Struvite precipitation and microbial fuel cell for recovery of nutrients and energy from digester effluent

Patent metadata

Field	Value
Publication number	US-2018282189-A1
Application number	US-201815943427-A
Country	US
Kind code	A1
Filing date	Apr 2, 2018
Priority date	Mar 31, 2017
Publication date	Oct 4, 2018
Grant date	—

Abstract

Provided are wastewater treatment processes that involves struvite precipitation and a microbial fuel cell for the recovery of nutrients and energy from a digester effluent.

First claim

What is claimed is:

1 . A wastewater treatment process comprising:
forming struvite precipitation from a liquid influent processed through a wastewater digester to thereby generate a first liquid effluent with a phosphorus concentration of less than 5%; providing the first liquid effluent to a nitrification reactor to convert ammonium in the first liquid effluent to nitrate or nitrite thereby generating a second liquid effluent; providing the second liquid effluent to a microbial fuel cell, wherein the microbial fuel cell includes an anodic chamber for organic decomposition, a cathodic chamber for denitritation/denitrification; and the microbial fuel cell generating energy and a third liquid effluent substantially free of nitrogen and phosphorus.

2 . The wastewater treatment process of claim 1 , wherein nitrogen concentration in the first liquid effluent is reduced by at least about 25% in the nitrification reactor.

3 . The wastewater treatment process of claim 1 , further comprising providing aeration to the nitrification reactor.

4 . The wastewater treatment process of claim 1 , further comprising adjusting pH to the liquid influent.

5 . The wastewater treatment process of claim 1 , further comprising adding primary wastewater or other electron-donating organic substrates to the microbial fuel cell.

6 . The wastewater treatment process of claim 1 , wherein the microbial fuel cell generates an average voltage in a range of 0 to 500 mV and/or an average current in a range of 0 to 500 μA.

7 . The wastewater treatment process of claim 1 , wherein the microbial fuel cell generates power in a range of 0 to 60 mW/m 2 .

8 . The wastewater treatment process of claim 1 , wherein the wastewater digester comprises an anaerobic digester.

9 . A wastewater treatment process comprising:
digesting waste activated sludge in an anaerobic digester to generate an digester effluent; centrifuging the digester effluent to produce a liquid influent; forming struvite precipitation from the liquid influent to thereby generate a first liquid effluent, wherein the phosphorus concentration in the first liquid effluent is reduced compared to the phosphorus concentration in the liquid influent; providing the first liquid effluent to a fixed-film nitrification reactor to convert ammonium in the first liquid effluent to nitrate or nitrite thereby generating a second liquid effluent comprising nitrate, nitrite, or a mixture thereof; and providing the second liquid effluent and an influent primary wastewater or other electron-donating organic substrate to a microbial fuel cell, wherein the microbial fuel cell comprises an anodic chamber for organic decomposition and a cathodic chamber for denitritation, denitrification, or both, wherein the second liquid effluent is provided to the cathodic chamber and the influent primary wastewater or other electron-donating organic substrate is provided to the anodic chamber, whereby the microbial fuel cell generates energy and a third liquid effluent is generated having reduced amounts of nitrogen and phosphorus compared to the waste activated sludge.

10 . The wastewater treatment process of claim 9 , wherein nitrogen concentration in the first liquid effluent is reduced by at least about 25% in the fixed-film nitrification reactor.

11 . The wastewater treatment process of claim 9 , wherein the phosphorus concentration in the first liquid effluent is reduced by at least about 70% compared to the phosphorus concentration in the liquid influent.

12 . The wastewater treatment process of claim 9 , wherein the third liquid effluent has at least about 50% less phosphorus and/or nitrogen compared to the waste activated sludge.

13 . The wastewater treatment process of claim 9 , wherein at least about 40% of the influent primary wastewater chemical oxygen demand (COD) is removed in the microbial fuel cell.

14 . The wastewater treatment process of claim 9 , further comprising providing aeration to the fixed-film nitrification reactor.

15 . The wastewater treatment process of claim 9 , further comprising adjusting the pH of the liquid influent.

16 . The wastewater treatment process of claim 9 , wherein struvite precipitation is achieved by adding MgCl 2 .6H 2 O to the liquid influent to achieve a Mg:P molar ratio of 1.6-2.0.

17 . The wastewater treatment process of claim 9 , wherein the anodic chamber of the microbial fuel cell is inoculated with Shewanella putrefaciens and the cathodic chamber of the microbial fuel cell is inoculated with Geobacter metallireducens.

18 . The wastewater treatment process of claim 9 , wherein the anodic chamber and cathodic chamber are maintained under anoxic conditions.

19 . The wastewater treatment process of claim 9 , wherein the microbial fuel cell generates an average voltage in a range of 0 to 500 mV and/or an average current in a range of 0 to 500 μA.

20 . The wastewater treatment process of claim 9 , wherein the microbial fuel cell generates power in a range of 0 to 60 mW/m 2 and/or 0 to 70 mW/m 3 .

Assignees

• Cunningham Jeffrey Allen
• Orner Kevin Daniel
• Mihelcic James R
• Univ South Florida

Inventors

• Cunningham Jeffrey Allen
• Orner Kevin Daniel
• Mihelcic James R

Classifications

• C02F2305/02

  Specific form of oxidant · CPC title

• C02F1/46176

  Galvanic cells · CPC title

• C02F3/005

  Combined electrochemical biological processes (aeration by electrolytically produced oxygen bubbles C02F3/202) · CPC title

• C02F3/303

  characterised by the nitrification · CPC title

• C02F2303/10

  Energy recovery · CPC title