Potential Environmental Impacts of a Hospital Wastewater Treatment Plant in a Developing Country

Abstract

Assessing the quality of a hospital wastewater treatment process and plant is essential, especially if the presence of chemical and biological toxic compounds is considered. There is less literature on hospital wastewater treatment in developing countries because of a lack of managerial awareness and stakeholder cooperation, accompanied by the limited capacity of investment meant to upgrade the existing infrastructures. Limited access to data further hampers the reliable analysis of hospital wastewater treatment plants (WWTPs) in developing countries. Thus, based on the possibility of collecting a sufficient amount of primary (i.e., field) data, this study performed an assessment of the potential impacts generated by the WWTP of Quaid-Azam International Hospital in Islamabad (Pakistan) considering its construction and operational phases. The major identified impacts were attributed to the energy mix used to operate the plant. Marine ecotoxicity was the most impactful category (34% of the total potential impacts accounted for), followed by human carcinogenic toxicity (31%), freshwater toxicity (18%), terrestrial ecotoxicity (7%), and human non-carcinogenic toxicity (4%). An analysis of potential impacts was combined with an assessment of potential damage according to an endpoint approach. In particular, the endpoint analysis results indicated that human health damage (quantified as DALY) was mainly dependent on the “fine PM (particulate matter) formation” category (51%), followed by “global warming and human health” (43%). Other categories related to human health impacts were human carcinogenic toxicity (3%), water consumption (2%), and human non-carcinogenic toxicity (1%). The other impact categories recorded a percentage contribution lower than 1%. With respect to ecosystem damage, “global warming and terrestrial ecosystems” played a major role (61%), followed by terrestrial acidification (24%), ozone formation (10%), water consumption (5%), and freshwater eutrophication (1%). This study’s findings support an increase in awareness in the hospital management board while pointing out the need to further implement similar studies to improve the quality of decision-making processes and to mitigate environmental impacts in more vulnerable regions. Finally, this research evidenced the need to overcome the existing general constraints on data availability. Consequently, further field work, supported by hospital managers in developing countries, would help in enhancing managerial procedures; optimizing treatment plant efficiency; and facilitating the implementation of circular options, such as sludge management, that often remain unexplored.

1. Introduction

The growth of population, the rapid urbanization process, and an increase in healthcare infrastructures have led to the increasingly significant production of hospital wastewater [1]. In developed countries, an average of 400–1200 L of wastewater per bed per day is generated from healthcare facilities, while in developing countries, the amount of wastewater generation is 200–400 L per person per day [2,3]. With respect to domestic wastewater, hospital wastewater contains more hazardous substances, such as pathogens, antibiotic-resistant bacteria, and toxic chemicals [4,5]. Therefore, hospital wastewater is more hazardous than domestic wastewater [6,7]. For example, contamination from pharmaceutically active compounds and endocrine-disrupting compounds has been observed in surface and groundwater even after treatment because of a lack of a proper plant design [8,9]. This is why advanced treatment options must be adopted to reduce the genotoxicity of hospital wastewater. On the other hand, the reuse of treated wastewater is highly desirable considering the impacts of growing anthropogenic activities. In fact, wastewater recovery can help in reducing water shortages in water-scarce areas [10]. Hence, advanced wastewater treatment and strict regulations for water contaminants are necessary [11].

Despite their purpose, wastewater treatment plants (WWTPs) can still impact human health and the environment because of their greenhouse gas (GHG) emissions, energy consumption, chemical utilization, and discharge of hazardous materials. During the WWTP construction and operation phases, greenhouse gases (GHGs) such as CO₂, CH₄, and N₂O, are emitted [12]. These emissions are primarily responsible for anthropogenic warming and global climate change [13]. Moreover, WWTPs are sources of effluent emissions, which impact aquatic ecosystems [14]. Moreover, WWTPs consume a significant amount of energy, globally sharing up to 20% of the total energy consumed by municipalities and other public utilities [15]. In particular, the operation of WWTPs is highly energy-demanding [16,17]. Advanced WWTPs consume more energy compared with conventional municipal WWTPs [18]. In fact, water reuse and reclamation require advanced treatment technologies, demanding a large amount of energy input [19]. Thus, energy consumption minimization and emission reduction have become important for wastewater policy-makers [20]. This is why WWTPs’ potential impacts should be understood during project evaluation and assessment [21].

Despite the significant relevance of this topic, only a few studies deal with the assessment of hospital wastewater treatment plants’ potential impacts in developing countries [22,23]. This context is especially relevant to fulfilling the Sustainable Development Goals (SDGs)—among them, SDG 3 (Good health and well-being), SDG 6 (Clean water and sanitation), SDG 12 (Responsible consumption and production), SDG 13 (Climate action), SDG 14 (Life below water), and SDG 15 (Life on land). In fact, there are many reported cases of untreated wastewater polluting water bodies and natural resources [24]. Moreover, the majority of WWTPs in developing countries often do not have tertiary treatments or sludge processing [25]. One study [26] reported that the major obstacles to the application of life cycle assessment (LCA) for the evaluation of environmental performance in developing countries are mainly due to (1) a lack of awareness of the benefits of LCA among decision-makers; (2) a lack of internal capacity in the government and industries; (3) quality assurance; (4) a need for adequate impact categories; and (5) a lack of collaboration among LCA experts in the region. These problems are further aggravated by the lack of available data, which could support informed decision-making processes and the implementation of more adequate policies. This is why, given their higher impacts and the higher risks for the environment and the biosphere, further efforts should be made to assess the potential impacts of hospital WWTPs in developing countries.

Coherently with the described framework, the objective of this work is to assess impacts along the life cycle of a hospital WWTP. This study focused on Quaid-e-Azam International Hospital (QIH) in Islamabad (Pakistan) as a case study. Besides the mentioned scarcity of research on hospital wastewater LCA, this study is relevant because it refers to the context of a developing country. Given the socio-economic conditions and more limited technological availability, paralleled by limited management skills and reduced public awareness, the current research interest in this topic from local authorities is often limited, resulting in a higher probability of delivering more impactful technological solutions [27,28,29]. This is why the obtained results can support healthcare managers and local authorities in planning the implementation of safer and healthier solutions. In parallel, the increased availability of data could improve the quality of delivered assessments, supporting the identification of appropriate circular solutions aimed at reducing wasted materials and increasing their partial reuse and recycling, which is already a research hotspot in the case of WWTPs [30,31,32].

2. Materials and Methods

2.1. Quaid-e-Azam International Hospital Wastewater Treatment Plant

Quaid-e-Azam International Hospital (QIH), located in Islamabad, the capital of Pakistan, was selected for this study. QIH not only serves locals in the Rawalpindi and Islamabad areas but also people who live near all of the country’s exits. In addition, QIH is located in the capital of the country and is accessible not only to locals but also to foreign consulates and other expats who reside in the capital. The current hospital WWTP was designed to fulfill the requirements of 400 beds. However, the hospital was designed to accommodate as many as 1000 patients, with a potential extension to 3000 patients in case of an emergency. For high-quality assurance, an extended aeration system was installed.

Wastewater from all the hospital’s facilities is transported via two 27.4 m long pipelines (diameter: 0.3 m). The total discharge of wastewater is 300 m³/day. The current WWTP has various treatment compartments. They include an equalization tank, an aeration tank, a settling tank, a sludge-holding tank, and a disinfection and control room. QIH’s WWTP includes four types of treatment: primary, secondary, and tertiary. A general reference scheme of hospital wastewater treatment phases is represented in Figure 1 and, later, specified in the case of QIH in Figure 2.

2.2. Aim of the Study

The environmental performance of the investigated WWTP case study was assessed by applying the LCA standardized framework, as defined by the ISO standards and ILCD handbook guidelines, in four steps [33,34,35,36]: (1) goal and scope definition; (2) inventory analysis; (3) impact assessment; and (4) interpretation of results.

Figure 2 consists of a diagram that represents the investigated system and its boundaries.

The system boundaries were set using a “gate-to-grave” perspective. The construction and operation phases of the plant were included in the impact assessment. In this respect, the transport of building materials and plant equipment from the manufacturing site to the plant site was considered [37]. First-order environmental impacts, such as direct discharge into air and the discharge of sewage, were also included [38]. Scenarios of sludge disposal and/or wastewater reuse phases were not included within the system boundaries.

The average wastewater inflow, which is regarded as a functional unit in this study, is 300 m³/day. The WWTP has a total life span of 20 years. The environmental impacts of a WWTP are quantified according to its functional unit [39].

2.3. Inventory Analysis

A life cycle inventory was built based on the various stages of the WWTP within the system boundary. Primary data for each phase of the process were collected on-site and through the company that built the WWTP. The primary data were collected through personal observations, questionnaires, and interviews following the same method used for a case study reported in the literature [40]. In particular, after obtaining consent from the chief executive of the Quaid-e-Azam International Hospital (QIH) in Islamabad for the purposes of academic research, site visits to the QIH wastewater treatment plant were made, which were aimed at assessing all the data related to the different treatment process steps. The technical specifications of the plant were collected from the plant’s design and manual and through the QIH management team’s interview materials, as previously performed in a different context for another LCA study [41]. Following the same study, moreover, an assessment of country-specific energy mix impacts was chosen instead of assessing global ones, which are available by default in the Ecoinvent impact database. The data on construction materials were collected from the WWTP site through a questionnaire and information from bills of quantity (BOQs). Three interviews were conducted involving the hospital management team following a semi-structured interview approach based on a set of predetermined questions to cover key aspects related to the plant’s design, operation, and performance. The interviewees were selected based on their specific roles and their ability to provide valuable insights into the technical aspects of the plant’s construction and operation processes. Prior to the identification of interviewees, a set of inclusion and exclusion criteria were fixed. In particular, the inclusion criteria for selecting participants included the following: (1) technical knowledge and experience in operating and managing the wastewater treatment plant; (2) familiarity with the specific challenges and requirements associated with hospital wastewater treatment in Pakistan; and (3) general expertise in the design, construction, and maintenance of wastewater treatment plants. The exclusion criteria were as follows: (1) individuals without direct experience or knowledge related to hospital wastewater treatment plants; (2) participants lacking expertise in wastewater treatment processes and regulations specific to Pakistan; and (3) those who did not possess the necessary technical skills or qualifications to provide valuable insights into the subject matter.

Initially, 20 potential participants were identified by the hospital management system. However, based on the defined inclusion or exclusion criteria, after reviewing their qualifications and relevance to the study objectives, the final selection was narrowed down to three individuals. In particular, the hospital wastewater treatment plant operator was chosen because of his first-hand experience in managing and operating the plant on a day-to-day basis. His expertise in the operational aspects of the plant, such as monitoring and maintaining equipment, optimizing treatment processes, and ensuring compliance with regulatory standards, made him the most suitable candidate for the interview. The plant engineer was selected given his in-depth understanding of the design and engineering principles behind hospital wastewater treatment plants. He possessed knowledge about the various components and systems involved in the plant’s construction, including the treatment units, pipelines, pumps, and control systems. The engineer’s insights were valuable for gaining a comprehensive understanding of the technical intricacies and considerations involved in the plant’s design and implementation. Finally, the media/communication officer was included in the interview process to provide insights into the challenges associated with hospital wastewater treatment plants, addressing any concerns or misconceptions and ensuring transparency in communication. The interview questions are listed in Table S2 as Supplementary Materials.

The main input flows within the construction phase are represented by cement, steel, iron, and diesel; meanwhile, electricity and chlorine are the major input flows of the operational phase of wastewater treatment [42,43]. Data on fuels and transportation were obtained from the contractor’s BOQs. The power consumption of the WWTP was estimated on the basis of the equipment’s size and time of operation. Secondary data were obtained from published journal articles, web links, and previous studies of the same nature. The main input flows of the construction phase of the WWTP are shown in

Table 1. Inventory of the construction phase flows of QIH-WWTP.

Item	Amount	Unit
Cement	55,951	kg
Steel	14,838	kg
Sand	27	m3
Crushed gravel	156.54	m3
Iron	11,690	kg
Water	449,750	L
Paint coat	5600	L
Al alloy	57	kg
PVC	15	kg
Polypropylene	17	kg
Diesel	15,000	L
Power cable (PVC + metal)	15	kg
Land occupation	464.5	m2

.

A product and a flow, termed “wastewater treatment plant”, were defined based on the inputs illustrated in Table 1. The given flow constitutes one of the components in assessing the impacts of a wastewater treatment process. Accordingly, we allocated the flow based on the functional unit considering the functional unit and the foreseen 20-year lifetime of the plant.

All the amounts included in the operational phase refer to a day and are coherent with the chosen functional unit. The operational phase inventory reported in

Table 2. Inventory of the operational phase flow of QIH-WWTP.

Item	Amount	Unit
Wastewater treatment plant	1/7300 × flow (wastewater treatment plant)	Item
Chlorine	0.427	kg
Electricity	414	kWh
Coating	15.342	L

is made up of flow; chlorine for water disinfection; electricity for plant operations; and coating paint, which is used once a year during maintenance operations.

Table 3. Basic hospital wastewater quality parameters fixed by QIH-WWTP managers and local regulations.

Parameter No.	Description of the Service	Mechanical and Biological Treatment
3	Suspended solid for influent water	90 mg/L
4	Suspended solid effluent water	10 mg/L
5	pH for influent water	6 to 9
6	pH for effluent water	6 to 9
7	BOD for influent water	60 mg O2/L
8	BOD for effluent water	10 mg O2/L

provides details of the basic wastewater quality parameters measured at the site.

Table 4. Power consumption of various machines of the treatment plant.

Item No.	Machine	Power	Measure Unit
1	Inlet Pump 1	1.1	kW
2	Inlet Pump 2	1.1	kW
3	Screen	0.37	kW
4	Blower 1	7.5	kW
5	Blower 2	7.5	kW
6	Effluent 1	3.0	kW
7	Effluent 2	3.0	kW
8	Chlorine Dosing Pump	0.015	kW
9	Lighting	0.06	kW

provides the power consumption of different machinery operating during the treatment.

The total energy consumption is calculated as the total power consumed by all the machines and equipment during the plant’s operating hours. The QIH-WWTP uses 414 kWh/day of power to pump water from the equalizing tank to the aeration tank to operate the treatment plant and run the control room. The contribution to the impacts is derived from the electricity consumed by each machine based on their operating hours. The data directly collected from the hospital managers are summarized in

Table 5. Energy mix (expressed as a percentage of the total) for the year 2015 derived from official IEA data.

Source	Percentage of Total Mix (%)
Coal	0.1
Oil	31.8
Natural gas	31.4
Nuclear	4.1
Hydro	31.1
Wind	0.7
Biofuels	0.5
Solar PPV	0.2

. In order to assess the impacts related to energy, given that the database Ecoinvent 3.1 did not contain the energy mix for Pakistan, we reconstructed it from official International Energy Agency (IEA) data for the year 2015.

2.4. LCA Impacts Assessment

After the LCA inventory phase, environmental impacts were calculated on the basis of the selected feature model. The applied impact method was ReCiPe 2016 (H), where “H” stands for hierarchist, that is, the consensus reference model used in LCA as a default [44]. The impact midpoint and endpoint categories included in this method are listed in

Table 6. Impact categories calculated by ReCiPe 2016 midpoint and endpoint impact methods.

Midpoint		Endpoint
Impact Category	Units	Impact Category	Units
Fine particulate matter formation	kg PM2.5 eq	Ozone formation, human health	DALY
Fossil resource scarcity	kg oil eq	Ionizing radiation	DALY
Freshwater ecotoxicity	kg 1,4-DCB	Global warming, human health	DALY
Freshwater eutrophication	kg P eq	Human carcinogenic toxicity	DALY
Global warming	kg CO2 eq	Human non-carcinogenic toxicity	DALY
Human carcinogenic toxicity	kg 1,4-DCB	Water consumption, human health	DALY
Human non-carcinogenic toxicity	kg 1,4-DCB	Stratospheric ozone depletion	DALY
Ionizing radiation	kBq Co-60 eq	Fine particulate matter formation	DALY
Land use	m2a crop eq	Global warming, terrestrial ecosystems	species.yr
Marine ecotoxicity	kg 1,4-DCB	Freshwater eutrophication	species.yr
Marine eutrophication	kg N eq	Ozone formation, terrestrial ecosystems	species.yr
Mineral resource scarcity	kg Cu eq	Marine eutrophication	species.yr
Ozone formation, human health	kg NOx eq	Global warming, freshwater ecosystems	species.yr
Ozone formation, terrestrial ecosystems	kg NOx eq	Terrestrial acidification	species.yr
Stratospheric ozone depletion	kg CFC11 eq	Terrestrial ecotoxicity	species.yr
Terrestrial acidification	kg SO2 eq	Freshwater ecotoxicity	species.yr
Terrestrial ecotoxicity	kg 1,4-DCB	Land use	species.yr
Water consumption	m3	Water consumption, aquatic ecosystems	species.yr
		Water consumption, terrestrial ecosystem	species.yr
		Marine ecotoxicity	species.yr
		Mineral resource scarcity	USD2013
		Fossil resource scarcity	USD2013

.

Based on the input data, the software converts different inputs, described as ”flows”, into potential outputs. As is usually performed in the assessment of life cycle impacts, the input flows include both the different components involved in the wastewater treatment process and the components derived from the construction phase, whose impact is assessed on the basis of the foreseen lifetime of the plant, which is generally indicated in the construction plans, as in the case of this study. Both the midpoint and endpoint values derive from the sum of impacts related to each flow, which, in turn, can refer either to the construction or operation phase.

In order to assess the life cycle impacts of the wastewater treatment plant, the inventory data were analyzed using the openLCA software [45], version 1.7.2 (https://openlca.org, accessed on 19 December 2023), based on the Ecoinvent impact analysis database, version 3.1, which enables the conversion of inputs into impacts through alternative methods, of which ReCiPe 2016 [H] was chosen [46,47].

3. Results

3.1. Midpoint Life Cycle Impacts Assessment

The characterized impacts related to the wastewater treatment plant are presented in

Table 7. Characterized impacts calculated with the ReCiPe 2016 midpoint (H) impact method.

Impact Category	Units	Impact
Freshwater ecotoxicity	kg 1,4-DCB	2.43 × 100
Ozone formation, human health	kg NOx eq	1.49 × 100
Marine eutrophication	kg N eq	4.55 × 10−1
Water consumption	m3	7.49 × 100
Stratospheric ozone depletion	kg CFC11 eq	1.70 × 10−4
Freshwater eutrophication	kg P eq	1.35 × 10−2
Terrestrial acidification	kg SO2 eq	2.24 × 100
Human carcinogenic toxicity	kg 1,4-DCB	9.13 × 100
Terrestrial ecotoxicity	kg 1,4-DCB	7.74 × 102
Global warming	kg CO2 eq	4.32 × 102
Human non-carcinogenic toxicity	kg 1,4-DCB	6.03 × 101
Fossil resource scarcity	kg oil eq	1.47 × 102
Fine particulate matter formation	kg PM2.5 eq	7.67 × 10−1
Ozone formation, terrestrial ecosystems	kg NOx eq	1.52 × 100
Land use	m2a crop eq	2.98 × 10−1
Marine ecotoxicity	kg 1,4-DCB	3.80 × 100
Ionizing radiation	kBq Co-60 eq	2.61 × 101
Mineral resource scarcity	kg Cu eq	7.33 × 10−1

.

According to the results for the normalized impacts related to the WWTP, the most impacted category is marine ecotoxicity, followed by human carcinogenic toxicity and freshwater toxicity. Together, they represent 89% of the accounted impacts (Figure 3). The results show that these are followed by terrestrial ecotoxicity, human non-carcinogenic toxicity, and fossil resource scarcity. Marine eutrophication, ozone formation, terrestrial acidification, ionizing radiation, global warming, fine PM formation, water consumption, freshwater eutrophication, stratospheric ozone depletion, and land use showed minor impacts. The relative impact on the different categories indicated that marine ecotoxicity accounted for 34% of the potential impacts, followed by human carcinogenic toxicity (31%). Freshwater toxicity (18%), terrestrial ecotoxicity (7%), and human non-carcinogenic toxicity (4%) were less relevant. Further impacts registered a contribution lower than 1%.

Table 8. Main wastewater treatment plant construction and operation contributor for each impact category.

Impact Category	Main Contributor	Percentage
Freshwater ecotoxicity	Electricity production	41.90%
Freshwater eutrophication	Electricity production	37.07%
Fine PM formation	Electricity production	63.24%
Fossil resource scarcity	Electricity production	63.08%
Global warming	Electricity production	63.89%
Human carcinogenic toxicity	Coating paint	51.60%
Human non-carcinogenic toxicity	Electricity production	38.60%
Ionizing radiation	Electricity production	96.99%
Land use	Electricity production	51.72%
Marine ecotoxicity	Electricity production	48.60%
Marine eutrophication	Electricity production	99.44%
Mineral resource scarcity	Hospital wastewater treatment plant	71.79%
Ozone formation, human health	Electricity production	46.88%
Ozone formation, terrestrial ecosystems	Electricity production	46.90%
Stratospheric ozone depletion	Electricity production	93.17%
Terrestrial acidification	Electricity production	69.37%
Terrestrial ecotoxicity	Electricity production	88.51%
Water consumption	Electricity production	60.15%

reports the main contributor for each impact category and its contribution percentage. Looking at the causes of the assessed impacts, toxicity-related categories are the most relevant ones. These results depend mainly on the indirect impacts generated by electricity production, which, in turn, reveals the embedded impacts depending on the country’s energy mix. Besides impacts derived from the energy mix that are indirect, there are impacts derived from the use of coating paint, which is used for the maintenance and insulation of wastewater treatment plants. In most categories, the main contributor is electricity production. Mineral resource scarcity mainly depends on the construction of treatment plant infrastructure, while water consumption is primarily related to coating paint during plant maintenance conducted once a year.

Figure 4 shows the contribution (percentage) of the different inflows to the impact categories, calculated according to the impact assessment method ReCiPe 2016—midpoint [H].

Electricity production is the major contributor to all the impact categories, with the exception of human carcinogenic toxicity and mineral resource scarcity. A second relevant contributor to the existing impacts is related to the use of coating paint. As the main contributor to human carcinogenic toxicity (51.6%), its relative contribution is above 30% for freshwater ecotoxicity, fine PM formation, fossil resource scarcity, human non-carcinogenic toxicity, ozone formation, and water consumption. The third contributor is the wastewater treatment plant because of its relevance in each impact category. In particular, it is the main contributor to mineral resource scarcity (71.79%). Moreover, its relative contribution is above 30% for freshwater eutrophication and human carcinogenic toxicity. Details about the values reported in Figure 4 are illustrated in the Supplementary Materials (Table S1).

3.2. Endpoint Life Cycle Impact Assessment

Table 9. Hospital wastewater treatment plant calculated according to ReCiPe 2016—endpoint (H).

Impact Category	Amount	Units
Ozone formation, human health	1.36 × 10−6	DALY
Ionizing radiation	2.21× 10−7	DALY
Global warming, human health	4.00 × 10−4	DALY
Human carcinogenic toxicity	3.03 × 10−5	DALY
Human non-carcinogenic toxicity	1.38 × 10−5	DALY
Water consumption, human health	1.66 × 10−5	DALY
Stratospheric ozone depletion	8.89 × 10−8	DALY
Fine particulate matter formation	4.80 × 10−4	DALY
Global warming, terrestrial ecosystems	1.21 × 10−6	species.yr
Freshwater eutrophication	9.06 × 10−9	species.yr
Ozone formation, terrestrial ecosystems	1.96 × 10−7	species.yr
Marine eutrophication	7.72 × 10−10	species.yr
Global warming, freshwater ecosystems	3.31 × 10−11	species.yr
Terrestrial acidification	4.74 × 10−7	species.yr
Terrestrial ecotoxicity	8.81 × 10−9	species.yr
Freshwater ecotoxicity	1.68 × 10−9	species.yr
Land use	2.65 × 10−9	species.yr
Water consumption, aquatic ecosystems	4.52 × 10−12	species.yr
Water consumption, terrestrial ecosystem	1.01 × 10−7	species.yr
Marine ecotoxicity	3.99 × 10−10	species.yr
Mineral resource scarcity	1.69 × 10−1	USD2013
Fossil resource scarcity	5.81 × 101	USD2013

illustrates the quantified impacts from an endpoint perspective.

Figure 5 represents the percentage contribution to disability-adjusted life year (DALY) derived from the impacts reported in Table 9 according to ReCiPe 2016—endpoint (H). Figure 6 demonstrates the percentage contribution to ecosystem damage (quantified as species/year) derived from the impacts reported in Table 9 according to ReCiPe 2016—endpoint (H). Contributions below 1% are not labeled in the two figures to preserve the clarity of the graphical representation.

In Figure 5, the main contributing category to DALY was “fine PM formation” (51%), followed by “global warming and human health” (43%), based on an endpoint evaluation. Three other impact categories had a relevance higher than 1% with respect to DALY: human carcinogenic toxicity (3%), water consumption (2%), and human non-carcinogenic toxicity (1%). The other impact categories recorded a percentage contribution lower than 1%.

In Figure 6, “global warming and terrestrial ecosystems” had a major impact (61%) on ecosystem damages, followed by terrestrial acidification (24%), ozone formation (10%), water consumption (5%), and freshwater eutrophication (1%). The other impact categories recorded a percentage value lower than 1%. Finally, mineral resource scarcity contributes the most to resource depletion (quantified as USD2013).

4. Discussion

The obtained results showed that the considered WWTP constitutes an energy-intensive infrastructure whose impacts are also dependent on the country’s energy mix. In fact, the used electricity was the most contributive inflow to almost all impact categories. The results of this study confirm the indications derived from previous literature findings, suggesting that the electricity and energy mix used during the wastewater treatment process has a direct relationship with global warming potential assessed through an LCIA [48,49]. Together with other significant impact contributors (i.e., the coating paint, which has to be renewed annually, and the WWTP construction step in terms of used energy, cement, steel, chemicals, etc.), electricity-generated burden reached about 94% of the total normalized impacts.

Since energy production constituted the main source of assessed impacts, the potential damage generated by the WWTP mainly depended on its design and operation, being, in turn, also dependent on its energy key performance indicators. This result confirms the findings of a previous comparative analysis, which included the construction and operation phases, proving that the environmental impacts resulting from the operation of the WWTP are more significant than those from the construction phase in all examined categories [26]. Moreover, with respect to acidification, the construction phase is responsible for more than 40% of the potential impact, mainly because of the use of diesel fuel in the machinery used.

The results displayed in Table 8 suggest that a more sustainable choice in the energy mix, better management of energy use, and efficiency would positively impact the climate change and particulate matter categories. This fact is confirmed by previous literature studies, which have identified a correlation between larger wastewater capacities and a reduction in energy costs [50].

The treatment of hospital wastewater should be considered a special case given the specific nature of chemical and biological contaminants that can be transported, for which tertiary treatment is especially needed. This is why the tertiary treatment phase had the highest energy expenditure, as confirmed by previous literature studies, which quantified it as being between 0.045 and 0.11 kWh/m³ [51]. In the case of QIH, sludge treatment is currently unmanaged, causing an increase in unmanaged impacts. According to the literature, this would generate an energy expenditure varying between 8% and 15% of the total wastewater treatment energy expenditure [51]. However, energy could be recovered through appropriate sludge treatment processes, considering that, because of its volatile organic contents, dried sewage sludge has energy content varying between 11.10 and 22.10 MJ/kg [52,53].

The observed potential toxicity did not translate into a very significant environmental issue when stepping further into the cause–effect chain from the midpoint to the endpoint perspective, where a shift in the contributions to the burdens is described. In fact, when considering effects on human health, the major potential consequences are due to the generated global warming and PM formation. Global warming is also acknowledged as the most significant issue in relation to its effect on ecosystems. The choice of simultaneously evaluating the midpoint vs. endpoint impacts allowed us to evaluate how different environmental impacts can acquire a different relevance along the cause–effect chain. Moreover, endpoint categories—expressed as the effect of environmental impacts on human health, ecosystems, and the depletion of resources—might be better understood by the general public and may facilitate decision making. Thus, the joint investigation of midpoint and endpoint results is beneficial for a deeper understanding of the burdens, and their effects, generated by the investigated case study.

The assessed burden related to the global warming (GW) endpoint category reflects environmental impacts related to the combustion of fossil fuels used for energy generation, machinery, and transportation. As shown by other studies, GW can be mitigated within WWTPs that integrate the anaerobic digestion process for sludge stabilization [26]. In this context, another study assessed how thermal energy can be an excellent substitute in reducing the environmental impacts of the use of Upflow Sludge Anaerobic Blanket (USAB) reactors [54].

Previous literature studies were inconclusive about the relative impact of WWTP infrastructure with respect to the overall treatment process. In particular, one work showed that the environmental impact of the construction phase could contribute, by 96%, to the total impacts of a WWTP, suggesting that differences in design and technological level can lead to changes in the outcome of the affected categories [55]. Moreover, according to some authors, infrastructure plays a major role in the generation of impacts [56]. Conversely, other studies have confirmed the prevalence of impacts generated by the operational phase [57,58], as also observed in this case study.

Despite the collection of primary data, whose quality was assessed during the field data collection phase of this study, the data were inevitably affected by some uncertainties since the management of the healthcare facility lacked a plan for a more detailed environmental monitoring system and primary data collection process. This is the case for the amount of produced sludge, whose data were not available since they were not collected, as it was impossible to collect them during this study. Thus, a further discussion on sludge processing and disposal from a circular economy perspective was not possible.

The impossibility of producing inventories based on primary data is not infrequent in LCA studies, for which the availability of primary data is one of the most critical concerns [59,60]. Most of the results produced in previous studies related to developing countries derived from previous literature data referred to other contexts, such as developed countries. If, from one side, this fact evidences the relevance of this study, which is based on field data collected in the case of a developing country, then on the other side, this lack of published studies referring to similar contexts limits the possibility of comparison and the possibility of extending the validity of the obtained results.

It is important to acknowledge other specific limitations of the research. Firstly, the collected primary data did not include a microbiological and chemical analysis of specific biological and chemical contaminants, including, for example, pharmaceuticals that could promote the presence of antibiotic-resistant bacteria [61,62]. This fact depended on a lack of appropriate management procedures, which currently exclude the detailed monitoring of different pollutants, as well as on a lack of appropriate on-site infrastructures to carry out the needed laboratory analyses. Consequently, a comprehensive assessment of the possible effects triggered by toxic compounds—including emerging ones such as pharmaceuticals, endocrine-disrupting chemicals (EDCs), viruses, antibiotic-resistant bacteria, and others—could not be conducted. Consequently, a broader collection of field data for future studies is recommended, especially in the case of developing countries. This would guarantee the improvement of the quality of impact assessments from one side. On the other hand, this would also improve the awareness of stakeholders and policy-makers, which would be further addressed in implementing informed policies and environmental management actions. Moreover, for future research, we recommend incorporating a more systematic chemical analysis of treated effluents, especially when conducting LCA studies on hospital wastewater.

Considering that, in relation to this case study, no technological upgrade of the treatment plant will be possible in the near future, this study did not include alternative infrastructure or technological scenarios for implementing the quality of the treatment process while reducing the most impactful categories identified. Nonetheless, future studies should address the implementation of cleaner process alternatives through LCA, which could be further integrated, encompassing assessments of economic costs with life cycle costing (LCC) analysis and social impacts considering the possibility of using social life cycle assessment (sLCA).

This work considered two phases of the life cycle of a wastewater treatment plant. The first one is the construction phase, and the second one is the operational phase. The latter corresponds to the evaluation of impacts related to the wastewater treatment process. The former, instead, is associated with the environmental impacts of the infrastructure, which depend on the construction materials and process and which are detailed in the infrastructure construction plan. Such an impact, as in the case of machinery in other LCA studies, is generally considered and included within LCA analytical processes, eventually assuming the timeframe of the performed analysis and the lifetime of the infrastructure or machinery. This study included construction costs thanks to the availability of all the primary data contained in the infrastructure’s construction plan. However, in other work, this impact remained unaccounted for or poorly considered because of a lack of primary data about construction plans and processes. This is why some studies focused either on operations or on both phases, considering the so-called “construction phase” to be a source of the environmental impacts of the infrastructure [63,64].

The findings of this study can contribute to the design and upgrade of future hospital WWTPs, especially in developing countries such as Pakistan, considering the lack of attention paid to this specific subject in the available literature. The relevance of such a contribution needs to be reframed within the need for more sustainable management of water resources. Pakistan was once a country characterized by its water surplus but now faces a water deficit. A reduction in water availability per capita by 2025 was already foreseen by a previous study based on the observation of a reduction from 1299 m³ in 1996–1997 to 1100 m³ in 2006 [65]. The availability of alternative water sources, like treated wastewater, mainly for irrigation, has become a significant challenge. However, given Pakistan’s limited economic resources available for environmental investments, the number of wastewater treatment facilities is still insufficient for the country despite their increase in the last few years. This constitutes an obstacle in developing effective policies for encouraging the installation of new plants.

On the other hand, an increased awareness of environmental impacts generated by defective environmental management practices can serve as a basis for developing informed policies and actions. This study can contribute to raising this awareness. In parallel, positive experiences provided by the introduction and implementation of cleaner production processes and efficient resource management elsewhere in the world could also serve as leverage on stakeholders and policy-makers in encouraging the installation of new plants [66]. This can be achieved within the Integrated Water Resource Management (IWRM) framework, which is currently under implementation in Pakistan and already involves the participation of different stakeholders [67].

In the case of Pakistan and other developing countries, there is certainly space for further improvements in the existing legislation and policies regarding hospital wastewater treatment, which could be based on the evidence of more extensive LCA studies. The inclusion of wastewater management in the larger framework of sustainable water resource management is desirable, together with the implementation of specific policies and legislation for hospital wastewater discharge and treatment. Though a comprehensive national policy and institutional framework for overall environmental management is in place, there are significant weaknesses in the current administrative and implementation capacity, which also depends on the limited number of people in the country trained in environmental management. Consequently, a clear strategy needs to be defined to implement these policies.

5. Conclusions

This study focused on the environmental performance of a hospital WWTP using the LCA method. This work represents the first LCA of a hospital WWTP in Pakistan addressing the research gap that is relevant to designing adequate policies and planning roadmaps for many similar cases existing in developing countries. The results showed that toxicity-related categories were the most significant impacts of the QIH-WWTP from a midpoint perspective. Meanwhile, climate change and particulate matter formation were identified as the most impactful categories from an endpoint perspective. This study identified the energy source mix used during the wastewater treatment process as the primary determinant of the assessed impacts, further proving the importance of including a higher fraction of renewable resources in the energy mix while also adopting solutions such as sludge-to-energy conversion processes under a circular economy perspective to further reduce the quantified impacts.

Hospital wastewater treatment requires greater attention starting with plant designs given the pollution load of hospital wastewater. In particular, a shift to larger wastewater capacities could reduce overall damage to ecosystem services, resource consumption, and the environment. Pakistan is a water-scarce country that has been greatly affected by climate change, which has resulted in floods, epidemics, heat waves, and extreme weather conditions. Limited resources and energy crises pose challenges to the more sustainable use of resources and a roadmap for minimizing the existing impacts of human activities. In this regard, this country still lacks adequate waste and wastewater management infrastructures and planning. Efficient and less energy-consuming treatment of wastewater, integrated with more appropriate management procedures, must be considered to protect human health and the environment.

Extending this work to other case studies would be very beneficial to improving the planning of future hospital wastewater treatment plants. In parallel, during field data collection, the still existing lack of widespread concern for informed environmental management emerged. For example, more complete data collection with respect to water quality parameters was missing, and data on the generation of by-products, such as sludge, should be collected and processed.

The implementation of this study in other contexts, within and outside Pakistan, would positively impact the management of investment and define future economic incentives; the management of investment; and future economic incentives that could be introduced for industries to acquire environmentally friendly technology. In parallel, the more accurate identification of current problems in wastewater treatment and wastewater’s potential reuse could be addressed, targeting the existing lack of environmental and economic policies and existing environmental management failures.

Accordingly, the obtained results are essential for supporting policies and improving the sustainable design of future WWTPs in Pakistan and other developing countries with similar socio-economic conditions, which might represent a relevant barrier to upgrading the sustainability of existing infrastructures.