Bio-electrochemical system for treating wastewater
Inventors
Silver, Matthew • Buck, Justin • Kiely, Patrick • Guzman, Juan J.
Assignees
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Publication Number
US-10099950-B2
Publication Date
2018-10-16
Expiration Date
Abstract
The invention relates to bio-electrochemical systems for treating wastewater, and sour gas produced by anaerobic digestion of organic material. The invention further relates to novel anode/cathode pairing schemes, and electric and hydraulic architectures for use in bio-electrochemical systems.
Core Innovation
The invention describes a fully enclosed anaerobic reaction chamber for treating wastewater using a bio-electrochemical system with two or more anode/cathode pairs disposed in substantial proximity. At least one anode is in proximity to a methanogenic microbe, and at least one power source applies a voltage to the anode/cathode pair to drive the bio-electrochemical treatment. The chamber is configured to receive wastewater or a gas and to enable internal interactions between the electrodes and the microbes within the enclosed anaerobic environment.
The core architecture arranges the two or more anode/cathode pairs in vertical succession while configuring the wastewater or gas to flow upwards past the anode and the cathode in each pair. The invention further constrains the cathode-to-anode surface area ratio within each pair to 1:5 to 5:1 and limits the distance between the anode/cathode pairs to approximately 0.01 cm to 1 cm. These geometric and flow constraints are presented as part of the overall chamber and electrode pairing arrangement for the enclosed anaerobic treatment.
In the described embodiments, the system includes additional structural and electrical features for the stacked electrode arrangement, including architectures such as up-flow and other succession arrangements. The disclosure also describes anode/cathode pair designs and configurations intended to manage internal resistance and pH gradients, and it includes optional elements such as air cathodes and electron storage devices between anode and cathode. The described coupling to anaerobic digestion is presented as enabling improved methane or biogas quality while also supporting bio-oxidation of sour gases via anodic oxidation chamber behavior.
Claims Coverage
The independent claim covers a fully enclosed anaerobic bio-electrochemical apparatus with stacked (vertical succession) anode/cathode pairs, up-flow of wastewater or gas through each pair, and constrained cathode-to-anode surface area ratio and inter-pair spacing. The claim set includes additional inventive refinements in dependent claims, including specific electrode materials, separator/conductor layer structures, mechanical flow features, and electrical distribution constraints.
Fully enclosed anaerobic reaction chamber with stacked anode/cathode pairs
A fully enclosed anaerobic reaction chamber comprising two or more anode/cathode pairs disposed therein in substantial proximity, with at least one anode in proximity to a methanogenic microbe, and at least one power source configured to apply a voltage to the anode/cathode pair.
Vertical succession arrangement of anode/cathode pairs
The two or more anode/cathode pairs are arranged in vertical succession within the anaerobic reaction chamber.
Upward flow configuration through each anode/cathode pair
The anaerobic reaction chamber is configured to allow the wastewater or a gas to flow upwards to the anode, and the cathode, in each of the anode/cathode pairs.
Cathode-to-anode surface area ratio and inter-pair spacing
A surface area ratio of each cathode: anode in a pair is 1:5 to 5:1 and the distance between the anode/cathode pairs is approximately 0.01 cm to 1 cm.
Same voltage to multiple anode/cathode pairs
At least one power source is configured to apply the same voltage to two or more anode/cathode pairs.
Stainless steel mesh coated with activated carbon/binder
Anodes and cathodes are made from stainless steel mesh coated with an activated carbon/binder mixture.
Porous insulating layer between anode and cathode
The anode and cathode are separated by a porous insulating layer.
Conductive paint on both sides of porous insulating layer
An anode and a cathode are formed by conductive paint applied to either side of a porous insulating layer.
Angled solid dividing layer
The anaerobic reaction chamber includes an angled solid dividing layer.
The independent claim centers on a stacked, fully enclosed anaerobic bio-electrochemical apparatus with up-flow of wastewater or gas through vertically successive anode/cathode pairs, where at least one anode is in proximity to methanogenic microbe and voltage is applied. Dependent refinements explicitly cover applying the same voltage to multiple pairs, specific electrode construction (stainless steel mesh with activated carbon/binder), porous insulating separation and conductive paint electrode formation, and an angled solid dividing layer.
Stated Advantages
Enables improved methane/biogas quality when coupled to anaerobic digestion.
Enables bio-oxidation of sour gases (notably hydrogen sulfide) via anodic oxidation chamber behavior.
Documented Applications
Bio-trickling filter BES with a bio-electrochemical system in an anaerobic chamber architecture.
Combined anaerobic digestion and H2S filter BES configuration.
Mobile bioelectric filtration system (MBFS) using an accelerated anaerobic digester architecture.
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