Electrochemical coagulation pump for the in-situ generation of ferric or aluminic coagulants for water and wastewater treatment

Abstract

A novel and compact electrochemical reactor integrated within a hydraulic pump, capable of simultaneously performing water transport and in situ generation of coagulants through electrocoagulation. The system eliminates the need for secondary chemicals, external reactors, or specialized personnel. In this configuration, the pump casing functions as the cathode, while the rotating impeller blades act as the anode, both made of sacrificial metals such as iron or aluminum. When direct current is applied between these components, the anode undergoes controlled dissolution, releasing metal ions (Fe3+ or Al3+) that undergo hydrolysis reactions to form active coagulant species directly in the flowing water.

Description

[0001] Electrochemical Coagulation Pump for the In-Situ Generation of Ferric or Aluminic Coagulants for Water and Wastewater Treatment

[0002] Field of the Invention

[0003] The present invention relates to the field of electrochemical water treatment, more specifically to a compact and integrated electrocoagulation system built into a pump. This system is designed for in-situ generation of trivalent ferric (Fe3+) or aluminic (Al3+) ions to remove colloidal and suspended pollutants from contaminated water sources.

[0004] Background of the Invention

[0005] Freshwater resources are facing growing threats from a wide range of pollution sources (1). Industrial effluents, agricultural runoff, and domestic wastewater discharge contribute heavily to the contamination of rivers, lakes, and reservoirs (2, 3). Among the many types of pollutants found in these waters, suspended solids and colloidal particles are especially problematic (4). These contaminants are characterized by their fine size and surface charges, which allow them to remain stable in suspension for extended periods. Their persistence in aquatic systems not only diminishes aesthetic and hygienic water quality but also disrupts natural ecosystems and hampers the efficiency of conventional water and wastewater treatment operations (5). For example, colloidal particles interfere with sedimentation and filtration units and reduce the efficacy of disinfection processes by shielding pathogens from exposure (6).

[0006] To remove these fine and often non-settleable materials, chemical coagulation and flocculation have long been employed as standard practices in water treatment facilities (7). These techniques typically involve the addition of pre-manufactured metal salts, such as ferric chloride (FeCI3) or aluminum sulfate (AI2(SO4)3), which introduce multivalent cations into the water (8). These cations neutralize the negative surface charges of colloids and induce the formation of larger flocs through bridging mechanisms (9). While these chemical methods are effective under controlled conditions, they are not without their drawbacks. The need for continuous chemical supply, proper storage, metering pumps, and operator oversight makes the process operationally complex and capital-intensive (10). Furthermore, the chemical reactions generate considerable amounts of sludge that require further handling, treatment, and disposal. In many remote or small-scale applications, the cost and logistical burden of chemical transport and storage also raise significant concerns regarding environmental safety and sustainability.

[0007] To address these limitations, electrocoagulation has gained attention as an innovative, efficient, and more environmentally sustainable alternative (11). This technique eliminates the need for external coagulant chemicals by using electricity to generate coagulants in situ. In a typical electrocoagulation setup, two metallic electrodes — commonly composed of iron or aluminum — are submerged in the polluted water and connected to a direct current power source. When electric current flows through the system, the anodic electrode undergoes oxidative dissolution, releasing Fe3+or Al3+ions directly into the aqueous phase (12). These freshly generated metal ions rapidly hydrolyze to form hydroxide species, such as Fe(OH)3orAI(OH)3, which act as efficient coagulants. The hydroxides possess high adsorption capacities and a strong ability to entrap suspended particles, pathogens, heavy metals, dyes, and even organic matter. The resulting flocs are then easily removed through sedimentation or subsequent filtration stages. This electrochemically driven approach significantly reduces chemical consumption, sludge volume, and operational complexity, making it more attractive for sustainable water treatment solutions. However, despite the many advantages of electrocoagulation, current implementations of this technology face important practical challenges. Most electrocoagulation systems are designed as stand-alone treatment units comprising separate tanks, rigid electrode holders, external rectifiers, and complex hydraulic configurations (see Figure 1) (13). Such systems require precise flow regulation and are generally stationary and large in size. Their operation also demands constant monitoring and skilled personnel to adjust electrical parameters, clean electrodes, and ensure system stability. This renders them unsuitable for mobile or decentralized water treatment, especially in rural areas, disaster zones, or temporary settlements where space, energy supply, and operator expertise are limited.

[0008] Another critical challenge lies in optimizing the configuration of electrodes within the EC reactor. Electrode placement directly affects the distribution of electric current, water turbulence, rate of coagulant generation, and energy consumption. Traditional flat-plate or mesh-type electrodes often suffer from uneven current density, passivation of surfaces, and suboptimal fluid dynamics. These limitations can reduce the system’s overall performance, increase energy demand, and lead to inconsistent treatment results.

[0009] In light of these challenges, there is a clear need for a new generation of compact, integrated electrocoagulation devices that simplify operation, minimize infrastructure requirements, and enhance process efficiency. An ideal solution would incorporate the electrodes within existing hydraulic equipment, such as pumps, and use the inherent motion and pressure of the system to facilitate both electrochemical reactions and effective mixing. This integrated design could eliminate the need for auxiliary tanks, stirrers, and dosing units, thus creating a more user-friendly and scalable EC system. The current invention addresses this very need by introducing a novel electrochemical coagulation pump wherein the electrodes are ingeniously embedded into the pump housing and impeller structure. This configuration ensures real-time generation of Fe3+or Al3+ions during the pumping process, offering a powerful and compact solution for the removal of suspended and colloidal impurities from contaminated waters.

[0010] Summary of the Invention

[0011] The present invention describes a novel and compact electrochemical reactor integrated within a hydraulic pump, capable of simultaneously performing water transport and in situ generation of coagulants through electrocoagulation. The system eliminates the need for secondary chemicals, external reactors, or specialized personnel. In this configuration, the pump casing functions as the cathode, while the rotating impeller blades act as the anode, both made of sacrificial metals such as iron or aluminum. When direct current is applied between these components, the anode undergoes controlled dissolution, releasing metal ions (Fe3+or Al3+) that undergo hydrolysis reactions to form active coagulant species directly in the flowing water.

[0012] Description

[0013] The invention introduces a novel compact electrochemical reactor integrated within a hydraulic pump, designed to perform simultaneous water transport and electrocoagulant generation (see Figure 2). The invention allows in-situ production of coagulants from pump-integrated electrodes without any need for secondary chemicals, external reactors, or specialized operators. In this system, the pump casing functions as the cathode, while the rotating impeller blades serve as the anode. These components are made from sacrificial metals such as iron or aluminum. When direct current is applied across the casing and impeller, the anode undergoes controlled dissolution, releasing Fe3+or Al3+ions directly into the flowing water. The generated ions undergo hydrolysis reactions such as:

[0014] Fe — > Fe3++ 3e“

[0015] Fe3++ 3H2O Fe(OH)3j + 3H+

[0016] Or

[0017] Al Al3++ 3e“

[0018] Al3++ 3H2O AI(OH)31 + 3H+

[0019] These hydroxide species act as powerful coagulants, neutralizing the surface charges of suspended solids and colloids, allowing them to aggregate and settle in a downstream sedimentation tank. No chemicals are added; only electricity is used to generate the coagulants on demand.

[0020] Detailed Description of the Invention

[0021] The invention consists of the following primary components:

[0022] 1. Electrochemical Pump Housing: The pump body is manufactured from a sacrificial metal (iron or aluminum) and serves as the cathode in the EC process.

[0023] 2. Rotating Impeller (Anode): The impeller is constructed from the same or compatible metal and is electrically isolated from the housing. It rotates using an electric motor and serves as the anode.

[0024] 3. Power Supply Unit: A low-voltage DC power supply is connected such that the impeller is the positive terminal (anode) and the pump housing is the negative terminal (cathode). The applied current can be controlled to optimize ion release. Although it has been proven that increasing the voltage and current connected to the electrodes directly improves the efficiency of the electrocoagulation process, raising the voltage above 24V is not recommended due to the risk of electric shock. For safety reasons, the maximum input voltage for the pump casing and motor should not exceed 24 volts.

[0025] 4. Electrode Configuration: The impeller blades' high surface area and rotation enhance turbulence, prevent passivation, and improve the uniform release of coagulant ions.

[0026] 5. Flow-through Treatment: Contaminated water enters the pump inlet. As it passes through the pump chamber, the EC reactions occur, and coagulants are generated in-line.

[0027] 6. Sedimentation Tank: After the water exits the pump, it enters a sedimentation tank or clarifier where the formed flocs settle by gravity.

[0028] Advantages Over Prior Art

[0029] • No need for external electrodes or tanks

[0030] • Compact and easy-to-install unit

[0031] • Simultaneous pumping and treatment

[0032] • Operable by unskilled personnel

[0033] • Reduces chemical handling and sludge volume

[0034] • Increases turbulence and mixing at the electrode surface due to impeller rotation

[0035] • Can be scaled for point-of-use or industrial applications

[0036] Industrial Application

[0037] This invention is suitable for a wide range of applications, including: Decentralized wastewater treatment

[0038] • Industrial effluent polishing

[0039] • Slaughterhouse and food industry water treatment

[0040] • Surface water purification

[0041] • Agricultural runoff treatment

[0042] • Portable water purification systems for disaster relief or military operations

[0043] Brief Description of Drawings

[0044] Figure 1 : A typical electrocoagulation system

[0045] Figure 2: Schematic of a pump cell

[0046] References:

[0047] 1. Musie W, Gonfa G. Fresh water resource, scarcity, water salinity challenges and possible remedies: A review. Heliyon. 2023;9(8):e18685.

[0048] 2. Sharma K, Rajan S, Nayak SK. Chapter 1 - Water pollution: Primary sources and associated human health hazards with special emphasis on rural areas. In: Madhav S, Srivastav AL, Chibueze Izah S, Hullebusch Ev, editors. Water Resources Management for Rural Development: Elsevier; 2024. p. 3-14.

[0049] 3. Adanez-Rubio I, Fonts I, De Blas P, Viteri F, Gea G, Alzueta M. Exploratory study of polycyclic aromatic hydrocarbons occurrence and distribution in manure pyrolysis products. Journal of Analytical Applied Pyrolysis. 2021 ; 155: 105078.

[0050] 4. Bilotta GS, Brazier RE. Understanding the influence of suspended solids on water quality and aquatic biota. Water Research. 2008;42(12):2849-61.

[0051] 5. Zezulka S, Marsalek B, Marsalkova E, Odehnalova K, Pavlikova M, Lamaczova A. Suspended Particles in Water and Energetically Sustainable Solutions of Their Removal — A Review. Processes [Internet], 2024; 12(12).

[0052] 6. Philipse AP. Colloidal sedimentation (and filtration). Current Opinion in Colloid & Interface Science. 1997;2(2):200-6.

[0053] 7. Loor-Moreira CL, Fernandez-Andrade KJ, Cedeno-Solorzano GS, Manzaba- Salazar GM, Gomez-Salcedo Y, Rodriguez-Diaz JM, et al. Generalities of the Coagulation-Flocculation Process: A Perspective on Biocoagulants. In: Maddela NR, Garcia LC, editors. Innovations in Biotechnology for a Sustainable Future. Cham: Springer International Publishing; 2021. p. 333-52.

[0054] 8. Pivokonsky M, Novotna K, Petricek R, Cermakova L, Prokopova M, Naceradska J. Fundamental chemical aspects of coagulation in drinking water treatment - Back to basics. Journal of Water Process Engineering. 2024;57:104660.

[0055] 9. Tahraoui H, Toumi S, Boudoukhani M, Touzout N, Sid AN, Amrane A, et al. Evaluating the Effectiveness of Coagulation-Flocculation Treatment Using Aluminum Sulfate on a Polluted Surface Water Source: A Year-Long Study. Water [Internet], 2024; 16(3).

[0056] 10. Tchobanoglous G, Burton FL, Stensel HDJM-H, Inc., New York. doi. Wastewater engineering: treatment and reuse, Metcalf & Eddy Inc. 2003; 10:0070418780.

[0057] 11. Tech ET. Evaluation of nitrate removal from wastewater using electrochemical method. Journal of Environmental Treatment Techniques. 2014;2(1):18-21.

[0058] 12. Hakizimana JN, Gourich B, Chafi M, Stiriba Y, Vial C, Drogui P, et al. Electrocoagulation process in water treatment: A review of electrocoagulation modeling approaches. Desalination. 2017;404:1-21.

[0059] 13. 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.

Claims

Claims1. A self-contained electrochemical coagulation pump comprising a pump housing made of iron or aluminum, a metallic impeller made of the same or compatible metal, and a DC power supply configured to create an electric potential difference between the housing (cathode) and the impeller (anode), such that trivalent coagulant ions are released into the water flowing through the pump.

2. The system of claim 1 , wherein the impeller rotation enhances turbulence and mass transfer, thereby increasing the coagulant generation rate and preventing electrode passivation.

3. The system of claim 1 , wherein the pump is designed for simultaneous water conveyance and contaminant treatment, without the addition of external chemicals or coagulants.

4. The system of claim 1 , further comprising a sedimentation or clarification chamber placed downstream of the pump to remove the coagulated particles.

5. The system of claim 1 , wherein the applied DC voltage and current are adjustable to control the rate of anode dissolution and coagulant release.

6. The system of claim 1 , wherein the invention is used for the treatment of waters containing colloids, suspended solids, dyes, or other finely dispersed pollutants.

Images