Electrochemical reactor with tumbling bed electrodes for wastewater treatment

Abstract

The invention relates to an electrochemical reactor with a unique tumbling bed electrode configuration. This reactor combines the operational advantages of both fixed-bed and fluidized-bed systems while eliminating their respective limitations.

Description

[0001] Electrochemical Reactor with Tumbling Bed Electrodes for Wastewater Treatment

[0002] Field of the Invention

[0003] The present invention relates to the field of electrochemical wastewater treatment, particularly to a novel reactor configuration that integrates the advantages of both fixed-bed and fluidized-bed electrochemical systems while overcoming their respective limitations.

[0004] Background of the Invention

[0005] Nowadays, wastewater treatment is a big issue for industries and residential areas (1). Electrochemical processes are increasingly employed for the treatment of industrial and municipal wastewater due to their efficiency in removing suspended solids, colloidal matter, heavy metals, and other contaminants (2-4). One of the most promising electrochemical techniques is electrocoagulation, wherein electric current is applied between two sacrificial electrodes (usually iron or aluminum) submerged in wastewater (5, 6). These electrodes release Fe3+ or AI3+ ions through anodic dissolution, which then hydrolyze to form hydroxide flocs (4). These flocs aggregate and destabilize suspended and colloidal particles, facilitating their removal by sedimentation or flotation.

[0006] In traditional electrocoagulation reactors employing fixed-bed electrode configurations, electrode fouling and clogging are major challenges (7). As flocs accumulate during treatment, they tend to settle or float depending on density, and in the absence of sufficient turbulence, they accumulate within the electrode bed, leading to blockage (see Figure 1). When clogging occurs, operators must shut down the system, manually clean the bed, and restart the reactor, which increases downtime and operational costs (8).

[0007] To address this issue, fluidized-bed reactors were introduced (9). In these systems, multiple anode and cathode plates are placed inside the reactor, with metal balls (matching the electrode material) added between them (see Figure 2). Aeration is used to agitate the balls, allowing them to move freely within the reactor. Upon contact with the electrodes, the metallic balls become momentarily energized, turning their surfaces into active electrode sites. This design reduces fouling as the continuous motion prevents floc accumulation and facilitates floc migration to downstream sedimentation tanks (10). However, a significant drawback remains: only a small proportion of the metallic balls are in contact with the energized electrodes at any given moment, resulting in low electrochemical surface utilization and inconsistent treatment efficiency (7).

[0008] Summary of the Invention.

[0009] The present invention describes an innovative electrochemical reactor with a unique Tumbling Bed Electrode (TBE) configuration, combining the advantages of fixed-bed and fluidized-bed systems while overcoming their limitations. The reactor consists of a rotating cylindrical chamber with a central shaft functioning as the anode and internally mounted cathodic electrodes. Metallic balls of the same material as the anode tumble inside the chamber, promoting a large active electrochemical surface and preventing floc accumulation through controlled reactor rotation. This design enables uniform and efficient coagulant generation, mechanical self-cleaning, low energy consumption, and reduced maintenance. The technology is applicable to industrial wastewater treatment with high suspended and colloidal particle loads, offering a compact and sustainable water purification solution.

[0010] Description

[0011] The invention introduces a novel electrochemical reactor with a unique tumbling bed electrode configuration, herein referred to as the Tumbling Bed Electrodes (TBE) system. This design merges the operational advantages of both fixed-bed and fluidized-bed systems while eliminating their weaknesses. The reactor comprises a horizontally mounted rotating cylindrical chamber supported by a central metallic shaft made of either iron or aluminum, depending on the target coagulant. The shaft functions as the anode. The cylinder body is separated from the shaft by non- conductive O-rings, ensuring no direct electrical contact between the rotating chamber and the shaft. Inside the cylindrical reactor, several cathodic electrode plates are mounted at regular intervals along the inner wall of the chamber (see Figure 3). Metallic balls of the same material as the anode (iron or aluminum) are introduced into the chamber such that their positions remain below the central shaft, without direct contact with it. The metallic balls continuously interact with each other and the installed cathodic electrodes, creating a network of electrochemical activity throughout the reactor volume. This configuration enables a broad and stable electrochemical surface area, similar to that of a fixed bed.

[0012] To mitigate clogging and the accumulation of flocs between the metallic balls, the entire cylindrical reactor slowly rotates via a motorized system. This rotation causes the metallic balls to tumble, dislodging floc particles from their surfaces and ensuring even movement and mixing throughout the reactor volume. The gradual agitation ensures continuous floc dispersion and prevents sediment buildup. This design ensures permanent electrical conduction through the metallic media, enabling effective and uniform coagulant generation, while simultaneously allowing automatic self-cleaning by mechanical agitation. The reactor, therefore, provides a compact, energy-efficient, and maintenance-friendly alternative to existing electrochemical reactors.

[0013] Advantages of the Invention:

[0014] • Combines the benefits of both fixed-bed and fluidized-bed electrochemical systems.

[0015] • Prevents clogging through continuous mechanical agitation.

[0016] • Provides consistent electrical contact and coagulant generation via extended surface interaction.

[0017] • Reduces maintenance and operational downtime.

[0018] • Operates with low energy input and minimal operator oversight.

[0019] Industrial Application

[0020] This invention is applicable to a wide range of industrial wastewater treatment scenarios, including electroplating, textile, pharmaceutical, municipal, and agricultural effluents where high loads of suspended and colloidal particles are present. Drawings

[0021] Figure 1 : Fixed bed reactor

[0022] Figure 2: Fluidized bed electrochemical reactor (multi-rod type)

[0023] Figure 3: Tumbling bed electrodes

[0024] References:

[0025] 1. Ahmad I, El-Sheekh MM, Abdullah N, Kamyab H, Iwamoto K, Chong JWR, et al. Batch cultivation of Chlorella vulgaris and simultaneous treatment of restaurant wastewater. Journal of the Taiwan Institute of Chemical Engineers. 2024:105815.

[0026] 2. Maarof HI, Daud WMAW, Aroua MK. Recent trends in removal and recovery of heavy metals from wastewater by electrochemical technologies. Reviews in Chemical Engineering. 2017;33(4):359-86.

[0027] 3. Garcia-Segura S, Eiband MMSG, de Melo JV, Martinez-Huitle CA. Electrocoagulation and advanced electrocoagulation processes: A general review about the fundamentals, emerging applications and its association with other technologies. Journal of Electroanalytical Chemistry. 2017;801 :267-99.

[0028] 4. Drogui P, Blais J-F, Mercier G. Review of electrochemical technologies for environmental applications. Recent patents on engineering. 2007;1(3):257-72.

[0029] 5. Javed A, Mushtaq A. A critical review of electrocoagulation and other electrochemical methods. Int J Chem Biochem Sci. 2023;23:98-110.

[0030] 6. Barrera-Diaz CE, Roa-Morales G, Hernandez PB, Fernandez-Marchante CM, Rodrigo MA. Enhanced electrocoagulation: New approaches to improve the electrochemical process. Journal of Electrochemical Science

[0031] Engineering in Life Sciences. 2014;4(4):285-96.

[0032] 7. Rodrigues AR, Seki CC, Ramalho LS, Argondizo A, Silva AP. Electrocoagulation in a fixed bed reactor-color removal in batch and continuous mode. Separation Purification Technology. 2020;253:117481.

[0033] 8. Hua L-C, Huang C, Su Y-C, Nguyen T-N-P, Chen P-C. Effects of electrocoagulation on fouling mitigation and sludge characteristics in a coagulation-assisted membrane bioreactor. Journal of membrane science. 2015;495:29-36.

[0034] 9. Asensio Y, Llorente M, Sanchez-Gomez A, Manchon C, Boltes K, Esteve- Nunez A. Microbial electrochemical fluidized bed reactor: a promising solution for removing pollutants from pharmaceutical industrial wastewater. Frontiers in microbiology. 2021;12:737112.

[0035] 10. Wang L, Zhou J, Chang Y, Xu H. Research progress on novel electrochemical descaling technology for enhanced hardness ion removal. Water. 2024;16(6):886.

Claims

Claims1. An electrochemical reactor comprising a central sacrificial anode shaft, a rotating cylindrical body, and multiple internal cathodic electrodes.

2. The reactor of claim 1 , wherein metallic balls of the same material as the anode are placed within the cylinder to act as extended electrochemical surfaces.

3. The reactor of claim 1 , wherein the cylindrical body rotates to induce tumbling motion of the metallic balls, facilitating self-cleaning and floc dispersion.

4. The reactor of claim 1 , wherein the shaft and rotating cylinder are separated by non-conductive sealing components to prevent short-circuiting.

5. A method of wastewater treatment using the reactor of Claim 1 , comprising: introducing wastewater into the cylinder, applying direct current to the shaft and cathodes, rotating the cylinder, and removing treated water for sedimentation.

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