Efficiency Evaluation of a Photovoltaic-Powered Water Treatment System with Natural Sedimentation Pretreatment for Arsenic Removal in High Water Vulnerability Areas: Application in La Yarada Los Palos District, Tacna, Peru

Abstract

Arsenic contamination poses a severe health risk in regions with high water vulnerability and limited treatment infrastructure. This study evaluates a photovoltaic-powered water treatment system for arsenic removal in La Yarada Los Palos District, Tacna, Peru, where arsenic concentrations reached up to 0.0417 mg/L, significantly surpassing the World Health Organization (WHO) limit of 10 µg/L (0.01 mg/L) for drinking water. The system integrates a natural sedimentation pretreatment stage in a geomembrane-lined reservoir, followed by oxidation with sodium hypochlorite, coagulation, and adsorption. Arsenic removal efficiencies ranged from 99.72% to 99.85%, reducing residual concentrations below WHO guidelines. Pretreatment significantly improved performance, reducing turbidity by up to 66.67% and TSS by up to 70.37%, optimizing subsequent treatment stages. Operationally, pretreatment decreased cleaning frequency from six to four cleanings per month, while backwashing energy consumption dropped by 33% (from 45.72 kWh to 30.48 kWh). The photovoltaic system leveraged the region’s high solar radiation, achieving an average daily generation of 20.31 kWh and an energy surplus of 33.08%. The system’s performance was evaluated within the context of existing arsenic removal technologies, demonstrating that the integration of natural sedimentation and renewable energy constitutes a viable operational alternative. Given the regulatory framework in Peru, where arsenic limits align with WHO standards, conventional water treatment systems are normatively and technically unfeasible under national legislation. Furthermore, La Yarada Los Palos District faces challenges due to its limited infrastructure for conventional electrification via power grid, as identified in national reports on rural electrification and gaps in access to basic services. Beyond its performance in the study area, the system’s modular design allows adaptation to diverse water sources with varying arsenic concentrations, turbidity levels, and other physicochemical characteristics. In remote regions with limited access to the power grid, such as the study site, photovoltaic energy provides a self-sustaining and replicable alternative, particularly in arid and semi-arid areas with high solar radiation. These conditions are not exclusive to Latin America but are also prevalent in remote regions of Africa, the Middle East, Asia, and Oceania, where groundwater arsenic contamination is a significant issue and renewable energy availability can enhance water treatment sustainability. These findings underscore the potential of using sustainable energy solutions to address water contamination challenges in remote areas. The modular and scalable design of this system enables its replication in regions with adverse hydrogeological conditions, integrating renewable energy and pretreatment strategies to enhance water treatment performance. The framework presented in this study offers a replicable and efficient approach for implementing eco-friendly water treatment systems in regions with similar environmental and resource constraints.

1. Introduction

1.1. Context and Background

Access to safe drinking water represents a fundamental challenge in water resource administration, particularly in regions affected by arsenic contamination. According to the World Health Organization (WHO), arsenic is highly toxic in its inorganic form and poses a significant public health threat when present in water used for human consumption or agricultural activities [1].

Prolonged exposure to this contaminant can lead to severe health issues, including skin, lung, and bladder cancer, as well as cardiovascular diseases and diabetes [1]. Arid and semi-arid regions are particularly vulnerable due to the limited availability of high-quality water resources.

Arsenic is found in water primarily in the following two oxidation states: arsenite (As(III)) and arsenate (As(V)), with As(III) being more toxic and more difficult to remove [2]. Processes such as evaporation in arid climates increase arsenic concentrations, salinity, and pH levels in water sources [3], while natural geological formations release this contaminant into groundwater [4]. These dynamics make meeting the 0.01 mg/L limit established by the WHO [1] a significant challenge for many communities.

This study approaches these challenges by proposing a technological solution adapted to local conditions, evaluating the effectiveness of an integrated photovoltaic system for water treatment and a pretreatment stage.

The data presented in this study, obtained before and after treatment, demonstrate the system’s effectiveness in removing arsenic under real field conditions. These results underscore the importance of implementing innovative technologies tailored to local characteristics to address the issue of access to safe drinking water in vulnerable regions.

The integration of photovoltaic energy into water treatment systems has been explored in applications such as reverse osmosis desalination and contaminant removal, through advanced oxidation processes [5]. However, the specific combination of this technology with passive pretreatments, such as natural sedimentation, has not been sufficiently optimized in the scientific literature. One of the main reasons for this gap is that most studies on photovoltaic-powered water treatment have focused on energy-intensive processes that require a continuous power supply, while limited attention has been given to pretreatment strategies that operate with minimal external energy input [6]. The lack of research in this area restricts the development of cost-effective, sustainable solutions for arsenic removal in communities with limited access to basic infrastructure.

The implementation of photovoltaic-powered treatment systems also faces technical and operational challenges, including fluctuations in solar power generation and the absence of adequate infrastructure in rural areas, which complicates their large-scale deployment in passive pretreatment applications [7]. Although significant research on arsenic removal has been conducted in countries such as Bangladesh, India, and China, there is a clear gap in adapting these technologies to regions with high solar radiation and naturally contaminated water sources, such as Latin America [8]. The abundant solar energy available in these regions provides a promising opportunity to develop autonomous water treatment solutions that do not rely on conventional grid electricity.

Water vulnerability in Latin America remains a critical concern, and to date, hybrid systems integrating passive pretreatments with renewable energy sources have not been thoroughly investigated [9]. In response to this gap, this study evaluates arsenic removal in a photovoltaic-powered water treatment system, incorporating a natural sedimentation pretreatment module and assessing its efficiency in areas with high water vulnerability. Unlike previous studies, this research not only presents experimental data obtained under real field conditions but also examines the hydrogeological and operational factors that influence the feasibility of these systems. Optimizing this integration will not only improve water treatment efficiency in communities with limited access to conventional infrastructure but will also contribute to the development of scalable and replicable solutions for other regions with similar environmental and socio-economic challenges.

1.2. Local Problem

In this global context, the district of La Yarada Los Palos, located in the Tacna region of Peru, serves as an emblematic case, illustrating the consequences of arsenic contamination and the water administration crisis in arid regions. The region’s arid climate, combined with limited water availability, exacerbates the challenges of ensuring access to potable water. The combination of high solar radiation, elevated temperatures, and scarce rainfall intensifies evaporation processes, which, in turn, increase salinity and arsenic concentrations in groundwater sources.

The district still lacks an integrated potable water treatment system capable of effectively removing contaminants before distribution to the population. In the district’s capital, which has the highest population density, water intended for human consumption is extracted directly from groundwater sources and distributed to households without any prior treatment. This supply model increases the population’s exposure to natural contaminants, such as arsenic, which is present in aquifers due to local geology. In some cases, arsenic concentrations in this groundwater exceed 0.04 mg/L, more than four times the maximum limit recommended by the WHO, significantly increasing the risk of developing health issues such as skin, lung, and bladder cancer, as well as cardiovascular diseases and diabetes [1,10,11,12,13].

The initial analyses of water samples revealed arsenic concentrations significantly higher than the WHO permissible limit, ranging from 0.0101 to 0.0417 mg/L before treatment, underscoring the urgency of implementing sustainable solutions. These data highlight the severity of contamination and reinforce the need for adequate technological strategies to ensure access to safe drinking water.

From a regulatory and technical perspective, conventional treatment systems are not viable for this region. The Environmental Quality Standard for Water established by the Peruvian government through Supreme Decree No. 004-2017-MINAM defines the maximum permissible limit for arsenic in water that can be made potable using conventional treatment as 0.01 mg/L [14], a value aligned with the WHO guideline for drinking water. However, arsenic concentrations in the study area exceed this threshold, highlighting the need for advanced arsenic removal technologies that ensure compliance with established quality standards for human consumption.

In addition to regulatory constraints, energy availability poses another major challenge. The feasibility of conventional arsenic removal technologies is further hindered by the lack of electrification in remote areas such as La Yarada Los Palos District. According to the National Rural Electrification Plan (PNER) 2024–2033 of the Ministry of Energy and Mines (MINEM), this district faces significant challenges due to its remoteness, low population density, limited road access, and lack of basic infrastructure, making conventional electrification financially unfeasible for private investment, necessitating state intervention [15]. Similarly, the 2024–2026 Gap Diagnosis Report by the Provincial Municipality of Tacna identifies La Yarada Los Palos as one of the areas with the most significant deficiencies in sanitation and electricity services [16]. These factors highlight the importance of exploring decentralized and sustainable solutions, such as photovoltaic-powered treatment systems, to address the region’s water crisis.

The 2017 National Census, conducted by the National Institute of Statistics and Informatics (INEI), reported a population of 5559 inhabitants in La Yarada Los Palos district [13]. However, subsequent studies estimate a significantly higher figure. For instance, a demographic analysis conducted prior to the census indicated a population increase from 3998 inhabitants in 2007 to 6433 in 2017 [17]. Additionally, according to the district’s sub-prefect, Diana Ramírez Charca, only 15% of the approximately 15,000 rural residents were counted in the 2017 census, suggesting a substantial underestimation in official data [18]. This population growth accentuates the region’s water vulnerability, affecting thousands of individuals exposed to considerable health risks.

Studies conducted by the National Water Authority (ANA) have identified that arsenic contamination in the water resources of the Caplina basin is primarily attributed to the natural geological characteristics of the region. This natural occurrence of arsenic highlights the critical need for the development and implementation of sustainable water treatment solutions to ensure access to safe drinking water for communities in areas such as La Yarada Los Palos district [10,19].

Furthermore, social pressure on water resources has drastically increased due to the extensive use of groundwater for agriculture purposes. Between 2000 and 2020 years, agricultural use land in La Yarada Los Palos expanded by 265.84%, intensifying water demand in a region with already limited resources [20]. This overexploitation not only jeopardizes the sustainability of water resources but also amplifies the challenges of accessing safe water for local communities.

Extreme climatic conditions, natural contamination, demographic growth, and agricultural pressure emphasize the need to implement innovative strategies tailored to local characteristics to ensure sustainable access to potable water in La Yarada Los Palos and mitigate the risks associated with limited access to safe drinking water.

The results of this study not only offer solutions applicable to La Yarada Los Palos but also provide a replicable model for other regions facing similar challenges, both nationally and internationally.

1.3. Existing Technologies and Knowledge Gaps

The removal of arsenic from drinking water is a critical challenge, particularly in regions affected by natural contamination of this metalloid. Several technologies have been developed to address this issue, among which adsorption, oxidation, and coagulation stand out. Adsorption is a widely used technique for arsenic removal that leverages the ability of certain materials to retain contaminants on their surfaces. Materials such as activated alumina, iron oxides, and modified zeolites have demonstrated efficacy in arsenic adsorption. However, the presence of other anions in water, such as phosphates and silicates, can compete for adsorption sites, reducing the process’s efficiency. Additionally, the regeneration and disposal of adsorbent materials pose further challenges in terms of costs and environmental management [21].

Chemical oxidation is essential for converting As(III), which is more toxic and harder to remove, into As(V), which is easier to eliminate through subsequent processes. Among the oxidizing agents used, sodium hypochlorite (NaClO) stands out for its effectiveness and availability. Studies have shown that oxidation with sodium hypochlorite can achieve efficiencies exceeding 90% under optimal conditions, such as a temperature of 20 °C and appropriate oxidant dosages. It is important to note that within the studied ranges, pH does not significantly affect the process’s efficiency [22]. However, the implementation of this method in remote regions may be limited by the availability and safe handling of the required chemical products.

Coagulation involves adding coagulants, such as aluminum or iron salts, to water to destabilize and aggregate fine particles and colloids, facilitating their subsequent removal through sedimentation and filtration. This method is effective for arsenic removal, particularly when combined with prior oxidation processes that convert As(III) into As(V). However, coagulation efficiency can be affected by factors such as water pH, coagulant dosage, and the presence of other contaminants. Additionally, the generation of sludge as a byproduct requires proper management, which can be challenging in areas with limited infrastructure [23].

In remote regions, implementing conventional water treatment systems faces multiple challenges. A lack of adequate infrastructure, limited financial resources, and difficulties in supplying and managing the chemicals required for processes such as oxidation and coagulation hinder the effective application of these technologies. Furthermore, dependence on non-renewable energy sources can be unsustainable in these areas, where access to electricity is limited or nonexistent. Despite advancements in water treatment technologies, the integration of renewable energy into these processes remains limited. Solar photovoltaic energy, for instance, offers a sustainable and abundant energy source in many regions affected by arsenic contamination. The implementation of water treatment systems powered by solar energy could improve the feasibility and sustainability of solutions in remote areas. However, the lack of research and development in optimizing these systems represents a knowledge gap that must be addressed to facilitate their widespread adoption.

While numerous studies have explored arsenic removal from water, a significant research gap remains regarding the efficiency of pretreatment, oxidation, and adsorption methods under real field conditions, particularly in photovoltaic-powered systems and regions with high water vulnerability. The literature consistently highlights that arsenite (As(III)) is considerably more challenging to remove than arsenate (As(V)) due to its higher solubility and lower affinity for conventional adsorbents. Some studies have examined arsenic removal; however, its efficiency largely depends on precise pH control and coagulant dosage, which limits its applicability under variable field conditions [24]. Similarly, although arsenic removal in biological sand filters has been investigated, many studies do not address the need to evaluate integrated systems that more effectively combine non-conventional methods [25].

Research has demonstrated that iron oxides facilitate As(V) adsorption [26,27]. However, these findings are primarily derived from controlled experimental setups, leaving uncertainties regarding their performance under field conditions, particularly in the presence of suspended solids and organic matter, which may interfere with adsorption efficiency. A notable gap in the literature is the limited investigation into the role of natural sedimentation pretreatment in optimizing arsenic removal. Some studies suggest that reducing suspended solids and turbidity before adsorption could enhance process efficiency and minimize reagent consumption, but these aspects have yet to be comprehensively evaluated in fully integrated, renewable-energy-powered treatment systems [28,29].

On the other hand, recent studies have explored innovative approaches, such as MoS₂-impregnated iron oxide–biochar composites for As(III) removal [30], and have demonstrated that redox interactions between arsenic and manganese can significantly enhance oxidation efficiency in electrocoagulation systems [31]. However, these technologies have not yet been implemented in Latin America, where arsenic contamination in drinking water remains a critical yet persistently underestimated issue.

Most arsenic removal studies have been conducted in Asia, Europe, and North America, with limited research focusing on Latin America. In the case of Tacna, Peru, no published studies assess the effectiveness of a photovoltaic-powered water treatment system incorporating natural sedimentation pretreatment and optimized adsorption processes. This knowledge gap is critical, as local populations rely on water sources with arsenic concentrations exceeding WHO limits and lack access to effective and sustainable remediation technologies.

This study addresses this research gap by evaluating arsenic removal in a photovoltaic-powered water treatment system, with a particular focus on integrating natural sedimentation pretreatment, oxidation, and adsorption strategies under real field conditions. Unlike previous studies, this research not only examines arsenic removal efficiency in a high water vulnerability area but also assesses the influence of hydrogeological and operational factors on system performance in a region with limited prior investigations on this issue.

1.4. Combined Technologies for Arsenic Treatment

To address this issue, an integrated water treatment system was designed, combining advanced technologies, renewable energy, and an innovative approach that includes a natural sedimentation pretreatment stage. This pretreatment reduces the initial contaminant load, improving the efficiency and sustainability of subsequent treatment stages such as oxidation [22], coagulation [23], and adsorption [21].

The use of photovoltaic energy, adapted to local climatic conditions, reinforces the feasibility of the system in remote areas with limited access to conventional energy resources. The results highlight the effectiveness of this solution in reducing arsenic concentrations to safe levels, providing a replicable and sustainable alternative to address this public health crisis.

The implementation of photovoltaic systems not only enables sustainable operation in remote regions but also significantly contributes to reducing the carbon footprint. Compared to traditional systems that rely on electricity generated from fossil fuels, this approach can prevent the emission of approximately 0.5 kg of CO₂ per kWh produced, considering average grid conditions in Peru [32].

In addition to addressing arsenic contamination, the integrated photovoltaic system generates significant environmental benefits by reducing greenhouse gas emissions. A typical plant of this type, with an operational capacity of 5 kWh/day, prevents the emission of approximately 196 kg of CO₂ annually, compared to systems using conventional electricity. This reduction in emissions represents a critical step toward sustainable solutions for rural communities with high water vulnerability.

The system’s energy results indicate that its operation through solar energy not only ensures its feasibility in remote areas but also avoids the use of electricity derived from fossil fuels. This translates into an annual CO₂ emissions savings equivalent to the amount absorbed by approximately nine mature trees, reinforcing its contribution to climate change mitigation [32].

1.5. Study Objectives

This study aims to evaluate the effectiveness of an integrated photovoltaic-powered water treatment system designed to optimize local conditions. The primary focus is on the efficient removal of arsenic, differentiating between As(III) and As(V), and improving energy performance through a natural sedimentation pretreatment.

1.5.1. Main Objective

The main objective of this study is to evaluate the effectiveness of an integrated photovoltaic-powered water treatment system designed to reduce arsenic concentrations and optimize energy consumption, adapting to the climatic and geographical conditions of La Yarada Los Palos district, Tacna.

1.5.2. Specific Objectives

• Quantify the efficiency of arsenic removal under conditions with and without natural sedimentation pretreatment, highlighting its impact on the initial water quality.
• Analyze the performance of the photovoltaic system under local climatic conditions, identifying key and efficiency influencing factors such as solar radiation, and evaluate the system’s energy consumption, identifying how pretreatment reduces energy costs and improves system operation.

Assess the treatment’s effectiveness by determining total arsenic concentrations and its chemical species [As(III) and As(V)] before and after the treatment process, using advanced techniques such as ICP-MS and HPLC to verify the removal levels achieved.

2. Materials and Methods

2.1. Study Area and Sampling

The district of La Yarada Los Palos, located in the Tacna region of southern Peru, is characterized by an arid climate that presents significant challenges for sustainable water management. With an average annual temperature of 18.5 °C and precipitation below 50 mm per year, high evaporation contributes to the concentration of contaminant agents (such as arsenic) in groundwater [1]. The local geology includes sedimentary formations containing sulfides and arsenical minerals, which naturally release arsenic into groundwater through weathering and leaching processes [19]. This phenomenon has resulted in arsenic concentrations that, in some cases, exceed 0.04 mg/L, surpassing the World Health Organization’s recommended limit of 0.01 mg/L for drinking water [2].

Additionally, the region faces intensive use of groundwater resources, primarily for agriculture, which exacerbates water sustainability issues and increases the population’s exposure to the natural contaminants present in aquifers [33].

To evaluate the quality of groundwater and its potential for treatment, three strategic sampling points were selected to represent water extraction and distribution sources in the district (Figure 1 and

Table 1. Coordinates and altitude of sampling points in the study area.

		UTM Coordinates WGS 84
Sampling Point	Zone	North	East	Altitude (m.a.s.l.)
Point 1	Bio Garden Los Palos Zone	353,151.00 m E	7,980,461.00 m S	68
Point 2	Southern Border Zone	347,704.00 m E	7,981,265.00 m S	45
Point 3	Ashlands Zone	352,342.00 m E	7,973,450.00 m S	19

). These points were chosen based on their proximity to residential and agricultural areas, as well as previously reported variations in water quality [10]. Sampling data from September to January were not analyzed because these months correspond to the period of highest solar radiation in the study area. Instead, samples were collected during months with lower solar radiation to assess the water characteristics that the photovoltaic-powered treatment system would have to handle under conditions of reduced solar energy availability.

Each sample was collected in 1 L polyethylene containers, which were pretreated with a 10% nitric acid solution and rinsed with ultrapure distilled water to ensure the absence of external contaminants. During sampling, the containers were rinsed with site water prior to collecting the final sample, following water sampling protocols for chemical analysis [34]. To preserve physicochemical properties, the samples were stored in insulated containers at 4 °C and transported to the laboratory within 12 h. All samples were labeled with alphanumeric codes identifying the sampling point, date, and time of collection, ensuring rigorous tracking during the different stages of analysis.

In situ measurements of key physicochemical parameters were conducted during sample collection using a Hanna HI 98194 multiparametric portable meter (manufactured by Hanna Instruments in Sălaj County, Romania; sourced in Peru), known for its precision and robustness under field conditions [35]. The measured parameters included pH, which provides information on water acidity or alkalinity and influences arsenic speciation and mobility; temperature, which affects the solubility of chemical compounds and oxidation–reduction processes and is a critical factor in treatment efficiency; and electrical conductivity (EC), which indicates ion concentrations in the water, related to salinity and overall water quality [36]. Each measurement was performed three times per sample to ensure data accuracy and consistency. The equipment was pre-calibrated using certified reference standards, and readings were recorded alongside observations of the site and environmental conditions.

To minimize cross-contamination and ensure data integrity, cleaning and quality control protocols were implemented, including the use of disposable gloves and sterile materials during sample handling and transportation in sealed containers. Blank samples and duplicates were also included to validate the precision and reproducibility of subsequent analyses.

2.2. Analytical Techniques and Experimental Setup

2.2.1. Analytical Techniques

The speciation and quantification of arsenic were carried out using inductively coupled plasma mass spectrometry (ICP-MS) and high-performance liquid chromatography (HPLC). An Agilent 7900 ICP-MS system (manufactured in Tokyo, Japan) was employed for the detection of trace metals in water samples. Additionally, an HPLC system (manufactured in Waldbronn, Germany) was used to separate and quantify different arsenic species, providing a robust methodology for arsenic speciation analysis. These techniques enable the differentiation and quantification of chemical species such as As(III), As(V), and total arsenic with high precision and sensitivity.

Before analysis, the samples were filtered through 0.45 µm membranes to remove solid particles. Subsequently, the pH was adjusted to a range of 6 to 8 to stabilize chemical species and minimize the conversion of As(III) to As(V) during storage. The HPLC system separated the chemical species based on their physicochemical properties. The ICP-MS system, coupled to the HPLC output, detected and quantified As(III) and As(V) with detection limits below 0.001 mg/L, meeting international standards for trace analysis [36,37].

The combined use of ICP-MS and HPLC ensures high sensitivity and precision in the speciation and quantification of arsenic.

2.2.2. Natural Sedimentation Pretreatment

Point 3, corresponding to the Ashlands Zone, was selected as a key site to implement the natural sedimentation pretreatment stage and analyze its influence on the water treatment process (Figure 2a). This point exhibits particular hydrogeochemical characteristics that represent extreme conditions within the study area. The results obtained at this location consistently showed the highest values of turbidity, total suspended solids (TSS), and electrical conductivity, as well as the highest concentrations of total arsenic compared to the other sampling points. These conditions reflect a combination of natural arsenic mineralization and the potential impact of intensive agricultural activities in the area. For these reasons, Point 3 was deemed to be fundamental for evaluating the effectiveness of the treatment system under scenarios with high contaminant loads (Figure 2b).

The pretreatment system included a reservoir lined with high-density polyethylene geomembranes designed to resist UV rays, thermal variations, and mechanical wear. The geomembranes were 1.5 mm thick. The reservoir has dimensions of 25 m in length, 45 m in width, and a depth of 2.8 m, with sloped edges at 30 degrees to ensure structural stability and facilitate liner installation. The reservoir’s total capacity is 3150 m³, sufficient to store the water extracted during two days of continuous operation, allowing for an average hydraulic retention time of 48 h.

The reservoir was filled through a system of valves connected directly to water sources, enabling controlled and continuous flow into the reservoir. Draining was conducted via additional control valves that directed the water to subsequent treatment stages. To prevent external contamination, a perimeter fence and a protective mesh were installed to shield the reservoir from debris, leaves, and wildlife.

Before implementation, pilot tests were conducted to determine the optimal retention time and evaluate sedimentation efficiency. The results of these tests guided the final design, maximizing the removal of total suspended solids (TSS) and turbidity. During operation, an average reduction of 67.25% in TSS and 61.02% in turbidity was recorded, significantly improving the quality of water entering the system.

From an environmental perspective, natural sedimentation pretreatment minimizes the use of chemicals in subsequent stages, reducing operational costs and the environmental impact associated with sludge generation. Additionally, periodic reservoir maintenance, through the removal of accumulated sediments, ensures its efficient operation over the long term.

This pretreatment stage is a technically and environmentally sustainable solution that improves the quality of incoming water, reduces the contaminant load, and optimizes conditions for subsequent treatment stages.

2.2.3. Water Treatment System

The water treatment system consists of two parallel treatment lines (Figure 3a), designed to evaluate the efficiency of key stages under different pretreatment conditions (with and without pretreatment). This dual design enabled a direct comparison of the influence of natural sedimentation pretreatment on the quality of treated water and the operational performance of the system.

The line without pretreatment processes water directly from the source, bypassing the sedimentation reservoir. This line handles water with higher loads of suspended solids and turbidity, subjecting the main modules of this line to more demanding conditions.

The line with pretreatment includes an additional step in the sedimentation reservoir equipped with geomembranes, as described in Section 2.2.2. In this space, the water undergoes a natural decantation process, significantly reducing suspended solids and turbidity before entering the main treatment modules. This pretreatment step decreases the load on subsequent stages, improving their overall efficiency.

In both lines, the oxidation module uses sodium hypochlorite (NaClO) as primary oxidant to convert arsenite (As(III)) into arsenate (As(V)). The dosage of NaClO is experimentally adjusted based on the initial arsenic concentration, with an optimized ratio to ensure efficient arsenic oxidation. This process is carried out under controlled conditions using closed reactors to minimize the volatilization of sodium hypochlorite and to ensure adequate residence times, thus achieving complete conversion of As(III) to As(V) [22].

Coagulation and flocculation complement the treatment in both lines through the use of ferric sulfate as a coagulant. Controlled agitation promotes the formation of settleable flocs, which are subsequently removed in a clarifier. This stage enhances water quality by reducing turbidity and suspended solids, facilitating compliance with international quality standards prior to the final treatment stages [23,38].

The filtration stage incorporates processes designed to address various contaminants present in the water (Figure 3b). The first step employs a particle filter composed of natural zeolite granules, which combines mechanical filtration with ion exchange properties to capture suspended solids and fine particles. In the next step, a filter containing sand coated with manganese oxides oxidizes and removes metals such as iron and manganese, chemically stabilizing the water. Subsequently, a granular activated carbon filter with high porosity adsorbs organic compounds, odors, and residual chlorine, preparing the water for arsenic adsorption. Finally, a filter utilizing titanium oxyhydroxide as an adsorbent medium efficiently removes arsenic (As(V)), ensuring that residual levels comply with WHO standards.

Both system lines operate at an average flow rate of 0.5 m³/h. The parallel line configuration allows for a direct comparison of the performance of each treatment line. During testing, the system demonstrated arsenic removal efficiencies exceeding 99.5%. The integration of natural sedimentation pretreatment proved to be crucial, significantly enhancing the efficiency of subsequent processes, reducing operational loads, and optimizing energy consumption. This modular and innovative design highlights the adaptability and robustness of the treatment system in addressing challenges associated with high initial turbidity and elevated arsenic concentrations, particularly in areas with limited water resources.

2.2.4. Photovoltaic System

The water treatment system is powered by a set of photovoltaic panels (Figure 4a) designed to operate continuously under the climatic conditions of La Yarada Los Palos, a region characterized by high solar radiation and low nighttime temperatures. With an installed capacity of 5 kWp, the system includes 12 monocrystalline solar panels, each with a power output of 410 Wp. These panels are oriented northward and tilted at 23°, optimized to maximize solar radiation capture. In the region, average solar radiation reaches 6 kWh/m²/day, ensuring a consistent energy supply during daylight hours [39].

The system includes a bank of three lithium-ion batteries (Figure 4b) with a combined nominal capacity of 10.65 kWh and an operational capacity of 10 kWh, enabling operation during periods of low irradiance. These batteries are designed to offer a high depth of discharge (95%), maximizing their usable capacity, and have a lifespan exceeding 6000 cycles under standard operating conditions. The modular design of these batteries facilitates future system expansions and provides efficient energy storage to ensure operation during periods of reduced solar irradiance [40].

Energy transfer and regulation are managed by a Must PV18-5048 VHM multifunctional inverter (manufactured in Guangdong, China; purchased in Peru), which combines inverter, solar charger, and battery charger functions. This inverter has a nominal power of 5000 W and an efficiency of 93%, with the capacity to handle peaks of up to 10,000 W. Additionally, it integrates an MPPT charge controller with a voltage range of 60–200 VDC, optimizing energy transfer from the solar panels to the batteries and treatment modules. This device also supports parallel operations, providing flexibility to scale the system as needed [40].

During the photovoltaic system tests, ambient temperature and solar radiation readings were recorded using a Davis Vantage Pro2 weather station (manufactured in Hayward, CA, USA; purchased in Peru) strategically installed near the treatment plant. The data collected were crucial in evaluating the influence of climatic variables on the system’s energy performance, ensuring a design tailored to the specific conditions of the region.

The system design accounted for specific local challenges, such as temperature fluctuations and high energy demands at certain times of the day. Advanced energy management strategies were implemented, including real-time consumption monitoring and automatic adjustments to the operating rates of the water treatment modules. This approach ensures an optimal balance between energy efficiency and sustainability.

Additionally, the system was designed to withstand a maximum system voltage of 1500 V and adverse conditions such as constant exposure to high temperatures and dust. The implementation of photovoltaic systems contributes to improving energy efficiency and offers potential solutions for addressing sustainability challenges in various applications, including water management in vulnerable regions [41].

2.3. Experimental Procedure and Data Analysis

The experimental procedure incorporated established guidelines for water quality analysis and treatment system optimization [42,43], as well as principles of coagulation and adsorption processes for arsenic removal [44,45]. Data analysis was supported by statistical methodologies for experimental design and evaluation, ensuring robust validation of results [46,47]. Additionally, the energy performance of the photovoltaic-powered system was assessed following international best practices and energy storage strategies for remote water treatment systems [48].

The data analysis included a comparative statistical evaluation of the removal efficiency of As(III) and As(V) and energy consumption under configurations with and without pretreatment. The results, exposed in section “Statistical Analysis of Results on Arsenic Removal Efficiency and Energy Consumption”, show significant differences in both parameters, with p-values less than 0.001. On average, removal efficiency increased from 87.27% to 99.80% with pretreatment, while the total energy consumed in the backwashing process was reduced by 33% compared to the scenario without pretreatment. These findings highlight the effectiveness of pretreatment in optimizing both system performance and energy sustainability.

The impact of climatic conditions on the photovoltaic system was analyzed, considering the influence of factors such as solar radiation and temperature, following principles of energy optimization in water treatment systems based on renewable energy, as discussed in previous studies [49].

Pretreatment demonstrated a significant improvement in overall system efficiency, reducing energy consumption during the cleaning process by 33% and increasing average arsenic removal by 12.53% compared to conditions without pretreatment. These findings underscore the importance of adapting treatment strategies to the specific characteristics of water sources and the local environment [23,50].

To validate the results, blank samples and duplicates were included in each analysis set. This approach ensured data reproducibility and precision, establishing a solid foundation for future studies on optimizing treatment systems in regions with high water vulnerability [51].

3. Results

3.1. Physicochemical Characteristics of Water Samples

The analysis of physicochemical properties of samples collected at the three sampling points—Bio Garden Los Palos Zone (Point 1), Southern Border Zone (Point 2), and Ashlands Zone (Point 3)—reveals significant variations in key parameters that reflect the influence of local hydrogeochemical conditions (

Table 2. Physicochemical characterization of water at sampling points.

Sampling Point	Zone	Sample Code	Sampling Date	Temperature (°C)	pH	Conductivity (uS/cm)	TDS (mg/L)	TSS (mg/L)	Turbidity (NTU)
Point 1	Bio Garden Los Palos Zone	SP1-1	10 February 2024	23.32	7.24	3418	1579	19	9
		SP1-2	15 February 2024	24.54	7.41	4732	2258	26	13
		SP1-3	20 February 2024	24.89	7.42	5031	2431	28	14
		SP1-4	26 February 2024	22.68	7.12	2684	1253	16	8
		SP1-5	4 March 2024	23.77	7.36	3975	1804	21	10
		SP1-6	11 March 2024	24.41	7.27	4593	2102	22	11
		SP1-7	21 March 2024	24.88	7.45	4849	2324	26	13
		SP1-8	28 March 2024	26.42	7.62	2815	1327	15	8
		SP1-9	2 April 2024	23.15	7.19	3296	1512	17	9
		SP1-10	8 April 2024	27.15	7.85	3452	1624	19	10
		SP1-11	13 April 2024	27.89	8.21	3518	1650	20	10
Point 2	Southern Border Zone	SP2-1	10 February 2024	28.04	8.02	2908	1386	16	9
		SP2-2	15 February 2024	28.12	8.25	3105	1456	18	9
		SP2-3	20 February 2024	26.54	7.81	2947	1381	16	8
		SP2-4	26 February 2024	25.88	7.76	3152	1495	18	9
		SP2-5	4 March 2024	26.89	7.94	3021	1415	15	8
		SP2-6	11 March 2024	27.65	8.14	3607	1690	20	10
		SP2-7	21 March 2024	28.05	8.15	3408	1601	19	10
		SP2-8	28 March 2024	22.85	7.16	2875	1334	17	9
		SP2-9	2 April 2024	22.75	7.11	2754	1286	16	8
		SP2-10	8 April 2024	23.57	7.35	3846	1746	21	11
		SP2-11	13 April 2024	25.92	7.72	2895	1378	16	8
Point 3	Ashlands Zone	SP3-1	10 February 2024	26.73	7.95	2984	1401	17	9
		SP3-2	15 February 2024	25.63	7.68	4135	1895	23	11
		SP3-3	20 February 2024	22.56	7.16	3067	1432	16	8
		SP3-4	26 February 2024	23.65	7.21	3728	1738	21	10
		SP3-5	4 March 2024	24.33	7.44	4973	2316	26	13
		SP3-6	11 March 2024	25.12	7.54	4512	2156	25	12
		SP3-7	21 March 2024	24.78	7.47	5238	2497	29	15
		SP3-8	28 March 2024	22.98	7.36	3152	1467	19	9
		SP3-9	2 April 2024	26.12	7.62	6723	3224	31	16
		SP3-10	8 April 2024	24.25	7.38	4289	2061	21	11
		SP3-11	13 April 2024	27.14	7.84	3275	1537	18	9

).

The pH of the samples ranged from 7.11 to 8.25, classifying them as neutral to slightly alkaline. These conditions are critical for arsenic speciation, favoring the predominance of As(V) at more alkaline values. The temperature ranged from 22.56 °C to 28.12 °C, being slightly higher at Point 2 (average of 26.02 °C). Although less influential in speciation, this parameter can affect adsorption processes in the treatment system.

Electrical conductivity (EC) was significantly higher at Point 3, averaging 4189 µS/cm, indicating a greater concentration of dissolved salts, possibly derived from natural mineralization and intensive agricultural activities in this area. This behavior is also reflected in the total dissolved solids (TDS) values, which averaged 1975 mg/L at Point 3, compared to 1806 mg/L and 1470 mg/L at Points 1 and 2, respectively. High salinity and mineralization can impact the effectiveness of coagulation and adsorption processes in water treatment.

Regarding total arsenic concentrations and its speciation, the samples revealed significant variability (

Table 3. Distribution of arsenic species and total concentration at sampling points.

Sampling Point	Zone	Sample Code	Sampling Date	Total As (mg/L)	Organic As			Inorganic As
					AB (mg/L)	DMA (mg/L)	MMA (mg/L)	As(III) (mg/L)	As(V) (mg/L)
Point 1	Bio Garden Los Palos Zone	SP1-1	10 February 2024	0.0094	0.0024	0.0013	0.0022	0.0013	0.0022
		SP1-2	15 February 2024	0.0111	0.0003	0.0040	0.0023	0.0027	0.0018
		SP1-3	20 February 2024	0.0110	0.0011	0.0003	0.0003	0.0003	0.0090
		SP1-4	26 February 2024	0.0085	0.0014	0.0017	0.0011	0.0024	0.0019
		SP1-5	4 March 2024	0.0099	0.0016	0.0018	0.0014	0.0030	0.0021
		SP1-6	11 March 2024	0.0124	0.0033	0.0019	0.0015	0.0031	0.0026
		SP1-7	21 March 2024	0.0105	0.0030	0.0017	0.0015	0.0024	0.0019
		SP1-8	28 March 2024	0.0098	0.0020	0.0017	0.0015	0.0027	0.0019
		SP1-9	2 April 2024	0.0071	0.0014	0.0012	0.0010	0.0021	0.0014
		SP1-10	8 April 2024	0.0102	0.0019	0.0016	0.0013	0.0032	0.0022
		SP1-11	13 April 2024	0.0095	0.0020	0.0017	0.0013	0.0026	0.0019
Point 2	Southern Border Zone	SP2-1	10 February 2024	0.0087	0.0018	0.0015	0.0013	0.0023	0.0018
		SP2-2	15 February 2024	0.0072	0.0014	0.0013	0.0011	0.0019	0.0015
		SP2-3	20 February 2024	0.0094	0.0019	0.0017	0.0014	0.0024	0.0020
		SP2-4	26 February 2024	0.0077	0.0016	0.0013	0.0011	0.0021	0.0016
		SP2-5	4 March 2024	0.0088	0.0017	0.0015	0.0013	0.0024	0.0019
		SP2-6	11 March 2024	0.0092	0.0019	0.0016	0.0014	0.0024	0.0019
		SP2-7	21 March 2024	0.0097	0.0019	0.0017	0.0014	0.0026	0.0021
		SP2-8	28 March 2024	0.0085	0.0016	0.0014	0.0012	0.0019	0.0024
		SP2-9	2 April 2024	0.0088	0.0018	0.0015	0.0013	0.0023	0.0019
		SP2-10	8 April 2024	0.0092	0.0018	0.0016	0.0014	0.0024	0.0020
		SP2-11	13 April 2024	0.0081	0.0016	0.0014	0.0012	0.0022	0.0017
Point 3	Ashlands Zone	SP3-1	10 February 2024	0.0086	0.0017	0.0015	0.0013	0.0023	0.0018
		SP3-2	15 February 2024	0.0105	0.0016	0.0019	0.0017	0.0030	0.0023
		SP3-3	20 February 2024	0.0134	0.0027	0.0023	0.0020	0.0035	0.0029
		SP3-4	26 February 2024	0.0183	0.0043	0.0051	0.0054	0.0022	0.0013
		SP3-5	4 March 2024	0.0250	0.0043	0.0007	0.0001	0.0116	0.0083
		SP3-6	11 March 2024	0.0101	0.0015	0.0018	0.0016	0.0030	0.0022
		SP3-7	21 March 2024	0.0271	0.0059	0.0047	0.0046	0.0010	0.0109
		SP3-8	28 March 2024	0.0147	0.0031	0.0022	0.0017	0.0045	0.0032
		SP3-9	2 April 2024	0.0417	0.0071	0.0081	0.0060	0.0118	0.0087
		SP3-10	8 April 2024	0.0125	0.0033	0.0020	0.0016	0.0032	0.0024
		SP3-11	13 April 2024	0.0105	0.0023	0.0017	0.0015	0.0030	0.0020

). Total arsenic ranged from 0.0071 mg/L to 0.0417 mg/L, occasionally exceeding the WHO recommended limit for drinking water (0.010 mg/L). As(III) was the dominant species in most of samples, representing an average of 25% of total arsenic. This finding is critical, as As(III) is more toxic and harder to remove than As(V).

The presence of As(III) highlights the need to include an efficient oxidation module in the treatment system to convert this species into As(V), which is easier to remove [22,52]. The high values of EC, TDS, and turbidity observed at Point 3 reflect greater mineralization and suspended particle loads, likely related to local geology and the intensive use of water resources for agriculture. This suggests that the system design should incorporate effective pretreatment stages to ensure the feasibility of treatment.

Parameters such as pH and temperature also influence system efficiency, particularly in processes like coagulation and adsorption. For instance, alkaline pH promotes the adsorption of As(V) onto adsorbent materials, while temperature can affect the kinetics of chemical reactions and separation processes.

The results clearly indicate that Sampling Point 3 (Ashlands Zone) exhibits the highest arsenic concentrations among the three locations studied (Figure 5), with no Table peaks reaching 0.0417 mg/L. This makes it the most critical area requiring intervention. Consequently, this site was selected for the implementation of the natural sedimentation pretreatment stage, as well as the treatment system and the photovoltaic energy solution, ensuring a comprehensive and targeted approach to mitigate the elevated arsenic levels and address the urgent water quality challenges in this zone.

3.2. System Performance Under Local Conditions

The efficiency and performance of the potable water treatment system were analyzed under local conditions, considering two scenarios: with and without pretreatment. The inclusion of a natural sedimentation pretreatment stage aimed to reduce critical influent water parameters, such as turbidity and total suspended solids (TSS), which directly impact the efficiency of the adsorption and coagulation processes.

Table 4. Water quality parameters and system performance with and without pretreatment under local conditions.

Sampling Date	Influent Condition	Temperature (°C)	pH	Conductivity (uS/cm)	Turbidity (NTU)	TSS (mg/L)
1 June 2024	Without Pretreatment	25.24	7.48	5832	15	29
1 June 2024	With Pretreatment	25.30	7.45	5800	5	9
15 June 2024	Without Pretreatment	23.11	7.18	3387	10	19
15 June 2024	With Pretreatment	23.15	7.2	3370	4	6
1 July 2024	Without Pretreatment	24.12	7.41	4672	12	24
1 July 2024	With Pretreatment	24.05	7.38	4650	6	10
15 July 2024	Without Pretreatment	23.89	7.22	4517	11	23
15 July 2024	With Pretreatment	23.95	7.19	4500	4	7
1 August 2024	Without Pretreatment	25.54	7.67	6218	14	28
1 August 2024	With Pretreatment	25.60	7.65	6200	5	9
15 August 2024	Without Pretreatment	23.87	7.35	4892	13	27
15 August 2024	With Pretreatment	23.85	7.37	4870	5	8

presents a detailed comparison of key water quality parameters observed during the study, highlighting the improvements achieved through pretreatment and their significance in optimizing the subsequent stages of the treatment system.

The water treatment system was evaluated under two main scenarios: with and without pretreatment. The results show that total arsenic removal efficiency reached up to 99.85% with pretreatment, compared to a maximum of 88.90% without this stage. This behavior can be attributed to reductions in critical parameters such as turbidity and total suspended solids (TSS), which enhance key processes like adsorption and coagulation. Pretreatment proved to be essential for improving the quality of incoming water and optimizing the subsequent stages of the system, ensuring compliance with international drinking water quality standards, such as the 0.01 mg/L limit for total arsenic established by the World Health Organization (WHO).

The removal efficiency of arsenic was calculated as follows:

$$\mathrm{Removal} \mathrm{Efficiency} (\%)=\left({\displaystyle \frac{\mathrm{C}\mathrm{i}\mathrm{n}\mathrm{i}\mathrm{t}\mathrm{i}\mathrm{a}\mathrm{l}-\mathrm{C}\mathrm{f}\mathrm{i}\mathrm{n}\mathrm{a}\mathrm{l}}{\mathrm{C}\mathrm{i}\mathrm{n}\mathrm{i}\mathrm{t}\mathrm{i}\mathrm{a}\mathrm{l}}}\right)\times 100$$

where Cinitial is the arsenic concentration before treatment (mg/L), and Cfinal is the arsenic concentration after treatment (mg/L).

Table 5. Arsenic and iron concentrations and removal efficiency under conditions with and without pretreatment.

Sampling Date	Influent Condition	As Cinitial (mg/L)	As Cfinal (mg/L)	Removal Efficiency (%)	Fe (mg/L)
1 June 2024	Without Pretreatment	0.0323	0.0047	85.50	1.92
1 June 2024	With Pretreatment	0.0274	0.0001	99.78	0.91
15 June 2024	Without Pretreatment	0.0157	0.0022	86.30	1.57
15 June 2024	With Pretreatment	0.0133	<0.0001	99.72	0.85
1 July 2024	Without Pretreatment	0.0241	0.0031	87.10	1.64
1 July 2024	With Pretreatment	0.0200	<0.0001	99.85	0.78
15 July 2024	Without Pretreatment	0.0212	0.0026	87.60	1.59
15 July 2024	With Pretreatment	0.0180	<0.0001	99.78	0.71
1 August 2024	Without Pretreatment	0.0344	0.0041	88.20	1.89
1 August 2024	With Pretreatment	0.0293	<0.0001	99.83	0.97
15 August 2024	Without Pretreatment	0.0302	0.0034	88.90	1.68
15 August 2024	With Pretreatment	0.0257	<0.0001	99.85	0.87

summarizes the obtained results, highlighting the significant differences between the scenarios with and without pretreatment.

The data presented highlight the variations in arsenic removal efficiency under different influent conditions. For further illustration of the relationship between initial arsenic concentration and removal efficiency, Figure 6 provides a visual representation of the correlation, emphasizing the trend observed across all sampling points.

The graph illustrates the correlation between initial arsenic (As) concentration and removal efficiency in the treatment system. The points represent the experimental data obtained during the study, while the trend line highlights a negative relationship between the two variables. This behavior suggests that as the initial arsenic concentration increases, the system’s efficiency tends to decrease slightly, which could be associated with a higher demand for adsorbent or limitations in treatment processes at higher concentrations. These results underscore the importance of adjusting operational conditions to maintain high removal efficiency, especially in scenarios with elevated As concentrations.

The treatment system was implemented at Sampling Point 3 (Ashlands Zone), selected because it exhibited the highest arsenic concentrations among all sampling locations. This site also presented significantly higher levels of turbidity, total suspended solids (TSS), electrical conductivity, and pH, making it an ideal environment to assess system efficiency under extreme contamination conditions.

The data obtained during system operation indicate that despite variations in influent arsenic concentrations, removal efficiency remained high and stable. Without pretreatment, removal efficiency ranged between 85.50% and 88.90%, whereas with natural sedimentation pretreatment, efficiency increased to values between 99.72% and 99.85%. This demonstrates that the system not only maintained consistent performance but also that the pretreatment stage optimized the removal process by reducing the initial contaminant load before the main treatment phase.

Data analysis reveals that the system maintained stable performance across different arsenic levels, with no reduction in removal efficiency at higher influent arsenic concentrations. Even in samples with the highest arsenic levels (up to 0.0344 mg/L without pretreatment) and pH variations between 7.16 and 7.95, system efficiency remained within the expected range. This behavior suggests that pH did not negatively impact arsenic removal, likely due to the stability of the adsorbent material used in the system. However, it is important to note that the lower removal efficiencies observed in Sampling Point 3 may not be solely attributed to arsenic concentration but could also result from higher levels of dissolved solids and competing ions, such as phosphates and silicates, which can interfere with adsorption processes.

Therefore, implementing the system at Sampling Point 3 allowed for a comprehensive evaluation of its effectiveness under high contaminant loads, demonstrating consistently high and stable removal efficiency over time. The combination of sedimentation pretreatment and the adsorption-based system resulted in a robust and adaptable process, capable of handling various arsenic concentrations and pH fluctuations in the influent water.

The high arsenic removal efficiency (99.72–99.85%) reported in this study was verified through ICP-MS and HPLC analyses, ensuring precise quantification of As(III) and As(V) concentrations before and after treatment. To evaluate the stability and consistency of the process over time, measurements were conducted at different operational periods, yielding highly reproducible values across trials. This consistency indicates that the observed efficiency was not due to isolated variations but rather to the robustness of the treatment process.

Although the results demonstrate highly efficient arsenic removal, the system’s performance may be influenced by variations in water quality. Factors such as initial arsenic concentration, pH, dissolved organic carbon (DOC) content, and the presence of other contaminants can impact removal efficiency. The reported values correspond to specific operational conditions optimized for As(III) oxidation and subsequent adsorption.

Previous studies have documented arsenic removal efficiencies exceeding 95% in integrated pretreatment, oxidation, and adsorption systems, aligning with the results obtained in this research [23,53,54,55]. Investigations on iron-oxide-modified adsorbents have demonstrated comparable efficiencies under optimal conditions [56]. However, given the variability in groundwater composition across different regions, further studies are recommended in diverse hydrochemical environments to assess the system’s applicability under varying water quality conditions.

The observed differences in arsenic removal efficiency between the two scenarios suggest that pretreatment performs a key role in optimizing the system (

Table 6. Summary One-Way Analysis of Variance.

Groups	Count	Sum	Mean	Variance
Removal Efficiency (%) Without Pretreatment	6	523.60	87.27	1.55
Removal Efficiency (%) With Pretreatment	6	598.81	99.80	0.0026

). To statistically confirm this improvement, a one-way analysis of variance (ANOVA) was performed (

Table 7. Analysis of variance (ANOVA).

Source of Variation	Sum of Squares	Degrees of Freedom	Mean Square	F	Probability	Critical Value for F
Between Groups	471.38	1	471.38	608.51	p < 0.001	4.96
Within Groups	7.75	10	0.77	-	-	-
Total	479.13	11	-	-	-	-

). The results indicated a highly significant difference between treatments (F = 608.51, p < 0.001), confirming that the removal efficiency with pretreatment (99.80% ± 0.0026, n = 6) is statistically superior to the efficiency without pretreatment (87.27% ± 1.55, n = 6). These findings confirm that the observed improvement in removal efficiency is not due to random variations but is directly related to the application of pretreatment. This result reinforces the validity of the method used and its contribution to optimizing the arsenic water treatment process.

Given that F = 608.51 far exceeds the critical value (F_critical = 4.96), and the p-value is significantly lower than 0.05, the statistical analysis confirms that pretreatment significantly enhances arsenic removal efficiency.

This result underscores the reliability and robustness of the approach, demonstrating that the application of a pretreatment stage effectively optimizes the adsorption and removal processes.

Beyond overall removal efficiency, it is also essential to consider how sedimentation influences the presence of competing ions that may interfere with arsenic adsorption.

The competition between phosphates, silicates, and arsenic in adsorption systems has been studied. It has been demonstrated that both phosphates and silicates compete with arsenic for adsorption sites on iron oxides, thereby reducing arsenic capture efficiency [57]. This finding is crucial, as it demonstrates how the saturation of adsorption sites due to the presence of competing ions can reduce the efficiency of contaminated water treatment.

Additionally, experiments have shown that As(III) adsorption in natural sediments is negatively influenced by competition with dissolved phosphates, implying that sedimentation in contaminated environments may exacerbate competition among these ions [58]. These results suggest that local geology and water chemistry not only affect arsenic mobility but also its retention and removal.

Moreover, the competitive adsorption of phosphates and silicates on the surface of granular ferric hydroxide shows that the presence of these ions significantly competes with arsenic, altering adsorption efficiency [59]. The polymerization of silicate in solution and its rapid reduction of arsenic adsorption capacity on iron surfaces suggest that sedimentation could block or change the surface chemistry of adsorption.

Furthermore, it has been reported that phosphate and silicate adsorption alters the dissolution kinetics of iron oxides, implying that these competing anions not only interfere with arsenic adsorption but also alter the chemistry of the adsorbents, thereby affecting their structure and effectiveness [60]. This effect is particularly relevant in systems where iron oxide sedimentation occurs, as aggregation can limit access to available adsorption sites.

Other studies highlight how interfering anions such as phosphates and bicarbonates affect arsenic removal, observing that the presence of these ions can result in an inverse relationship between the amount of arsenic adsorbed and phosphate concentration [61]. This suggests that in sedimentary environments, where phosphates may concentrate, arsenic removal efficiency could be compromised.

Additionally, it has been noted that dissolved organic matter and competing anions can influence the mobility of arsenic adsorbed onto iron oxide surfaces, reinforcing the idea that aqueous chemistry, influenced by mineral sedimentation, can affect the mobilization and retention of arsenic [62].

Therefore, sedimentation can significantly impact the concentration and behavior of competing ions (phosphates and silicates), which, in turn, may interfere with the efficiency of arsenic adsorption in contaminated waters. Understanding these mechanisms is essential for developing effective arsenic removal strategies and designing more efficient water treatment systems.

The coagulation process plays a crucial role in arsenic removal, but it also generates waste that must be properly managed to prevent environmental risks. Ferric sulfate (Fe₂(SO₄)₃) was used as a coagulant in this study to facilitate arsenic removal through the formation of settleable flocs. The Fe₂(SO₄)₃ dose applied in the coagulation process depended on the characteristics of the influent water and was set within the following ranges: for conditions with pretreatment, characterized by lower turbidity and lower total suspended solids (TSS), the dosage ranged from 10 to 14 mg/L, while for conditions without pretreatment, where turbidity and TSS levels were higher, the dosage was between 15 and 18 mg/L. The waste generated during the coagulation process consisted mainly of total iron in sludge, with 30–50% of the added Fe precipitating and incorporating into the sludge as iron oxides and sulfates, depending on the applied dosage and the influent water conditions. Additionally, 70–85% of As(V) was adsorbed onto the flocs formed by Fe₂(SO₄)₃. Given the arsenic concentrations in the influent water (ranging from 0.0133 to 0.0344 mg/L), the sludge contained between 0.009 and 0.029 mg of As per liter of treated water. These results indicate that the generated sludge has a significant load of Fe and As, highlighting the importance of proper waste management to prevent the re-dissolution of contaminants and potential environmental impacts.

Local climatic conditions, such as solar radiation and ambient temperature, significantly influenced the system’s performance. During warmer months, solar radiation peaked at 1080 W/m², maximizing the photovoltaic system’s energy generation capacity and enabling the treatment system to achieve maximum efficiency (99.85%). Ambient temperatures, which reached 29.5 °C in August, enhanced chemical reactions in the coagulation and adsorption stages. These conditions highlight the feasibility of leveraging climatic resources in arid regions like Tacna, where the high availability of solar energy constitutes a strategic advantage.

Operational comparisons between the two scenarios revealed significant differences (

Table 8. Comparison of Backwash Energy Consumption: With and Without Pretreatment.

Average Parameter	Energy Consumption of Backwash (kWh)	Frequency (per Month)	Number of Months	Total Energy Consumption in the Backwash Process (kWh)
Without Pretreatment	2.54	6	3	45.72
With Pretreatment	2.54	4	3	30.48

). Without pretreatment, the system required an average cleaning frequency of six times per month, while, with pretreatment, this frequency was reduced to four, improving operational time and lowering maintenance costs. Additionally, total energy consumption during the backwashing process was significantly lower with pretreatment, amounting to 30.48 kWh compared to 45.72 kWh without this stage, representing a 33% reduction in energy consumption. This energy savings is attributed to the reduction in suspended solids and other impurities, decreasing the load on filters and other key system components.

Pretreatment not only enhances arsenic removal efficiency but also increases the system’s operational sustainability by reducing energy consumption and optimizing available resources. These improvements, combined with leveraging local climatic conditions, underscore the importance of designing treatment systems tailored to the specific characteristics of each region.

The 99.85% removal efficiency achieved in this study aligns with the values reported by Mohan and Pittman (2007) [21], who highlighted that pre-oxidation combined with adsorption significantly improves As(V) removal in potable water treatment systems. This finding confirms the effectiveness of integrating these technologies in similar contexts, particularly in regions with groundwater characterized by high salinity and solid content, such as La Yarada Los Palos district.

3.3. Energy Efficiency of the Photovoltaic System

The photovoltaic system installed in the district of La Yarada Los Palos was evaluated to determine its energy efficiency under local conditions of high solar radiation and warm temperatures. These conditions, characteristic of an arid region, provide an optimal scenario for the system’s operation and highlight its viability in meeting the energy needs of water treatment systems in vulnerable rural areas. The average energy generation reached values of up to 21.58 kWh/day during months of higher solar radiation, such as August, with a daily average of 1080 W/m² (Figure 7). In contrast, during months with lower solar incidence, radiation decreased to 991 W/m², reducing average energy generation to 19.38 kWh/day, representing an approximate reduction of 10.19%. This seasonal variability underscores the importance of properly sizing photovoltaic systems to ensure a stable supply throughout the year, especially in scenarios with high treatment demand.

The analysis of energy consumption revealed significant differences between conditions with and without water pretreatment. The lower system cleaning frequency under pretreatment conditions, which decreased from six to four times per month, optimized operations and reduced associated costs, including maintenance and component replacement. The data shows that higher initial turbidity values led to a slight decrease in arsenic removal efficiency in stages without pretreatment, achieving an average of 87.27% compared to 99.85% with pretreatment. This result highlights the importance of pretreatment in improving influent water quality and maximizing system efficiency.

It should be noted that both treatment lines, with and without pretreatment, operate in parallel and share a single energy generation source. During months with lower solar radiation, such as June and July, the combined consumption of both lines utilized up to 72.91% of the available energy generation, indicating a tight energy balance. In months with higher solar radiation, such as August, the system achieved an energy surplus of up to 41.51% (

Table 9. Solar radiation, energy generation, consumption, and energy surplus.

Date	Solar Radiation (W/m2)	Total Energy Consumption (kWh/Day)	Energy Generation (kWh/Day)	Energy Surplus (kWh/Day)	Energy Surplus (%)
1 June 2024	1001	15.15	19.98	4.83	31.89%
15 June 2024	1034	15.19	20.64	5.45	35.88%
1 July 2024	991	15.25	19.38	4.13	27.09%
15 July 2024	1012	15.32	19.79	4.47	29.18%
1 August 2024	1049	15.41	20.49	5.08	32.95%
15 August 2024	1080	15.25	21.58	6.33	41.51%

), which could be utilized for storage or to meet additional demands.

The analysis of total energy consumption and the daily surplus of the photovoltaic system during the study period highlights its capacity to ensure the continuous operation of water treatment, with an average energy consumption of 15.26 kWh, an average generation of 20.31 kWh, and an average surplus of 33.08%. (Figure 8)

The recorded energy surplus not only guarantees a consistent supply but also offers the possibility of implementing energy storage systems, such as batteries, to maximize autonomy under low solar irradiation conditions. Additionally, this surplus could be utilized for complementary applications, such as powering other critical plant systems, thereby improving the overall system sustainability and efficiency.

The photovoltaic system installed in La Yarada Los Palos operated in an environment with stable climatic conditions favorable for solar energy generation. The reported 33.08% average energy surplus in photovoltaic generation is supported by solar irradiance data recorded at the local monitoring station throughout the study period. The region is characterized by an arid and stable climate, with predominantly clear skies year-round. The solar irradiance values in the study area, from January to December 2024, ranged between 991 and 1193 W/m², ensuring a continuous and predictable energy supply for system operation.

The system’s design incorporated a safety margin in photovoltaic generation, ensuring energy availability even during minor irradiance variations, thereby compensating for any temporary reductions in energy production. Throughout the operational period, the measured energy generation consistently exceeded the water treatment system’s energy demand, confirming the reliability of the reported 33.08% average surplus.

The seasonal variability analysis indicates that the difference between the lowest and highest irradiance months is approximately 16.9%, suggesting no extreme fluctuations that could significantly impact the photovoltaic system’s performance. Additionally, the Tacna Solar 20T Plant [63], a 20 MW photovoltaic installation located in the region, operates under similar conditions and generates approximately 45 GWh annually, further validating the stability and efficiency of solar energy utilization in this area.

Since the study region exhibits solar irradiance conditions comparable to other high-radiation desert areas, such as the Atacama Desert, the photovoltaic system’s stability is supported by a highly predictable renewable energy source. Therefore, the observed energy surplus margin is consistent with the area’s climatic reality and the system’s design strategy to ensure energy autonomy.

From an environmental perspective, the photovoltaic system proved to be an effective solution for reducing carbon footprint associated with water treatment. Based on an average emission factor of 0.4 kg CO₂/kWh, it was estimated that the system avoided the emission of approximately 0.049 t of CO₂ during the evaluation period. This result underscores the system’s contribution not only to operational sustainability but also to climate change mitigation, positioning it as a strategic alternative in the context of clean technologies.

The environmental impact of the photovoltaic energy generation system was assessed using the avoided emissions formula below, applied to calculate the monthly reduction in CO₂ emissions for each evaluation period:

$$\mathrm{Avoided} \mathrm{Emissions} \left({\mathrm{tCO}}_2\right)={\displaystyle \frac{\mathrm{T}\mathrm{o}\mathrm{t}\mathrm{a}\mathrm{l} \mathrm{G}\mathrm{e}\mathrm{n}\mathrm{e}\mathrm{r}\mathrm{a}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n} \left(\mathrm{k}\mathrm{W}\mathrm{h}\right)\times \mathrm{E}\mathrm{m}\mathrm{i}\mathrm{s}\mathrm{s}\mathrm{i}\mathrm{o}\mathrm{n} \mathrm{F}\mathrm{a}\mathrm{c}\mathrm{t}\mathrm{o}\mathrm{r} (\mathrm{k}\mathrm{g}{\mathrm{CO}}_2/\mathrm{k}\mathrm{W}\mathrm{h})}{1000}}$$

where Total Generation (kWh) represents the total energy generated by the photovoltaic system during each month, Emission Factor (kgCO₂/kWh) refers to the average CO₂ emissions from non-renewable energy sources (e.g., 0.4 kgCO₂/kWh, according to the IEA), and 1000 is the conversion factor from kilograms (kg) to metric tons (t).

The results obtained are summarized in

Table 10. Detailed environmental impact of energy generation and monthly emission reductions.

Period	Total Monthly Generation (kWh)	Monthly Avoided Emissions (tCO2)	Global Standard Emissions (tCO2)	Reduction Percentage (%)
June 24	40.62	0.016	0.03656	44.34%
July 24	39.17	0.016	0.03525	44.53%
August 24	42.07	0.017	0.03786	44.37%

, which shows the monthly energy generation, avoided emissions, global standard emissions, and reduction percentages achieved:

The values for global standard emissions (tCO₂) correspond to estimated emissions of a similar treatment system powered by non-renewable energy sources during the same period. This calculation is based on the international standard established by the International Energy Agency (IEA) [51], which estimates an average emission factor of 0.4 kgCO₂/kWh for electricity generated from fossil fuels. This average value considers various non-renewable sources, such as coal, natural gas, and oil, which dominate the global energy matrix. Using this standard allows for direct comparisons between systems reliant on fossil fuels and those operating with renewable energy sources.

With an average monthly generation of 40.62 kWh, the system prevented the emission of 0.049 t of CO₂ (49 kg) over three months, resulting in an annual projection of 0.196 t of CO₂ (196 kg) avoided. This environmental benefit underscores the system’s contribution to climate change mitigation and positions it as a strategic solution within the framework of clean and sustainable technologies.

The reduction percentage highlights the positive impact of the photovoltaic system, not only in terms of avoided emissions but also in its contribution to climate change mitigation and the transition to clean technologies. This approach underscores the importance of adopting sustainable systems in vulnerable regions, emphasizing that the evaluated photovoltaic system not only ensures autonomous energy supply but also significantly reduces the carbon footprint of rural communities. The direct comparison with global standards showcases the effectiveness of this system in minimizing greenhouse gas emissions in scenarios of high water vulnerability.

Additionally, warm temperatures, which reached a peak of 29.5 °C in August, enhanced chemical reactions during treatment stages, contributing to a slight improvement in arsenic removal efficiency and a reduction in energy consumption. These local conditions highlight the importance of considering climatic factors in the design of renewable energy-powered systems.

The photovoltaic system installed in La Yarada Los Palos proved to be a technically and environmentally viable solution for powering water treatment systems. Its ability to adapt to local conditions, maximize energy efficiency, and reduce carbon footprint positions it as a replicable model for regions with similar characteristics. These results underscore the significance of integrating renewable technologies into development projects in vulnerable rural areas.

4. Discussion

4.1. Evaluation of Treatment System Efficiency Under Different Conditions

Water treatment systems that combine oxidation, coagulation, and adsorption have been widely used to address arsenic contamination in rural regions. Technologies based on adsorbents such as granular ferric oxides or activated alumina have demonstrated As(V) removal efficiencies exceeding 95%. However, these technologies face limitations when treating As(III) due to its lower chemical reactivity [21,64]. In contrast, systems that include a preliminary oxidation stage, such as using sodium hypochlorite (NaClO), can achieve removal efficiencies of 98–99% for both As(III) and As(V), aligning with the results obtained in this study.

The developed system stands out not only for its high efficiency in arsenic removal but also for its energy sustainability, achieved through the use of photovoltaic energy. Compared to conventional technologies that rely on non-renewable energy sources, this system significantly reduces carbon emissions, avoiding approximately 196 kg of CO₂ annually. Furthermore, its modular design allows for more efficient adaptation to local climatic conditions, such as the high solar radiation in arid regions. These features position the system as a superior solution in terms of both environmental and operational sustainability.

The integration of a natural sedimentation pretreatment significantly reduced turbidity and total suspended solids (TSS), improving the quality of influent water and optimizing subsequent treatment stages. With pretreatment, the removal efficiency reached an average of 99.80%, compared to 87.27% observed without this stage. This finding reinforces the importance of initial stages in optimizing complex treatment systems and highlights their crucial role in enhancing overall efficiency.

The system with pretreatment decreased the frequency of monthly maintenance, from six cleanings to four. The average energy consumption for system cleaning was significantly lower with pretreatment, reaching 30.48 kWh compared to 45.72 kWh without this stage. These results emphasize the importance of incorporating pretreatment strategies as an effective measure to reduce operational costs and improve the sustainability of treatment systems in rural settings.

The system evaluated in this study outperformed conventional technologies due to the incorporation of pretreatment and the use of photovoltaic energy as its energy source. Recent studies have shown that drinking water treatment plants can optimize their energy consumption through the implementation of control and monitoring systems, as well as the adoption of more efficient technologies [39,47,65]. Furthermore, the integration of energy generation through photovoltaic systems specifically designed for this purpose positions the presented technology as a scalable and sustainable solution in vulnerable regions.

Overall, the integrated system not only demonstrated its effectiveness in arsenic removal but also confirmed its energy and operational feasibility in remote regions. The results obtained underscore the positive impact of adopting advanced and locally adapted technologies, positioning this system as a replicable model to address water quality challenges in rural contexts.

Arsenic speciation was performed using a combined ICP-MS and HPLC system, which enabled highly precise identification and quantification of As(III) and As(V) chemical species concentrations. This advanced method ensures accurate and reliable characterization of changes in arsenic’s chemical composition during the treatment process.

The results (

Table 11. Total arsenic and inorganic species concentrations (As(III) and As(V)) after treatment with and without pretreatment.

Sampling Date	Influent Condition	Total Arsenic Concentration Before Treatment (mg/L)	Total Arsenic Concentration After Treatment (mg/L)	Arsenic Species After Treatment		Arsenic Removal Efficiency (%)
				As(III) (mg/L)	As(V) (mg/L)
1 June 2024	Without Pretreatment	0.0323	0.0047	<0.0001	0.0010	85.50
1 June 2024	With Pretreatment	0.0274	0.0001	<0.0001	<0.0001	99.78
15 June 2024	Without Pretreatment	0.0157	0.0022	<0.0001	0.0004	86.30
15 June 2024	With Pretreatment	0.0133	<0.0001	<0.0001	<0.0001	99.72
1 July 2024	Without Pretreatment	0.0241	0.0031	<0.0001	0.0006	87.10
1 July 2024	With Pretreatment	0.0200	<0.0001	<0.0001	<0.0001	99.85
15 July 2024	Without Pretreatment	0.0212	0.0026	<0.0001	0.0005	87.60
15 July 2024	With Pretreatment	0.0180	<0.0001	<0.0001	<0.0001	99.78
1 August 2024	Without Pretreatment	0.0344	0.0041	<0.0001	0.0008	88.20
1 August 2024	With Pretreatment	0.0293	<0.0001	<0.0001	<0.0001	99.83
15 August 2024	Without Pretreatment	0.0302	0.0034	<0.0001	0.0006	88.90
15 August 2024	With Pretreatment	0.0257	<0.0001	<0.0001	<0.0001	99.85

) indicate that pretreatment significantly enhances arsenic removal efficiency. Without pretreatment, the efficiency ranged from 85.50% to 88.90%, whereas with pretreatment, it consistently exceeded 99.70% across all analyzed dates. Furthermore, the concentrations of As(III) and As(V) after treatment with pretreatment were consistently below the detection limit (<0.0001 mg/L).

On the other hand, data on organic arsenic species are not included, as their presence in the treated samples was negligible (<0.0001 mg/L) and does not pose a potential risk to water quality. This highlights the system’s high effectiveness in removing total arsenic and inorganic species, which are the most toxic.

This behavior underscores the importance of pretreatment in optimizing the process not only to reduce total arsenic but also to minimize the most toxic inorganic species. This is particularly relevant to ensuring potable water quality in highly water-vulnerable areas such as La Yarada Los Palos.

The integration of locally adapted solutions was key to the system’s success. In La Yarada Los Palos, high temperatures and average solar radiation, which reached up to 1080 W/m², were efficiently harnessed to power a standalone photovoltaic system. This modular and scalable design generated an average of 20.31 kWh/day, sufficient to operate two parallel treatment lines, ensuring energy sustainability in a region with abundant solar resources.

The sedimentation pretreatment played a fundamental role in improving the quality of the influent water, reducing turbidity by an average of 61.02% and total suspended solids by an average of 67.25%. This initial stage not only optimized conditions for subsequent processes but also reduced the system’s cleaning frequency by 33%, from six to four monthly cleanings, as detailed in Section 3.2 and summarized in Table 6. This operational improvement not only lowered maintenance costs but also increased the system’s uptime, directly benefiting the communities served.

During the months of highest solar radiation, such as August, the system’s energy generation reached 21.58 kWh/day, exceeding operational demand by 41.51%. This energy surplus could be utilized for storage or operational backups, reinforcing the system’s viability in arid areas with high solar radiation availability.

The modularity and climate-adapted design make the system a replicable model for other arid or semi-arid regions facing similar arsenic contamination challenges. These adaptations not only enhance operational efficiency but also broaden the potential for integrating such technologies into broader sustainable development initiatives.

4.2. Statistical Analysis of Results on Arsenic Removal Efficiency and Energy Consumption

To ensure the scientific validity of the observed improvements in arsenic removal efficiency and energy consumption between the “with pretreatment” and “without pretreatment” scenarios, a one-way analysis of variance (ANOVA) was conducted. This statistical method determines whether the observed differences are statistically significant, providing robust evidence to support the conclusions.

The analysis revealed a statistically significant difference in arsenic removal efficiency (F = 486.32, p < 0.001). The average removal efficiency was significantly higher for conditions with pretreatment (99.80%) compared to those without pretreatment (87.27%). Similarly, significant differences were identified in total energy consumption in the backwash process (F = 15.27, p < 0.001). Conditions with pretreatment exhibited lower average consumption (30.48 kWh) compared to conditions without pretreatment (45.72 kWh).

The statistical significance of these results confirms that the observed improvements are not attributable to chance but reflect consistent effects of pretreatment (

Table 12. Comparative statistical analysis of removal efficiency and energy consumption.

Parameter	F	p-Value	Average with Pretreatment	Average without Pretreatment
Removal Efficiency (%)	486.32	<0.001	99.80	87.27
Total Energy Consumption in the Backwash Process (kWh)	15.27	<0.001	30.48	45.72

). The inclusion of a natural sedimentation stage significantly enhances system performance by reducing the load of suspended solids, optimizing subsequent treatment, and lowering energy consumption during the backwashing process.

The findings highlight the importance of incorporating a pretreatment stage in systems designed for arsenic removal. The statistically validated improvements in efficiency and energy sustainability enhance the system’s replicability in similar contexts, ensuring reliable performance under different environmental and operational conditions. Furthermore, the statistical validation provides quantitative evidence that reinforces the study’s credibility, supporting the adoption of this innovative approach in regions facing critical water quality challenges.

4.3. Environmental and Climatic Factors

Solar radiation and high temperatures are critical determinants for the efficiency of photovoltaic systems and the chemical processes involved in arsenic removal. During this study, maximum average solar radiation levels of 1065 W/m² were observed in August, enabling an average daily energy generation of 21.04 kWh. This energy supply was sufficient not only to meet the demands of the water treatment system but also to generate energy surpluses, strengthening the system’s operational sustainability. Average temperatures during the analysis period ranged from 27.3 °C to 29.5 °C, promoting chemical reactions such as the oxidation of As(III) to As(V) and adsorption on the materials used.

To further analyze the influence of climatic conditions on system performance,

Table 13. Monthly Solar Radiation and Temperature Data in the Study Area.

Date	Solar Radiation (W/m2)	Temperature (°C)
1 January 2024	1193	26.8
15 January 2024	1189	26.5
1 February 2024	1181	26.0
15 February 2024	1172	25.5
1 March 2024	1165	24.8
15 March 2024	1145	24.0
1 April 2024	1117	22.5
15 April 2024	1103	21.8
1 May 2024	1078	17.5
15 May 2024	1045	17.2
1 June 2024	1001	15.3
15 June 2024	1034	16.5
1 July 2024	991	12.5
15 July 2024	1012	13.2
1 August 2024	1049	14.8
15 August 2024	1054	15.2
1 September 2024	1066	16.0
15 September 2024	1070	16.8
1 October 2024	1079	18.5
15 October 2024	1083	19.0
1 November 2024	1173	23.5
15 November 2024	1181	24.8
1 December 2024	1187	25.5
15 December 2024	1191	26.2

presents monthly variations in solar radiation and ambient temperature recorded during the study period. The data indicate that solar radiation remains consistently high throughout the year, ranging from 991 W/m² in July to 1193 W/m² in January, ensuring a stable and predictable energy supply for system operation.

While seasonal variations in solar radiation and temperature are relatively moderate, they can influence the kinetics of oxidation and adsorption reactions. Warmer months, such as January (26.8 °C) and February (26.0 °C), favor more efficient chemical reactions, particularly oxidation and coagulation. In contrast, cooler months such as July (12.5 °C) and August (14.8 °C) exhibited lower reaction rates, though system efficiency remained within expected parameters.

Previous studies have confirmed that warm climates enhance these processes, increasing arsenic removal efficiency, although they also highlight the challenges associated with seasonal variability [66]. In months like July, with lower solar radiation levels (991 W/m²), a slight reduction in energy generation was observed, underscoring the need for energy storage strategies to ensure continuous operation (

Table 14. Relationship between climatic variables and system energy generation.

Date	Ambient Temperature (°C)	Solar Radiation (W/m2)	Energy Generation (kWh/day)
1 June 2024	28.00	1001	19.98
15 June 2024	28.50	1034	20.64
1 July 2024	27.30	991	19.38
15 July 2024	27.50	1012	19.79
1 August 2024	29.10	1049	20.49
15 August 2024	29.50	1080	21.58

).

The integration of photovoltaic energy not only ensures the system’s operational sustainability but also protects communities from risks associated with fluctuating arsenic concentrations during periods of lower solar radiation. This reinforces the system’s capacity to maintain arsenic levels within WHO standards, even under adverse climatic conditions, thereby mitigating public health issues such as cardiovascular diseases and various types of cancer associated with prolonged arsenic exposure. To address this variability, a battery bank was implemented to ensure a stable energy supply during periods of low radiation. This approach proved crucial for maintaining system efficiency under adverse climatic conditions, reaffirming the importance of integrating storage strategies in designs intended for regions with significant seasonal fluctuations [47,67].

In terms of replicability, the treatment model evaluated in La Yarada Los Palos shows great potential for application in other arid regions with abundant solar resources. This strategic resource positions photovoltaic systems as an efficient and sustainable solution for powering water treatment modules. According to the International Renewable Energy Agency (IRENA), the installation costs of photovoltaic systems have significantly decreased over the last decade, facilitating their adoption in rural communities with limited resources [66].

However, replicating these systems requires addressing specific challenges. Hydrogeological conditions, such as the chemical and mineralogical composition of groundwater sources, can significantly influence the efficiency of arsenic removal processes. This necessitates particular adaptations in pretreatment stages and the selection of adsorbent materials to optimize performance in different locations. Additionally, while solar energy reduces energy costs, factors such as the acquisition and management of coagulants and oxidants may vary depending on local accessibility and availability, impacting operational costs. Moreover, implementing similar systems requires technical training programs to ensure proper handling, monitoring, and maintenance of the equipment, guaranteeing efficient and sustainable long-term operation.

This study demonstrates that integrating photovoltaic systems in arid regions can facilitate access to drinking water, providing a replicable model for other vulnerable communities with similar climatic and socioeconomic characteristics.

4.4. Operational Feasibility and Long-Term Sustainability

The operational feasibility of the system has been evaluated by considering key aspects of maintenance, sustainability, and replicability in environments with similar conditions. System maintenance requires periodic monitoring of the pretreatment, oxidation, and adsorption modules [53,68]. Monthly inspections were conducted to assess the saturation of the adsorbent material and the efficiency of the sedimentation process. During the study and operational period, the process efficiency remained stable without the need for regeneration or replacement of the adsorbent material, indicating high system stability under the evaluated conditions. Based on the contaminant load of the influent water and the operational conditions reported in this study, the water treatment system can maintain its removal efficiency for up to 12 months before requiring regeneration or replacement. Additionally, to ensure continuous treatment and long-term system efficiency, the replacement of certain filter media should be considered, such as natural granular zeolite and manganese-oxide-coated sand every 12 to 24 months, granular activated carbon every 12 months, and titanium oxyhydroxide used for arsenic adsorption every 12 months.

The inclusion of a pretreatment stage via natural sedimentation significantly reduced the suspended solids load, thereby decreasing the need for frequent backwashing in the adsorption filters and improving system stability. To optimize system performance, weekly preventive maintenance through backwashing is recommended, which extends the lifespan of the filter material and prevents clogging of the adsorption process.

Regarding sustainability, the district of La Yarada Los Palos lacks access to the electrical grid in most of its territory, and specifically in the study area, there is no conventional power infrastructure. In this context, photovoltaic energy is not only the most viable alternative but also the only feasible option for powering the water treatment system. The district is characterized by an arid, warm, and stable climate throughout the year, with predominantly clear skies and high solar radiation availability in all seasons. Data recorded at the local monitoring station indicate that solar irradiance in the area ranges between 991 and 1193 W/m² throughout the year, ensuring a continuous and stable energy supply for system operation. Its implementation not only provides energy autonomy but also reduces operating costs and enhances long-term sustainability [56].

The feasibility of implementation in remote regions depends on the local hydrogeological conditions of each area. However, the modular design of the system allows its adaptation to various water sources with variations in arsenic concentration, turbidity, and other physicochemical characteristics. In environments with limited access to the electrical grid, such as the study area in this research, photovoltaic energy represents a self-sustaining and replicable alternative, particularly in arid and semi-arid regions with high solar radiation. These conditions are not only present in Latin America but also in remote regions of Africa, the Middle East, Asia, and Oceania, where arsenic contamination in groundwater is a significant issue and the availability of renewable energy can enhance the sustainability of water treatment [69,70,71].

Therefore, the findings obtained in La Yarada Los Palos can be applied to other regions worldwide with similar hydrogeological and climatic characteristics, particularly those where arsenic contamination in groundwater poses a critical challenge. The combination of natural sedimentation pretreatment, sodium hypochlorite oxidation, and adsorption has proven to be effective in arsenic removal, suggesting that this approach could be implemented in different contexts with comparable conditions.

While this study provides key information for developing arsenic removal strategies in areas with high water vulnerability, it is essential to assess its performance in other hydrogeological and climatic settings. In this regard, the modular design of the system facilitates its adaptation to various water sources with variations in arsenic concentration and turbidity, expanding its potential application in remote regions with limited access to the electrical grid.

Furthermore, the integration of pretreatment via natural sedimentation has been shown to optimize suspended solids removal, which not only reduces the consumption of chemical reagents but also extends the system’s lifespan [55].

To assess the replicability and long-term performance of the system, it is recommended to establish a periodic monitoring program that measures arsenic removal, energy consumption, and adsorbent material stability. Previous studies have demonstrated that implementing these protocols in similar systems has enabled system longevity to exceed five years with proper maintenance [72]. While this study has demonstrated system efficiency under controlled conditions, long-term degradation tests have not been conducted. Therefore, future research could focus on evaluating the long-term degradation of the adsorbent material and optimizing the process using real-time monitoring sensors, facilitating the system’s adaptation to various hydrochemical conditions.

4.5. Toxicological and Environmental Implications

The conversion of As(III) to As(V) during the oxidation stage is essential for reducing the toxicity of treated water. As(III) is notably more toxic, mobile, and challenging to remove than As(V), due to its low affinity for adsorbent materials and its greater ability to penetrate human cells [73,74]. The use of sodium hypochlorite (NaClO) as an oxidizing agent proved highly effective, achieving conversion rates exceeding 90% under optimal conditions, as reported by similar studies [22].

Oxidation transforms As(III) into As(V), which can be readily adsorbed onto materials such as granular ferric oxide or activated alumina. This process significantly improves the efficiency of the treatment system and ensures compliance with international drinking water quality standards, including the World Health Organization (WHO) limit of 0.01 mg/L [1]. By effectively reducing arsenic concentrations, the system minimizes community exposure to this contaminant, mitigating severe public health risks such as cardiovascular diseases and various types of cancer [75,76].

Consistent compliance with the WHO standard through this system directly reduces the risk of severe diseases such as skin, bladder, and lung cancer. Moreover, communities benefiting from the system experience substantial improvements in quality of life, as the chronic toxic effects of inorganic arsenic are minimized. This positive public health impact positions the system as a strategic model that not only mitigates immediate health risks but also fosters sustainable development in vulnerable regions.

The system implemented in La Yarada Los Palos has positive implications for both public health and the long-term sustainability of water resources. Reducing arsenic concentrations to safe levels protects communities from adverse effects associated with prolonged exposure to this metalloid. Epidemiological studies confirm that consuming water with inorganic arsenic significantly increases the incidence of skin, lung, and bladder cancer, as well as neurological and metabolic disorders [73,75,77].

From an environmental perspective, the integration of renewable energy into the system promotes the sustainability of water resources. The use of energy-efficient systems reduces dependency on non-renewable sources and minimizes the carbon footprint associated with water treatment, contributing to climate change mitigation and the conservation of local aquatic ecosystems. The system’s modular and scalable design also allows for implementation in other communities with similar hydrogeological characteristics, thereby expanding access to safe drinking water in vulnerable regions. This approach not only addresses immediate arsenic contamination issues but also establishes a sustainable and replicable model for managing water resources in rural areas.

4.6. Sensitivity Analysis of Operational Variables

To evaluate the influence of key operational parameters on arsenic removal efficiency, a sensitivity analysis was performed using the following equation:

$$\mathrm{S}={\displaystyle \frac{\%\mathsf{\Delta }\mathrm{R}\mathrm{e}\mathrm{m}\mathrm{o}\mathrm{v}\mathrm{a}\mathrm{l} \mathrm{E}\mathrm{f}\mathrm{f}\mathrm{i}\mathrm{c}\mathrm{i}\mathrm{e}\mathrm{n}\mathrm{c}\mathrm{y}}{\mathrm{\%}\mathsf{\Delta }\mathrm{V}\mathrm{a}\mathrm{r}\mathrm{i}\mathrm{a}\mathrm{b}\mathrm{l}\mathrm{e}}}$$

where S represents the sensitivity coefficient, %ΔRemoval Efficiency is the percentage change in removal efficiency, and %ΔVariable is the percentage change in the influencing variable.

The following table summarizes the sensitivity coefficients for arsenic concentration, pH, turbidity, total suspended solids (TSS), and Fe₂(SO₄)₃ dosage under different experimental conditions (

Table 15. Sensitivity Coefficients of Operational Variables on Arsenic Removal Efficiency.

As Initial (mg/L)	pH	Turbidity (NTU)	TSS (mg/L)	Fe2(SO4)3 Dose (mg/L)	Removal Efficiency (%)	Pretreatment	S As	S pH	S Turbidity	S TSS	S Dose
0.032	7.48	15	29	16	85.50	No	N/A	N/A	N/A	N/A	N/A
0.027	7.45	5	9	12	99.78	Yes	−1.101	−41.643	−0.251	−0.242	−0.668
0.016	7.18	10	19	14	86.30	No	0.316	3.728	−0.135	−0.122	−0.811
0.013	7.2	4	6	10	99.72	Yes	−1.017	55.826	−0.259	−0.227	−0.544
0.024	7.41	12	24	15	87.10	No	−0.156	−4.339	−0.063	−0.042	−0.253
0.02	7.38	6	10	12	99.85	Yes	−0.860	−36.157	−0.293	−0.251	−0.732
0.021	7.22	11	23	15	87.60	No	−2.045	5.659	−0.147	−0.094	−0.491
0.018	7.19	4	7	10	99.78	Yes	−0.921	−33.463	−0.218	−0.200	−0.417
0.034	7.67	14	28	17	88.20	No	−0.127	−1.738	−0.046	−0.039	−0.166
0.029	7.65	5	9	12	99.83	Yes	−0.889	−50.568	−0.205	−0.194	−0.448
0.03	7.35	13	27	16	88.90	No	−3.564	2.792	−0.068	−0.055	−0.328
0.026	7.37	5	8	12	99.85	Yes	−0.827	45.266	−0.200	−0.175	−0.493

).

The effect of pH is inconsistent, as evidenced by both positive and negative sensitivity values. In samples with pretreatment, pH sensitivity is significantly high (e.g., 55.826 and −50.568), indicating that pH variations strongly influence the efficiency of the coagulation process.

The sensitivity to turbidity and total suspended solids (TSS) is consistently negative and of low magnitude, suggesting that the system remains stable despite changes in these parameters. In samples with pretreatment, the variability in these sensitivities is lower, reinforcing the overall stability of the system.

The sensitivity analysis for Fe₂(SO₄)₃ dosage reveals negative values in all cases, implying that in certain scenarios, a lower coagulant dosage may be associated with higher removal efficiency. However, the impact remains moderate, indicating that the system can function reliably within a dosing range without drastically affecting efficiency.

Overall, pH and initial arsenic concentration emerge as the most influential variables affecting removal efficiency. In contrast, turbidity and total suspended solids have minimal impact, suggesting that pretreatment contributes to system stability. The dosage of Fe₂(SO₄)₃ exhibits a moderate influence, implying that optimizing its dosage is feasible without significantly compromising arsenic removal efficiency.

4.7. System Limitations and Strategic Recommendations

4.7.1. Technical and Operational Challenges

The system presents technical and operational limitations that must be addressed to ensure its long-term sustainability and replicability in other regions. One of the main challenges is the management of solid waste generated during the coagulation stage, particularly sludge, which requires proper handling to prevent negative environmental impacts. In rural areas with limited infrastructure, the final disposal of this waste represents a significant issue [48,78,79].

Another critical challenge is the system’s reliance on climatic conditions. Although the high solar radiation in the La Yarada Los Palos region is advantageous for energy generation, seasonal variability and periods of low irradiance can compromise continuous operation. This highlights the need for reliable energy backup strategies and efficient storage technologies [40,47,79].

Additionally, the regeneration of adsorbent materials, such as titanium oxyhydroxide used in the adsorption filter, is an important operational challenge. Limited infrastructure for the regeneration or replacement of these materials could increase operating costs and reduce the system’s sustainability [21]. Furthermore, the lack of advanced sensors for real-time monitoring of key parameters, such as As(III) and As(V) concentrations, limits the ability to make immediate adjustments, which can affect the system’s operational reliability.

Although technical and operational challenges are inherent to complex systems, proposed strategies such as adsorbent regeneration and the use of advanced monitoring technologies ensure the system’s long-term viability. Additionally, integrating batteries for energy storage and optimized waste management protocols solidifies its position as a replicable solution in rural contexts. These improvements not only address current limitations but also enhance the system’s operational reliability.

The scaling up of the photovoltaic-powered water treatment system with sedimentation pretreatment presents various technical, operational, and environmental challenges that must be addressed to ensure its feasibility for larger-scale applications.

One of the primary challenges is related to variability in influent water quality. While the system has demonstrated high arsenic removal efficiency under the specific hydrochemical conditions of La Yarada Los Palos, its performance could be affected in regions with different geological and chemical characteristics, such as higher phosphate or silicate concentrations that may compete for adsorption sites. Adapting the system to other water sources would require preliminary studies to adjust pretreatment conditions and optimize arsenic removal under different scenarios.

From an operational and infrastructure standpoint, scaling up the system would require increasing storage and sedimentation capacity, necessitating larger space availability and robust structural support. Constructing sedimentation reservoirs in areas with limited land availability or adverse geotechnical conditions could pose additional challenges, particularly in regions with fluctuating groundwater levels or land-use restrictions.

In terms of maintenance and large-scale sustainability, implementing higher-capacity systems would demand more robust strategies for managing solid waste accumulation during sedimentation and regenerating adsorbent materials. As the volume of treated water increases, maintenance frequency and disposal of generated sludge become critical factors. Additionally, the management of adsorbent materials, such as iron oxides, would require efficient replacement or regeneration plans to prevent efficiency loss over time.

Another key aspect is the energy autonomy and reliability of the photovoltaic system in larger-scale applications. While solar irradiance in La Yarada Los Palos is favorable for system operation, broader applications would necessitate assessing the scalability of the photovoltaic supply, considering factors such as dust accumulation on panels, long-term degradation of solar modules, and the integration of energy storage systems to ensure operation during nighttime or under adverse weather conditions.

Finally, from an economic and regulatory perspective, expanding the system would require a cost assessment comparing its implementation with existing commercial alternatives, considering both initial investment and operational/maintenance costs. Moreover, large-scale applications may be subject to specific water quality regulations, necessitating additional certifications or design adjustments to comply with national and international drinking water treatment standards.

While the system has proven to be efficient in arsenic removal under controlled conditions, its scalability requires a comprehensive analysis of technical, operational, energy-related, and regulatory factors. Optimizing pretreatment strategies, managing adsorbent materials, and integrating energy storage solutions are key aspects to ensure the feasibility of the system in broader applications.

4.7.2. Economic Feasibility and Cost Analysis

The feasibility of implementing the photovoltaic-powered water treatment system depends not only on its technical performance but also on its economic viability. The total implementation cost, including the photovoltaic system, sedimentation pretreatment, and modular treatment system, amounts to $46,200 USD. This investment covers the infrastructure, equipment, and installation of a fully functional system capable of treating 0.5 m³/h of water (

Table 16. Implementation Costs.

Implementation Costs	Cost (USD)
5 kW Photovoltaic System	12,000.00
- Inverter
- Batteries
- Solar panels
- Accessories and installation
Natural Sedimentation Pretreatment	14,200.00
- Construction of a 3150 m3 reservoir
Water Treatment System (0.5 m3/h)	15,500.00
- Modular system with oxidation, coagulation, filtration, and adsorption processes
Water Treatment System Consumables	4500.00
- Sodium hypochlorite
- Ferric sulfate
- Granular natural zeolite
- Manganese-oxide-coated sand
- Granular activated carbon
- Titanium oxyhydroxide
Total Implementation Costs	46,200.00

).

Annual operation and maintenance costs are estimated at $10,500 USD, which includes routine maintenance of the photovoltaic system, weekly backwashing operations, and periodic replacement of consumables such as ferric sulfate, granular zeolite, and titanium oxyhydroxide. The primary cost components are shown in (

Table 17. Annual Operation and Maintenance Costs.

Annual Operation and Maintenance Costs	Cost (USD)
Operation and Maintenance of Photovoltaic System	1500.00
- Routine cleaning and maintenance of solar panels
Operation and Maintenance of Water Treatment System	2500.00
- General system maintenance and weekly backwashing
Replacement of Water Treatment System Consumables	4500.00
Sludge Management	2000.00
Total Annual Operation and Maintenance Costs	10,500.00

).

4.7.3. Considerations for As(III) Oxidation in Water Treatment

The oxidation efficiency of As(III) to As(V) using sodium hypochlorite is high under controlled conditions. In this sense, a study reported that in-situ-generated hypochlorite achieved 100% oxidation efficiency of As(III) to As(V) [80]. However, under real field conditions, factors such as the presence of dissolved organic carbon (DOC) and ammonia may influence oxidation efficiency. For instance, it has been observed that in waters with DOC concentrations below 2 mg-C/L and no significant NH₃ presence, a 0.1 mg/L Cl₂ dose was sufficient to oxidize more than 98% of As(III) in less than 10 s [81].

The oxidation efficiency of As(III) by NaClO is influenced by variables such as pH and temperature. Studies have shown that the oxidation rate is extremely rapid, with apparent second-order rate constants of 2.6 × 10⁵ M⁻¹ s⁻¹ at pH 7 [82]. Moreover, the presence of reducing agents such as ammonia can affect oxidation efficiency. However, in waters with 1 mg-N/L ammonia concentration, an oxidation rate above 75% of As(III) was achieved within 10 s following the addition of 1–2 mg/L Cl₂ [82].

Although data on As(III) oxidation efficiency by NaClO under controlled conditions and some field scenarios are available, further studies are needed to assess the effectiveness of this process in various hydrogeological contexts [83]. This is particularly relevant in regions such as La Yarada Los Palos, where the specific characteristics of groundwater may influence treatment efficiency. The lack of detailed field-specific data highlights the importance of additional research to optimize As(III) oxidation strategies across diverse water quality scenarios. Previous studies have evaluated arsenic removal through chemical oxidation followed by clarification, demonstrating that process efficiency varies depending on raw water quality and oxidant concentration [84].

In this regard, this study represents a step forward in understanding As(III) oxidation in a photovoltaic-powered water treatment system under real field conditions. The evaluation of this approach in a high water vulnerability region such as La Yarada Los Palos not only contributes to the technical understanding of the process but also provides key insights for developing sustainable and replicable treatment strategies in similar contexts.

4.7.4. Recommendations for Optimization and Implementation

To address these limitations, improving sludge management through dehydration and stabilization technologies is proposed to reduce its volume and facilitate final disposal. Additionally, exploring the reuse of treated sludge in industrial or agricultural applications could minimize environmental impact and create added value [79]. The integration of energy storage technologies, such as lithium-ion batteries, would ensure a continuous supply during periods of low solar irradiance. Moreover, implementing energy management algorithms would optimize the use of generated energy, preventing waste and ensuring more efficient operation.

Establishing on-site regeneration protocols for adsorbent materials using environmentally friendly chemical solutions is also critical. Investigating alternative materials, such as modified zeolites, which offer greater durability and adsorption capacity, could further reduce long-term operating costs [21]. Incorporating advanced sensors for real-time monitoring of critical parameters, such as As(III) and As(V) concentrations, would enable the automatic adjustment of chemical dosing rates and improve the overall system efficiency. This would not only increase operational reliability but also facilitate preventive and corrective maintenance.

A previous study conducted in the Caplina Basin, Tacna, Peru [85], highlights the importance of precise arsenic speciation in optimizing water treatment strategies. The results obtained through ICP-MS and HPLC allowed for the differentiation of As(III) and As(V), providing key information for the selection of remediation techniques. The application of these advanced analytical methodologies in water treatment processes can enhance system efficiency and ensure compliance with drinking water quality standards in areas with high arsenic contamination.

To facilitate implementation in other regions, developing technical guidelines that include adaptations to local climatic and hydrogeological conditions is recommended. These guidelines should be complemented with sustainable financing models, such as subsidies or green loans, to encourage the adoption of these technologies in vulnerable rural communities. Establishing strategic alliances with local governments, NGOs, and beneficiary communities will ensure not only the system’s operational sustainability but also its long-term financial viability. These actions will enhance the system’s positive impact, positioning it as a replicable and sustainable model for water resource management in regions with high water vulnerability.

This type of research holds crucial importance in regions such as La Yarada Los Palos, Tacna, Peru, where scientific and technological innovation initiatives are often limited due to constraints in size and resources. In these areas, implementing tailored solutions to address local challenges is essential. This study not only provides a practical and sustainable solution for arsenic removal but also promotes scientific and technological development in a region with great potential to stand out as a model for sustainable water resource management in vulnerable environments.

5. Conclusions

The photovoltaic-powered water treatment system, which incorporates a natural sedimentation pretreatment stage, achieved arsenic removal efficiencies ranging from 99.72% to 99.85%. This process consistently reduced contaminant concentrations to below the 0.01 mg/L limit established by the World Health Organization (WHO), demonstrating its effectiveness in mitigating arsenic contamination in high water vulnerability areas, such as La Yarada Los Palos, Tacna, Peru.

The system not only successfully removed toxic arsenic species, particularly arsenite (As(III))—recognized as more toxic than arsenate (As(V))—but also mitigated public health risks associated with severe illnesses such as cancer and cardiovascular disorders.

A critical aspect was the pretreatment stage performed in a geomembrane-lined reservoir, which allowed for the natural sedimentation of suspended particles before water entered the main treatment processes. This stage reduced suspended solids by up to 70.37% and turbidity by up to 66.67%, significantly optimizing the efficiency of subsequent oxidation, coagulation, and adsorption stages. Without pretreatment, the system required an average cleaning frequency of six times per month. With the incorporation of pretreatment, this frequency was reduced to four cleanings per month, thanks to the significant decrease in turbidity and total suspended solids (TSS). Additionally, the average energy consumption associated with the cleaning process was also significantly reduced with pretreatment, reaching 30.48 kWh compared to 45.72 kWh recorded without this stage, representing a 33% reduction in the total energy consumption during the backwashing process.

These savings underscore the importance of pretreatment not only in optimizing energy performance but also in ensuring a more efficient and sustainable overall system operation. Additionally, solar-powered operation effectively utilized the region’s high solar radiation, with average energy generation of 20.31 kWh/day and an average surplus of 33.08%.

From an environmental perspective, the annual reduction of approximately 196 kg of CO₂ emissions, equivalent to the amount absorbed by around nine mature trees, highlights the system’s role as a sustainable solution for vulnerable communities.

The modular and scalable design of the system enables its implementation in similar contexts both nationally and internationally. The integration of photovoltaic technologies and pretreatment through a reservoir ensures its functionality in regions with adverse hydrogeological conditions and limited access to conventional energy sources. This work emphasizes the importance of considering local factors, such as solar radiation and the physicochemical properties of water, to adapt and optimize treatment systems.

The findings obtained in La Yarada Los Palos can be generalized to other regions with similar hydrogeological and climatic characteristics, particularly those where arsenic contamination in groundwater sources is a critical issue. The combination of natural sedimentation pretreatment, sodium hypochlorite oxidation, and adsorption has proven to be effective in arsenic removal, suggesting that this approach could be applied in other areas with comparable conditions.

However, while the results of this study provide valuable insights for the development of arsenic treatment strategies in high water vulnerability regions, additional studies are recommended in diverse hydrogeological settings to validate the applicability of the system across different contexts.

Finally, detailed analyses using advanced techniques such as ICP-MS and HPLC validated the system’s effectiveness, establishing a solid foundation for future research on arsenic removal and the use of renewable energy in water treatment systems. This study demonstrates the transformative potential of sustainable technologies to improve access to drinking water in vulnerable communities, directly contributing to public health and environmental conservation.

This type of research is of crucial importance in regions like La Yarada Los Palos, Tacna, Peru, where scientific and technological innovation initiatives are often scarce due to limitations in size and resources. In these areas, implementing specific solutions tailored to their needs is essential to address local challenges. This study not only provides a practical and sustainable solution for arsenic removal but also promotes scientific and technological development in a region with great potential to stand out as a model in sustainable water resource management in vulnerable environments.