Electrocoagulation Process as an Efficient Method for the Treatment of Produced Water Treatment for Possible Recycling and Reuse

Abstract

The objective of this study is to examine the effectiveness of the electrocoagulation (EC) process in treating real produced water (PW). The impact of the EC process on water quality parameters (pH and conductivity, turbidity, and oil content) was studied using bench-scale 5 L PW for this process. The findings indicate that prolonged EC leads to the release of metal ions and secondary electrode reactions, which resultantly increase the pH of the outlet water. The EC process decreased in several water quality parameters, including Chemical Oxygen Demand (COD), Total Organic Carbon (TOC), and oil and grease (O&G). COD decreased by roughly 1300 mg/L, resulting in a 33% removal. In the same manner, TOC dropped from an initial value of 1300 mg/L to approximately 585 mg/L, exhibiting a maximum removal efficacy of nearly 60%. Oil and gas (O&G) decreased to a value below 10 mg/L, accompanied by a remarkable removal efficacy of up to 99.6%. The turbidity, which was initially recorded at an average of 160 NTU, was reduced to approximately 70 NTU, which is a 44% reduction. The application of centrifugation after EC treatment resulted in a turbidity reduction above 99%. EC treatment removed BTEX (benzene, toluene, ethyl benzene, and xylenes) from PW by more than 99%. The inorganic constituents, specifically heavy metals, exhibited minimal changes following the application of EC, emphasizing the necessity for additional treatment methods to effectively address their presence. In summary, EC demonstrates an acceptable level of efficacy in the removal of turbidity and pollutants from PW, with a special emphasis on organic compounds such as BTEX, but it does not address the elimination of inorganic compounds. Subsequent investigations should prioritize the optimization of EC parameters and the integration of supplementary interventions to effectively address the removal of inorganic elements and insoluble metals from treated PW. The study evaluates the pollutant removal efficiency using iron and aluminum electrodes and the effects of the applied current and electrolysis time on the EC process.

1. Introduction

PW is the water that exists in subsurface formations, and it comes to the surface during oil and gas excavation. It poses a significant challenge in the context of wastewater generated from oil and gas extraction activities [1,2]. The diverse nature of the constituents in PW underscores the complexities involved in effectively managing and treating this byproduct associated with oil and gas extraction operations [1,3]. On a worldwide scale, the quantity of PW is on the rise due to the expansion of gas and oil fields, as shown on Figure 1, which in turn leads to significant environmental consequences.

This wastewater contains organic and hazardous substances, including benzene, toluene, ethyl benzene, and xylenes, collectively referred to as BTEX, polyaromatic hydrocarbons (PAHs), and alkylphenols (APs) [5]. Additionally, it contains inorganic elements, like heavy metals [1]. Moreover, PW contains dissolved and suspended solids, as well as other pollutants, including chemicals added during processing units [6].

The removal efficiency and treatment performance vary depending on the technology used and PW characteristics. Removal of phosphate and COD from medical sterilization wastewater was examined using EC application to determine the optimum treatment condition by considering current density, pH, and initial wastewater concentration [7]. The experiment runs with different operating conditions. It was concluded that the maximum removal of COD is 53%, and phosphate is removed completely when pH is at 5 and current density is at 3.5 mA/cm². This result demands further consideration to increase the removal efficiency of COD. Similarly, a comprehensive review of using EC coupled with the advanced process was conducted to measure the process effectiveness of pollutant removal from wastewater. The result showed that nearly 80% of the removal of COD was achieved using EC–electroflotation, and further study is recommended to improve water quality and toxic compound removal as a hybrid system [8].

Most of the regulatory policies target the industrial contents mainly from oil and gas producers. This is adding guidelines to the industrial sector for water discharging and revealing the impact on the environment. Moreover, the treatment methods depend on the required water quality for disposal or reusing purposes. For example, the United States Environmental Protection Agency (USEPA) set limits for wastewater effluent discharge for treated PW due to the high concentration of pollutants and the potential impact on the environment [5]. Moreover, PW technologies are continually advancing to reusing options, considering many factors such as operating cost and maintainability.

The existing conventional treatment technologies are limited due to the complexity of PW and partially treated by removing suspended solids and heavy metals, but they do not address organic components [9,10]. After treatment, the water is re-injected into the underground using disposal injection wells [11,12]. However, deep well injection is not considered a viable solution due to its potential to cause adverse environmental effects, including contamination of underground water sources, soil degradation, and the risk of inducing seismic activity [13]. Therefore, it is not viewed as a suitable remedy due to associated uncertainties and potential harm to ecosystems and groundwater quality. Due to the above concerns and conventional treatment limitations, advanced treatment technologies were evaluated theoretically and experimentally by many researchers to improve the water quality according to the regulatory limits and reusing options for different applications. Commonly, the outcomes of the studies are referring to further evaluation to address the limitations that mainly related to the treatment performance or sustainability. Consequently, ongoing research aims to find alternative advanced treatments to improve the overall process and enable water reuse instead of the re-injection method.

2. Literature Review

Several studies have been conducted to enhance the treatment procedures for PW, with the goal of investigating feasible techniques encompassing chemical, physical, biological, and hybrid approaches [1,4,6,14]. The ultimate objective of these treatments’ combination is to improve the effectiveness and ecological sustainability of managing PW, offering valuable knowledge on sustainable water treatment processes [2]. The proposed treatment processes include chemical processes that utilize diverse reactants and substances to mitigate contaminants, physical processes designed to separate impurities through physical actions, biological processes harnessing the capabilities of microorganisms for purification, as well as hybrid processes that integrate multiple approaches for comprehensive treatment solutions [2]. The extensive research in this sector seeks to discover novel and efficient methods that deal with the intricate makeup of PW. Olajire et al. implemented a physical treatment process to treat PW in the oil and gas industry [2]. The method involves filtration to remove large particles, followed by gravity separation to separate oil from lighter components. The sludge accumulates at the bottom and undergoes further treatment. The separated oily fraction undergoes liquid–liquid separation to eliminate the remaining traces of oil from PW. The schematic is shown below in Figure 2.

Although suitable results were reported, the reuse of this treated PW was not recommended due to the remaining suspended solids and hydrocarbons [2]. Santos et al. employed dissolved air flotation (DAF) to treat produced water, focusing on removing suspended solids, greases, oil, biochemical oxygen demand (BOD), and insoluble particles via coagulation mechanism [15]. It was reported that the DAF system design depended on the PW flow rate for efficient air system sizing. The study found optimal efficiency with coagulant and flocculation concentrations at 50 and 2 mg/L, respectively. Results showed high removal efficiencies for calcium (92%), magnesium (94%), and turbidity (95%). The promising outcomes suggest the potential for further research on removing macromolecules, fibers, dyes, and other materials in PW [15]. Yet, the possible reuse of this wastewater was not confirmed as it requires further polishing. The utilization of biological treatment is becoming a feasible method for treating PW. However, this approach is particularly sensitive and requires specific conditions to efficiently accelerate the breakdown of organic components. Factors like pH, temperature, and aeration play crucial roles in optimizing the biological treatment process. Therefore, attaining optimal operating conditions is crucial for maximizing the effectiveness of biological treatment and obtaining successful outcomes in the whole treatment process [16]. In addition, incorporating biological treatment faced challenges due to the presence of toxic components like phenol and BTEX, making a single treatment method for PW impractical [17]. In the study by Jiménez et al., various advanced oxidation processes (AOPs) such as ozonation, Fenton reaction, and photocatalysis were explored for the treatment of PW [18]. The research involved using synthetic wastewater with added contaminants like BTEX, malonic acids, phenol, and naphthalene. Among all the studied AOPs, photocatalysis exhibited the lowest efficiency in treating PW, achieving only a 20% removal of TOC [19]. On the other hand, the combination of ozonation with H₂O₂ proved to be the most effective, with a TOC removal efficiency of 74% and a notable 78% elimination of acetic acid. Despite high organic removal efficiency, the study highlighted the need for additional treatment, particularly biological processes, due to the persistence of other contaminants [20].

EC process is an advanced technology for treating PW. A recent study introduced a novel EC design with shift polarity, resulting in effective pollutant removal through electrode passivation [21]. The system exhibited excellent performance, achieving a 99% removal of COD and 98% removal of O&G from PW while generating significantly less sludge compared to other electrochemical treatment methods like coagulation and flocculation [22]. In their study, [21] investigated various EC systems, assessing their performance and efficiency through electro-activation and thermal activation with iron electrodes for PW treatment. The study demonstrated a notable removal of nearly all hydrocarbon pollutants, accompanied by a significantly lower operating cost compared to AOPs. Laboratory results indicated considerable pollutant removal efficiencies of 96%, 99%, 84%, and 97% of H₂S, oil and grease, COD, and turbidity, respectively. However, the EC system was found inadequate for the removal of soluble organics and ammonia, prompting the need for further investigation. While EC has demonstrated impressive efficacy in treating synthetic PW, there remains a scarcity of experimental data regarding its performance with real PW from the oil and gas industry. Specifically, the influence of real PW’s water chemistry has yet to be investigated.

The literature review highlights the promising nature of EC for the treatment of PW, particularly emphasizing its effectiveness in removing most pollutants in PW. This technology is favored for its low cost when coupled with photovoltaic cells for higher operational efficiency. The basic operating principles involve electron neutralization, which releases metal ions from electrodes under the influence of an electrical field. Thus, this study aims to investigate the potential of EC for enhanced PW treatment, with the objectives of achieving optimum treatment conditions and maximum pollutant removal efficiency. The experimental design, performance, and limitations were explored to identify the capability of EC treating PW, with an emphasis on developing advanced treatment processes for potential recycling and reuse.

3. Mechanism of Electrocoagulation

The mechanism of EC is based on certain steps as illustrated in Figure 3. It all starts with the application of an electrical current to dissociate the metal anode and results in the anode material dissolving into the water. As the anode dissolves, M^z+ ions are released into the water. These ions are crucial for the subsequent reactions that lead to pollutant removal. The dissolved metal ions react with water to form metal hydroxides (e.g., M(OH)_z(s)), which are gelatinous and have a large surface area. These reactions are influenced by the pH of the water, which can be altered by the process itself as hydroxide ions (OH⁻) are produced at the cathode [23]. The main chemical reactions involved are as follows:

• Anodic Reaction (Oxidation)

M_(s) →M^z+_(aq) + ze⁻

(1)

• Cathodic Reaction (Reduction)

2H₂O + 2e⁻ → 2OH⁻_(aq) + H_2(g)

(2)

• Hydroxide Formation

M^z+_(aq) + zH₂O → M(OH)_z(s) + zH⁺_(aq)

(3)

The generated hydroxides act as coagulants to neutralize the charges of the suspended particles, making them aggregate into larger particles, or flocs. This aggregation is enhanced by the presence of other ions in the water, which can vary depending on the water’s original composition and the specific contaminants present [24]. The flocs are capable of adsorbing and trapping various pollutants, including organic compounds and heavy metals. The larger flocs settle more easily or can be removed by filtration, thus clearing the water of contaminants. At the cathode, hydrogen gas is often produced as a byproduct, and it is called the hydrogen evolution reaction (HER). This can help in the flotation of flocs, aiding in their removal from the treatment system. The EC process is particularly effective because it transforms soluble pollutants into insoluble forms, which are easier to separate from the water. It is also adaptable to various types of wastewater, influenced by factors such as initial contaminant levels, pH, and the composition of the electrodes.

Many electrochemical subsequential reactions can occur during this process. For example, the oxidation of metal anode results in the formation of metal cations and water oxidation to produce oxygen in electrolyte solution. Therefore, current density is one of the important operating parameters that control the overall reaction of EC [25].

Current density (CD) is the key effective parameter in the EC process as it determines the coagulant rate, gas formation, and growth of the flocs, which significantly affects the performance of EC. As the CD increases, the dissolution of the anode and metal hydroxide flocs increases, resulting in increased EC efficiency and contaminant removal and vice versa [26]. Besides releasing ions from the anode, a parallel reaction occurs by PW hydrolyzing, resulting in bubbles of oxygen at the anode, which is called the oxygen evolution reaction (OER). However, this reaction is rarely present in the EC process, and it was observed in some studies while using Fe-EC, according to the reports [25].

Iron and aluminum are the most recommended electrodes that are used in the EC process [27]. The main reactions that occur can be presented from the above reactions (1)–(3). Moreover, the ferric ions (Fe³⁺) released from the anode along with O2 that generated by hydrolyze aqueous solution to form Fe(OH)₃:

4Fe²⁺ + O_2(g) + 2H2O → 4Fe³⁺ + 4OH⁻_(aq)

(4)

Fe³⁺ + 3OH⁻_(aq) → Fe(OH)_3(s)

(5)

Reaction (5) is not directly connected to the EC process, and it depends on the oxygen level in the solution [28]. Also, the dissolved Fe²⁺ to Fe³⁺ ions strongly depend on the pH of PW, as reported by [28]. The study investigated the process of iron oxidation rate at different pH and CD conditions and compared it with Faraday’s law calculated values. The difference between the theoretical values and experiment values is the possible dissolution of the anode at lower pH even without applied current. This can lead to a higher theoretical oxidation rate. The second is the other reaction of electrons from the electrical current than anode dissolution at higher pH.

4. Materials and Methods

4.1. PW Pre-Treatment

To evaluate the real-world applicability of this technology and identify potential limitations, actual PW from the natural gas industry in Qatar is utilized using 5 L PW bench-scale EC experiments. The received water underwent a degassing process, a crucial step aimed at eliminating volatile and hazardous gases, such as light hydrocarbons and hydrogen sulfide, from untreated PW. This procedure involves aerating the PW and injecting the resulting gases into a sodium hydroxide solution. Typically, this process runs for approximately two hours, during which samples are collected to measure pH, conductivity, and turbidity prior to EC treatment.

4.2. Electrocoagulation Tests

The EC procedure begins by drawing power from a photovoltaic cell and converting it from alternating current (AC) to direct current (DC) using the ISO-TECH IPS1603D (Vaughan, Canada) Digital Bench power supply (see Figure 4). This electrical power supply offers a single output ranging from 0 to 60 V and 0 to 3 A, totaling 360 W, with voltage adjustments made according to specified parameters. Iron and aluminum are selected as the electrode metals for EC treatment, and the selection is based on specific criteria that are discussed in the next section. The process operates on the principle of releasing metal ions from these electrodes by applying an electric current, thereby neutralizing the charge and precipitating pollutants from the water. The electrodes have dimensions of 2 cm in width, 5 cm in length, and a thickness of 2 mm. The gap between electrodes during treatment was set at 1 cm based on the literature review recommendation (inter-electrodes distance 0.5–2 cm) in order to increase the efficiency with lower power consumption [29]. Post-treatment, the water extraction is facilitated by the Masterflex™ (Gelsenkirchen, Germany) 77200-50 professional pump, designed for bench-scale use. Operating at a flow rate of 50 mL/min, the pump ensures the extraction of treated water from the beaker after the settling period. Extraction is carried out through a rubber tube inserted into the PW, drawing clear water from the middle of the beaker and collecting it for further analysis. EC tests were conducted for 30 min with 5 min sampling at a constant voltage in the range of 2 to 18 V.

4.3. Electrode Type Selection

The EC process is an advanced wastewater treatment technology, and it is applicable to treat PW to its highest degree. Manilal et al. reported a novelty in designing EC to treat PW with shift polarity and reduce the issues that result from electrode passivation [22]. The system was evaluated in terms of pollutant removal efficiency, operating cost, and energy consumption. Other factors were considered to enhance the performance and evaluate the effects on the overall efficiency, such as the electrolyte concentration, the gaps between the electrodes, electrolysis time, and pH [22]. The study showed a removal efficacy of COD and O&G at 99% and 98%, respectively.

Electrode passivation is the formation of an oxide layer on the electrode surface when electric power is applied during the reaction, where it highly inhibits the metal dissolution from the anode and the electron transfer to the cathode. These phenomena result in increasing resistance and power consumption [22].

The electrode material is a key factor for the EC process to enhance the overall pollutant removal efficiency. The selection is highly dependent on the influent components and corresponding oxidation potential [30]. Iron and aluminum electrode metal places are most common and are widely used for EC processes to treat PW influent due to high pollutant removal efficiency, low operating cost, and availability [30].

Gholami et al. evaluated the efficiency and performance of EC on real PW using iron electrodes and the effects of operating conditions at different responses [21]. The result showed that the highest performance achieved in removing O&G, heavy metals, and COD are 99%, 92%, and 94%, respectively [21].

Another EC experiment to treat PW was conducted by Mahdieh et al. to evaluate the effectiveness of electrode material on the EC process [31]. The experiment was run and used zinc, copper, iron, and aluminum electrode materials for the anode. The result showed that the COD removal of 89% is achieved by using iron, and the highest COD removal of 95% is achieved using aluminum, compared to 87% and 85% for zinc and copper electrodes, respectively [31].

Most of the research and experimental studies used stainless steel, iron, and aluminum electrodes, whereas few runs used other metals such as copper, nickel, and sacrificial electrode, as reported by Sivaranjani et al. [32]. In addition to the above research, a comprehensive study was conducted by Markus Ingelsson et al., and they reported that aluminum electrodes are more attractive, followed by iron and then other metals in terms of performance, operating cost, and limitations, such as passivation, fouling, and long operation sustainability [33].

The selection of electrode materials for this study is based on the above research and its efficiency for PW treatment using the EC process. Therefore, aluminum and iron were selected for this study.

5. Results and Discussions

5.1. PW Characterization

The untreated PW underwent comprehensive analysis at the Gulf Laboratory, encompassing parameters like TOCCOD, O&G, BTEX, ions, and metals. The tested parameters with the corresponding methods are presented in

Table 1. Characteristics of real PW and the applied testing method.

Tested Parameter	Test Method	Results Obtained	Units
Chemical Oxygen Demand	SMWW 5220 D	3790	mg/L
Total Organic Carbon	SMWW 5310 B	1320.3	mg/L
Bromide (Br-)	SMWW 4110-B Br	59.70	mg/L
Chloride (Cl-)	SMWW 4110-B Cl	9360.00	mg/L
Oil and Grease	SMWW 5520 B	44.80	mg/L
Fluoride (F-)	SMWW 4110-B F	0.59	mg/L
Nitrite (N)	SMWW 4110-B NO2	<0.01	mg/L
Phosphate (PO43-)	SMWW 4110-B PO4	2.60	mg/L
Sulfate (SO42-)	SMWW 4110-B SO4	76.90	ml/L
Bromate (BrO3-)	SMWW 4110 D	<5	µg/L
Chlorite (ClO2-)	SMWW 4110 D	0.57	mg/L
Chlorate (ClO3-)	SMWW 4110 D	69.86	mg/L
Nitrate (NO3)	SMWW 4110-B NO3	0.38	mg/L
Metals
Cadmium	US EPA 6010C/3005A	<0.005	mg/L
Chromium	US EPA 6010C/3005A	0.096	mg/L
Potassium	US EPA 6010C/3005A	208.322	mg/L
Sodium	US EPA 6010C/3005A	2768.980	mg/L
Silica	US EPA 6010C/3005A	4.922	mg/L
Copper	US EPA 6010C/3005A	0.067	mg/L
Iron	US EPA 6010C/3005A	6.791	mg/L
Lead	US EPA 6010C/3005A	0.089	mg/L
Mercury	US EPA 6010C/3005A	<0.01	µg/L
Boron	US EPA 6010C/3005A	10.600	mg/L
Manganese	US EPA 6010C/3005A	0.279	mg/L
Barium	US EPA 6010C/3005A	0.223	mg/L
Zinc	US EPA 6010C/3005A	0.148	mg/L
Arsenic	US EPA 6010C/3005A	<0.200	µg/L
Selenium	US EPA 6010C/3005A	<0.200	µg/L
Sulfur	ICP-OES	176.700	mg/L
Strontium	US EPA 6010C/3005A	29.852	mg/L
Aluminum	US EPA 6010C/3005A	0.698	mg/L
Lithium	US EPA 6010C/3005A	4.074	mg/L
Molybdenum	US EPA 6010C/3005A	0.036	mg/L
BTEX
Toluene	US EPA 5030 C/8260 C	36,330.0	µg/L
Ethyl Benzene	US EPA 5030 C/8260 C	1322.0	µg/L
Xylenes	US EPA 5030 C/8260 C	13,430.0	µg/L
Benzene	US EPA 5030 C/8260 C	72,272.0	µg/L

. These comprehensive analyses provide insight into the composition and potential contaminants present in the untreated PW, which is essential for understanding its environmental impact and determining appropriate treatment strategies. The data serve as a basis for further assessment and evaluation of the effectiveness of the EC treatment process in removing these pollutants and improving the quality of the produced water.

It was observed that untreated PW contains high concentrations of COD and TOC of 3790 mg/L and 1320.3 mg/L, respectively, suggesting a higher level of organic pollutants. Bromide (Br⁻) and chloride (Cl⁻) levels are recorded at 59.70 mg/L and 9360.00 mg/L, respectively. These values are significant and can impact water quality and potentially pose health risks. The concentration of O&G in the water is measured at 44.80 mg/L, indicating the presence of high concentrations of hydrocarbon pollutants. Sulfate (SO₄²⁻) and chlorite (ClO₂⁻) have high concentration (>69 mg/L). Other parameters such as fluoride (F⁻), nitrite-N (NO₂⁻), phosphate (PO₄³⁻), bromate (BrO₃⁻), chlorate (ClO₃⁻), and nitrate (NO₃⁻) exhibited low concentration (≤2.60 mg/L). These parameters represent various ions and compounds present in the water, each with its own environmental significance. The concentrations of various metals were very low except for moderate concentrations of silica, iron, boron, and strontium and high concentrations of sulfur, potassium, and sodium. Metals can originate from various sources, including industrial activities, and can have significant environmental and health implications. Monitoring their levels is crucial for assessing water quality and ensuring regulatory compliance [4].

The concentrations of BTEX are important indicators of hydrocarbon contamination in the water. High levels of BTEX compounds can pose serious environmental and health risks. Overall, the results highlight the complex composition of the untreated PW and the presence of various pollutants.

5.2. Electrocoagulation (EC) of PW

5.2.1. Turbidity Removal

Figure 5 presents the turbidity (NTU) evolution of the PW during and after the EC process as well as after centrifugation for 5 min. Samples were taken in 5 min increments. The turbidity of the PW during an EC process decreased from 160 NTU to 105 NTU after 30 min of EC. This represents an improvement in turbidity of 34.4%. The turbidity of the sample further decreased after centrifugation to 1.99 NTU, representing a percentage improvement in turbidity over 98%. From these results, one can infer that EC must be coupled with polishing treatment to complete the removal of the turbidity. Gholami et al. reported that an EC experiment was conducted on real oilfield PW, and the result showed that the turbidity was removed by 91–97% [21]. Moreover, another EC experiment was tested, and the highest turbidity achieved was 98.1% [34]. Those experiments confirm the effectiveness of the EC process for PW treatment in terms of water clarity and appearance. In the context of water treatment and purification, using AOP has resulted in 90% turbidity removal efficiency. Although AOPs have been found to be highly effective, achieving a 90% reduction in turbidity, these processes include a set of chemical reactions that require many preparations and chemicals. Therefore, AOPs are considered an expensive process to treat high volumes of industrial wastewater.

5.2.2. Effect of EC on the pH of PW

During the EC process, the initial pH of PW was 4.5. It then increased to more than 9, as shown in Figure 6. The pH change is related to the increase in the releasing rate of ion metals and the secondary reaction from the electrodes. Based on Figure 5, the data indicate that the pH levels of the PW after a 30 min EC treatment fall within the acceptable range of 6 to 8, adhering to the established quality standards for pH. The observed rise in pH can be attributed to electrochemical reactions at the electrodes: as iron ions are reduced from Fe³⁺ to Fe²⁺, hydrogen ions (H⁺) are consumed, and hydroxide ions (OH⁻) are simultaneously generated at the cathode [35]. This shift in ion concentration leads to an increased pH level in the PW.

Throughout the EC process, there is a marked accumulation of OH⁻ ions, which combine with H⁺ ions to produce water (H₂O). The excess of OH⁻ ions not only contributes to the pH increase but also facilitates the generation of hydrogen and oxygen gases. The formation of these gas bubbles enhances the flotation process, aiding in the removal of contaminants by carrying them to the surface of the water. This improved flotation performance is a beneficial byproduct of the chemical changes induced by the EC treatment [35].

5.2.3. Total Suspended Solids (TSS) Removal

The initial TSS level in the PW was 124.0 mg/L, which gradually decreased during EC time to 53 mg/L as shown in Figure 7. The corresponding %TSS removal after EC reached 58.1% after 25 min, then slightly decreased to 57.3% after 30 min. Centrifugation of the treated PW shows the concentration of TSS to decrease from 53 mg/L to 9.5 mg/L (82.1% removal). The overall % TSS removal after EC/Centrifugation was found to be 92.3%. The obtained results suggest that EC followed with centrifugation is an effective process to reduce TSS from PW. The slight increase in TSS measured during EC from 25 to 30 min (from 52 to 53 mg/L) could be due to various factors, such as a change in the process conditions or measurement variability. Despite this, the overall trend shows a decrease in TSS concentration over time. During the EC process, the reaction led to the formation of Fe(OH)₃, which acts as a coagulating agent. This substance helps to stabilize organic materials and metal ions, enabling their aggregation and subsequent precipitation. Concurrently, hydrogen gas (H₂) generated during the reaction facilitated the flotation of colloidal particles, effectively separating them from the solution, which contributed to a reduction in Total Suspended Solids (TSS) levels. Additionally, the proximity of the electrodes played a role in the efficiency of the process; a closer distance allowed for a quicker transfer of electrons from the anode to the cathode, where reduction reactions occur, enhancing the overall removal of suspended particles and thus leading to a marked decrease in TSS concentrations within the sample [36].

5.2.4. Effect of EC on Conductivity of PW

The initial water conductivity is measured at approximately 14 Ms/cm, whereas the value is maintained or slightly increased after EC, as presented in Figure 8. Almukdad et al. conducted a pilot-scale EC experiment, observing a 12% increase in water conductivity due to ion secretion [37]. The result adequately represents the electrical conductivity in terms of available ion species. The study found that the highest pollutant removal efficiencies were achieved with hybrid systems, specifically 98% for EC–Forward Osmosis and 98.3% for EC–Electrodialysis. Moreover, higher conductivity is favorable for high performance, lower cost, and energy consumption [38]. Thus, the electrical conductivity must be maintained at a higher level as much as possible since it varies for the EC process, as illustrated in the figure shown on the next page, due to process behavior that could be influenced positively and even negatively due to potential involvement of electrode passivation, convection, and electro-migration [38]. Additionally, electrical conductivity changes over time in the EC reactor due to the amount of ions released in the water and the performance of the coagulation process of ions transferred.

5.2.5. Removal of Other Contaminates via EC Process

The concentration of organic matter present in PW represented by COD demonstrated a reduction from 3790 mg/L to 2849 mg/L over a 30 min period of EC, translating to a 25% removal (see Figure 9). To put this into perspective, the initial COD levels reported in the used PW are considerably higher than those reported for other PW from different oil fields, such as the 1560 mg/L found in Malaysian oil fields. Ezechi et al. reported a 52% COD removal efficiency using EC in treating PW with an initial COD of 1560 mg/L [30]. Another study showed that a subsequent biological treatment could achieve up to 97% COD removal efficiency from PW with an initial COD concentration of 600 mg/L [39]. Notably, the EC and biological treatment efficiencies reduced to 39% when applied to PW with high initial COD, indicating that while biological treatment is highly effective in certain conditions, its efficacy is contingent upon the concentration of pollutants. This suggests the necessity of tailoring treatment systems to the specific characteristics of the PW.

The EC exhibited a substantial reduction in TOC from an initial concentration of 1320.30 mg/L to 490.25 mg/L at its lowest point over 30 min, as shown in Figure 10. This corresponds to a peak removal efficiency of nearly 60%. Such results confirm the efficacy of EC in removing TOC from PW, aligning with other treatments like photo-Fenton oxidation, which also reports TOC removal efficiencies of around 60%. The obtained TOC removal via simple EC configuration confirms the suitability of this process in treating PW. Other studies reported TOC removal of 60% from PW using photo-Fenton oxidation. The utilization of a heterogeneous catalyst was pointed out to be instrumental in enhancing the TOC removal efficiency, particularly by optimizing hydrogen peroxide use. It is noteworthy, however, that over time, the removal rate tends to decline, attributed to the decomposition of hydrogen peroxide into less reactive oxygen, thus slowing down the reaction rate [40]. The investigation further identifies the LaFeO₃ catalyst structure as particularly effective, exhibiting a 60% removal efficiency for TOC, underscoring the significant role that tailored catalyst structures can play in improving PW treatment outcomes. This suggests a promising area for further research and optimization in the field of water treatment technologies, aiming to achieve high efficiency in TOC removal from PW.

Figure 11 presents the reduction in O&G levels in PW during EC tests. The O&G was markedly reduced from 44 mg/L to 2.0 mg/L via EC, achieving a removal efficiency of 99.6%. This signifies that EC is an exceptionally effective method for the elimination of O&G. Fine-tuning controllable parameters is essential to further decrease pollutant levels to target concentrations. In their 2020 study, Manilal et al. examined O&G removal in synthetically prepared PW using an EC system. They discovered that increasing current density and salt content in the water improved removal efficiency due to the oxidative mechanisms involved. They reported a maximum removal efficiency of 96.4% with an optimal pH of 7 and a current density of 0.8 A/dm² [41]. In contrast, experiments conducted in this study employed a higher current density of 2.0 A/dm² and achieved a slightly elevated pH of just over 10. The discrepancy in O&G removal efficiency between these studies is attributed to the differences in the initial O&G concentration in the PW.

The process of removing O&G during EC involves both physical and chemical elements. The electric current passed through the water induces the dissolution of iron electrodes, which release metal ions into the solution. In an alkaline environment, these ions form iron hydroxide coagulants that destabilize the colloidal O&G particles in the PW. These destabilized particles then aggregate, forming larger flocs that can settle out or be floated to the surface. Furthermore, electroflotation plays a significant role in this process. It generates gas bubbles at the electrodes, which adhere to the coagulated O&G particles, causing them to rise to the surface for easier separation. The experiments observed the dual behavior where some oils would settle while others would float, demonstrating the complexity of the process. Together, these actions—coagulation, flocculation, and flotation—work in concert to effectively remove O&G from PW during EC treatment, proving the technique’s high potential for pollutant reduction in water treatment applications.

Chloride ions (Cl⁻) are a significant concern in PW, with implications for the corrosion of steel structures; the corrosion mechanisms intensify as the chloride concentration increases. The data presented in Figure 12 reflect the variable behavior of chloride concentration during a 30 min EC treatment process. The initial chloride concentration was approximately 9360 mg/L, with a minor removal observed throughout the treatment, reaching a low of 7835.62 mg/L. The apparent inconsistency in chloride reduction could be due to several factors, including the complex nature of EC and its interactions with various contaminants in PW. It is essential to recognize that chloride levels in PW can be significantly higher than in freshwater, sometimes up to fourteen times the concentration found in seawater. The removal of chloride ions from PW can be approached through various methods such as adsorption, membrane separation [42], advanced oxidation, and chemical precipitation [43]. A comparative study by Olajire et al. on PW from a Chinese shale gas field evaluated the effectiveness of the RO process [2]. This study reported a dramatic reduction in chloride concentration from 11,000 mg/L to 97 mg/L, corresponding to a chloride removal efficiency of 99.1%. Such high efficiency proposes the RO for the treatment of high-chloride PW. The variance observed in the EC treatment process points to potential limitations when dealing with ionic contaminants such as chloride. It suggests that while EC is effective for certain types of contaminants, it might require optimization or combination with other treatment processes, like RO, for comprehensive decontamination. To enhance the removal efficiency of chloride and other ions from PW, it is imperative to continue investigating the interaction of EC with ionic species and to explore integrated treatment systems that combine EC with other established methods. Such integrative approaches could offer a more robust solution for the treatment of PW, ensuring the mitigation of corrosion risks and the protection of infrastructure.

Figure 13 and Figure 14 reveal the effectiveness of the EC process in the removal of diluted concentrations of hydrocarbons, specifically BTEX, from PW. At the outset, benzene exhibited the highest initial concentration at 2801.0 µg/L, followed by toluene at 1674 µg/L, xylenes at 811 µg/L, and ethyl benzene at the lowest with 101 µg/L. After undergoing EC treatment, substantial reductions were observed, resulting in concentrations of 1024 µg/L for benzene, 432 µg/L for toluene, 129 µg/L for xylenes, and 11.0 µg/L for ethyl benzene.

The data point to xylenes achieving the highest removal efficiency, with a final concentration demonstrating an 84.1% decrease. Toluene follows with a peak removal efficiency of 74.2%. Benzene’s removal efficiency was lower at 63.4%. Interestingly, ethyl benzene, despite starting at the lowest concentration, exhibited the lowest removal efficiency of 8.9%.

Another set of EC experiments was carried out with the original BTEX concentration from PW. Untreated PW has alarmingly high levels of toluene at 36,000 µg/L and benzene at 72,000 µg/L. These constituents were significantly reduced through the EC treatment process, with removal efficiencies exceeding 99%, illustrating EC’s capability to drastically reduce BTEX concentrations in PW. Silvia Jiménez et al. underscored the rapid removal of BTEX using AOP in PW treatment [18], Olajire et al. highlighted that microalgae could achieve 100% benzene removal from PW [2], regardless of concentration by Alsarayreh et al. [44].

Fenton oxidation was also mentioned as favorable for benzene removal due to its higher reaction rate [19]. However, all these processes are expensive and complicated. On the other hand, the EC process particularly showed a remarkable removal efficiency for xylenes, with reductions from 13,400 µg/L to 130 µg/L. Yet, to achieve complete BTEX removal, EC likely needs to be combined with advanced polishing systems [45]. Fakhru’l-Razi et al. reported a 54% removal efficiency for xylenes using membrane filtration (MF and UF), which also nearly completely removed heavy metals [46]. While EC experiments have shown that heavy metals are not effectively removed by EC, this aligns with theoretical expectations. Consequently, combining EC with membrane processes is recommended for comprehensive heavy metal removal [31]. Conventional adsorption differs from EC by generating adsorbent particles for colloidal removal but is less effective for heavy metal ions. AOPs have been efficacious in degrading heavy metal complexes, Du et al. have documented [47], with various AOPs achieving between 60 and 90% efficiency for heavy metal removal. In conclusion, EC demonstrates promise for BTEX removal in PW. However, to optimize its effectiveness, further investigation into the process’s degradation efficiency and electrode longevity is warranted, particularly at higher BTEX concentrations. Integrating EC with advanced oxidation and membrane technologies appears to be the most effective approach for holistic PW treatment, efficiently addressing both organic compounds like BTEX and inorganic constituents such as heavy metals.

Figure 15 illustrates the progression of various ions throughout EC tests. The initial potassium concentration is 208.322 mg/L and exhibits a gradual decline over time, reaching a final value of 193.000 mg/L after 30 min of EC. This suggests that potassium ions may be consumed or removed during the electrochemical process. The initial sodium concentration is 2768.980 mg/L, reaches its highest point at 15 min (3159.960 mg/L), and subsequently drops gradually, reaching a final value of 2664.160 mg/L. The EC reactions may entail the participation of sodium ions, and their oscillations can be attributed to a range of variables, including the production and dissolution of compounds. The concentration of silica exhibits significant fluctuations, with a decrease from 4.922 to 3.234 mg/L after 25 min. The iron concentrations exhibit a notable increase subsequent to the initial test, potentially suggesting the deposition of iron on the electrodes as a component of the electrochemical therapy.

There is a progressive decrease in the concentration of boron from 10.600 mg/L to 9.961 mg/L. The sulfur concentration has an atypical trend, characterized by a subsequent decline to 5.785 mg/L at 30 min. This observation may suggest the occurrence of precipitation or flocculation. Based on the observed trends, it is possible to postulate that the EC process is exerting varying effects on the concentrations of various ions. It is probable that several factors, such as the production of complexes, precipitation of salts, pH fluctuations, and electrode reactions, are contributing to the observed phenomenon. Additionally, it is crucial to consider the experimental parameters, including the applied current, solution pH, electrode composition, and starting concentrations of other components in the solution, as these factors can impact the observed outcomes.

5.2.6. Characteristics of Treated PW

PW is a complex wastewater that contains many constituents as well as a mixture of organic and inorganic components [48].

Table 2. Water quality parameters of PW after EC experiments.

	PW	EC
Parameter (Unit)	Initial	5 min	10 min	15 min	20 min	25 min	30 min
COD (mg/L)	3790	2600	2620	2545	2450	2615	2525
TOC (mg/L)	1320.3	740.0	704.0	776.5	561.5	585.5	619.0
BROMIDE (Br−) (mg/L)	59.70	67.70	71.90	65.60	34.00	62.0	60.30
CHLORIDE, (CL−) (mg/L)	9360.00	8943.0	8688.0	8593.0	8340.54	8088.08	7835.62
Oil and Grease (MG/L)	44.80	<10	<10	<10	<10	<10	<10
Sulfate (${\mathrm{SO}}_4^{-2}$) (mg/L)	76.90	74.00	88.00	84.00	80.00	72.0	77.00
Bromate (${\mathrm{BrO}}_3^{-}$)	<5	<5	<5	<5	<5	<5	<5
Metals
Cadmium (mg/L)	<0.005	<0.005	<0.005	<0.005	<0.005	<0.005	<0.005
Chromium	0.096	0.023	0.024	0.022	0.039	0.035	0.029
Potassium	208.322	175.142	191.650	194.567	195.907	193.89	231.155
Sodium (mg/L)	2768.9	2915.8	2613.9	3159.9	3082.2	2497.8	2664.1
Silica (mg/L)	4.922	4.641	4.359	4.078	3.797	3.515	3.234
Iron (mg/L)	6.791	21.022	35.253	49.484	63.715	77.946	92.177
Boron (mg/L)	10.600	7.490	7.633	8.104	8.913	9.735	9.961
Barium (mg/L)	0.223	0.114	0.113	0.122	0.141	0.121	0.124
Zinc (mg/L)	0.148	0.011	0.053	0.024	0.026	0.037	0.034
Sulfur (mg/L)	176.700	147.232	117.764	88.296	58.828	29.360	5.786
Strontium (mg/L)	29.852	23.571	25.273	25.800	24.374	25.60	28.780
Lithium (mg/L)	4.074	2.899	3.083	3.126	3.351	3.45	3.855
BTEX
Toluene (µg/L)	36,330.0	1674.0	1061.0	706.0	786.0	543.0	432.0
Ethyl benzene (µg/L)	1322.0	101.0	44.0	28.0	27.0	15.0	11.0
Xylenes (µg/L)	13,430.0	811.0	404.0	255.0	270.0	156.0	129.0
Benzene (µg/L)	72,272.0	2801.0	1761.0	1083.0	1584.0	1228.0	1024.0

provides a comprehensive analysis of various contaminants in untreated PW and the corresponding reductions achieved at incremental time intervals through EC treatment. The COD was initially at 3790 mg/L. EC treatment progressively decreased this parameter, reaching 2525 mg/L at the 30 min mark, reflecting a modern purification effect that required further treatment to reuse that water for industrial purposes. Similarly, TOC levels saw a substantial decline from 1320.3 mg/L to 619.0 mg/L, indicating the breakdown of organic compounds and the potential for further reuse after EC treatment. For specific inorganic ions like bromide, chloride, sulfate, and heavy metals such as chromium, potassium, and sodium, the variations in concentration after EC treatment depict a complex behavior. Notably, while bromide levels reduced to 60.3 mg/L, chloride saw an unusual peak at the 20 min mark before settling at 9426.00 mg/L, hinting at ion-specific interactions within the EC process. The EC method also proved highly effective in reducing O&G content to less than 10 mg/L, significantly decreasing the environmental impact and enhancing the feasibility of water reuse. Remarkably, the EC process showed impressive efficacy in reducing BTEX concentrations. For instance, toluene was reduced from 36,330.0 µg/L to 432.0 µg/L, and benzene from 72,272.0 µg/L to 1024.0 µg/L, showcasing the potential of EC in mitigating these harmful organic compounds. Despite these positive outcomes, the variable results for heavy metals suggest that while EC can significantly purify PW, it may not be uniformly effective across all contaminants. Metals like cadmium, copper, and mercury remained below detection limits, while iron and lead showed decreased concentrations after treatment. This indicates that EC, while capable of treating certain metal contaminants, might require a supplementary treatment process for others to achieve comprehensive water reuse standards.

The fluctuations in certain concentrations, such as sulfur, which significantly increased during the EC process, stress the need for a nuanced understanding of the interactions occurring within EC. As such, for full-scale water reuse, especially for purposes requiring stringent quality control, it is advisable to couple EC with other treatment processes like membrane filtration or advanced oxidation to target and remove residual contaminants effectively. In summary, EC demonstrates significant potential for reducing a broad spectrum of contaminants in PW, improving the quality for potential reuse. However, the data also underscore the importance of tailoring the treatment to specific water quality requirements and possibly integrating EC with other treatment technologies for a comprehensive purification system.

According to the study of EC technique for processing wastewater treatment reported by [27], CD and hydrolysis time are the most effective parameters for EC efficiency. Therefore, the link between the coagulant dissolved load and EC process intensity from the anode can be explained by using Faraday’s law of electrolysis (Formula (6)) [28]:

$$w={\displaystyle \frac{MIt}{nF}}$$

(6)

where w is the total amount of metal dissolved (g). M is the molecular weight (g/mol). I is the current applied from the power supply (A). t is the hydrolysis time (s). n refers to the number of electrons involved in the reaction. F represents Faraday’s law constant (96,500 C/mol).

The removal rate of the contaminants is highly dependent on the anode ions released into the solution. According to Faraday’s law, the number of electrons involved in the reaction for selected metal and Faraday’s constant are fixed. Therefore, the scientific method to achieve a high removal rate is to either increase the hydrolysis time or increase the CD.

The first experiment (Table 2) showed a slight improvement in terms of pollutant removal by increasing the hydrolysis time and maintaining the current at 1.35 amps (CD = 630 A/m²). The first possible reason for lower efficiency refers to the increment of pH from 4 to 10 with extended hydrolysis time and the possibility of other reactions that took place than the electrons released from the anode. The change in Ph could be attributed to the CO₂ stripping off due to hydrogen gas production at the cathode [26]. It also strongly depends on the carbonate concentration in PW [49]. The second possible contribution could be connected to the ion exchange by chloride and sulfate ions into flocs Fe(OH)₃ [49]. The third possible reason is the limitation of the released iron due to the fouling of the electrode, which was clearly observed after the experiment.

Effects of the applied electrical current were demonstrated at 0.75 amps (CD = 350 A/m²) and 1.87 amps (CD = 870 A/m²) while maintaining the hydrolysis time at 25 min for 2 L PW. During this process, the electrodes were visibly checked and cleaned every 5 min intervals to eliminate the fouling factor effects on the process and to evaluate the efficiency.

Operating time is proportional to the electrode consumption. Figure 16 shows the electrode consumption for different electrical currents applied to the EC process almost steadily for every minute. The weight of the iron electrode decreased by 0.8 and 1.5 g when applied current at 0.75 and 1.87 amps, respectively. This indicates that the higher current or extended electrolysis time can increase the removal rate of pollutants. Nevertheless, it was observed that the quantity of flocs is more when supplying a high current. The result indicates that the dry solids are 2.41% and 2.62% when applied 0.75 and 1.87 amps, respectively. Furthermore, in Faraday’s law, the calculated amount of metal dissolved (Formula (6)) was found to be 0.3 and 0.8 g for the 0.75 and 1.87 amps tests, respectively. The deviation is observed between the experimental and theoretical dissolution rates. According to the literature review, Sasson et al. described the gap and highlighted the correction factors, such as Faradic yield and current efficiency, that were not predicted in Faraday’s law since it was approved at the beginning of the 20th century. The theoretical values of dissolution rate are valid only when all electrons participate in the metal dissolution reaction at the anode and should not react with any other reaction, such as OER near the anode [28]. The applied current controls the amount of dissolved ions and hydroxyl production [50].

5.2.7. Effect of Voltage on EC Performance

The impact of applied voltage on the efficacy of the EC process is depicted in Figure 17. With a rise in the applied voltage, a significant decrease in the concentration of iron ions in the water is seen. The observed pattern indicates that elevated voltages exhibit greater efficacy in diminishing iron concentration, which is associated with a decline in efficiency during the EC process at lower voltages. The EC method initially produces hydrogen gas bubbles as a result of electron release at the cathode, hence facilitating the precipitation of pollutants from the water. When the voltage increased to 18 V, the iron levels experienced the most substantial decrease, dropping from 36 ppm to a paltry 0.086 ppm, resulting in a 99.76% reduction. Additional voltages also yielded significant iron removal, although with significantly lower efficiency compared to the 18 V configuration. The aforementioned results are consistent with previous research that has documented heavy metal removal efficiencies ranging from 90% to 100% when employing EC, hence demonstrating its superiority over other techniques like membrane filtration or adsorption–oxidation. A significant decrease in iron content was seen upon increasing the voltage from 12 V to 15 V, suggesting that this voltage range may be advantageous for the procedure. The observed decrease in iron concentrations serves as a conspicuous indication of the occurrence of EC, wherein the generation and sedimentation of floc result in a reduction in pollutant concentrations. Ohm’s law (I = V/R) states that an increase in voltage results in an increase in electrical current [51]. According to Faraday’s First Law, this leads to an increase in the oxidation rate of the iron electrodes, which in turn enhances the production of Fe(OH)₃ coagulant [50]. The aforementioned procedure leads to an increased concentration of contaminants and their eventual elimination from the effluent.

5.3. Key Challenges of the EC Process

The experiments that were carried out have uncovered many critical issues associated with the EC procedure. These include the following:

• The phenomenon of electrode fouling: A notable obstacle encountered was the pronounced fouling on the electrodes, impeding the reaction process and diminishing the efficacy of pollutant elimination. Although the use of sandpaper to clean the electrode plates after each cycle provided a transient enhancement, the problem of fouling necessitates additional examination;
• The Impact of Voltage on Electrochemical Performance: The research conducted revealed that the manipulation of voltage had an impact on the concentration of iron ions present in the treated water. A drop in EC efficiency was seen as the iron ion content decreased at higher voltages. The data indicate that the maximum removal efficiency for iron was observed at a voltage of 18 volts. However, it also highlights the necessity of careful power supply control to maintain the effectiveness of EC during the full duration of the operation.

In order to tackle these issues, we have suggested the following:

• Further investigation is necessary to gain a comprehensive understanding of the fouling phenomena and to devise more enduring strategies for its prevention or mitigation;
• Further investigation is required to assess the influence of metal deterioration on the performance of EC. One such approach is to examine various electrode materials or coatings that exhibit resistance to deterioration;
• A proposal has been made to carry out the experiment with a hybrid system that combines EC with a Forward Osmosis (FO) membrane in order to enhance water quality. This suggests that although EC is efficient, it may be necessary to incorporate it into a multi-stage treatment procedure.

6. Conclusions

The present investigation and laboratory experiments have substantiated the efficacy of the EC system as a viable approach for the treatment of PW with the aim of rendering it appropriate for sustainable reutilization. Research has demonstrated that the EC process has a substantial impact on water quality metrics by a set of involved experiment runs. The experiments have been conducted to determine the mechanisms behind the applied current and electrolysis time on the EC process on real PW treatment and address all challenges and effects of the treatment process. Initially, it was discovered that the pH of the water increased as the length of the EC process extended. The turbidity and O&G levels exhibited a notable decrease of more than 99%, resulting in enhanced water quality and a near eradication of oil content. The EC technique exhibited exceptional efficacy in eliminating BTEX chemicals from PW, resulting in a reduction of over 99% in their concentrations. The EC system has a diverse effect on metals and ions. Although there were variations in the concentration of certain ions, heavy metals such as cadmium, copper, and mercury remained below the limits of detection following the treatment, and most of the heavy metals remained unchanged and subjected to further evaluation of suitable treatment methods for metals. The EC process demonstrated significant efficacy in reducing the concentrations of BTEX. The obtained results of removal efficiency are relatively similar to those of the literature review to some extent, as compared in each parameter removal section. The composition of the real PW is one a key factor for EC process efficiency since it is changed according to the winter and summer basis in addition to the additives such as corrosion inhibitor and during winter season such as KHI and MEG injection to avoid hydrate formation that needs further study. Nevertheless, the available data indicate that a hybrid system incorporating EC in conjunction with advanced treatment techniques such as Forward Osmosis (FO) membranes may be required to attain optimal reuse water quality for the complete elimination of BTEX and heavy metals.

Recommendations

The EC treatment method was selected based on a comprehensive literature review to treat real PW. When comparing the elimination efficiency of the EC system with that of other research, it demonstrated a slightly superior performance, thereby establishing its acceptability as a standalone treatment approach at this level. However, certain problems were identified that will necessitate additional optimization. The aforementioned factors encompass electrode degradation, fouling, and pH regulation throughout the course of the experiment. In order to effectively tackle these concerns, forthcoming research endeavors must consider several factors, including electrode materials and diameters, current density, power supply, and the inter-electrode gap. Additionally, it is advisable to broaden the scope of experimentation by incorporating a hybrid system that combines EC with a FO membrane. Additional experiments should be conducted on both untreated and EC-treated PW at regular intervals of 5 and 30 min in order to ascertain the most favorable circumstances for the removal of pollutants. This EC exhibits significant promise in mitigating a diverse range of pollutants in PW, hence enhancing the overall water quality for potential reutilization. However, the observed disparities in outcomes underscore the importance of tailoring the treatment procedure to meet the particular demands of water quality and perhaps incorporating EC with other treatment methodologies to develop a more all-encompassing purification framework. Moreover, the renewable energy resources approach is to be evaluated since it is applied widely to reduce treatment cost.