Wastewater Reuse In Agriculture Research Articles

Assessment of public knowledge, perception and willingness towards treated hospital wastewater reuse in peri-urban agriculture in Ibadan, Nigeria

Assessment of public knowledge, perception and willingness towards treated hospital wastewater reuse in peri-urban agriculture in Ibadan, Nigeria

Modelling the impacts generated by reclaimed wastewater reuse in agriculture: From literature gaps to an integrated risk assessment in a One Health perspective

The reuse of reclaimed wastewater is increasingly recognized as a viable alternative water source for irrigation. Its application, whether direct or indirect, impacts several interconnected compartments, including groundwater, surface water, soil, crops, and humans. Reclaimed wastewater provides essential resources for crops, like water and nutrients. However, it also introduces pathogens, and contaminants of emerging concern (CECs), defined as chemicals that may pose risks to human health and ecosystems but are not yet fully regulated, such as pharmaceuticals and personal care products, among others. Additionally, reclaimed wastewater may contain antibiotic-resistant bacteria (ARBs) and disinfection by-products (DBPs), all of which present potential health and environmental risks. Therefore, regulatory bodies stress the need for preventive risk assessments to ensure safe reuse.This paper critically reviews available models for assessing the impacts of reclaimed wastewater reuse in agriculture. It identifies gaps in current modelling approaches and outlines future research directions. Key areas requiring further investigation include the fate and transfer of CECs, ARBs and DBPs, and the co-occurrence of multiple risks in such interconnected systems, especially in the indirect reuse. To address these gaps, we proposed a simplified approach to integrate three types of risk associated with CECs in indirect reuse, focusing on risks posed by antibiotics and other pharmaceuticals: human health risk, environmental risk and risk from antibiotic resistance development. This approach aids in identifying the most critical endpoints within the One Health approach, supporting (i) CECs prioritization in regulations based on their critical endpoints and (ii) the adoption of CEC-specific mitigation measures.

Exploring Moringa oleifera: Green Solutions for Sustainable Wastewater Treatment and Agricultural Advancement

Increasing concerns over water pollution have driven the search for sustainable wastewater treatment alternatives. This study evaluates the effectiveness of two coagulants derived from Moringa oleifera seeds–powder and extract–as sustainable solutions for wastewater reuse in agriculture. Comparative experiments were conducted using aluminum sulfate, a conventional coagulant, at various doses under controlled laboratory conditions. The results demonstrated that both M. oleifera-based coagulants were highly effective, achieving turbidity reductions of 97% and 99%, respectively. Notably, the powder form required lower doses than the extract but had longer sedimentation times. Further detailed analyses at optimized doses (500 mg/500 mL for powder and 12.5 mL/500 mL for extract) met international standards for wastewater quality in agricultural irrigation. Comprehensive analyses encompassing pH, turbidity, COD, BOD5, TSS, DO, conductivity, NO2−, NO3−, SO42−, PO43−, and fecal and total coliforms consistently adhered to stringent criteria, confirming the effectiveness of M. oleifera-derived coagulants. These findings highlight the potential of M. oleifera in wastewater treatment, offering sustainable solutions to environmental challenges and enhancing food security in resource-limited regions. Our research supports the broader adoption of these eco-friendly alternatives, which could significantly reduce water scarcity and promote sustainable agricultural practices, addressing critical environmental concerns.

Generalized Richards model of slow sand filtration to remove lead pollutant from polluted waters: study of velocity effect

In Morocco, numerous regions face water scarcity. To address water shortages in the arid Marrakech region, agricultural reuse of wastewater can be a viable solution, provided that accessible and cost-effective methods, such as slow sand filtration, are employed to reduce pollutant levels. In the vicinity of the Mine Draa Lasfar, wastewater discharged into the Tensift River has led to significant contamination by metallic trace elements, including lead (Pb). This contamination spreads from the water to the soil, plant cover, and living organisms, with severe Pb contamination observed in children, leading to serious neurological diseases. Addressing this critical issue, our study explores the application of slow sand filtration for water treatment. This method is reliable and environmentally friendly, particularly effective at lower water velocities, ensuring optimal contaminant removal. We introduced the Generalized Richards model, a versatile mathematical tool, which outperformed the standard logistic model by providing a more accurate fit to our experimental data. In conclusion, slow sand filtration, when implemented in areas like Mine Draa Lasfar, offers a promising solution for mitigating metallic trace elements contamination in water sources, with the Generalized Richards model enhancing our understanding and optimization of the filtration process.

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.

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

In the Apulia region (Southern Italy), the issue of water scarcity is escalating, making wastewater reclamation and reuse crucial options for promoting sustainable development. Despite substantial financial investments, the practical adoption of wastewater reuse for agricultural irrigation remains constrained. Using a quantitative SWOT framework, we analyzed market, social, and product-related factors impacting water reuse. A questionnaire with 23 out of 30 expert stakeholders, including researchers, public administration officials, utility members, farmers, and engineers, was used to evaluate the significance of each aspect identified in the SWOT analysis. The key drivers of a wastewater-reuse-based economy include improved water availability during drought, a commitment to the circular economy, and existing successful agricultural reuse projects. Conversely, identified obstacles encompass the lack of storage basins for storing wastewater between seasons to synchronize production with crop water needs, inadequate political dedication to oversee groundwater withdrawals, difficulties in controlling investments, and bureaucratic demands arising from stringent regulation. Underpinned by the recently enacted EU Water Reuse Regulation, the reuse of wastewater is crucial for addressing water scarcity, mitigating aquifer over-exploitation, and achieving objectives related to the circular economy. However, moving forward, an updated governance framework integrating continuous monitoring, active stakeholder engagement, and investments in intermediate storage facilities is imperative for effective and sustainable wastewater reuse. This research provides novel empirical evidence and expands upon existing studies on barriers and opportunities related to reclaimed water in a Mediterranean context and regions facing similar challenges. The findings can serve as a valuable reference for future research in this field.

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.