Cylindrical disk pump with integrated electrocoagulation for water treatment and self-cleaning via radial scraper blades

Abstract

A cylindrical pump in which both the pump housing and rotating disks are made from electrochemically active materials such as aluminum or iron. The housing acts as the anode, while the disks function as the cathode. The rotation of the disks pumps water through the unit according to Tesla's disk pump principles. During operation, electrical current applied between the housing and the disks produces trivalent aluminum or iron ions, depending on the material used. These ions serve as coagulants, destabilizing suspended particles and enabling their removal in downstream treatment stages. To prevent fouling, radial scraper blades are mounted inside the cylindrical housing. These blades mechanically remove precipitates and scale deposits from the interior surfaces during rotation, ensuring continuous performance and reducing maintenance requirements.

Description

[0001] Cylindrical Disk Pump with Integrated Electrocoagulation for Water Treatment and Self-Cleaning via Radial Scraper Blades

[0002] Field of the Invention

[0003] The present invention relates to water treatment technologies. More specifically, it concerns a cylindrical pump design based on Tesla disk pump principles, adapted for electrochemical coagulation of water or wastewater.

[0004] Background of the Invention

[0005] With the growing global demand for water and increasing environmental concerns caused by climate change, industrialization, and urbanization, the need for advanced technologies to effectively remove pollutants is stronger than ever (1 , 2). Electrochemical treatment is an efficient water treatment method that removes suspended solids, heavy metals, and certain dissolved organic contaminants (3). Electrochemical treatment systems traditionally require separate reactors and pumping units, leading to bulky and expensive installations. Tesla-type disk pumps, which operate without impellers and instead use a stack of closely spaced disks, provide smooth, low-shear flow (4). However, their application in electrochemical water treatment remains limited. Current electrochemical treatment systems have two major limitations: (a) complexity and cost - they require separate pumping, power supply, and coagulation chambers; and (b) fouling and scaling - precipitates from coagulation can adhere to electrodes and internal surfaces, reducing efficiency.

[0006] There remains a strong need for a compact, integrated, and self-cleaning electrocoagulation system that can pump and treat water simultaneously, with minimal maintenance. Electrochemical treatment processes, by utilizing oxidationreduction reactions at electrode surfaces, can remove persistent organic pollutants, heavy metals, and emerging contaminants (such as pharmaceuticals and hormones). These processes can convert pollutants into harmless mineral compounds or biodegradable products (5, 6).

[0007] Various mechanisms are introduced for pollutants removal using electrochemical treatment processes such as direct anodic oxidation, indirect oxidation, electrocoagulation, electroflotation, and electrochemical advanced oxidation processes (7). In direct anodic oxidation, the pollutant molecules are destroyed right on the surface of the anode (8). This occurs when the contaminant comes into contact with the electrode and loses electrons directly to it (9). The anode material plays a key role here — materials like boron-doped diamond (BDD) or mixed metal oxides (MMOs) are often used because they are highly conductive and resist corrosion (10). For example, phenol (CeHsOH) can be oxidized completely to carbon dioxide and protons:

[0008] C6H5OH + 14W2O 6CO2+ 28H++ 286-

[0009] In this pathway, there are no intermediate oxidants in the bulk water; instead, electrons are transferred directly between the pollutant and the anode. This method works well for small, simple molecules, but for more complex or hydrophobic contaminants, the reaction can be slower because they may not easily reach the electrode surface. Indirect oxidation is different because it first produces highly reactive oxidants in the water, which then attack and break down pollutants (11). One of the most important oxidants is the hydroxyl radical (’OH), which can be formed at the anode (12):

[0010] H2O -^• 0H + H++ e~

[0011] These radicals have a very short life but are extremely powerful. They can oxidize almost all types of organic molecules, turning them into carbon dioxide, water, and inorganic salts. In chloride-containing water, the process can also create chlorine gas:

[0012] 2Cl~ -> Cl2+ 2e~Cl2+ H2O -> HOCl + H++ Cl~

[0013] The hypochlorous acid (HOCl) formed is another strong oxidizing agent that can remove many organic and microbial pollutants. This method is more versatile than direct oxidation because the oxidants can reach pollutants that are far from the electrode. Electrocoagulation is another mechanism involved in the electrochemical treatment of water and wastewater. Electrocoagulation works by producing coagulants directly inside the water using sacrificial metal electrodes. When an iron electrode is used, iron ions are released into the water: Fe -> Fe2++ 2e

[0014] These ions quickly react with hydroxide ions to form iron hydroxide:

[0015] Fe2++ 20H~ -> Fe(OH)2I

[0016] These metal hydroxide particles are sticky and can trap suspended solids, oils, and some dissolved organic compounds (13). As they settle, they remove pollutants from the water. Aluminum electrodes work similarly, producing AI(OH)s flocs. This method is particularly effective for turbid water, dye wastewater, and oily effluents. When aluminum electrodes are used in electrocoagulation, the aluminum metal dissolves into the water during the oxidation process at the anode:

[0017] Al -> Al3++ 3e~

[0018] These aluminum ions (Al3+) quickly react with hydroxide ions (OH“) that are either naturally present in water or produced at the cathode during electrolysis:

[0019] The AI(OH)3 produced is a gelatinous precipitate with a high surface area (14). This allows it to adsorb and trap fine suspended particles, organic molecules, and even some dissolved metals. At the cathode, water is reduced and hydroxide ions are generated:

[0020] The hydroxide ions from this reaction help maintain the pH in the range where aluminum hydroxide is most stable (usually pH 5-8) (14, 15). The gelatinous AI(OH)s flocs then aggregate and settle or float, carrying the captured pollutants with them. This mechanism is especially effective for removing dyes, phosphates, arsenic, fluoride, and emulsified oils because the aluminum hydroxide can form strong chemical bonds or surface complexes with these substances (13). Another mechanism involved in the electrochemical treatment of water and wastewater is electroflotation process. Electroflotation uses the gases produced during electrolysis to separate pollutants from water physically (16). At the cathode, hydrogen gas is released:

[0021] 2H2O + 2e~ H2+ 2OH~

[0022] At the anode, oxygen gas is generated:

[0023] 2H2O + O2-> 4W++ 4e“

[0024] The fine bubbles attach to particles, oils, or grease, making them float to the surface where they can be skimmed off (17). This technique is beneficial for wastewater containing fats, oils, and suspended solids (18). Electrochemical advanced oxidation processes (EAOPS) are other usages of the electrochemical treatment of water and wastewater. EAOPs combine electrochemical methods with other strong oxidation techniques like UV light, ozone, or the Fenton reaction to speed up the breakdown of pollutants (19, 20). One important EAOP is the electro-Fenton process, where hydrogen peroxide is produced at the cathode (21):

[0025] O2+ 2H++ 2e~ -> H2O2

[0026] This hydrogen peroxide reacts with iron ions to produce hydroxyl radicals:

[0027] Fe2++ H2O2-> Fe3++ OH~ +• OH

[0028] These radicals then attack organic pollutants, breaking them into smaller molecules and finally into carbon dioxide and water (22). EAOPs are highly efficient for removing pharmaceuticals, pesticides, and other persistent organic pollutants that are hard to degrade with conventional methods (23). Three-dimensional ceramic carbon foam electrodes have high capability for removing pharmaceuticals and phenolic compounds, but they may produce toxic by-products such as 2,4- dichlorophenol (24, 25). In-situ analyses using microscopy and spectroscopy reveal the activation and deactivation details of catalysts, helping to optimize process selectivity and stability (26).

[0029] The electrochemical treatment of water and wastewater has been a subject of scientific investigation for many years (27, 28). Researchers have studied various electrochemical processes, including electrocoagulation, electrooxidation, and electroflotation, for their potential to remove contaminants efficiently (29, 30). However, the practical implementation of these methods still requires complex and expensive equipment, including specialized power supplies, advanced electrode materials, and precise flow control systems. Such requirements often limit the application of electrochemical treatment technologies to large-scale, centralized facilities (29). To date, only limited research has focused on designing and developing compact, simple, and small-scale electrochemical systems that can be deployed in decentralized or mobile applications. The absence of such practical designs creates a significant gap in the market, particularly for rural communities, remote areas, and emergencies where rapid and reliable water purification is critical. As a result, there remains a strong demand for low-cost, portable electrochemical treatment devices that combine operational simplicity with high treatment efficiency.

[0030] Summary of the Invention

[0031] The invention is a cylindrical pump in which both the pump housing and rotating disks are made from electrochemically active materials such as aluminum or iron. The housing acts as the anode, while the disks function as the cathode. The rotation of the disks pumps water through the unit according to Tesla’s disk pump principles. During operation, electrical current applied between the housing and the disks produces trivalent aluminum or iron ions, depending on the material used. These ions serve as coagulants, destabilizing suspended particles and enabling their removal in downstream treatment stages. To prevent fouling, radial scraper blades are mounted inside the cylindrical housing. These blades mechanically remove precipitates and scale deposits from the interior surfaces during rotation, ensuring continuous performance and reducing maintenance requirements.

[0032] Description

[0033] The invention is a cylindrical pump in which both the pump housing and rotating disks are made from electrochemically active materials such as aluminum or iron.

[0034] The housing acts as the anode, while the disks function as the cathode. The rotation of the disks pumps water through the unit according to Tesla’s disk pump principles. During operation, electrical current applied between the housing and the disks produces trivalent aluminum or iron ions, depending on the material used. These ions serve as coagulants, destabilizing suspended particles and enabling their removal in downstream treatment stages.

[0035] To prevent fouling, radial scraper blades are mounted inside the cylindrical housing. These blades mechanically remove precipitates and scale deposits from the interior surfaces during rotation, ensuring continuous performance and reducing maintenance requirements.

[0036] Referring to Figure 1 , the pump consists of a cylindrical housing fabricated from aluminum or iron.

[0037] Inside the housing is a central shaft connected to multiple circular disks positioned with small gaps between them. The disks are constructed from the same metal as the housing to maintain electrochemical compatibility. The housing functions as the anode, while the disks act as the cathode.

[0038] A power supply applies direct current across the housing and disks, initiating electrocoagulation. When aluminum is used, Al3+ions are released into the water; when iron is used, Fe3+ions are generated. These ions react with hydroxide ions in water to form metal hydroxide flocs, which capture and settle suspended particles.

[0039] Water is pumped through the unit by the Tesla disk principle: as the shaft rotates, viscous drag between the disks and the water generates a smooth spiral flow toward the outlet.

[0040] To prevent blockage from precipitate buildup, radial scraper blades are fixed to the inner surface of the housing.

[0041] These blades mechanically dislodge deposits during rotation, allowing the treated water to exit without obstruction. Increasing the number of disks proportionally increases the total cathode surface area, enhancing coagulant production and treatment efficiency. Brief Description of Drawings

[0042] [Fig 1]: Electrocoagulation unit with cylindrical electrodes

[0043] References:

[0044] 1. Saxena V. Water quality, air pollution, and climate change: investigating the environmental impacts of industrialization and urbanization. Water, Air, Soil Pollution. 2025;236(2):73.

[0045] 2. Nishat A, Yusuf M, Qadir A, Ezaier Y, Vambol V, Ijaz Khan M, et al. Wastewater treatment: A short assessment on available techniques. Alexandria Engineering Journal. 2023;76:505-16.

[0046] 3. Dube A, Malode SJ, Alshehri MA, Shetti NP. Electrochemical water treatment: Review of different approaches. Journal of Environmental Management. 2025;373: 123911.

[0047] 4. TDP. Advanced Pumping Technology for Demanding Industrial Fluids: Tesla Disk

[0048] Pumps 2025 [cited 2025 12 Aug 2025], Available from: https: / / www.tesladiskpumps.com.

[0049] 5. Ganiyu SO, Martinez-Huitle CA, Oturan MA. Electrochemical advanced oxidation processes for wastewater treatment: Advances in formation and detection of reactive species and mechanisms. Current Opinion in Electrochemistry. 2021 ;27: 100678.

[0050] 6. de Vargas Briao G, da Costa TB, Antonelli R, Costa JM. Electrochemical processes for the treatment of contaminant-rich wastewater: A comprehensive review. Chemosphere. 2024;355:141884.

[0051] 7. Martinez-Huitle CA, Ferro SJCsr. Electrochemical oxidation of organic pollutants for the wastewater treatment: direct and indirect processes. 2006;35(12): 1324-40.

[0052] 8. Hu Z, Cai J, Song G, Tian Y, Zhou M. Anodic oxidation of organic pollutants: anode fabrication, process hybrid and environmental applications. Current Opinion in Electrochemistry. 2021 ;26: 100659.

[0053] 9. Sires I, Brillas E, Oturan MA, Rodrigo MA, Panizza M. Electrochemical advanced oxidation processes: today and tomorrow. A review. Environmental Science Pollution Research. 2014;21 (14):8336-67. 10. Brosler P, Girao AV, Silva RF, Tedim J, Oliveira FJ. In-house vs. commercial boron-doped diamond electrodes for electrochemical degradation of water pollutants: A critical review. Frontiers in Materials. 2023; 10: 1020649.

[0054] 11 . Scialdone O. Electrochemical oxidation of organic pollutants in water at metal oxide electrodes: A simple theoretical model including direct and indirect oxidation processes at the anodic surface. Electrochimica Acta. 2009;54(26):6140-7.

[0055] 12. Wang C, Niu J, Yin L, Huang J, Hou L-A. Electrochemical degradation of fluoxetine on nanotube array intercalated anode with enhanced electronic transport and hydroxyl radical production. Chemical Engineering Journal. 2018;346:662-71.

[0056] 13. Ghernaout D, Naceur M, Ghernaout B. A review of electrocoagulation as a promising coagulation process for improved organic and inorganic matters removal by electrophoresis and electroflotation. Desalination Water Treatment. 2011 ;28(1- 3):287-320.

[0057] 14. Mouedhen G, Feki M, Wery MDP, Ayedi H. Behavior of aluminum electrodes in electrocoagulation process. Journal of hazardous materials. 2008;150(1):124- 35.

[0058] 15. Cahizares P, Jimenez C, Martinez F, Rodrigo MA, Saez C. The pH as a key parameter in the choice between coagulation and electrocoagulation for the treatment of wastewaters. Journal of Hazardous Materials. 2009; 163(1): 158-64.

[0059] 16. Kyzas GZ, Matis KA. Electroflotation process: A review. Journal of Molecular Liquids. 2016;220:657-64.

[0060] 17. Alam R. Fundamentals of electro-flotation and electrophoresis and applications in oil sand tailings management. Ontario, Canada: The University of Western Ontario; 2016.

[0061] 18. Mohtashami R, Shang JQ. Electroflotation for treatment of industrial wastewaters: a focused review. Environmental processes. 2019;6(2):325-53.

[0062] 19. Oturan MA, Brillas E. Electrochemical advanced oxidation processes (EAOPs) for environmental applications. Portugaliae Electrochimica Acta. 2007;25(1):1. . Fang C, Megharaj M, Naidu R. Electrochemical Advanced Oxidation Processes (EAOP) to degrade per-and polyfluoroalkyl substances (PFASs). Journal of Advanced Oxidation Technologies. 2017;20(2):20170014. . Shu Y, Hu M, Zhou M, Yin H, Liu P, Zhang H, et al. Emerging electrocatalysts for electrochemical advanced oxidation processes (EAOPs): recent progress and perspectives. Materials Chemistry Frontiers. 2023;7(13):2528-53. . Gligorovski S, Strekowski R, Barbati S, Vione D. Environmental implications of hydroxyl radicals (’OH). Chemical reviews. 2015;115(24):13051-92. . Martinez-Sanchez C, Robles I, Godinez L. Review of recent developments in electrochemical advanced oxidation processes: application to remove dyes, pharmaceuticals, and pesticides. International Journal of Environmental Science Technology. 2022;19(12):12611-78. . Froment J, Pierpaoli M, Gudersen H, Davanger K, Bjorneby SM, Eikenes H, et al. Transformation Product Formation and Removal Efficiency of Emerging Pollutants by Three-Dimensional Ceramic Carbon Foam-Supported Electrochemical Oxidation. ACS EST Water. 2025;5(2):902-12. . Zhan J, Li Z, Yu G, Pan X, Wang J, Zhu W, et al. Enhanced treatment of pharmaceutical wastewater by combining three-dimensional electrochemical process with ozonation to in situ regenerate granular activated carbon particle electrodes. Separation Purification Technology. 2019;208:12-8. . Seok Cheon W, Kim J, Won Jang H. Probing Activation and Deactivation Mechanisms in Electrochemical CO2 Reduction Reaction and Water Splitting through I n-Situ / Operando Analysis. Chemistry-Methods. 2025; 5(6) :e202400066.. 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. . Chen G. Electrochemical technologies in wastewater treatment. Separation and Purification Technology. 2004;38(1):11-41. 29. Thuch JMM, Sanga JN, Lakare AM. Electrochemical Wastewater Treatment for Various Industries. In: Kumar S, Sarkar UR, Shah MP, editors. Electrochemical Perspective Towards Wastewater Treatment. Singapore: Springer Nature Singapore; 2025. p. 141-61.

[0063] 30. Muddemann T, Haupt D, Sievers M, Kunz II. Electrochemical Reactors for Wastewater Treatment. ChemBioEng Reviews. 2019;6(5):142-56.

Claims

Claims1. A cylindrical disk pump for water treatment comprising:• a cylindrical housing made of aluminum or iron functioning as an anode;• a central shaft with multiple closely spaced metallic disks functioning as a cathode;• a direct current power supply electrically connected to the housing and disks;• wherein rotation of the disks pumps water according to Tesla disk pump principles while simultaneously producing trivalent metal ions for electrocoagulation.

2. The pump of claim 1 , wherein the housing and disks are made of the same electrochemically active material to ensure uniform ion release.

3. The pump of claim 1 , further comprising radial scraper blades mounted within the housing to remove precipitate buildup and prevent flow obstruction.

4. The pump of claim 1 , wherein the number of disks is selected to increase cathode surface area and enhance coagulant generation efficiency.

5. The pump of claim 1 , wherein the produced trivalent ions form hydroxide flocs that facilitate the removal of suspended solids in downstream processes.

Images