digestion reactor is adapted for maintaining a thermophilic aerobic digestion environment to produce thermophilically digested biosolids;
- a mesophilic digestion reactor fluidly connected to the anaerobic digestion reactor, or to the thermophilic aerobic reactor if present, so as to receive the anaerobically digested biosolids or the thermophilically digested biosolids, wherein the mesophilic digestion is adapted to produce mesophilically digested biosolids;
- a liquid/solid separation tank fluidly connected to the mesophilic digestion reactor, wherein the liquid/solid separation tank is adapted to separate the mesophilically digested biosolids into a phosphorus-rich centrate and dewatered digested phosphorus-lean biosolids;
- and
- a precipitation tank fluidly connected to the separation tank so as to receive the phosphorus-rich centrate.
4 more elements
Dependencies are inferred from the claim text.