Wastewater Reuse In Agriculture Research Articles

Unveiling drivers and barriers in advancing agricultural wastewater reuse in Southern Italy: A SWOT analysis informed by stakeholder insights

Unveiling drivers and barriers in advancing agricultural wastewater reuse in Southern Italy: A SWOT analysis informed by stakeholder insights

Risks associated with wastewater reuse in agriculture: investigating the effects of contaminants in soil, plants, and insects

Rapid urbanization has heightened the urgency of the necessity for sustainable water management in agriculture. This review focuses on the impacts of using reused wastewater in agricultural practices, specifically highlighting the nutrient benefits and consequences of pollutants on important environmental elements. It investigates the impact of contaminants on agricultural ecosystems by assessing the soil composition and nutrient equilibrium. This research also examines the impact of pollution exposure on plants and insects, elucidating the behavioural adaptations and their broader ecological consequences in agricultural environments. Eventually, a comprehensive analysis was conducted to consolidate these findings, emphasizing the challenges and significance of implementing sustainable practices. This study highlights the necessity of addressing the health and environmental concerns associated with the agricultural reuse of wastewater, while also giving valuable information to guide future regulations.

Demo-scale up-flow anaerobic sludge blanket reactor coupled with hybrid constructed wetlands for energy-carbon efficient agricultural wastewater reuse in decentralized scenarios

The impact of climate change on water availability and quality has affected agricultural irrigation. The use of treated wastewater can alleviate water in agriculture. Nevertheless, it is imperative to ensure proper treatment of wastewater before reuse, in compliance with current regulations of this practice. In decentralized agricultural scenarios, the lack of adequate treatment facilities poses a challenge in providing treated wastewater for irrigation. Hence, there is a critical need to develop and implement innovative, feasible, and sustainable treatment solutions to secure the use of this alternative water source. This study proposes the integration of intensive treatment solutions and natural treatment systems, specifically, the combination of up-flow anaerobic sludge blanket reactor (UASB), anaerobic membrane bioreactor (AnMBR), constructed wetlands (CWs), and ultraviolet (UV) disinfection. For this purpose, a novel demo-scale plant was designed, constructed and implemented to test wastewater treatment and evaluate the capability of the proposed system to provide an effluent with a quality in compliance with the current European wastewater reuse regulatory framework. In addition, carbon-sequestration and energy analyses were conducted to assess the sustainability of the proposed treatment approach. This research confirmed that UASB rector can be employed for biogas production (2.5 L h−1) and energy recovery from organic matter degradation, but its effluent requires further treatment steps to be reused in agricultural irrigation. The AnMBR effluent complied with class A standards for E. coli, boasting a concentration of 0 CFU 100 mL−1, and nearly negligible TSS levels. However, further reduction of BOD5 (35 mg L−1) is required to reach water quality class A. CWs efficiently produced effluent with BOD5 below 10 mg L−1 and TSS close to 0 mg L−1, making it suitable for water reuse and meeting class A standards. Furthermore, CWs demonstrated significantly higher energy efficiency compared to intensive treatment systems. Nonetheless, the inclusion of a UV disinfection unit after CWs was required to attain water class B standards.

A comparative analysis of regional infection risk due to wastewater recontamination in the Mezquital Valley, Mexico

Urban wastewater reuse for agriculture provides reliable nutrient-rich water, reduces water stress, and strengthens food systems. However, wastewater reuse also presents health risks and characterizing the spatial dynamics of wastewater can help optimize risk mitigation. We conducted comparative risk analysis of exposure to wastewater in irrigation canals, where we compared those exposed to a) treated vs. untreated wastewater, and b) wastewater upstream vs. downstream from communities in the Mezquital Valley. The canal system with treated wastewater was sampled prior to being treated, directly after treatment, as well as before and after it flowed through a community. Along the canal system that carried untreated wastewater, we sampled before and after a community. We quantified the concentrations of bacterial, protozoal, and viral pathogens in the wastewater. Pathogen concentration data were used to calculate measures of relative risk between sampling points. Wastewater treatment reduced predicted bacterial pathogen infection risk in post-treatment locations (RR = 0.73, 95 % CI 0.61, 0.87), with no evidence of similar reductions in Giardia or viral pathogens (RR = 1.02, 95 % CI 0.56, 1.86 and RR = 1.18, 95 % CI 0.70, 2.02 respectively). Although infection risk decreased further down the canals, infection risk increased for bacterial pathogens after our sentinel community (RR = 1.94, 95 % 1.34, 2.86). For Giardia and viral pathogens infection risk was elevated but not significantly. We found similar evidence for increases in risk when comparing the treated section of the canal system with a canal section whose wastewater was not treated, i.e., the risk benefits of wastewater treatment were lost after our sentinel community for bacteria (RR = 5.27 vs. 2.08 for sampling points before and after our sentinel community respectively) and for Giardia (RR = 6.98 vs. 3.35 respectively). The increase in risk after transit through communities could have resulted from local community recontamination of the treated wastewater stream.

Cold plasma turns mixed-dye-contaminated wastewater bio-safe

The excessive and uncontrollable discharge of diverse organic pollutants into the environment has emerged as a significant concern, presenting a substantial risk to human health. Among the advanced oxidation processes used for the purification of wastewater, cold plasma technology is superior in fast and effective decontamination but often fails facing mixed pollutants. To address these issues, here we develop the new conceptual approach, plasma process, and proprietary reactor that ensure, for the first time, that the efficiency of treatment (114.7%) of two mixed organic dyes, methylene blue (MB) and methyl orange (MO), is higher than when the two dyes are treated separately. We further reveal the underlying mechanisms for the energy-efficient complete degradation of the mixed dyes. The contribution of plasma-induced ROS and the distinct degradation characteristics and mechanism of pollutants in mixed treatment are discussed. The electron transfer pathway revealed for the first time suggest that the mixed pollutants reduce the overall redox potentials and facilitate electron transfer during the plasma treatment, promoting synergistic degradation effects. The integrated frameworks including both direct and indirect mechanisms provide new insights into the high-efficiency mixed-contaminant treatment. The degradation products for mixed degradation are revealed based on the identification of intermediate species. The plasma-treated water is proven safe for living creatures in waterways and sustainable fishery applications, using in vivo zebrafish model bio-toxicity assay. Overall, these findings offer a feasible approach and new insights into the mechanisms for the development of highly-effective, energy-efficient technologies for wastewater treatment and reuse in agriculture, industry, and potentially in urban water networks.

Tackling climate change through wastewater reuse in agriculture: A prioritization methodology

Water shortages, exacerbated by climate change, are posing a major global challenge, particularly impacting the agricultural sector. A growing interest is raised towards reclaimed wastewater (RWW) as an alternative irrigation source, capable of exploiting also the nutrient content through the fertigation practice. However, a prioritization methodology for selecting the most appropriate wastewater treatment plants (WWTPs) for implementing direct RWW reuse is currently missing. Such prioritization would benefit water utilities, often managing several WWTPs, and policymakers in optimizing economic asset allocation. In this work, a prioritization framework is proposed to evaluate WWTPs' suitability for implementing direct RWW reuse considering both WWTP and surrounding territory characteristics. This procedure consists of four key steps. Firstly, a techno-economic model was developed, in which monthly mass balances on water and nutrients are solved by matching crop requirements, rainfall conditions, and effluent characteristics. Economic suitability was quantified considering economic benefits due to savings in freshwater resource, mineral fertilizers and avoided greenhouse gases emissions, but also losses in crop yield due to RWW salinity content. Secondly, a classification procedure was coded to select representative WWTPs among a set of WWTPs, based on their size, presence of nutrient removal processes, and type of crops in their surroundings. The techno-economic model was then applied to these selected WWTPs. Thirdly, input parameters' relevance in determining WWTP suitability for RWW reuse was ranked. Finally, scenario analyses were conducted to study the influence of rainfall patterns and nutrient treatment removal on the RWW reuse feasibility. The type of crops surrounding the WWTPs and RWW salinity content resulted to be crucial elements in determining WWTPs suitability for RWW reuse implementation. The proposed methodology proved to be an effective support tool for policymakers and water utilities to assess the techno-economic feasibility of direct RWW reuse, generalizing results to several combinations of WWTPs and crops.

Treated waste water reuse in agriculture: An Overview

The reuse of treated wastewater in agriculture is a promising solution to the water scarcity challenge faced by many regions worldwide. This review paper provides an overview of the current state of knowledge on treated wastewater reuse in agriculture, highlighting its potential benefits and challenges. The paper begins by discussing the importance of treating wastewater before reuse and the potential it offers. The benefits of using treated wastewater in agriculture are discussed, including increased water availability, improved soil fertility and reduced fertilizer use. The risks associated with the use of treated wastewater, such as the accumulation of pollutants and the potential for pathogen transmission, are also discussed. The review paper then presents some examples of reuse projects for irrigation and their success criteria. The current regulations governing the use of treated wastewater in agriculture are examined, and their evolution presented. The paper concludes with a discussion of future research needed to address the remaining challenges surrounding the use of treated wastewater in agriculture. Overall, the review paper emphasizes the importance of careful management and regulation of treated wastewater reuse in agriculture to ensure safety and sustainability to meet the growing demand for water in agriculture.

A Numerical Study of the Efficiency of the Sono Galvano-Fenton Process as a Tertiary Treatment Technique for the Wastewater Reuse in Agriculture

In the present study, the Sono-Galvano-Fenton process is studied numerically as a tertiary treatment process for treated wastewater reuse in irrigation, with in situ generation of the Fenton’s reagent and catalyst, i.e., H2O2 and Fe2+. The sonochemical pathway is examined as a source of hydrogen peroxide under the pre-optimized condition of acoustic frequency, 200 kHz. The macroscopic model accounting for the performance of the single acoustic cavitation bubble and the bubble population density is combined with the Fe/Cu galvanic cell operating in acidic conditions (pH 3), following a cumulative and instantaneous production approach in terms of Fenton’s reagent. The combination is optimized based on the rate of hydroxyl radicals generated by the Galvano-Fenton process, as a non-selective powerful oxidant against recalcitrant pollutants, then considering the synergetic effect of the hybrid process in terms of HO● pumped sonochemically and via the Fenton based pathway, treated using simulations of the isolated processes then their combined configuration following both aforementioned approaches.

The fate of bacteria in urban wastewater-irrigated peach tree: a seasonal evaluation from soil to canopy

Irrigation with wastewater can be a solution to preserve and mitigate freshwater demand, in particular during drought periods. Unfortunately, wastewater, although being treated at different levels, could be a carrier of human pathogens (e.g., E. coli) and potentially contaminate crops for human consumptions.This study investigated the seasonal microbiological concentrations, on soil, shoot and fruit tissues of potted peach trees, following two irrigation treatments: freshwater (FW) and secondary urban wastewater without the final disinfection treatment (SW).E. coli was only detected in SW irrigated soil, whereas total coliforms (TC) and total bacteria counts (TBC) were similar in both treatments throughout the season. Endophytic E. coli, Salmonella spp. and TC were not detected in shoot and fruit, but a higher presence of total bacteria (TBC) was observed in SW-irrigated tree compared to FW-irrigated tree. In particular, SW shoots had a higher load compared to fruits, thus showing a potential effect of leaf transpiration, that promoted the transfer of water-borne bacteria from soil to the epigeal part (shoot). The adoption of low-quality SW (even above the microbiological limits of the European Regulation 2020/741 for wastewater re-use in agriculture), when a drip irrigation method is applied, could be a valid alternative to save fresh water without compromising fruit safety.

Wastewater quality index (WWQI) as an indicator for the assessment of sanitary effluents from the oil and gas industries for reliable and sustainable water reuse

With the development of numerous industries, the increasing use of water resources and the discharge of pollutants into the environment, particularly industrial wastewater, has become extremely important. The purpose of this study was the assessment of sanitary wastewater treatment plants attributed to the oil and gas industries as reliable and sustainable water resources based on the wastewater quality index (WWQI). The findings revealed that the facilities under investigation effectively process and discharge their effluents following the Environmental Protection Organization's standards. Springtime has the maximum removal in wastewater treatment plants (WWTPs), with typical removal values of COD and BOD5 of 96.1% and 97.1%, while pH in the effluent of these WWTPs was 7.22, and DO in the range of 1–6.3 mg/L throughout this period. In addition, fecal coli removal efficiencies were 98.6%, respectively. Finally, the wastewater treatment system in the four refineries investigated has resulted in a considerable decrease in microbiological and organic pollutants in conformity with environmental regulations permitting wastewater reuse for irrigation and agriculture, as well as discharge into adsorption wells. However these treatment plants perform poorly in terms of cumulative and WWQI models (13.86–16.05), it is clear from the results and discussion of this research that the results of the treated wastewater from the under-investigation plants comply with the Environmental Protection Organization of Iran's standards required for discharge to surface water or reuse in agricultural land irrigation. Still, the treatment system should be constantly audited and improved to reach a higher rank according to the WWQI.

Sustainable treatment of municipal secondary effluent from UASB systems by solar photo-Fenton: CECs removal and toxicity control

Upflow Anaerobic Sludge Blanket (UASB) systems are vastly implemented for municipal wastewater treatment in developing tropical countries. Despite that, efforts related to the removal of contaminants of emerging concern (CECs) from municipal secondary effluents (MSE) via post-treatment by solar photo-Fenton are mainly conducted with MSE from Conventional Activated Sludge (CAS). Hence, it is critical to investigate the efficiency of solar photo-Fenton to treat MSE from UASB systems. This is the first study to evaluate the performance of solar photo-Fenton and dark Fenton conducted with intermittent additions of Fe2+ and at circumneutral pH for the removal of CEC from UASB followed by Trickling Filter (UASB+TF) and UASB effluent. Acute and chronic ecotoxicity to Aliivibrio fischeri and Raphidocelis subcapitata, respectively, and phytotoxicity to Lactuca sativa were also evaluated for both matrixes. Solar photo-Fenton removed 83% of ΣCECs from UASB+TF effluent and resulted in non-toxic samples. Solar photo-Fenton performed in MSE from UASB system alone showed 65% ΣCECs removal and reduced chronic effect to R. subcapitata (growth inhibition) from 11% to 26%. In addition, no acute toxicity was verified for A. fischeri nor L. sativa. This work shows the feasibility of applying solar photo-Fenton at circumneutral pH to improve the quality of MSE resulting from UASB systems prior to wastewater discharge or reuse in agriculture.

Legionella contamination and human health: the risk of wastewater reuse in agriculture

Legionella contamination and human health: the risk of wastewater reuse in agriculture

Delivering on sustainable development goals in wastewater reuse for agriculture: Initial prioritization of emerging pollutants in the Tula Valley, Mexico

Wastewater reuse for agricultural irrigation is a widespread beneficial practice, in line with the sustainable development goals. However, contaminants of emerging concern (CECs) present in wastewater, such as pharmaceuticals, pose an environmental risk. The Tula Valley in Mexico is one of the world's largest agricultural areas reusing wastewater for agriculture. However, no untargeted CEC monitoring has been undertaken there, limiting the information available to prioritise local environmental risk assessment. Furthermore, CEC environmental presence in the Global South remains understudied, compared to the Global North. There is a risk that current research efforts focus on CECs predominantly found in the Global North, leading to strategies that may not be appropriate for the Global South where the pollution profile may be different. To address these knowledge gaps, a sampling campaign at five key sites in the Tula Valley was undertaken and samples analysed using multi-residue targeted and untargeted liquid chromatography mass spectrometry methods. Using the targeted data, ten CECs were found to be of environmental risk for at least one sampling site: 4‑tert-octylphenol, acetaminophen, bezafibrate, diclofenac, erythromycin, levonorgestrel, simvastatin, sulfamethoxazole, trimethoprim and tramadol as well as total estrogenicity (combination of three steroid hormones). Six of these have not been previously quantified in the Tula Valley. Over one hundred pollutants never previously measured in the area were identified through untargeted analysis supported by library spectrum match. Examples include diclofenac and carbamazepine metabolites and area-specific pollutants such as the herbicide fomesafen. This research contributes to characterising the presence of CECs in the Global South, as well as providing site-specific data for the Tula Valley.

Prospects for treated wastewater reuse in agriculture in low- and middle-income countries: Systematic analysis and decision-making trees for diverse management approaches

The Middle East and North Africa (MENA) region is suffering from severe water scarcity. Decision-makers in MENA are tackling this challenge by tapping the potential of reusing treated wastewater in agriculture so that large volumes of freshwater sources can be released for priority domestic needs. This aligns with the global efforts to make wastewater reuse mainstream in developing countries by overcoming the technological, infrastructural, health, and socio-cultural barriers that are limiting the expansion of wastewater reuse in agriculture. In this regard, this paper analyses the management modalities of wastewater reuse practices in agriculture in MENA by studying two case studies from Egypt and Jordan. The result of this analysis is a proposed decision-tree tool to help decision-makers in making optimal wastewater reuse decisions based on contextual factors including agricultural field demands, location, freshwater resources, sanitation coverage, and infrastructure, as well as regulations, policies, and restrictions for wastewater reuse. The decision-tree framework was operationalized and validated using the two case studies. The decision tree proved to be an effective framework in assisting decision-makers in making the optimum choice for wastewater reuse in agriculture. It aided the decision maker in evaluating potential reuse options and selecting between several courses of action.

Wastewater reuse in agriculture: A review of soil and crops parasitic contamination, associated health risks and mitigation approach

Background: Wastewater reuse in agriculture can potentially result in adverse health implications including parasitic diseases spread. Trichuris, Ascaris, and Giardia are major pathogenic parasites of concern associated with this practice. This review investigated their occurrence in wastewater, and environmental components reached through wastewater application, including irrigated soil and grown crops. Exposure pathways and evidence for health risks were also explored. Methods: Several databases (Google Scholar, PubMed, Science Direct, Scopus, Web of Science, and ResearchGate) and other sites were searched for published literature up to 2021. The searched keywords include wastewater reuse, soil-transmitted helminths (STHs), Ascaris, Trichuris, Giardia, crop contamination, soil contamination, health risk, epidemiological studies, exposure pathways, and risk mitigation. Overall, 160 papers have been yielded. After screening for relevance, 60 studies were considered for inclusion. Results: Giardia, Ascaris, and Trichuris were frequently detected in wastewater with up to 5×105 cysts/L and 5.73×103 eggs/L. Concentrations of 750 eggs/100 g and 2.8×104 cysts/100 g were reported in wastewater irrigated soil. Ascaris was reported in irrigated crops with up to 70 eggs/kg versus 6.6×103 cysts/kg for Giardia, depending on the type of crops. Epidemiological studies provided evidence supporting the increase of ascariasis, trichuriasis, and giardiasis diseases related to the exposure to wastewater irrigated soil and crops. Conclusion: The findings suggest that wastewater reuse in agriculture leads to contamination of soil, and crops with pathogenic parasites, increasing health risks in the exposed groups. To remedy this issue, protection measures, including a multi-barrier approach, can be applied to mitigate the health risks engendered by wastewater reuse for irrigation.

Metatranscriptome Revealed the Efficacy and Safety of a Prospective Approach for Agricultural Wastewater Reuse: Achieving Ammonia Retention during Biological Treatment by a Novel Natural Inhibitor Epsilon-Poly-l-Lysine.

Appropriate inhibitors might play important roles in achieving ammonia retention in biological wastewater treatment and its reuse in agriculture. In this study, the feasibility of epsilon-poly-l-lysine (ε-PL) as a novel natural ammonia oxidation inhibitor was investigated. Significant inhibition (ammonia oxidation inhibition rate was up to 96.83%) was achieved by treating the sludge with ε-PL (400 mg/L, 12 h soaking) only once and maintaining for six cycles. Meanwhile, the organic matter and nitrite removal was not affected. This method was effective under the common environmental conditions of biological wastewater treatment. Metatranscriptome uncovered the possible action mechanisms of ε-PL. The ammonia oxidation inhibition was due to the co-decrease of Nitrosomonas abundance, ammonia oxidation genes, and the cellular responses of Nitrosomonas. Thauera and Dechloromonas could adapt to ε-PL by stimulating stress responses, which maintained the organic matter and nitrite removal. Importantly, ε-PL did not cause the enhancement of antibiotic resistance genes and virulent factors. Therefore, ε-PL showed a great potential of ammonia retention, which could be applied in the biological treatment of wastewater for agricultural reuse.

A critical scientific and policy opinion on reuse and reclamation of contaminated wastewater for agriculture and other purposes

Contaminants of emerging concern and other chemicals are widespread in the environment. While their effects are ambiguous, a wealth of literature now illustrates their ability to induce various effects at concentrations/doses smaller than the toxicological threshold, leading to hormetic biphasic responses. Such responses are increasingly understood, can be positive or negative, and present an issue for wastewater reuse and reclamation for agriculture and other purposes. Considerable efforts have been placed by stakeholders at multiple levels to address the issue of low-dose effects, but there is more that can be done. To effectively address the low-dose issue, treatment/remediation sites for pollutant elimination should be improved, the number and amounts of chemicals released to the environment should be better controlled/prevented, and citizen-science approach with the involvement of NGOs and other organizations should be employed to expand the coverage of assessing pollution and its effects. This Opinion paper summarizes the main challenges introduced by the continuous discovery of emerging contaminants in the environment and the low-dose effects, discusses what has been done by stakeholders to address low-dose effects, and proposes a path forward.

Transforming Agriculture: Innovations in Sustainable Wastewater Reuse – A review

This scientific review delves into the crucial role of wastewater reuse in agriculture for sustainable water resource management, especially in the context of water scarcity. The paper examines innovative wastewater treatment methods like biofiltration, membrane bioreactors, and electrocoagulation, exploring their effectiveness and limitations. It emphasizes the significance of proper wastewater treatment in mitigating risks and maximizing benefits. Key considerations such as economic viability and social acceptance are highlighted, urging comprehensive cost-benefit analyses and active engagement with stakeholders. Drawing from case studies in Tshwane, Egypt, Valencia, and Sde Warburg, successful wastewater reuse practices underscore the importance of stringent water quality standards, public education, regulatory frameworks, and stakeholder involvement in achieving sustainable wastewater management. Despite global advancements, challenges persist in the adoption of these technologies in many African countries, necessitating collaborative efforts and targeted capacity-building for widespread implementation. Historical insights reveal the evolution of wastewater irrigation from European and American cities to its current global prevalence, impacting around 10% of the world’s irrigated land with untreated or partially treated wastewater. Technological advancements, such as biofiltration relying on microbial activities, membrane bioreactors integrating biological treatment with filtration, and electrocoagulation as an electrochemical process, offer sustainable solutions. Case studies highlight the economic, environmental, and social benefits of successful wastewater reuse programs. However, the review acknowledges the risks associated with wastewater reuse, including environmental contamination and public health hazards. To strike a balance between risks and benefits, the paper advocates for proper wastewater treatment, robust regulatory frameworks, and responsible farming practices. It concludes by stressing the need for collaborative efforts, international partnerships, and targeted capacity-building initiatives to overcome barriers to the adoption of advanced wastewater treatment technologies in African countries, fostering water management, ensuring food security, and contributing to social and economic development amid global challenges.

Modeling slow sand filtration for sustainable safe wastewater reuse in agriculture in Draa Sfar mine region (Marrakech, Morocco)

Modeling slow sand filtration for sustainable safe wastewater reuse in agriculture in Draa Sfar mine region (Marrakech, Morocco)

Wastewater Reuse for Irrigation Agriculture in Morocco: Influence of Regulation on Feasible Implementation

Morocco is a water-scarce developing country with a growing marketable agro-food industry, where untreated or insufficiently treated wastewater represents less than 1% of the irrigation water and treated wastewater reuse is virtually nil. The Government of Morocco is planning to increase the volume of treated wastewater reuse for irrigation agriculture under the current permissive regulation to alleviate the pressure on conventional water sources. However, the reuse of insufficiently treated wastewater implies environmental and human health risks besides the degradation of land and renewable natural resources. This paper shows the feasibility of increasing wastewater reuse for irrigation agriculture in Morocco and how the existing permissive regulation must be improved to force more efficient technologies aimed at ensuring the export of agricultural goods to the most restrictive international markets. The results show how the quality standards of Moroccan regulation are below that of their equivalents in developed countries, as well as in most of the consulted developing countries. After verifying that tertiary treatment is financially feasible, the updated regulation must also consider climatic water scarcity and the locally low cultural perception of environmental and human health risks in order to design optimal solutions.