Novel Insights into Agro-Industrial Waste: Exploring Techno-Economic Viability as an Alternative Source of Water Recovery

Abstract

The growing challenges of freshwater scarcity and the high generation of agro-industrial waste, particularly from fruit and vegetable (F&V) processing, pose significant threats to the sustainability of global food systems. F&V waste, which represents a major portion of the 1.3 billion tons of annual food waste, is characterized by a high moisture content (80–95%), making it a largely overlooked but promising source of water recovery. This review critically assesses the techno-economic and environmental feasibility of extracting water from moisture-rich agro-industrial waste streams. Potential technologies such as solar distillation and membrane separation are evaluated to determine their capacity to treat complex organic effluents and recover high-quality water. The potential end uses of reclaimed water in all sectors are explored, focusing on agricultural irrigation, fertigation, industrial reuse and environmental restoration. This study addresses a key research gap and proposes the reclassification of agro-industrial waste as a viable water resource aligned with circular bioeconomy principles and Sustainable Development Goals (SDGs) 6 and 12.

1. Introduction

Water scarcity and agro-industrial waste generation represent two of the most pressing environmental challenges of the 21st century, especially in global food systems. As climate change intensifies and the world’s population continues to grow, the availability of freshwater resources is rapidly diminishing, putting greater pressure on the agricultural and food processing sectors to optimize their use of resources. According to projections, by 2050, almost 30% of agricultural land, including that dedicated to F&V, will be exposed to severe water shortages, posing a significant threat to global food security and rural livelihoods [1]. Current estimates already show that more than 4 billion people suffer from severe water scarcity for at least one month a year, and almost 500 million suffer from it all year round [2]. Furthermore, projections suggest that by 2050, global water demand could surpass supply by up to 40%, driven primarily by population growth, economic development, and the intensification of agricultural water use [3]. Agriculture alone already consumes around 70% of all freshwater withdrawals, much of it for irrigated food crops that feed over 60% of the world’s population [4]. Alarmingly, climate models indicate that a warming of just 2 °C above current levels could expose an additional 15% of the world’s population to severe water shortages and increase the number of people facing absolute water scarcity (defined as less than 500 m³/person/year) by up to 40% [5]. These figures paint a sobering picture of the growing competition for water between food production, industry and domestic needs. Today, any effort to promote the use and reuse of water represents a valuable alternative.

At the same time, the agro-industrial sector, especially the F&V processing industry, is a major contributor to organic waste generation. Worldwide, food waste is estimated at 1.3 billion tons per year, and F&V accounts for almost 40–50% of this total due to its high perishability and strict aesthetic or quality standards in all markets and consumer segments [6]. A significant portion of this loss occurs in the post-harvest, processing and retail stages. In India, for example, more than 72% of harvested fruit is lost annually due to inadequate cold storage, inefficient logistics and lack of processing support [7]. Similarly, retail operations in Paraguay reported F&V waste rates of up to 11.5%, which occur mainly before the products reach consumers’ shelves [8].

Wholesale markets are also critical points of waste generation. In Nepal’s main wholesale markets (Kalimati, Pokhara and Narayangadh), studies have shown considerable product losses caused by a lack of cold storage and inadequate packaging. These losses often exceed 20% of total input volumes and are compounded by limited redistribution or waste management efforts [9]. Similarly, in Brazil, a study conducted in CEASA wholesale markets found self-reported waste rates of 22.5% for lettuce, 5.8% for papaya and potatoes, 3.3% for tomatoes and 2.2% for oranges, which highlights the variability of waste rates depending on the type of crop and storage conditions [10].

The high moisture content of these waste streams, between 80 and 95% water, makes them difficult to store and manage. For example, waste samples collected from the General Wholesale Market in Milan showed high perishability due to this high water content, leading to proposals to press and dehydrate the waste to improve management efficiency [11]. Despite these challenges, this same moisture content represents an untapped opportunity for sustainable water recovery. With the right technological interventions, such as solar distillation or membrane treatment, this waste could serve as an alternative source of reclaimed water, providing a double environmental benefit: reducing the volume of organic waste and contributing to water conservation in water-scarce regions.

The dual crisis of declining water availability and growing agro-industrial waste calls for integrated and cross-cutting solutions. One promising but underexplored strategy is the recovery of water directly from high-moisture F&V waste. This approach aligns closely with the goals of the circular bioeconomy and the United Nations SDGs, in particular SDG 6 (Clean Water and Sanitation) and SDG 12 (Responsible Consumption and Production). It offers the potential to simultaneously reduce pressure on freshwater systems and divert substantial volumes of organic waste from landfills. However, although the nutritional and biochemical valorization of this waste has gained significant attention, the concept of moisture extraction for water recovery remains largely ignored in both academic and industrial research. Agricultural waste represents approximately 998 million tons of waste per year, and F&V waste constitutes a significant proportion of this amount [12]. These waste streams, if untreated, not only waste valuable resources but also contribute to climate change and soil and water pollution.

This review addresses this important research gap by evaluating the technical, environmental and economic feasibility of recovering water from F&V waste. It is based on the premise that horticultural waste with a high moisture content is currently an environmental problem, but could become a valuable contribution to decentralized water recovery systems, especially in water-scarce regions where innovative solutions are urgently needed. By exploring cutting-edge technologies, treatment challenges and reuse possibilities, this article contributes to reimagining agro-industrial waste as a key component of sustainable water resource management.

2. Potential of Agro-Industrial Wastes for Water Recovery

The agro-industrial sector generates vast amounts of organic waste, particularly from wholesale F&V markets. These wastes, including peels, pulps, leaves, and non-commercial root residues, are rich in moisture, making them a potentially valuable water source. However, inadequate waste management often leads to rapid decomposition, producing leachates with significant environmental impact [13].

Wholesale and retail F&V markets are primary contributors to this issue, generating hundreds of tons of waste daily. For example, in the Philippines, a single wholesale market has been reported to produce between 100 and 200 kg of F&V waste per day, underscoring the urgent need for waste recovery strategies [14]. Similarly, Brazilian markets discard up to 48.6% of their processed products, a significant loss of moisture-rich organic matter that could otherwise be recovered for sustainable applications [13]. The same situation is observed in Nepal, where major wholesale markets—such as Narayangadh, Pokhara and Kalimati—record considerable post-harvest losses due to inadequate storage and handling. These losses highlight the need for improved management systems, not only to reduce environmental impact but also to enable innovative recovery approaches [15]. In Europe, research at Milan’s General Wholesale Market revealed the high moisture content in F&V wastes, making them highly perishable and challenging to store. The study indicated that processing techniques such as pressing could reduce moisture content by up to 50%. However, this research only considered solid residues obtained from pressing for industrial and agricultural reuse and did not evaluate the potential reuse of the extracted water [11]. In Iran, where food waste levels are reportedly six times higher than the global average, inefficient market logistics and a lack of economic incentives have been identified as key drivers of F&V waste generation [16].

Beyond waste disposal issues, surplus redistribution initiatives have also shown limitations. In Chile, an analysis of food redistribution from wholesale markets to homeless shelters revealed that, while these initiatives reduce waste, excess donations often lead to spoilage, ultimately creating additional organic waste. The study noted that, during the winter, 152 g of vegetable waste and 74 g of fruit waste per person per day were discarded in the shelters, reinforcing the need for alternative approaches to waste utilization [17] and highlighting another area of opportunity to reclaim waste that can be used for water extraction.

In addition to wholesale and retail market waste, other factors exacerbate food losses. Studies in Brazil have highlighted logistical problems such as inadequate cold-chain management and consumer rejection of imperfect produce, significantly increasing waste percentages. Self-reported residue rates varied notably by product: 22.5% for lettuce, 5.8% for papaya and potatoes, 3.3% for tomatoes, and 2.2% for oranges [10], revealing variations in water recovery potential depending on product composition and seasonal demand. Furthermore, a key challenge in the reuse of water extracted from F&V waste with a high moisture content lies in its potential to contain bioactive compounds and residual nutrients, such as polyphenols, sugars and proteins that can accelerate microbial growth and chemical degradation, compromising storage stability without proper treatment [18,19].

Together, these results show the global scale of F&V waste in wholesale and retail markets and highlight the urgent need for effective waste valorization strategies. Approaches such as moisture recovery, composting and bioenergy production could mitigate environmental impact while creating valuable resources. Despite these promising alternatives, there is a lack of literature discussing the utilization of water contained in wastes such as fruits and vegetables, including the economic feasibility and the large-scale application of water recovery from these agro-industrial wastes. While studies have documented the nutritional potential of F&V wastes, research quantifying their water extraction and reuse capacity is limited. This gap represents a key opportunity for further research, particularly in the development of sustainable water recovery systems tailored to high-moisture agro-industrial by-products.

To determine the potential of obtaining water from wastes, it is important to identify the main wastes generated, and whether they have a high moisture content, including lettuce, tomatoes, orange peels, cabbage leaves, carrot peels, banana peels, papaya peels, watermelon rind and potato peels [10,14,16,17,20,21,22]. These materials exhibit high moisture levels and significant water activity, making them prime candidates for water recovery and reuse. However, their rapid decomposition requires immediate processing to avoid microbial spoilage and optimize water extraction efficiency [23].

Table 1. Moisture content, water activity and challenges in water recovery from major market residues.

Waste Type	Moisture Content (%)	Water Activity	Technical Challenges and Processing Considerations	References
Lettuce	95–96	0.99	Fast microbial degradation; requires immediate processing.	[24,25]
Tomatoes	93–95	0.98	Pectin-rich consistency may require additional filtration steps.	[11,22]
Orange Peels	70–75	0.94	Lower moisture but can be used for hydrothermal treatments and bioactive compound extraction.	[23,26]
Cabbage Leaves	94	0.98	Tougher structure; enzymatic breakdown may be required for efficient extraction.	[22,27]
Carrot Peels	86–90	0.97	Fibrous nature reduces pressing efficiency; enzymatic hydrolysis needed.	[28]
Banana Peels	70–90	0.96	High sugar and starch content complicates recovery; enzymatic pre-treatment required.	[22,29]
Papaya Peels	85–90	0.96	Significant soluble sugars and pectin; enzyme-assisted pressing recommended.	[30,31]
Watermelon Rinds	92–94	0.99	Soft structure allows high-efficiency pressing with minimal processing.	[32]
Potato Peels	80–85	0.94	Dense composition; enzymatic pre-treatment needed for effective pressing.	[22,33]

Data compiled from experimental moisture and degradation profiles reported in multiple studies.

summarizes the moisture content, water activity and key challenges associated with water recovery from various agro-industrial wastes, highlighting their potential and limitations for practical applications.

These findings underscore the untapped potential of F&V residues as candidates for water recovery, yet their economic feasibility and large-scale applicability remain largely unexplored. Addressing this research gap could open the idea for innovative water recovery technologies that align with sustainability goals and resource-efficient agro-industrial practices. This conceptual pathway is illustrated in Figure 1, which summarizes the sequential stages from waste generation to water recovery and reuse applications.

3. Potential Technologies for Water Recovery from Agro-Industrial Wastes

Water recovery from agro-industrial wastes, particularly from F&V wastes, represents a promising solution for valorizing high-moisture waste streams while promoting resource efficiency in agriculture. This approach is especially relevant for horticultural wastes, which typically contain significant amounts of recoverable moisture. Technologies such as solar distillation and integrated membrane systems have shown considerable promise in treating effluents with high organic loads. However, their application to water extraction from horticultural residues remains largely unexplored. These solutions not only contribute to water conservation but also support circular economy principles by enabling the safe and efficient reuse of water recovered from organic waste streams in sectors such as agriculture, industry and municipal services. Despite these prospects, there is limited documentation regarding the economic feasibility of valorizing agro-industrial wastes and virtually no studies specifically focused on water recovery, highlighting a significant gap for future research to fill.

3.1. Solar Distillation

Solar distillation is recognized as one of the most energy-efficient and environmentally sustainable technologies for water recovery, particularly suitable for regions with high solar irradiance. It operates by harnessing solar energy to evaporate and subsequently condense water, effectively removing impurities and producing clean, distilled water. In a notable study, Jaladi et al., (2019) developed a solar-driven wastewater treatment system enhanced with carbon foam porous media to localize heat, significantly increasing evaporation rates and overall recovery efficiency [34]. Their findings suggest strong scalability potential for solar distillation in agro-industrial settings, such as hydroponic greenhouses, where high-moisture effluents are common.

For water extraction from horticultural waste, it is important to note that solar distillation has proven effective in treating effluents with high organic loads, as shown in several studies. For example, Shaikh et al., (2024) demonstrated that integrating solar-powered membrane distillation with humidification-dehumidification systems significantly improved water flux and energy performance in the treatment of complex textile wastewater, showing promise for application in organic-rich agro-industrial effluents [35]. Similarly, Castro et al., (2024) used membrane distillation to simultaneously recover reusable water and valuable acids from industrial waste streams, reinforcing the dual potential of solar-assisted systems in both purification and valorization [36]. These dual benefits—clean water and the recovery of bioactive compounds—highlight the suitability of solar distillation for managing organic-rich waste streams, particularly those from F&V processing.

A more recent innovation comes from Tanvir et al., (2021), who designed a passive solar thermal membrane distillation system capable of treating wastewater, seawater and surface water [37]. Their system achieved an impressive 67.5% energy efficiency, one of the highest recorded for a single-stage system, and produced water that met U.S. potability standards by effectively removing COD, turbidity, and microbial contaminants [37]. Similarly, Chen et al., (2021) investigated solar interfacial distillation (ISD) as a cost-effective and energy-efficient option for the treatment of contaminated industrial wastewater [38]. Although their study focused on seawater, it raised valid concerns regarding the potential transfer of volatile organic compounds in the distillate, recommending the integration of activated carbon adsorbents to ensure output quality [38]. This consideration is especially relevant given the diverse and complex composition of agro-industrial waste streams.

The application of solar distillation to the valorization of horticultural wastes seems particularly promising due to the high moisture content of these residues and the typically decentralized nature of agro-industrial operations. By relying on renewable energy and passive mechanisms, this approach reduces both treatment costs and environmental impact. Importantly, as demonstrated by Nahim-Granados et al., (2021), solar-treated agri-food wastewater has been successfully used for crop irrigation, showing no microbial contamination and minimal absorption of organic micropollutants into edible plant tissues, an essential consideration for agricultural reuse, with solar distillation being shown as a method for treating this water [39].

Moreover, solar distillation can serve as a pre-treatment step that enhances the performance of more advanced water recovery systems, such as membrane filtration or bioelectrochemical technologies. In the context of this article, which focuses on water extraction from F&V waste, solar distillation represents a particularly viable and underutilized solution. However, as the literature review shows, there is limited documentation of the cost-effectiveness of solar distillation in agro-industrial contexts, and virtually no studies on its specific use for water recovery, underscoring the need for further research in this area.

3.2. Membrane Distillation

Membrane distillation (MD) has emerged as a flexible and promising technology for water reclamation, especially when dealing with effluents with a high organic load, such as those generated in agro-industrial environments. Several studies have validated its efficacy in the treatment of complex wastewater streams, supporting its potential application to F&V waste management. For example, M. K. Gupta et al., (2023) evaluated a solar-assisted membrane distillation system designed to treat highly contaminated wastewater from the textile industry [40]. Despite the effluent’s composition, the system demonstrated high technical and economic performance, successfully removing dyes and persistent organic pollutants [40]. These results suggest that similar MD configurations could be adapted to agro-industrial wastewater, which often contains similarly complex organic fractions derived from sugars, fibers and polyphenolic compounds.

Furthermore, Yadav et al., (2022) studied an innovative approach to membrane distillation, known as membrane distillation crystallization (MDCr) [41]. In their study, MDCr was used to treat highly saline and organic-rich wastewater from industrial and agro-industrial sources, achieving zero liquid discharge (ZLD) [41]. In addition to producing clean water, MDCr enabled the recovery of valuable salts and minerals, highlighting the broad resource recovery potential of this technology. Its economic viability and sustainability profile make MDCr particularly attractive in regions where water scarcity and environmental regulations drive the need for integrated solutions in addition to the potential recovery of some bioactive compounds present in horticultural waste.

Recent reviews by Zhang and Xian (2024) also confirm the potential of hybrid MD systems for simultaneous water recovery and compound valorization when treating high-strength agro-industrial effluents [42]. These approaches are especially relevant in the context of F&V wastes, which may also contain compounds with biological properties. Ngo et al. (2023) proposed innovative photothermal and localized heating solutions to improve energy efficiency and reduce membrane fouling in MD systems, addressing many of the traditional challenges in agro-industrial contexts [43]. The most common issues include membrane fouling and pore wetting, both of which reduce system efficiency and lifespan. However, recent developments in amphiphobic and omniphobic membranes, as well as the integration of hybrid systems, offer promising solutions to overcome these obstacles and improve long-term operational stability.

For applications focused on extracting water from horticultural waste, MD offers a compelling combination of low-temperature operation, high separation efficiency and modular design adaptability. Nonetheless, literature documenting MD’s cost-effectiveness for agro-industrial waste valorization and specific water recovery applications remains scarce. To bridge this gap, future research should focus on adapting MD systems for use in decentralized, small-scale agro-industrial operations, where they could offer sustainable water solutions.

3.3. Other Technologies

Beyond distillation systems, several emerging pressure-based membrane technologies have shown strong potential for recovering water from agro-industrial waste streams. Among them, forward osmosis (FO) stands out as an energy-efficient alternative that uses osmotic pressure gradients to draw water through a semi-permeable membrane. Unlike reverse osmosis (RO), FO does not rely on high hydraulic pressures, which significantly reduces energy consumption. Lutchmiah, (2014) evaluated the feasibility of FO in wastewater extraction applications and reported effective removal of contaminants from organic-rich wastewater [44]. These results support the possibility of integrating FO in agro-industrial contexts, especially when dealing with F&V wastewater, allowing both the extraction of clean water and the concentration of organic fractions for biogas production or subsequent valorization [44].

Also, pressure-driven membrane technologies, such as ultrafiltration (UF), nanofiltration (NF) and reverse osmosis, are already widely used in the treatment of wastewater from food and beverage processing. Castro-Muñoz et al., (2020) highlighted the dual functionality of these systems: they not only purify water, but also facilitate the recovery of bioactive compounds, such as antioxidants and polyphenols [45]. This dual benefit is particularly relevant in the context of F&V wastes, which are known to contain a wide spectrum of phytochemicals.

In an industrial context, Dagar et al., (2023) demonstrated the effectiveness of combining UF and RO for treating wastewater from the pulp and paper industry, another sector characterized by complex effluents [46]. Their integrated system achieved up to 88% removal efficiency for total dissolved solids (TDS), chemical oxygen demand (COD), and biological oxygen demand (BOD), producing water suitable for reuse in non-potable industrial applications [46]. These results point to the adaptability of such systems to treat agro-industrial wastewater, especially when preceded by simple pre-treatment steps that remove coarse organic matter or fibers.

Together, these membrane technologies underscore the feasibility of implementing water recovery systems in agro-industrial settings, especially in F&V processing facilities. The nature of these wastes, rich in water, soluble compounds and biodegradable matter, fits well with the mechanisms of FO, UF and RO, making them promising candidates for efficient water recovery. While extensively studied in other industries, direct application to F&V waste for water recovery remains limited, presenting opportunities for innovation.

In general, the integration of FO and pressure-driven membrane technologies complements other approaches, such as solar and membrane distillation. When properly combined, these systems can significantly reduce the water footprint of agribusiness operations while supporting the circular economy. Overcoming technical limitations, especially those related to membrane fouling, operational cost and scalability, will be key to realizing their full potential in decentralized or small-scale F&V processing units. Other technologies must also be considered for the necessary pre- or post-treatment of the resulting water, which can meet quality standards and can be put to a wide range of uses.

To facilitate a clearer understanding of the different technologies available for recovering water from agro-industrial waste, a qualitative comparison is presented in

Table 2. Comparison of technologies for water recovery.

Technology	Estimated Recovery Efficiency	Reported Technical Indicators	Key Benefits	Key Limitations	Practical Applicability	Cost vs. Efficiency	References
Solar distillation	40–65%	T = 60–80 °C; water yield: 2–6 L/m2·day	Low cost, solar powered, ideal for rural areas	Low productivity, dependence on climate	Small scale, areas with high solar radiation	High (low cost, low efficiency)	[47,48,49]
Membrane distillation	70–90%	T = 60–80 °C; recovery up to 98%; flux 5.4–7.1 L/m2·h	High efficiency, suitable for high-organic-load wastewater	Membrane fouling, high initial cost	Medium to large agro-industries	Medium (high cost, high efficiency)	[50,51]
Crystallization by MD	~90%	Operates at 60 °C; salt recovery ≥ 95%; flux: 20 L/m2·h	Enables ZLD and simultaneous salt and bioactive recovery	Operational complexity, limited commercial availability	Specialized applications	Low (very high cost, high efficiency)	[41,52]
Forward osmosis	50–80%	Flux: 2–10 LMH; >95% rejection; NaCl/MgCl2 draw	Low energy consumption, treatment of complex waste	Need for extraction solution, incomplete water recovery	Experimental and pilot use	Average (moderate efficiency)	[53,54]
Reverse osmosis	>90%	P = 4–8 bar; >99% salt rejection; stable output	High quality treated water, mature technology	High energy consumption, sensitive to dissolved solids	Industrial use, demanding applications	High (high efficiency vs. high energy cost)	[55,56]
Ultrafiltration/Nanofiltration	60–85%	Ambient T, low P; MWCO: 300–1000 Da	Water recovery + bioactive compounds	Requires pre-treatment, sensitive to soiling	Complementary in hybrid schemes	High (favorable ratio in hybrid systems)	[57,58]

The technologies and technical indicators presented in this table are based on studies involving municipal, industrial or synthetic wastewater. To date, these methods have not been specifically tested for water recovery from F&V waste. Therefore, the values shown are indicative and should be interpreted as reference points for potential application. Further experimental studies are needed to evaluate their actual feasibility and required conditions in F&V waste matrices. Technical values such as flux (LMH), operating temperature (°C), and membrane pore size (MWCO) are based on ranges reported in recent literature. LMH refers to L per square meter per h; MWCO (Molecular Weight Cut-Off) indicates the smallest molecular weight solute retained by the membrane. Cost and energy demand levels are estimated qualitatively based on typical system configurations and scale.

. This includes an overview of each method’s typical recovery efficiency, major strengths, limitations, cost-efficiency, relevant technical indicators and suitable contexts for application. The data are drawn from recent studies focusing on hybrid and advanced systems including membrane distillation, forward osmosis and reverse osmosis. It is important to note, however, that these technologies have primarily been studied in the context of other wastewater types, such as municipal or industrial effluents, and not specifically for F&V waste. While they show potential for future application in this area, dedicated studies are still needed to assess their technical feasibility, including process parameters, possible pre- and post-treatment steps, and the characteristics of the recovered water.

3.4. Post-Treatment of Water by Adsorption from Agro-Industrial Wastes

Although primary water reclamation technologies such as solar and membrane distillation or pressure-driven membranes are effective in removing a broad spectrum of contaminants, additional post-treatment steps are often required to ensure that the final water quality meets specific reuse standards, particularly for applications in agriculture, industry or recreational environments. In this context, adsorption-based treatment systems offer a sustainable, low-cost post-treatment strategy capable of polishing water by removing residual organic contaminants, heavy metals and emerging contaminants that may persist after initial purification.

Recent research has demonstrated the effectiveness of using materials derived from agro-industrial wastes as adsorbents, turning what is traditionally considered trash into a resource for water remediation. Mo et al., (2018) reviewed the adsorption capacities of various agricultural wastes-including fruit peels, sugarcane bagasse and coconut husks-for the removal of dyes and heavy metals [59]. Their findings revealed that simple chemical or thermal modifications, such as carbonization or acid activation, significantly improve the surface area and adsorption capacity of these materials [59].

This post-treatment potential is especially relevant when dealing with wastewater from agro-industrial wastes, which not only have a high moisture content, but may also contain bioactive compounds, dyes or soluble nutrients that require selective removal depending on the final water application, e.g., Simón et al., (2022) reported that adsorbents based on agricultural residues, such as corn residues and sunflower seed hulls, achieved removal efficiencies above 50% for heavy metals such as zinc and cadmium [60]. These types of residual contaminants, although present in trace amounts, may limit the safe use of reclaimed water in irrigation unless it is treated in a final polishing stage [60]. In addition, Aftab et al., (2024) highlighted the value of green adsorbent technologies for wastewater post-treatment, emphasizing that natural agricultural waste materials can be functionalized to remove phenolic compounds and even pharmaceuticals [61]. Such capabilities are vital in agro-industrial contexts where certain fruit residues may carry pesticide residues or plant metabolites that could affect soil microbiota or crop quality [61].

Additionally, biochar derived from pyrolyzed F&V waste has gained attention for its stability, porosity and high adsorption performance. Monica et al., (2023) demonstrated that biochar from food waste could effectively remove nitrates, phosphates and even persistent organic pollutants, making it ideal for conditioning water prior to reuse in agricultural irrigation systems [62]. Similarly, Yunus et al., (2022) reported that activated carbon produced from agricultural wastes such as rice or coconut husks showed strong performance in binding heavy metals and improving overall water clarity [63].

As a final treatment stage, adsorption not only ensures compliance with stricter water quality standards but also supports a closed-loop system, where waste materials are repurposed to treat water extracted from other waste. This dual valorization aligns with circular economy principles and reduces reliance on expensive synthetic materials or chemicals. The need for integrated research efforts that combine primary recovery techniques with sustainable post-treatment methods is clear. In future system designs, adsorption units could be modularly integrated downstream of distillation or membrane-based processes, offering efficient removal of residual contaminants with minimal energy consumption. This approach would ensure that recovered water would not only be plentiful, but also safe and versatile in its reuse, whether for irrigation, cleaning or even as process water in agro-industrial settings.

The growing interest in water recovery from agro-industrial wastes has led to the exploration of various sustainable technologies capable of meeting both environmental and water scarcity challenges. Among them, solar distillation and membrane-based processes stand out for their efficiency in treating effluents with high organic loads, such as those generated from horticultural waste. While solar distillation offers a low-cost alternative based on renewable energy and suitable for rural or decentralized contexts, membrane distillation and pressure-driven systems offer scalability and high-quality production for industrial reuse. Emerging technologies such as direct osmosis and membrane distillation crystallization (MDCr) further expand the possibilities for water recovery and resource valorization, including zero liquid discharge systems. However, to ensure the final quality of the recovered water, additional post-treatment is often necessary. In this regard, these technologies support circular agro-industrial systems through water reuse and by-product recovery.

4. Uses and Applications of Water Extracted from Agro-Industrial Wastes

Water recovery from agro-industrial waste offers an opportunity to address increasing water stress and support sustainable reuse. In this context, the agricultural sector—which consumes the majority of global freshwater resources—is under growing pressure to implement innovative water reclamation and reuse strategies that ensure food security and long-term sustainability [64]. Fortunately, advances in treatment technologies including ultrafiltration, reverse osmosis, membrane bioreactors, and electrocoagulation have shown strong potential for recovering high-quality water from agro-industrial wastewater streams [65,66]. This reclaimed water can be reused in a variety of applications, such as agricultural irrigation, industrial cooling, cleaning processes and depending on treatment level, even for recreational or potable use. As climate variability, population growth and intensive production put pressure on conventional water supplies, the integration of advanced treatment technologies with sustainable management practices has become essential not only to ensure water availability but also to reduce the environmental impacts of agro-industrial operations [67]. This section explores the various applications of reclaimed water in different sectors, emphasizing its strategic importance for improving sustainability in agriculture and food processing, especially when the reclaimed water comes from nutrient-rich bioactive waste streams. Figure 2 summarizes the main potential applications of water recovered from F&V waste, highlighting its versatility across multiple sectors.

Recent studies have shown that reclaimed water from non-traditional sources holds significant promise for expanding water availability in various sectors. In industrial contexts, treated wastewater has been effectively employed in non-potable applications such as thermal regulation systems, industrial washing and in certain manufacturing processes, offering both environmental relief and operational savings [68,69]. Advanced treatment methods, including membrane filtration and oxidation techniques, have made it possible to meet the stringent quality requirements of sensitive industries like pharmaceuticals and food processing, enabling safe integration of reclaimed water into these systems [70]. Furthermore, from a sustainability perspective, Maeseele & Roux (2021) emphasize how industrial reuse of treated effluents can decrease reliance on energy-intensive water sources like desalination [71]. Life cycle assessments also show substantial reductions in the environmental footprint of manufacturing operations when water recovery strategies are incorporated [72]. In regions facing chronic water stress, these practices are critical for long-term water resilience.

The agricultural and recreational sectors are also embracing reclaimed water, particularly under increasing water stress. In Europe, treated urban wastewater has been successfully used for irrigation, with models showing that it can maintain crop yields while reducing freshwater withdrawals under climate change scenarios [73]. In Spain, reclaimed water has contributed to the circular use of water in the Western Mancha aquifer, helping to reduce aquifer depletion and promote more sustainable agricultural systems [74].

Beyond agriculture, there is growing interest in the use of reclaimed water for recreational purposes. Projects in Japan, for example, have demonstrated the safe use of treated wastewater for ornamental and recreational reuse, including in streams and parks, with strict quality standards to ensure public safety [75]. In Australia, community acceptance studies have shown that, with adequate communication and health guarantees, the public is receptive to reclaimed water for irrigating sports fields and urban green spaces during periods of drought [76].

Water recovered from F&V processing offers benefits beyond hydration. Studies indicate that this wastewater may contain phenolic compounds, antioxidants and nutrients, making it useful for irrigation or as a liquid fertilizer [77]. Green extraction technologies now make it possible to recover these compounds for secondary uses in biostimulants, functional foods or cosmetics [78]. Although water recovery from agro-industrial waste represents a circular opportunity, its use in food agriculture requires a rigorous assessment of the risks associated with residual bioactive compounds. Several studies have documented that these contaminants can persist in treated water and be absorbed by edible crops, posing risks to human health if they accumulate in edible organs or are transferred to the food chain [79,80,81]. For example, phenols such as BPA and nonylphenol have been found to accumulate in plant tissues, and pharmaceutical residues can promote the presence of antibiotic-resistant bacteria.

Therefore, it is recommended to complement recovery processes with adsorption or advanced oxidative treatment stages, especially when the water is intended for edible crops. In turn, the need to establish specific standards for water recovered from agro-industrial waste is highlighted, as most current regulations were designed for urban wastewater and do not consider emerging contaminants specific to this matrix. A critical issue that affects the application of water recovery technologies from agro-industrial waste is the absence of a specific legal framework. Unlike urban wastewater, for which international guidelines such as those of the WHO (2020) or the FAO exist, water extracted from industrial organic waste is not always covered by clear regulations. In many jurisdictions, the use of reclaimed water for agricultural irrigation is limited to authorized operators or requires specific licenses that may be inaccessible to small agro-industries or rural communities.

In regions such as the European Union, Regulation (EU) 2020/741 establishes microbiological, nutrient and emerging contaminant parameters for reuse in agriculture, but does not explicitly address matrices with high bioactive compound contents, such as those generated in F&V processing. This legal loophole imposes a barrier to the scaling up of technologies that could be sustainable and safe provided they are combined with advanced treatments. It is therefore a priority to promote differentiated, risk-based regulations that take into account the specific composition of recovered water and its end use, in order to facilitate the adoption of circular models in the agro-industrial sector [79,82].

The recovery and reuse of water from alternative sources, including agro-industrial waste, represents a promising and largely untapped opportunity to address the growing pressure on the world’s water resources. Advances in treatment technologies have enabled the production of high-quality reclaimed water suitable for applications ranging from industrial processes and agricultural irrigation to urban landscaping and recreation. Particularly relevant is the potential of F&V wastewater, which not only offers a significant volume of recoverable water but also contains bioactive compounds that could improve soil fertility and crop productivity. As recent studies have shown, the integration of water recovery systems into agro-industrial processes can contribute to a circular economy, reduce environmental impacts and improve the sustainability of water management.

5. Environmental Impact of Water Recovery from Organic Waste

The world’s growing population, urbanization and industrialization are generating massive quantities of waste, leading to serious environmental consequences. Food waste is produced through spoilage or as a by-product at various stages of the food supply chain. These stages include agricultural production, food processing, distribution (such as municipal and wholesale markets), and final consumption. This substantial volume of waste has far-reaching environmental, health and economic impacts. In response, various alternative technologies are being developed to extract biofuel precursors and value-added compounds from food waste [83].

Due to its high water and nutrient content, food waste is more prone to deteriorate during the collection, transportation and storage processes. Untreated waste from juice industries, unprocessed leftover fruits and vegetables such as tomatoes, oranges, mangoes, jackfruit, pineapple, bananas and many more are extremely perishable; they contain high levels of BOD and COD as well as suspended solids that are not utilized, which raises serious concerns about environmental pollution [84,85]. Food waste degrades faster compared to other organic wastes, which can bring various negative consequences to the environment if not properly disposed of or managed [86]. The composition of organic waste is rich in carbohydrates, proteins and lipids which are easily decomposed by microorganisms, emitting greenhouse gases (CH₄) into the atmosphere. It is estimated to be the third most important source of greenhouse gases (CH₄ and CO₂). Additionally, microbial degradation can lead to the leaching of organic and inorganic materials, polluting surface and groundwater and contributing to eutrophication and acidification [85,87].

There is a strong relationship between organic waste and water. Improper disposal of organic matter can worsen water wastage and pollution. Effective waste management is essential to reduce the negative effects on water resources, as landfilled organic waste generates leachates with high pollutant loads that threaten water quality. It is estimated that one-quarter of the freshwater used in global food production is wasted on uneaten food. By addressing food waste through valorization and recovery strategies, the interlinked challenges of food security, water scarcity and environmental sustainability can be better managed, paving the way for a more resilient and balanced ecosystem [88].

Microbial degradation can produce leachates containing organic and inorganic materials, polluting surface and groundwater and posing serious environmental risks. To mitigate these risks, initiatives such as reusing overripe fruits and producing by-products including supplements, bio-adsorbents, fertilizers and biofuels have been introduced. These efforts contribute to protecting water sources and supporting environmental goals, particularly SDGs 6 (Clean Water and Sanitation) and 12 (Responsible Consumption and Production) [89].

Reclaimed water contributes to environmental restoration and rural water security in regions under water stress. In agriculture, for example, reclaimed water can contribute to local environmental restoration and support agricultural resilience in water-scarce regions. Moreover, it can be used to support economic activities in peri-urban farming communities, increasing water availability and improving livelihoods [90].

According to data collected by Del Mar and García (2017), water demand is estimated to increase by 55% by the year 2050 due to population increase, growing urbanization, food consumption, and water and economic development [91]. New food habits, consumption and basic needs imply water costs, known as a water footprint. A positive correlation has been observed between greenhouse gas footprint (GHS) and water footprint with the reduction of global food waste [86].

6. Technical Limitations and Challenges

The extraction of water from agro-industrial waste, particularly F&V waste, is a promising but technically demanding process. One of the most immediate challenges lies in adapting existing infrastructures to accommodate water recovery technologies. As Albusaimi et al., (2024) point out, the shift toward circular economy practices in water reuse requires significant investments in robust treatment systems and distribution networks, which are often beyond the reach of small and medium-sized agro-industrial farms [92]. This is especially relevant when attempting to expand water recovery from organic wastes with high moisture contents, such as lettuce or watermelon rinds, which are abundant in wholesale markets but degrade quickly without proper management.

Furthermore, achieving water of sufficient quality for reuse requires highly efficient treatment systems capable of handling complex effluents. In these circumstances, Figueredo et al., (2022) reported that although anaerobic digestion and root zone treatment systems were effective in reducing pollutant loads in wastewater from the sugar industry, the resulting effluents still exhibited high coloration and organic content, which limited their reuse in applications such as firefighting or irrigation [93]. These findings highlight the need for multi-stage treatment processes, often combining biological, physical and chemical methods to meet quality standards. This challenge becomes more pronounced given the variable pH, turbidity, and microbial loads in F&V waste.

Beyond infrastructure, operational efficiency represents another critical limitation on the implementation of water recovery systems from agro-industrial waste. One of the main concerns is the high energy demand associated with many treatment technologies. As noted by Lung et al., (2012), a significant proportion of water and wastewater treatment facilities still rely on obsolete systems that are not only inefficient but also expensive to operate [94]. This is particularly problematic in agro-industrial contexts, where waste streams fluctuate greatly in volume and composition depending on seasonal production. This variability makes it difficult to design energy-efficient treatment systems that can maintain performance under dynamic operating conditions.

In addition, regulatory and safety concerns must be addressed when considering the reuse of reclaimed water, particularly for agricultural applications. Engida et al. (2020) assessed the potential for reuse of brewery sludge and identified the presence of contaminants such as heavy metals and persistent organic compounds as a major obstacle [95]. Similar concerns arise in the context of agro-industrial waste, where the accumulation of agricultural residues, pesticides or post-harvest chemicals could pose risks if not properly treated. Therefore, ensuring that reclaimed water meets quality standards for irrigation or industrial reuse is a prerequisite, adding further complexity and cost to the treatment process.

The incorporation of nature-based solutions (NBS), such as constructed wetlands, has become a promising sustainable strategy for treating agro-industrial wastewater. As Hagenvoort et al., (2019) have pointed out, these systems take advantage of ecological processes to reduce pollutant loads and improve water quality, thus offering an environmentally harmonious approach to resource recovery [96]. In agro-industrial contexts, NBS can complement more intensive technologies by polishing effluents for safe reuse. However, their application is limited by factors such as land availability, process control and scalability, which may not be feasible for densely operated or infrastructure-limited facilities.

From a technical standpoint, the variability and complexity of agro-industrial wastewater represent a major challenge. These waste streams often have high levels of suspended solids, organic matter and residues of agricultural inputs such as pesticides and fertilizers. Taddeo et al., (2018) showed that a high total solids content significantly limits the performance of nutrient recovery processes such as struvite precipitation [97]. This results in clogged filters, reduced reaction efficiency and increased maintenance needs, all of which undermine system reliability. Similarly, membrane-based technologies, while capable of producing high-quality effluents, are susceptible to fouling, particularly when treating organic-rich waste. Alegre, (2017) reported that although microfiltration (MF), ultrafiltration (UF) and reverse osmosis (RO) systems are capable of producing high-quality effluents, they remain highly vulnerable to fouling, especially when treating complex agro-industrial wastewater [98]. For F&V waste—rich in sugars, fibers and fine particles—these challenges necessitate customized pre-treatment and membrane maintenance strategies. As such, despite their promise, real-world application of these technologies to F&V waste remains underexplored.

Compounding these issues are poor waste segregation practices, especially in developing countries. A study on the Central Grocery Market in Thessaloniki reported that the sustainable management of organic waste is often hampered by the lack of adequate waste segregation practices at the source, especially in F&V retail and wholesale markets [99]. Similarly, research in India emphasized that although anaerobic digestion and composting technologies offer viable solutions for F&V waste, the lack of differentiated collection systems for organic and inorganic waste remains a major obstacle to their implementation [100]. In many developing regions, waste is mixed at the source and proper sorting practices are not well established, especially in wholesale and municipal markets [101]. In addition to technical limitations, waste segregation practices in many developing countries present a critical barrier to the efficient recovery of water from F&V waste. This lack of segregation contaminates high-moisture organic streams and reduces the viability of water extraction initiatives. Overcoming this requires not only infrastructure upgrades, but also community education and behavioral change.

Water reclamation from agro-industrial waste, particularly F&V waste, shows great promise, but is not without considerable technical and infrastructural challenges. Issues such as high total solids content, membrane clogging and effluent composition variability complicate treatment processes and demand customized, multi-stage technologies. While sustainable solutions such as solar distillation, membrane systems and nature-based treatments have shown encouraging results, their scalability, energy efficiency and integration into existing facilities remain key barriers, especially for small and medium-sized agricultural processors. Additionally, regulatory uncertainties and economic barriers limit widespread adoption. Most importantly, this review identifies a critical research gap in water recovery specifically from F&V waste, calling for dedicated studies to validate and optimize these approaches.

7. Economic Viability

Agro-industrial waste represents a significant cost to both businesses and the environment when it is indiscriminately disposed of in general landfills. The implementation of valorization techniques represents a decrease in the impact on the environment while contributing to profitability when fruit waste recovery strategies are implemented, such as composting that allows the capture of methane gas that can be used for energy generation [102]. Other options include industrial applications such as paper production and agronomic uses like biofertilizer development [103].

However, the implementation of these projects must be accompanied by profitability assessments that determine their financial feasibility and help communicate the opportunities for success [104]. Key indicators of economic viability include capital investment, processing costs, cost-benefit analysis, sensitivity analysis, net present value, and internal rate of return [103,104]. However, the literature review found limited documentation of the profitability of the proposals developed on the valuation of agro-industrial wastes and none in terms of water recovery, revealing an area that calls for deeper investigation in future work.

Some sources suggest that using agro-industrial residues could help reduce production costs [30,105], but there are few studies that delve into the presentation of financial indicators. In this line, four studies conducted in Peru, Spain, Mexico and Brazil and published between 2022 and 2024 were identified. The results of these studies coincide in terms of the potential economic benefits that the reincorporation of agro-industrial waste generates for emerging business models within the framework of the circular economy.

Table 3. Economic feasibility of agro-industrial waste recovery projects.

Country/Author	Description	General Benefits	Economic Analysis of the Project	Potential Economic Benefits	Reference
Peru	Proposal for an agro-industrial waste processing plant for the production of compost.	Decrease in environmental impact. Reduction of costs for the acquisition of fertilizers and fertilizers. Processing of 100 tons of solid agro-industrial waste per day.	Implementation costs: Investment: US$1,000,000.00. Fixed investment: US$500,000.00 dollars Intangible assets: US$50,000.00 dollars Working capital: US$120,000.00 dollars Financing: 15 years Interest rate: 12%.	Reduction in daily agro-industrial waste costs of 138.7 metric tons. Approximate annual landfill costs: US$2,000,000.00.	[106]
Spain	Proposal for the generation of bioenergy from olive, almond and pistachio residues.	Bioenergy generation through biomass pyrolysis. Reduction of greenhouse gases. Sustainable practices. Reuse of agro-industrial waste.	Profitability (pistachio): Net Present Value (NPV): 178.48 million euros. Internal Rate of Return (IRR): 185.15%.	High economic viability. Investment payback in two years.	[107]
Mexico	Proposal for the generation of green energy from tomato waste to provide heat in greenhouses.	Biofuel generation. Reduction of 87% of ecological footprint per production period. Reduction in the use of fossil resources.	Fossil energy production. LP gas heating cost: US$1189. Production with green energy Heating cost of tomato pellets: 61 dollars. Supplementary LP gas heating cost: US$271. Cost reduction greater than US$918 per production cycle.	Economic feasibility with a 71% savings in the cost of providing heat in the greenhouses during each production period.	[108]
Brazil	Integration of guava residues in sheep feed.	Increased product quality. Increased productive performance of the consumer.	Effective operating cost: US$515 Gross revenues: US$732 Gross margin: US$217 Rate of return: US$0.13 Safety margin: 9%. Daily cost benefit: US$0.43.	Economic viability: 30% decrease in selling price. 1 dollar of investment = 0.43 dollars of return.	[109]

Note: The table shows four agro-industrial waste recovery proposals with a favorable profitability projection. In the proposals from Spain and Brazil, the return on investment is 43% and 85%, indicating an optimal efficiency of profits in relation to the investment required for the development of the project. On the other hand, the proposals from Peru and Mexico show a significant cost reduction that is reflected in the profitability of transforming their waste into new resources.

details the description of the proposals, the general benefits, the economic analysis of the project and the potential economic benefits derived from its development.

In general, projects developed to reuse agro-industrial waste show a bilateral potential. First, they contribute to the reduction of the environmental impact of agro-industrial activities. Second, they are a means to improve a business’s profitability. This is achieved through the reduction of operating costs, development of new sources of income, access to tax incentives, or the improvement in corporate image that is reflected in greater credibility in the eyes of green consumers.

8. Future Perspectives

The future of agro-industrial waste management is increasingly shaped by the principles of biorefineries and the circular bioeconomy, two interconnected frameworks that promote the comprehensive recovery of resources including energy, nutrients and water from organic waste streams. Waste biorefineries equipped with membrane and adsorption technologies offer the integrated recovery of water, nutrients and energy from agro-industrial residues. In this context, agro-industrial by-products are no longer mere disposal challenges. They become inputs for sustainable systems that align with global objectives such as the SDGs, in particular SDG 6 (Clean Water and Sanitation), SDG 12 (Responsible Production and Consumption) and SDG 13 (Climate Action).

Among the various recovery opportunities, water reclamation from agro-industrial waste with high moisture contents is emerging as a particularly promising avenue. F&V waste offers opportunities for water recovery due to its physical and biochemical characteristics relevant to treatment. When properly treated, this recovered water retains soluble nutrients, polyphenols and other bioactive compounds, which can improve its functionality for agricultural uses such as fertigation, liquid biofertilizers or even microbial fermentation media in biotechnological applications. This not only reduces the pressure on freshwater resources but also introduces new dimensions of value to waste streams.

In this context, waste biorefineries—facilities designed to extract multiple products from biomass—are gaining ground as practical and scalable solutions. When equipped with advanced treatment technologies such as membrane separation, oxidation processes and adsorption systems, these biorefineries can produce high-quality reclaimed water suitable for irrigation, industrial processes and even landscape restoration. Furthermore, by integrating solar energy recovery and low-consumption systems, biorefineries can reduce energy costs and promote decentralized models of water reuse, which are especially valuable in rural or water-scarce regions.

In agricultural systems, reclaimed water may serve dual purposes as irrigation and nutrient support, especially in controlled environments. Looking ahead, the integration of multi-stage treatment technologies into biorefinery models represents a strategic step in the sustainable transformation of agro-industrial supply chains. These systems can combine energy recovery, nutrient cycling and water purification in one operational framework, maximizing resource yields from a single waste stream. However, although the recovery of energy and fertilizers from organic waste has been widely studied, water recovery remains critically underrepresented in the literature and current pilot projects. This highlights the urgent need for research into the economic viability, technological scalability for SMEs and regulatory frameworks that enable the safe reuse of reclaimed water.

Finally, water recovery from fruit and vegetable waste contributes to circular, resilient and sustainable food systems. In particular, F&V waste, due to its abundance, high moisture content and biochemical richness, stands out as a prime candidate for this transformation. Unlocking its water potential could not only address local waste burdens but also help build more resilient, circular and regenerative food systems for the future.