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Article

Life Cycle Assessment and Environmental Impact Evaluation of Demineralized Water Production at Al-Hilla Second Gas Power Plant, Iraq

by
Qasim Mudher Modhehi
and
Haider Mohammed Zwain
*
Water Resources Management Engineering Department, College of Engineering, Al-Qasim Green University, Babylon 51013, Iraq
*
Author to whom correspondence should be addressed.
Resources 2025, 14(9), 137; https://doi.org/10.3390/resources14090137 (registering DOI)
Submission received: 13 June 2025 / Revised: 29 July 2025 / Accepted: 5 August 2025 / Published: 30 August 2025
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Abstract

This study conducts a detailed and systematic Life Cycle Assessment (LCA) of demineralized (DEMI) water production at the Al-Hilla Second Gas Power Plant in Iraq, employing the Open LCA-ReCiPe 8 Midpoint (H) method to evaluate potential environmental impacts across 18 midpoint categories. The analysis focuses on the production of 1 cubic meter of high-purity water, offering a comprehensive evaluation of the environmental burdens associated with chemical usage, energy consumption, and resource depletion. The results indicate that terrestrial ecotoxicity is the most dominant impact category (20.383 kg 1,4-DCB-eq), largely driven by the extensive use of treatment chemicals such as coagulants, disinfectants, and antiscalants. Climate change follows as the second highest impact category (3.496 kg CO2-eq), primarily due to significant electricity consumption during energy-intensive stages, particularly reverse osmosis (RO) and electro-deionization (EDI). These stages also contribute notably to fossil resource depletion (1.097 kg oil-eq) and particulate matter formation, reflecting the heavy reliance on fossil fuel-based energy in the region. Additional environmental concerns identified include human toxicity (both carcinogenic and non-carcinogenic), freshwater and marine ecotoxicity, and metal/mineral resource depletion, all of which underscore the need for improved chemical and material management throughout the treatment process. While impacts from categories such as ozone layer depletion, ionizing radiation, and eutrophication are relatively low, their cumulative effect over time remains a concern for long-term sustainability. The energy assessment reveals that the RO and EDI units alone account for over 70% of the total energy consumption, estimated at 3.143 kWh/m3. This research provides insights into minimizing environmental burdens in water treatment systems, especially in regions facing energy and water stress.

1. Introduction

The generation of high-purity demineralized (DEMI) water is an indispensable component of modern thermal and gas-fired power plants [1]. In such facilities, DEMI water serves multiple critical functions, including its use as boiler feedwater, for turbine blade cooling, and within steam generation cycles [2,3]. The stringent purity requirements stem from the fact that impurities such as dissolved salts, silica, and organic contaminants, can cause scaling, corrosion, and fouling within heat exchangers and high-pressure steam systems, leading to significant reductions in thermal efficiency, increased maintenance demands, and premature equipment failure [4,5]. Hence, ensuring a continuous and reliable supply of DEMI water is essential not only for maintaining optimal power plant performance but also for safeguarding long-term operational integrity and reducing unplanned downtime [6,7].
In this context, the Al-Hilla Second Gas Power Plant, located in Babylon Province, Iraq, represents a critical node in the national energy infrastructure. As one of the key facilities contributing to regional power supply stability, the plant operates with a high dependency on DEMI water to sustain its electricity generation capacity [8,9]. The primary water source for the plant is the Euphrates River, from which raw surface water is extracted and subjected to an advanced, multi-stage treatment train designed to meet the stringent quality standards required for turbine and boiler systems [10].
The plant’s water treatment system comprises several sequential processes: coagulation and flocculation to remove suspended solids and colloidal matter; dual stage reverse osmosis (RO) to eliminate dissolved salts, heavy metals, and organics; and electro-deionization (EDI) to achieve ultrapure water by removing residual ionic species [11,12]. Each stage is designed for maximum contaminant rejection, but this comes at a substantial operational cost, most notably in terms of energy consumption and chemical usage [13]. High-pressure pumps are required to drive water through RO membranes, and electrochemical energy inputs sustain the ion exchange mechanisms in EDI systems [14]. Additionally, significant volumes of treatment chemicals such as ferric sulfate, sodium hypochlorite, hydrochloric acid, and antiscalants are used throughout the process for disinfection, pH regulation, and membrane cleaning [15,16].
These resource-intensive operations result in considerable environmental impacts, both direct (e.g., emissions from on-site power consumption) and indirect (e.g., upstream emissions associated with chemical manufacturing and electricity generation) [17,18]. Traditional performance assessments of water treatment facilities have typically prioritized water quality outcomes and system reliability, often overlooking these broader environmental implications [19]. However, as Iraq confronts rising energy demands, water scarcity, and increasing pressure to align with global climate mitigation goals [20], it is imperative to adopt comprehensive evaluation frameworks that encompass not only technical and economic metrics but also environmental sustainability dimensions.
In this regard, the application of Life Cycle Assessment (LCA) has gained international traction as a holistic, ISO-standardized methodology for quantifying the environmental burdens associated with products and processes across their entire life cycles, from raw material extraction through to operation and end-of-life management [21,22]. Within the water treatment sector, LCA enables the identification of environmental hotspots, such as stages with disproportionately high greenhouse gas (GHG) emissions, ecotoxicity contributions, or fossil fuel consumption, thereby informing strategies for technological improvement and resource efficiency [23].
Recent global studies have underscored the relevance of LCA in water and wastewater systems. For example, Li et al. [24] assessed the life cycle performance of wastewater reclamation plants in China and highlighted the dominant role of electricity use, particularly in membrane filtration in driving climate change and ecotoxicity potentials. Similarly, Rahman et al. [25] and Luo et al. [26] evaluated industrial water treatment systems, concluding that RO and chemical-intensive stages contribute most significantly to cumulative environmental impacts, including eutrophication, ozone depletion, and human toxicity. Regionally, Alkhuzai et al. [27], Mohammed and Farzaneh [28], and Alsultani et al. [29] extended the application of LCA to infrastructure projects in Iraq and emphasized the importance of integrating site-specific energy profiles and chemical inventories to better reflect the contextual sustainability challenges in the Middle East.
Despite these advancements, a notable research gap persists concerning the environmental evaluation of DEMI water production in Iraqi gas power plants. The absence of localized LCA data hinders effective benchmarking, policy formulation, and operational optimization [30]. Furthermore, with Iraq facing intensifying water stress, limited renewable energy integration, and aging utility infrastructure, understanding the full energy–environment nexus of DEMI water production is essential for supporting national energy transition pathways and water resource resilience planning.
Therefore, the primary objective of this study is to assess the life cycle environmental impacts and energy consumption per cubic meter of DEMI water produced at the Al-Hilla Second Gas Power Plant. This includes (1) quantifying electricity usage for pumping across each treatment stage; (2) estimating the mass and impact of chemical inputs; (3) conducting an LCA using 17 environmental indicators, including climate change, human toxicity, ecotoxicity, and resource use. This assessment not only highlights the energy and environmental burdens of DEMI water production but also offers insights into potential improvement strategies to enhance efficiency and reduce ecological impacts in similar contexts across Iraq and other arid regions.

2. Materials and Methods

2.1. Study Area Description

The present study was conducted at the Al-Hilla Second Gas Power Plant, a major energy production facility located in Babylon Province, central Iraq. The facility plays a vital role in supplying electricity to the surrounding region and relies heavily on high-purity DEMI water for its steam turbines and boiler operations. The plant is geographically situated at approximately 32°32′32″N latitude and 44°19′15″E longitude, adjacent to the Euphrates River, which serves as the primary surface water source for the water treatment process, as shown in Figure 1.

2.2. Deminerlized Water Treatment Plant Description

The raw water intake is sourced directly from the Euphrates River through a series of pumping and pre-screening units. The raw water quality varies seasonally but typically contains a high concentration of suspended solids, total dissolved solids (TDS), and microbial contaminants, necessitating advanced multi-stage treatment to meet the ultrapure water specifications required by gas turbine systems. The design treatment capacity of the plant is 160 (m3/h), with an operational target to produce sufficient volumes of DEMI water for continuous power generation cycles. To achieve the production of high-purity demineralized (DEMI) water, the treatment system is designed as a series of integrated unit operations that work in tandem to progressively eliminate contaminants and improve water quality.
The process begins with chemical dosing and pre-treatment, where coagulants such as ferric sulfate are added to destabilize colloidal particles. pH adjustment agents, including sulfuric acid and sodium hydroxide, are used to optimize water chemistry for the efficiency of downstream membrane processes. Biocides and antiscalants are also introduced at this stage to inhibit microbial growth and minimize scaling within the system. Following pre-treatment, the water undergoes media filtration through multimedia pressure filters. This stage is critical for removing residual suspended solids, turbidity, and other particulate matters. By reducing the particulate load, the filters protect the reverse osmosis (RO) membranes and maintain operational stability.
The filtered water is then directed into a two-stage reverse osmosis system. This dual-pass RO process utilizes high-pressure membrane modules to remove dissolved salts and organic compounds. The reverse osmosis units in this system utilize thin-film composite (TFC) polyamide membranes, selected for their superior salt rejection efficiency and durability under high-pressure conditions. TFC membranes are the industry standard for producing high-purity water due to their multilayer structure, which provides a high permeability while maintaining excellent separation performance. Despite their benefits, these membranes are sensitive to oxidants such as chlorine and therefore require effective pre-treatment, including dechlorination steps, to prevent chemical degradation. Additionally, their operation under elevated pressures (12–16 bar) contributes significantly to the overall energy consumption of the treatment process.
In the first stage, the majority of ionic and organic contaminants are removed, while the second stage further refines the permeate to meet stringent purity standards. Operating under pressures of approximately 12 to 16 bar, the RO units are one of the most energy-intensive components of the treatment process. The final treatment phase involves electro-deionization (EDI), a continuous process that uses electrically active ion exchange membranes and resins to eliminate the remaining ionic impurities. Unlike conventional ion exchange systems, EDI does not require chemical regeneration, making it more environmentally friendly. The result is ultrapure water with an electrical conductivity typically below 0.2 µS/cm, which meets the strict quality requirements for use in turbine cooling systems and as boiler feedwater in gas and thermal power plants.
This multi-stage treatment configuration reflects a hybrid design that combines conventional physico-chemical treatment with advanced membrane and electrochemical technologies to meet stringent quality standards while minimizing chemical usage and environmental discharge. The geographical location, treatment design, and operational conditions of the selected power plant make it an ideal case study for evaluating the life cycle environmental impacts and energy consumption associated with DEMI water production in a semi-arid, resource-constrained setting. Figure 2 shows the general plan of the station, which shows the mechanism of transfer between the station units.

2.3. Data Collection and Inventory Analysis

The data collection and inventory analysis for this study were carried out through a combination of on-site measurements, operational logs provided by the Al-Hilla Second Gas Power Plant, and reference data from established life cycle inventory databases. The focus was on compiling a comprehensive life cycle inventory (LCI) of all material and energy inputs associated with the production of 1 cubic meter of demineralized (DEMI) water, which serves as the functional unit (FU) for this assessment. The functional unit (FU) of this study is defined as the production of 1 cubic meter (1 m3) of demineralized (DEMI) water with an electrical conductivity of less than 0.2 µS/cm, meeting the ultrapure water standards for the Al-Hilla Power Plant.
Data were gathered for each treatment stage, including raw water abstraction, chemical dosing, multimedia filtration, two-stage reverse osmosis (RO), and electro-deionization (EDI). Operational records provided hourly flow rates, pump specifications, chemical dosing rates, and system recovery ratios, enabling a detailed mass and energy balance. Electricity consumption was quantified for each treatment component using equipment power ratings and average operational durations. The RO and EDI systems, being the most energy-intensive processes, were examined in detail. Chemical consumption was based on site-specific dosing practices and verified through procurement records. The main chemicals used include ferric sulfate (20 mg/L) for coagulation, sulfuric acid (15 mg/L) and sodium hydroxide (12 mg/L) for pH adjustment, along with antiscalants and disinfectants at approximately 8 mg/L combined. The energy required for raw water pumping, intermediate transfers, and final product distribution was also included in the inventory.
Seasonal variations in raw water quality were not included in the life cycle inventory due to a lack of detailed temporal data. This limitation is acknowledged and recommended for future studies, as it may influence energy and chemical consumption rates. All inventory data were converted to standardized environmental units and modeled using the OpenLCA-ReCiPe 8 Midpoint (H) life cycle databases to ensure regional accuracy for electricity generation and chemical production. The system boundary was defined as cradle-to-gate, encompassing resource extraction, chemical manufacturing, electricity production, and operational use up to the delivery of DEMI water.
Capital equipment, including infrastructure and membrane production, was excluded from the system boundary to focus on operational phase impacts, which are typically dominant in short-term assessments of water treatment performance. This approach aligns with previous LCA studies on similar systems. Capital infrastructure and downstream use phases were excluded in accordance with the ISO 14040 [31] and 14044 standards [32]. This detailed inventory analysis forms the foundation for the life cycle impact assessment, enabling a robust evaluation of the environmental burdens associated with DEMI water production at the facility. Based on field measurements, the water balance for the treatment system is as illustrated in Table 1.
Where available, standard deviations or uncertainty intervals have been added to the flow rate and energy consumption data to reflect measurement variability and operational fluctuations. These estimates are based on the precision of the instrumentation and typical variations observed in plant operations. While some parameters lack comprehensive repeated measurements due to operational constraints, we acknowledge the potential variability and its influence on environmental impact assessments. Future work will aim to expand data collection for more rigorous uncertainty quantification.
Flow rate measurements were recorded at all critical control points in the water treatment process. The plant receives approximately 160 m3/h of raw water. Of this, 77 m3/h is diverted for sanitary and utility purposes, while the remaining 83 m3/h is processed through the main treatment line. After initial filtration and RO stage 1, 61 m3/h advances to RO stage 2. A portion of this flow (59 m3/h) successfully passes through the EDI units to produce high-quality DEMI water, while 3 m3/h is returned to the raw water tank for reprocessing. Approximately 22 m3/h of concentrate and brine is discharged back to the river. Energy consumption was quantified across all treatment stages using pump ratings and operational data. The plant’s total specific energy consumption for producing 1 m3 of DEMI water is approximately 3.143 kWh. The distribution of energy use by treatment unit is detailed in Table 2.
Chemical dosing is critical to conditioning the feedwater for membrane processes and ensuring effective disinfection. Chemical usage was assessed based on plant records and standard dosing rates. Table 3 presents the main chemicals used, their typical concentrations, and calculated hourly and per-unit water mass flows. These values serve as the basis for estimating upstream environmental impacts related to chemical production and transport in the life cycle model.
It is worth noting that the chemical dosing concentrations listed in Table 3 were derived from on-site operational records and standard dosing protocols routinely used at the Al-Hilla Second Gas Power Plant. These values represent typical doses applied to feedwater streams during routine operation. The plant’s operational team provided hourly usage rates and confirmed the typical dosing concentrations for each chemical based on the system design and performance requirements. No direct chemical analyses were performed; instead, data were collected from plant logs, dosing pump calibration sheets, and engineer interviews to ensure accuracy and representativeness.
To evaluate the environmental performance of the DEMI water production system, a Life Cycle Assessment was conducted using a functional unit of 1 m3 of produced DEMI water. The system boundaries encompass all stages from raw water intake to post-EDI output, including pumping, chemical dosing, membrane separation, and residual handling. The assessment was implemented using LCA software tools such as OpenLCA (version 2.3.1.0) and Excel-based calculations, aligned with 14040/14044 standards [31,32]. Eighteen impact categories were selected for analysis, including climate change, acidification, freshwater and marine eutrophication, human and ecological toxicity, resource depletion, and water use. Inventory flows and emissions were mapped to appropriate characterization factors from recognized ReCiPe databases. Environmental impacts were assessed using the ReCiPe 2016 Midpoint (H) method, which provides a harmonized life cycle impact assessment framework at both midpoint and endpoint levels [33]. This methodology provides a comprehensive evaluation of the energy and environmental burdens associated with high-purity water production and helps identify opportunities for system optimization and sustainability enhancement in Iraq’s power sector and similar arid regions.

3. Results and Discussion

3.1. Life Cycle Impact Assessment of Demineralized Water Production

A comprehensive life cycle impact assessment (LCIA) was performed for the production of 1 cubic meter (1 m3) of demineralized water at the treatment plant, utilizing the Open LCA-ReCiPe 8 Midpoint (H). The analysis aimed to quantify and interpret environmental impacts across 18 midpoint categories covering climate change, ecotoxicity, human health risks, resource depletion, and other environmental stressors. The results are presented in Table 4 and discussed in detail below.
The input data for material and energy flows were derived from on-site operational records, plant logbooks, and equipment specifications. Chemical dosing quantities, energy consumption by each treatment stage, and water flows were integrated into the model to represent the full treatment process. The environmental impacts were calculated by linking the foreground system inventory with the ReCiPe 2016 characterization factors, enabling quantification across 18 midpoint impact categories such as terrestrial ecotoxicity, climate change, human toxicity, and resource depletion. Sensitivity analyses were performed to assess the influence of key parameters on the impact categories.

3.2. Climate Change and Energy-Related Impacts

The environmental impacts, particularly global warming potential (GWP) and fossil resource depletion, were largely driven by electricity consumption during the treatment processes. For this analysis, the electricity profile was modeled using the Ecoinvent v3.8 database, selecting the ‘Electricity, medium voltage, production mix—Iraq’ dataset (year: 2025) as a proxy for the national grid. This dataset reflects the Iraqi energy matrix, which is predominantly based on fossil fuels, and is consistent with regional conditions during the study period. Electricity consumption was modeled using the Ecoinvent 3.8 database. The specific dataset used was ‘Electricity, high voltage (ME) market group for Middle East and North Africa, GLO’, to represent regional electricity supply and ensure geographical relevance for the Iraqi context.
The GWP, expressed as CO2-equivalent, was estimated at 3.496 kg CO2-eq per 1 m3 of demineralized water. This category, reflecting the total radiative forcing from greenhouse gases, is primarily influenced by electricity consumption throughout various treatment stages, particularly reverse osmosis and electro-deionization units. These components are highly energy-intensive due to their reliance on high-pressure pumps and continuous operation. Consistent with earlier studies by [34,35], this impact demonstrates that electricity demand is the dominant contributor to the carbon footprint in water treatment plants that incorporate membrane technologies. Additionally, the non-renewable fossil energy depletion was quantified at 1.097 kg oil-eq, indicating a significant dependency on fossil fuels for plant operations.

3.3. Toxicity and Ecotoxicological Impacts

The most prominent environmental burden observed was in the terrestrial ecotoxicity category, which reached 20.383 kg 1,4-dichlorobenzene-equivalents (kg 1,4-DCB-eq). This high value reflects emissions from chemical manufacturing and usage during the treatment process, particularly the application of coagulants (e.g., ferric chloride), disinfectants (e.g., chlorine gas or sodium hypochlorite), and antiscalants. These substances can cause significant harm to soil organisms and vegetation when released into the environment via improper sludge disposal or atmospheric deposition. In addition to terrestrial ecotoxicity, the human toxicity (non-carcinogenic) potential was measured at 1.268 kg 1,4-DCB-eq, while human toxicity (carcinogenic) stood at 0.418 kg 1,4-DCB-eq. These figures represent the potential chronic health risks posed by exposure to non-carcinogenic and carcinogenic substances throughout the life cycle of the treatment process—from raw material extraction to effluent discharge. Freshwater and marine ecotoxicity impacts were calculated at 0.068 kg and 0.106 kg 1,4-DCB-eq, respectively, indicating pollution from runoff and treated water discharges. These results are in line with the findings of [36], who reported similar impacts in membrane-integrated water treatment systems in Southeast Asia.

3.4. Materials and Energy

The metal/mineral resource depletion category was evaluated at 0.064 kg Cu-eq. This is associated with the extraction and use of materials for infrastructure (e.g., pipelines, pressure vessels, and structural supports). The reliance on copper, stainless steel, PVC, and composite materials contributes to this impact category. The embedded environmental burdens arise from the mining, refining, manufacturing, and transportation of these materials. This result underscores the importance of considering infrastructure sustainability and end-of-life recycling when planning future plant upgrades or expansions. A shift towards modular, recyclable systems could substantially reduce long-term material footprints.

3.5. Acidification and Eutrophication

The acidification potential, primarily due to emissions of sulfur dioxide (SO2) and nitrogen oxides (NOₓ) from fuel combustion and grid electricity generation, was measured at 0.0119 kg SO2-eq. This reflects the contribution of airborne pollutants that result in soil and freshwater acidification, with downstream effects on biodiversity and soil buffering capacity. Freshwater eutrophication was reported at 0.000253 kg P-eq, while marine eutrophication was 7.39 × 10−5 kg N-eq, reflecting the leaching or discharge of nutrients such as phosphates and nitrates into water bodies. Although relatively low compared with other categories, these emissions may result in algal blooms and hypoxic conditions if accumulated over time.

3.6. Air Quality and Human Exposure

The formation of fine particulate matter (PM2.5), an indicator of air pollution and respiratory risk, was determined to be 0.00422 kg PM2.5-eq. This impact primarily stems from emissions during chemical manufacturing and fuel combustion. Additionally, photochemical oxidant formation, which contributes to ground-level ozone generation, was calculated as 0.00752 kg NOₓ-eq for terrestrial ecosystems and 0.00703 kg NOₓ-eq for human health. These values emphasize the need for stringent emission controls during upstream energy and material processing phases.

3.7. Ozone Depletion and Ionizing Radiation

The ozone layer depletion potential was relatively minor at 2.95 × 10−6 kg CFC-11-eq, attributed to the potential leakage of refrigerants or halogenated chemicals during infrastructure maintenance or material life cycles. The ionizing radiation impact, calculated at 0.0483 kBq Co-60-eq, is generally associated with electricity production from nuclear sources or rare earth material refining.

3.8. Land and Water Use

The land use for biomass production or infrastructure occupation was 0.0184 m2·year crop-eq, reflecting minor contributions from agricultural-based bio-materials and construction activities. Water use stood at 0.00978 m3, a low value relative to the overall system function, given the process input of surface water and efficient treatment chain design.

3.9. Energy Consumption by Process Stage

The production of DEMI water involves several energy-intensive treatment stages, including water intake, sand filtration, two stages of reverse osmosis (RO1 and RO2), chemical dosing, and electro-deionization (EDI). Based on equipment specifications, operational data, and validated energy modeling, the total energy consumption was calculated to be approximately 3.143 kWh per cubic meter of treated water.
Table 5 summarizes the energy use of each unit process. The RO and EDI units were found to be the most energy-demanding components, accounting for over 70% of the total energy consumption. This is primarily due to the high pressures required for membrane separation and the continuous electrical load associated with ion exchange in the EDI unit.
The energy intensity of this process highlights the operational cost and environmental footprint associated with high-purity water production, particularly in regions where electricity is largely generated from fossil fuels, such as Iraq.

4. Interpretation of the Results

The Life Cycle Assessment (LCA) of 1 m3 of treated water at the selected plant reveals a wide range of environmental impacts across 18 midpoint categories, as presented in Figure 3. The findings show that terrestrial ecotoxicity is the most dominant environmental impact, contributing approximately 78.0% of the total burden. This result highlights significant ecological stress on land ecosystems, likely due to chemical additives and residual sludge from the treatment process. The second highest contributor is climate change, accounting for 13.4%, primarily driven by carbon dioxide emissions from energy consumption and fuel use throughout the plant’s operations. Human toxicity (non-carcinogenic effects) ranks third with a 4.9% share, indicating potential health risks related to exposure to certain pollutants during the life cycle of chemical inputs. Additional contributions come from fossil energy resource depletion (4.2%) and carcinogenic human toxicity (1.6%), reflecting the environmental costs of non-renewable energy use and trace emissions of hazardous substances. The remaining 13 impact categories each contribute less than 2% individually, with minimal influence on the overall environmental profile. These findings underline the need for targeted improvements in chemical management, energy efficiency, and emission controls to enhance the plant’s sustainability and reduce its environmental footprint.
To better understand the relative significance of each environmental impact category resulting from the LCA of the Al-Hilla Second Gas Power Plant, a normalization process was applied, with terrestrial ecotoxicity taken as the reference category (normalized to 1.0). The outcomes, presented in Figure 4, reveal stark differences in the magnitude of various impacts. Terrestrial ecotoxicity dominates the environmental profile with the highest normalized value of 1.000, indicating that pollutant emissions causing ecological harm to land ecosystems represent the most significant impact of the plant operations per 1 m3 of processed water. Following this, climate change impacts are the second most prominent (normalized at 0.1715), suggesting a considerable carbon footprint from fossil fuel combustion.
Human toxicity impacts, both non-carcinogenic and carcinogenic, though less severe, still represent a meaningful share of the burden with normalized values of 0.0622 and 0.0205, respectively. Similarly, fossil energy consumption contributes at a normalized value of 0.0538, reinforcing the link between energy inputs and emissions. All other categories, including marine and freshwater ecotoxicity, acidification, water use, ionizing radiation, photochemical oxidant formation (PMO), and ozone depletion, show significantly lower normalized values, mostly under 0.01, indicating relatively minimal contributions in the current operational context. These findings support the prioritization of mitigation strategies focusing on reducing ecological toxicity and greenhouse gas emissions, while continuing to maintain efficiency in other environmental domains.
The normalization method used in Figure 4 is a max-based normalization, where the maximum value among all impact categories is used as the reference (set to 1.0), and all other values are scaled relative to this maximum. In this case, the highest impact value is ecotoxicity: terrestrial = 20.38251153, which is normalized to 1.0. The LCA of the selected case study power plant, evaluated per cubic meter (1 m3) of water treated, reveals distinct contributions across key environmental impact groups. As presented in Table 2, the ecosystem quality group exhibits the highest cumulative burden, accounting for 20.5689 kg 1,4-DCB-Eq, primarily due to terrestrial, freshwater, and marine ecotoxicity impacts. This indicates significant ecological stress linked to emissions and waste discharge from plant operations. The climate/energy group ranks second, with a combined impact of 4.5924 kg CO2-Eq, highlighting the substantial greenhouse gas emissions and fossil energy dependency associated with power generation. The human health group follows with an aggregated impact of 1.7459 kg 1,4-DCB-Eq, encompassing carcinogenic and non-carcinogenic toxicity, ionizing radiation, particulate matter formation, and photochemical oxidant formation, posing moderate health-related environmental risks.
In contrast, resource use demonstrates a relatively low impact of 0.0918, reflecting the efficient consumption of water, minerals, and land resources at the unit level. Finally, the ozone depletion group registers a negligible value of 2.95 × 10−6 kg CFC-11-Eq, suggesting minimal influence on stratospheric ozone degradation. These findings, as detailed in Figure 5, underscore the priority areas for environmental improvement, particularly in ecosystem protection and carbon emission reduction, while maintaining efficiency in resource consumption and ozone safety.
The above results show that DEMI water production, although important for energy processes, imposes a significant environmental burden, particularly due to the high electricity consumption in membrane processes and the use of chemicals in the pre-treatment stages. The findings indicate a strong correlation between the energy intensity of the system and its environmental impacts. Notably, the RO and EDI units, which operate under high pressure or electrical fields, dominate both electricity consumption and the associated greenhouse gas emissions. This mirrors the conclusions of Chaplin [37], Sun et al. [38], and Nath [39], who found that membrane and electrochemical technologies are critical hotspots in LCA evaluations of water treatment systems. Chemical usage, particularly sodium hypochlorite (NaOCl), ferric sulfate (Fe2(SO4)3), hydrochloric acid (HCl), and sodium hydroxide (NaOH), also contributes significantly to ecotoxicity and human toxicity indicators. These chemicals, while essential for coagulation, disinfection, and pH regulation, present environmental risks due to their upstream production and downstream release pathways.
The results are consistent with regional studies by Marcellin et al. [40], which emphasized the importance of energy and material accounting in infrastructure projects in areas with arid and resource-constrained conditions like Iraq. When benchmarked against international data, the energy footprint of 3.143 kWh/m3 aligns with values reported for comparable plants in the Middle East yet still presents a substantial opportunity for optimization.
Currently, the RO system at the Al-Hilla Power Plant does not incorporate energy recovery devices, which are commonly used in modern RO installations to reduce energy consumption. Energy recovery devices (ERDs), such as pressure exchangers or turbochargers, capture and reuse the high-pressure brine stream’s energy, significantly lowering the overall electrical demand of the system. The absence of ERDs contributes to the high energy intensity observed in this study. Integrating ERDs in future plant upgrades could lead to substantial reductions in operational energy use and associated greenhouse gas emissions, improving both the economic and environmental performance.
To mitigate the environmental burden of DEMI water production in power plants, several strategic interventions are suggested. First, the integration of renewable energy sources, particularly photovoltaic (PV) solar arrays, can significantly reduce indirect emissions and the dependence on fossil fuels by powering reverse osmosis (RO) and electrodeionization (EDI) units. This shift supports the transition to cleaner energy and aligns with broader sustainability objectives. Second, improving pump efficiency by upgrading to variable speed and high-efficiency pumps would lower the electricity demand during intake and recirculation processes. These enhancements contribute to overall energy conservation and reduce operational costs. Third, chemical optimization through the real-time monitoring and automation of chemical dosing can minimize overuse and mitigate the residual toxicity of treatment processes.
The system boundary defined for this study did not include membrane replacement and disposal (e.g., RO and EDI membranes), as detailed data on frequency, lifespan, and end-of-life treatment specific to the Al-Hilla Plant were unavailable. These components were therefore excluded from the life cycle inventory. However, it is acknowledged that membranes have finite operational lifespans and possess significant embodied environmental impacts, particularly in categories such as human toxicity and resource depletion. This limitation has been noted in Section 3 (Results and Discussion Section) as a potential area for future improvement once reliable operational data become accessible.
This approach ensures that only the necessary quantities of chemicals are used, enhancing both the environmental and economic outcomes. Additionally, adopting hybrid treatment designs such as incorporating advanced oxidation processes or biofiltration can serve as a complementary or alternative step, thereby reducing the reliance on harsh chemicals [41,42]. These advanced techniques offer more sustainable and effective treatment options. By implementing these measures, the Al-Hilla Second Gas Power Plant and similar facilities across Iraq, can make measurable progress toward energy efficiency, reduced environmental impact, and alignment with national sustainability goals under the Sustainable Development Goals (SDGs) framework.

5. Validation

To better contextualize the environmental performance of the Al-Hilla Power Plant’s demineralized (DEMI) water production system, comparative results from other Life Cycle Assessment (LCA) studies are considered. These studies, conducted in regions with varying energy matrices and technological designs, highlight the importance of contextual factors such as electricity source, membrane type, and operational practices.
For instance, Anshelm and Simon [43] analyzed ultrapure water production in Sweden using a system powered predominantly by hydroelectric and wind energy. Their study reported a global warming potential (GWP) of approximately 0.35 kg CO2-eq per cubic meter of ultrapure water, indicating a very low carbon footprint due to the renewable-rich grid. Similarly, Nilkar et al. [44] reported GWP values ranging from 0.3 to 0.6 kg CO2-eq/m3 for membrane-based systems in the UK, where natural gas is a dominant but less carbon-intensive source compared with coal.
In contrast, Sharifzadeh et al. [45] evaluated an RO-EDI system operating within a coal-dominated grid in northern China, where the GWP was estimated at 4.0–4.5 kg CO2-eq/m3, closely aligning with our result of 3.50 kg CO2-eq/m3. The similarity in GWP values suggests that the high impact in our study is primarily attributed to the Iraqi national electricity grid, which remains heavily dependent on fossil fuels, particularly oil and gas.
Furthermore, a study by Moreno et al. [46] in the Gulf region using data from Ecoinvent (v3.6) assumed a regional fossil fuel electricity mix and reported GWP impacts around 2.8 kg CO2-eq/m3, which, while slightly lower, reinforces the role of grid carbon intensity in determining environmental burdens.
This comparative analysis underlines two key points: (1) electricity use is the dominant driver of environmental impacts in DEMI and ultrapure water production systems, particularly in processes like RO and EDI that require a continuous, high-energy input; (2) the carbon intensity of the electricity grid directly influences impact categories such as GWP, fossil resource depletion, and human health toxicity.
Therefore, mitigation strategies such as the integration of renewable energy sources (e.g., solar PV), the implementation of energy recovery devices, and the optimization of membrane cleaning/replacement schedules can significantly reduce environmental burdens. Future work should explore the feasibility of hybrid power solutions or demand-side management strategies within Iraqi water–energy infrastructure to improve sustainability.

6. Conclusions

This study applied the Open LCA-ReCiPe 8 Midpoint H method to conduct an LCA of DEMI water production at the Al-Hilla Second Gas Power Plant in Iraq. The environmental impacts associated with producing 1 m3 of high-purity water were evaluated across 18 midpoint categories. The key conclusions are as follows:
  • Terrestrial ecotoxicity was the most significant environmental burden (20.383 kg 1,4-DCB-eq), primarily driven by the use of treatment chemicals such as sodium hypochlorite, ferric sulfate, and hydrochloric acid.
  • Climate change impact (3.496 kg CO2-eq) and fossil resource depletion (1.097 kg oil-eq) were also substantial, reflecting the high electricity demand of the RO and EDI units, which together accounted for over 70% of total energy consumption (3.143 kWh/m3).
  • Additional impacts were observed in human toxicity (non-carcinogenic: 1.268 kg 1,4-DCB-eq; carcinogenic: 0.418 kg 1,4-DCB-eq), marine and freshwater ecotoxicity, and metal/mineral resource depletion, indicating a need for the more sustainable management of chemical inputs and infrastructure materials.
  • The energy assessment revealed that the RO and EDI units are responsible for over 70% of the plant’s total energy consumption (3.143 kWh/m3), emphasizing the urgency of adopting energy-efficient technologies, particularly in regions like Iraq where electricity production is predominantly fossil fuel-based.
  • Although categories such as ozone depletion and eutrophication had relatively low values, they may pose long-term environmental risks and should not be overlooked in future mitigation efforts.
To reduce the environmental footprint, the following strategies are recommended: (i) replacing or optimizing chemical dosing using real-time monitoring, (ii) improving pump and membrane energy efficiency, (iii) integrating renewable energy sources to offset fossil fuel dependency. Circular economy practices, such as sludge valorization and material recycling, could further enhance sustainability. By implementing these improvements, the plant can significantly lower its ecological impact while supporting Iraq’s transition toward more sustainable water and energy infrastructure.

Author Contributions

Q.M.M.: Data collection, investigation, and writing the original draft. H.M.Z.: Conceptualization, methodology, software, supervision, validation, review, and editing consecutive drafts. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author(s).

Acknowledgments

The authors would like to thank the technical staff at the Al-Hilla Plant, lab team, Ministry of Electricity, etc.

Conflicts of Interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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Figure 1. Al-Hilla Second Gas Power Plant (Google Earth).
Figure 1. Al-Hilla Second Gas Power Plant (Google Earth).
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Figure 2. Flow chart of selected station units. The red line is the reject from RO1 stage 1, and the blue line is the reject from RO2 stage 1 and returned to RO1.
Figure 2. Flow chart of selected station units. The red line is the reject from RO1 stage 1, and the blue line is the reject from RO2 stage 1 and returned to RO1.
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Figure 3. Life cycle environmental impact results per 1 m3 of treated water at Al-Hilla Second Gas Power Plant.
Figure 3. Life cycle environmental impact results per 1 m3 of treated water at Al-Hilla Second Gas Power Plant.
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Figure 4. Normalized environmental impact values (reference: terrestrial ecotoxicity = 1.0).
Figure 4. Normalized environmental impact values (reference: terrestrial ecotoxicity = 1.0).
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Figure 5. Grouped environmental impacts from Al-Hilla Second Gas Power Plant per 1 m3 of treated water.
Figure 5. Grouped environmental impacts from Al-Hilla Second Gas Power Plant per 1 m3 of treated water.
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Table 1. Field measurements of treatment system.
Table 1. Field measurements of treatment system.
Treatment StageFlow Rate (m3/h)SD (±m3/h)Comments
Raw water intake from Euphrates River160±5Total water entering the plant
Domestic and sanitary use77±3Internal non-process consumption
Water fed to media filters83±4Net volume directed to DEMI production
RO-1 feed61±3Supplied to the first RO stage
Return to RO-12±0.5Recycled concentrate
RO-1 reject (returned to river)22±1Brine discharged from RO
RO permeate to Tank T1059±3Net product water from RO
Output from electro-deionization (EDI)56±2Final DEMI product
Return to raw tank3±0.5Recycled concentrate
Table 2. Energy consumption by treatment stage.
Table 2. Energy consumption by treatment stage.
Treatment StageEnergy Use (kWh/m3)SD (±kWh/m3)
River Intake and Transfer0.1875±0.01
Sand Filtration0.2338±0.02
RO Stage 10.5422±0.03
RO Stage 20.6066±0.03
Electro-Deionization (EDI)0.8814±0.04
Chemical Dosing0.0094±0.001
Total2.4609±0.07
Table 3. Chemical input inventory.
Table 3. Chemical input inventory.
ChemicalDose(mg/L)Hourly Use (kg/h)Use per 1 m3 (g/m3)
Sodium Hypochlorite (NaOCl)100.8310
Ferric Sulfate Fe2(SO4)3201.6620
Hydrochloric Acid (HCl)151.2515
Sodium Hydroxide (NaOH)12112
Table 4. Life cycle environmental impact categories for 1 m3 of demineralized water.
Table 4. Life cycle environmental impact categories for 1 m3 of demineralized water.
Impact CategoryUnitImpact Value
Terrestrial Ecotoxicitykg 1,4-DCB-eq20.383
Climate Changekg CO2-eq3.496
Human Toxicity—Non-Carcinogenickg 1,4-DCB-eq1.268
Fossil Resource Depletionkg oil-eq1.097
Human Toxicity—Carcinogenickg 1,4-DCB-eq0.418
Marine Ecotoxicitykg 1,4-DCB-eq0.106
Freshwater Ecotoxicitykg 1,4-DCB-eq0.068
Metal/Mineral Resource Depletionkg Cu-eq0.064
Ionizing RadiationkBq Co-60-eq0.048
Land Usem2·a crop-eq0.0184
Acidification—Terrestrialkg SO2-eq0.0119
Water Usem30.00978
Photochemical Oxidant Formation—Ecosystemskg NOₓ-eq0.00752
Photochemical Oxidant Formation—Human Healthkg NOₓ-eq0.00703
Particulate Matter Formationkg PM2.5-eq0.00422
Freshwater Eutrophicationkg P-eq0.000253
Marine Eutrophicationkg N-eq7.39 × 10−5
Ozone Depletionkg CFC-11-eq2.95 × 10−6
Table 5. Energy consumption by treatment stage (per 1 m3 of DEMI water).
Table 5. Energy consumption by treatment stage (per 1 m3 of DEMI water).
Treatment StagePower (kW)Time (h)Flow (m3/h)Energy Use per m3 (kWh/m3)Total Energy Use (%)
Intake pump from river3041600.18755.97%
Pump before sand filter system184770.23387.44%
Pump before RO Unit 1454830.542217.25%
Pump before RO Unit 2374610.606619.30%
Pump before electro-deionization (EDI)154220.681821.70%
Electro-deionization system524590.881428.05%
Chemical dosing pumps0.5284560.00940.30%
Total---3.143100%
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Modhehi, Q.M.; Zwain, H.M. Life Cycle Assessment and Environmental Impact Evaluation of Demineralized Water Production at Al-Hilla Second Gas Power Plant, Iraq. Resources 2025, 14, 137. https://doi.org/10.3390/resources14090137

AMA Style

Modhehi QM, Zwain HM. Life Cycle Assessment and Environmental Impact Evaluation of Demineralized Water Production at Al-Hilla Second Gas Power Plant, Iraq. Resources. 2025; 14(9):137. https://doi.org/10.3390/resources14090137

Chicago/Turabian Style

Modhehi, Qasim Mudher, and Haider Mohammed Zwain. 2025. "Life Cycle Assessment and Environmental Impact Evaluation of Demineralized Water Production at Al-Hilla Second Gas Power Plant, Iraq" Resources 14, no. 9: 137. https://doi.org/10.3390/resources14090137

APA Style

Modhehi, Q. M., & Zwain, H. M. (2025). Life Cycle Assessment and Environmental Impact Evaluation of Demineralized Water Production at Al-Hilla Second Gas Power Plant, Iraq. Resources, 14(9), 137. https://doi.org/10.3390/resources14090137

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