Adaptation and performance of Portulaca oleracea L. in a hybrid constructed wetland system for dairy wastewater treatmentABSTRACT
The aim of this study was to evaluate the potential use of Portulaca oleracea L. in constructed wetlands (CWs) as part of a hybrid wastewater treatment system for small-scale dairy agroindustries. The experimental setup, located at the Federal University of Campina Grande, Brazil, consisted of a biodigester followed by a two-stage CW system. The first CW stage utilized Eichhornia crassipes M., while the second stage, the focus of this study, employed P. oleracea L. The research, conducted from 2018 to 2021, assessed the performance of P. oleracea in treating dairy wastewater. Water quality variables were monitored at four stages: raw wastewater, biodigester wastewater, and outputs from both CW stages. While the overall system demonstrated significant reductions in chemical oxygen demand (99.3%), biochemical oxygen demand (98%), and total Kjeldahl nitrogen (93.1%), the performance of P. oleracea was suboptimal. The species showed poor adaptation to the constantly flooded environment of the CW, exhibiting reduced growth and signs of physiological stress after 15 days. Despite these challenges, the second CW stage still contributed to pollutant removal, achieving a 40.9% reduction in total phosphorus compared to raw wastewater. This study highlights the importance of species selection in CW design and suggests that while P. oleracea may have potential in phytoremediation; its application in constantly flooded CW systems requires further investigation or modified management strategies.
Keywords:
species adaptation; phytoremediation; agroindustry
RESUMO
O objetivo deste estudo foi avaliar o potencial uso de Portulaca oleracea L. em Sistemas Alagados Construídos (SACs) como parte de um sistema híbrido de tratamento de efluentes para agroindústrias de laticínios de pequena escala. O arranjo experimental, localizado na Universidade Federal de Campina Grande, Brasil, consistiu em um biodigestor seguido por um SAC de dois estágios. O primeiro estágio do SAC utilizou Eichhornia crassipes M., enquanto o segundo estágio, foco deste estudo, empregou P. oleracea L. A pesquisa, conduzida de 2018 a 2021, avaliou o desempenho de P. oleracea no tratamento de efluentes de laticínios. As variáveis de qualidade da água foram monitoradas em quatro estágios: efluente bruto, efluente do biodigestor e saídas de ambos os estágios dos SACs. Embora o sistema geral tenha demonstrado reduções significativas na Demanda Química de Oxigênio (99,3%), Demanda Bioquímica de Oxigênio (98%) e nitrogênio total de Kjeldahl (93,1%), o desempenho de P. oleracea foi subótimo. A espécie apresentou adaptação deficiente ao ambiente constantemente alagado do SAC, exibindo crescimento reduzido e sinais de estresse fisiológico após 15 dias. Apesar desses desafios, o segundo estágio do SAC ainda contribuiu para a remoção de poluentes, alcançando uma redução de 40,9% no fósforo total comparado ao efluente bruto. Este estudo destaca a importância da seleção de espécies no projeto de SACs e sugere que, embora P. oleracea possa ter potencial em fitorremediação, sua aplicação em sistemas de SAC constantemente alagados requer investigação adicional ou estratégias de manejo modificadas.
Palavras-chave:
adaptação de espécies; fitorremediação; agroindústria
INTRODUCTION
The intensification of agroindustrial activities in developing countries such as Brazil has significantly contributed to economic growth, particularly in the dairy sector. In 2021, the agribusiness sector accounted for 27.4% of Brazil's GDP (CNA, 2021). However, this growth has also led to increased environmental concerns, especially regarding the management of wastewater from small-scale family dairy agroindustries. These wastewaters, characterized by high organic loads, nutrients, and pathogens, pose significant risks to water bodies and ecosystems if left untreated (Kaur, 2021).
The challenge lies in developing cost-effective and efficient wastewater treatment systems tailored for small rural producers, who often lack the financial resources for conventional treatment methods. Constructed wetlands (CWs) offer a promising solution, utilizing natural processes for pollutant removal while being low-cost and low-maintenance (Srivastava; Srivastava; Singh, 2023). However, the effectiveness of CWs is heavily dependent on the selection of appropriate plant species.
P. oleracea L., commonly known as purslane, is a facultative halophyte that exhibits exceptional adaptability and bioaccumulation capabilities, particularly in nutrient-rich environments (Carrascosa et al., 2023). Its potential for use in phytoremediation has been noted in various studies, but its application in constantly flooded environments, such as those found in CWs, remains largely unexplored.
This study aims to bridge this knowledge gap by evaluating the potential of P. oleracea in a hybrid wastewater treatment system designed for small-scale dairy operations. The system integrates anaerobic digestion through a biodigester with a two-stage CW, where P. oleracea is employed in the second stage. This configuration was designed to assess the plant's performance in a real-world application, focusing on its ability to adapt to flooded conditions and contribute to pollutant removal.
By investigating the viability of P. oleracea in CWs, this research seeks to contribute to the development of sustainable, low-cost wastewater treatment solutions for small-scale dairy producers. The findings of this study have implications not only for environmental protection but also for the economic sustainability of family-owned dairy agroindustries in Brazil and similar contexts worldwide.
METHODS
Characterization of the study area
The study was conducted from September 2018 to December 2021 at the Universidade Federal de Campina Grande (UFCG) in Pombal, Paraíba, located in Brazil's semi-arid Northeast region. The local climate is classified as Aw’ according to the Köppen system, characterized by semi-arid conditions with summer and autumn rainfall. The area experiences an average annual precipitation of 800 mm, with significant intra-annual variability. The majority of rainfall (60–80% of the annual total) occurs between February and April. Average monthly temperatures range from 23.4 to 27.9°C, with recorded maxima of 35.7°C in December and minima of 19.3°C in July and August (Moura, 2007).
A hybrid wastewater treatment system was developed, comprising a biodigester connected in series with a two-stage CW. The system's schematic representation and dimensions are illustrated in Figure 1. Four strategic sampling points were established to monitor treatment efficacy: raw wastewater (RW), biodigester wastewater (BIO), first vegetated bed wastewater (CW1), and second vegetated bed wastewater (CW2).
Schematic representation of the hybrid wastewater treatment system comprising a biodigester in series with a two-stage constructed wetland (CW). All dimensions are in meters. Sampling points: (A) raw wastewater; (B) biodigester wastewater; (C) first vegetated bed wastewater (CW1); (D) second vegetated bed wastewater (CW2).
Wastewater for treatment was sourced from a local dairy agroindustry specializing in cheese production. The primary treatment unit consisted of a 600 L capacity biodigester, adapted from the Chinese model. This biodigester, operated as a batch reactor, had dimensions of 1.44 m in height and 0.95 m in diameter. The wastewater inlet was positioned at 1.36 m, the outlet at 1.26 m, and the sludge outlet at 0.95 m from the base. To enhance biofilm formation and optimize microbial activity, corrugated flexible conduit fragments were installed inside the biodigester, increasing the available surface area. Wastewater transfer was facilitated by a PVC tank and an SB 1,000 motor pump. To stimulate the development of internal microbiota, 200 mL of diluted bovine manure was added to the system. The hydraulic retention time in the biodigester was set at 30 days to ensure adequate anaerobic digestion.
Following the hydraulic retention period in the biodigester, the wastewater was directed into a two-stage CW system. The CW comprised two beds in series: the first with vertical flow (VF) and the second with horizontal subsurface flow (HSSF). Each bed was constructed using two circular polypropylene containers, each measuring 0.6 m in radius and 0.3 m in depth, with a water layer height of 0.2 m. The containers were interconnected using flanges and 25 mm PVC pipes. The hydraulic retention time in each vegetated bed was set at 3 days.
The first bed (CW1) was planted with E. crassipes M., a species selected for its capacity to reduce organic concentrations in wastewater before reaching the second bed (CW2). This choice was informed by previous experiments demonstrating that P. oleracea L. could not tolerate direct exposure to biodigester wastewater. E. crassipes, readily available in the study area, is well-adapted to hot climates, thriving in temperatures between 28°C and 30°C, typical of Northeast Brazil. A 0.5 m layer of limestone aggregates (gravel 4–10 mm) served as a substrate, enhancing surface area and promoting microbial growth. E. crassipes specimens were sourced from the Piancó River in Pombal-PB and transported to the experimental site in water containers. CW1 was elevated on a brick column, 0.46 m above ground level.
CW2 was planted with P. oleracea L., a halophyte prevalent in the study region and adapted to high salinity and water stress conditions. The substrate consisted of a 0.2 m layer of limestone aggregates (gravel 4–10 mm) overlaid with 0.08 m of soil, carefully placed to avoid compaction. CW2 was constructed with a 0.1 m slope relative to CW1 to facilitate gravitational flow. P. oleracea L. was cultivated in seedbeds and transplanted 21 days post-germination. Additional specimens found on the campus were also incorporated. The treatment process commenced 30 days after transplantation to allow for root system development. A 40 mm diameter PVC pipe was installed vertically in CW2, extending 0.1 m above the surface, to monitor water levels.
The system design incorporated strategically positioned inlet and outlet pipes in each bed, with gravel substrate ensuring uniform flow distribution. This configuration minimized preferential flow paths and short-circuiting, promoting effective treatment across the entire bed. Flow control valves were installed for manual and gravitational flow regulation, along with additional valves for bed emptying, facilitating sludge removal and system maintenance.
To assess system performance, weekly morning samples were collected from four key points: raw wastewater (RW), biodigester wastewater (BIO), first vegetated bed wastewater (CW1), and second vegetated bed wastewater (CW2). Physicochemical and microbiological analyses were conducted at the Water Analysis Laboratory of the Federal University of Campina Grande. Variables measured included ambient temperature (AT), wastewater temperature (WT), relative humidity (RH), solar irradiance (SI), pH, electrical conductivity (EC), turbidity (TB), dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total phosphorus (TP), total Kjeldahl nitrogen (TKN), settleable solids (SS), total solids (TS), fixed solids (FS), and volatile solids (VS). On-site measurements of DO, AT, WT, RH, SI, and SS were performed following Standard Methods for the Examination of Water and Wastewater (APHA, 2017).
Data analysis involved single-factor analysis of variance (ANOVA) to identify significant differences, followed by Tukey's test at a 5% significance level for posthoc analysis, using Sisvar 5.7 software. Continuous monitoring of AT, WT, RH, and SI was facilitated by an Arduino®-based microcontroller system.
RESULTS AND DISCUSSION
Table 1 highlights the climatic conditions, with averages of AT, WT, RH, SI, pH, EC, turbidity, and dissolved oxygen at the times the samples were collected.
Average variation of ambient temperature, wastewater temperature, relative humidity, solar irradiance, pH, electrical conductivity, turbidity, and dissolved oxygen.
AT fluctuated between 29.2 and 37.8°C across the treatment stages, with notable variations during CW1 and CW2 wastewater sampling periods coinciding with light precipitation events. The WT maintained a more stable range of 25.8–33.7°C due to water's high specific heat capacity, which moderated thermal fluctuations in the system. These temperature ranges align with optimal conditions for both microbial activity and plant development, which exhibits optimal growth between 25 and 35°C (Srivastava; Srivastava; Singh, 2023). The thermal conditions observed in the system favor key treatment processes, including enhanced biodegradation rates and plant metabolic functions, contributing to overall treatment efficiency. The stability of WT, maintained within the optimal range for biological processes, suggests favorable conditions for consistent treatment performance throughout the study period.
Relative humidity and SI exhibited distinct patterns throughout the monitoring period, significantly influencing the CW system's performance. During vegetated bed sampling, particularly in CW1, RH increased markedly due to precipitation events and evapotranspiration processes. SI measurements remained stable during RW and biodigester sampling (656–659 W.m-2) but decreased substantially during vegetated bed sampling, reaching as low as 148 W.m-2 in CW1 due to cloud cover.
These variations in solar radiation impact the CW system's performance through multiple mechanisms. Fluctuating light levels directly affect photosynthetic rates, nutrient uptake, and overall plant growth dynamics of E. crassipes and P. oleracea L. During periods of higher irradiance, these plants can increase their photosynthetic activity, leading to enhanced biomass production and potentially greater nutrient removal from wastewater. Conversely, during low-light conditions, plants may reduce their metabolic rates, temporarily decreasing their capacity for pollutant uptake (Dahanayake et al., 2017; Bawiec et al., 2018). Additionally, high SI can diminish soil moisture, particularly in surface layers of poorly vegetated areas (Yaghoobian; Srebric, 2015). However, the natural cycling between high and low irradiance levels observed in this study can promote plant resilience and adaptability.
Furthermore, solar radiation influences water temperature and evaporation rates within the CW, affecting microbial activity and hydraulic retention times. The observed variability in SI contributes to creating a dynamic environment that supports diverse microbial communities and plant physiological responses. Thisvariability ultimately enhances the robustness and efficiency of the wastewater treatment process, as the system adapts to changing environmental conditions.
Automated UV monitoring revealed a clear diurnal pattern, with peak values (3.7) occurring between 12:30 PM and 4:00 PM, classified as moderate according to the World Health Organization's Global Solar UV Index. UV levels exhibited an inverse relationship with RH, as peak UV periods coincided with minimum humidity levels (15%, 11:00 AM–4:00 PM), while maximum humidity (93%, 6:00–7:00 AM) corresponded with negligible UV radiation. This natural cycling between high and low UV exposure, combined with varying humidity levels, creates favorable conditions for plant growth and microbial activity in the CW system.
The pH analysis of the treated wastewater revealed a trend toward neutrality, with a 38.2% increase compared to the RW. This aligns with findings from similar studies using vegetated CWs (Rahman et al., 2014). The observed pH range falls within the 6–9 bracket that Metcalf and Eddy (2016) identified as optimal for most aquatic species. During daylight hours, photosynthetic activity by aquatic plants and algae in the CWs consumes dissolved CO2, potentially raising the pH. Additionally, the denitrification process consumes H+ ions, leading to an increase in pH. In anaerobic zones of the CWs, sulfate-reducing bacteria can produce alkalinity, further contributing to pH elevation. Moreover, if carbonates are present in the substrate, they can dissolve over time, buffering the system and potentially increasing pH (Ricart et al., 2023).
The pH increase observed in the system suggests efficient buffering mechanisms within the CWs, potentially enhancing nutrient removal processes. However, it's important to note that while the trend toward neutrality is generally beneficial, extreme pH fluctuations could disrupt microbial communities and plant nutrient uptake. Therefore, continuous monitoring and understanding of the factors influencing pH in CWs remain crucial for optimizing treatment efficiency. The interplay between these various pH-altering processes contributes to the complex and dynamic nature of the CW system, underlining the importance of maintaining a balanced pH for effective wastewater treatment.
Electrical conductivity (EC) showed significant variations across treatment stages, with notable changes in CW2. The biodigester stage didn't markedly reduce EC, possibly due to added bovine manure contributing ions. The overall treatment achieved a 48% EC reduction, comparable to findings by Silva et al. (2021) in CWs with different plant species. This similarity suggests CWs consistently mitigate dissolved ion concentrations regardless of specific vegetation. Silva et al. (2021) noted that concurrent pH increases and EC reduction, as observed here, suggest oxidative conditions, particularly in alkaline environments. This relationship provides insight into the CW system's complex biogeochemical processes.
The variable EC reduction across treatment stages underscores the complementary roles of biological and physical processes in ion removal. While the biodigester showed limited EC reduction, subsequent CW stages demonstrated significant ion removal, highlighting the importance of multi-stage treatment. The substantial EC reduction in CW2 suggests that extended hydraulic retention time and multiple treatment stages enhance ion removal efficiency. This has implications for CW design, indicating that longer treatment chains or increased retention times may benefit high-dissolved solid wastewater management.
Turbidity in CW2 decreased by 91.1%, indicating substantial removal of suspended matter, fine particles, soluble organic compounds, algae, and microorganisms (Gameiro; Zwolinski; Brotas, 2011). Kasenene, Machunda and Njau (2021) attributed this to macrophytes, substrates, and microbial communities facilitating complex removal mechanisms. The biodigester achieved a 79.3% turbidity reduction, likely due to the rapid settling of denser particles. These results align with findings by Sanchez et al. (2018) in CWs using different plant species. Kasenene, Machunda and Njau (2021) emphasized filtration and sedimentation as key processes in turbidity reduction. High turbidity can impair photosynthesis in submerged plants and algae (Sinha; Eggleton; Lochmann, 2018).
Dissolved oxygen (DO) levels increased significantly in the vegetated beds, with the final wastewater showing a 132.4% higher concentration compared to the RW. This substantial increase in DO is noteworthy and contrasts with findings by Ding et al. (2012), who observed decreased DO levels post-treatment. The increase in this study can be attributed to several factors elucidated by Piñeiro Di Blasi et al. (2013): atmospheric diffusion, turbulence-induced aeration, and photosynthetic activity of aquatic plants and algae in the CWs.
While the observed DO increase indicates improved water quality, it's crucial to maintain a balance. Piñeiro Di Blasi et al. (2013) cautioned that DO concentrations exceeding 110% saturation can potentially harm aquatic life. Conversely, they warn that prolonged exposure to DO levels below 2.0 mg.L-1 can lead to significant fish mortality. These thresholds underscore the importance of monitoring and maintaining appropriate DO levels in treated wastewater.
The marked increase in DO in the system, particularly in the CW stages, suggests effective aeration and potentially robust photosynthetic activity. This could indicate healthy plant growth, including that of P. oleracea, and efficient microbial processes. However, further investigation into the specific contributions of P. oleracea to DO levels would be valuable for optimizing CW design and plant selection for similar wastewater treatment systems.
Table 2 shows the variation of COD, BOD, TP, TKN, sedimentable solids, TS, FS, and VS.
Variation of chemical oxygen demand, biochemical oxygen demand, total phosphorus, total Kjeldahl nitrogen, sedimentable solids, total solids, fixed solids, and volatile solids.
Chemical oxygen demand (COD) showed a remarkable 99.3% reduction compared to RW, with the biodigester accounting for 74.6% of this decrease. Both vegetated beds demonstrated similar efficacy, significantly differing from raw and biodigester wastewater, highlighting their effectiveness as tertiary treatment for dairy wastewater. Ngoma et al. (2020) attributed this to organic matter removal through sedimentation and decomposition processes inherent to CWs. Despite initially high organic content, the treated wastewater met environmental discharge standards, as evidenced by low final COD levels (Dell'osbel et al., 2020). Biochemical oxygen demand (BOD) mirrored COD trends, achieving a 98% removal rate in treated wastewater, aligning with Guedes-Alonso et al. (2020), while the biodigester reduced BOD by 90%. This high efficiency indicates effective biodegradable organic matter degradation by microorganisms. The BOD reduction is crucial, representing dissolved oxygen consumed in organic matter oxidation.
The observed BOD/COD ratio of 0.9 suggests improved operational performance and lower energy requirements for biological treatment (Herrera; Sigcha; Banchón, 2024). The high removal rates indicate that the system, particularly the CWs, provided optimal conditions for microbial activity. Factors such as adequate oxygen supply, appropriate hydraulic retention time, and diverse microbial communities likely contributed to efficient organic matter breakdown and BOD reduction. Microbial breakdown of organic matter is key in wastewater treatment systems, especially in CWs and biodigesters. Microorganisms utilize organic matter as an energy source, converting it to CO2 through mineralization, reducing wastewater organic load, and contributing to nutrient cycling (Yousaf; Vonhoegen; Thiele-Bruhn, 2023).
Total phosphorus (TP) dynamics were particularly noteworthy, with a 67.6% increase in the biodigester stage, likely due to organic matter degradation and bovine manure addition. However, the subsequent vegetated beds effectively mitigated this increase, with CW2 achieving a 40.9% reduction compared to RW and a remarkable 64.7% reduction compared to biodigester wastewater. While these results are promising, they fall short of the 89.7–94.7% removal rates reported by Baldovi et al. (2021) using E. crassipes, sedimentation, and algal assimilation. This discrepancy suggests potential for system optimization, possibly through enhanced sedimentation processes or algal integration. The stark contrast with Guedes-Alonso et al. (2020), who reported only 9.2% TP removal in CWs with diverse plant species, underscores the importance of species selection and system design in phosphorus removal efficiency.
Nitrogen removal, measured as TKN (total Kjeldahl nitrogen), showed similar trends. While the biodigester had minimal impact, likely due to reasons similar to those affecting TP, the vegetated beds, particularly CW2, demonstrated significant removal capacity. The overall 93.1% reduction in TKN surpasses the findings of Caselles-Osorio et al. (2011), who reported a 62% reduction in ammoniacal compounds and 33% in nitrates. This superior performance suggests that the system design and plant species selection effectively facilitate nitrification and denitrification processes.
Solids removal exhibited a staged efficiency, with settleable solids (SS) primarily reduced in the biodigester, while total solids (TS) and volatile solids (VS) showed significant reductions of 75.5 and 81.6%, respectively, across the entire system. The increase in fixed solids (FS) in the biodigester, followed by a decrease in vegetated beds, illustrates the complex dynamics of solids transformation and removal throughout the treatment process. Matos et al. (2017) highlighted the role of plant root systems in enhancing solid retention, although this benefit comes with the potential drawback of system clogging, necessitating regular maintenance.
The visual improvement in water quality throughout the treatment process, particularly the high turbidity removal, underscores the system's efficiency. The superior performance of CW2, which incorporated soil in its substrate, aligns with Kasenene, Machunda and Njau's (2021) findings on the effectiveness of soil as a mechanical and biological filter. This suggests that substrate composition plays a crucial role in treatment efficiency and could be an area for future optimization.
The performance of plant species in the CW exhibited significant variability, underscoring the critical importance of species selection in CW design and efficiency. E. crassipes M. in CW1 demonstrated exceptional adaptability, exhibiting robust growth and increased biomass. This performance aligns with Muchtasjar et al.'s (2021) findings, which highlighted the species’ remarkable resilience to high-pollutant loads. E. crassipes’ success can be attributed to its well-developed aerenchyma tissue, extensive root system, and rapid growth rate, all of which contribute to its effectiveness in nutrient uptake and pollutant removal in aquatic environments.
In contrast, P. oleracea L. in CW2 displayed reduced biomass and signs of physiological stress after 15 days in the flooded environment. This observation supports Buchade and Karadge's (2016) assertion regarding P. oleracea's sensitivity to waterlogged conditions. Despite its known tolerance to saline environments, this adaptation did not translate effectively to constant inundation. Osca, Galán and Moreno-Ramón (2021) noted that P. oleracea's physiology is more suited to terrestrial conditions with periodic water stress, explaining its poor performance in the CW setting. These contrasting performances emphasize the need to align plant species selection with specific environmental conditions and treatment objectives in CW design. While E. crassipes proves suitable for high-pollutant, aquatic environments, P. oleracea's performance suggests it may be better suited for less saturated conditions or require modified management strategies in CW applications.
This comparative analysis informs future species selection for CWs and highlights the potential for developing hybrid systems that leverage the strengths of different plant species. Future research should focus on expanding the repertoire of suitable plant species for various CW conditions and exploring innovative system designs to enhance the overall efficiency and applicability of CW technology in wastewater treatment.
CONCLUSIONS
The biodigester system in series with CW has demonstrated remarkable efficacy in removing both organic and inorganic pollutants from dairy wastewater. The comprehensive analysis of physicochemical and biological variables revealed a synergistic relationship between anaerobic and aerobic treatment processes, resulting in significant improvements across multiple water quality indicators.
The system's performance was particularly noteworthy in the reduction of COD (99.3%) and BOD (98%), surpassing results reported in comparable studies. Additionally, substantial reductions in TP (40.9%) and TKN (93.1%) underscore the system's potential in mitigating eutrophication risks in receiving water bodies. The efficient removal of various solid fractions further demonstrates the complementarity between the biodigester's sedimentation processes and the CWs’ filtration capabilities.
However, the study also highlighted critical considerations in plant species selection for CWs. While E. crassipes M. exhibited robust growth and increased biomass, P. oleracea L. showed impaired development, particularly after 15 days, with reduced growth and leaf yellowing. This differential adaptability emphasizes the need for careful species selection based on their tolerance to specific environmental conditions, especially in flooded environments.
The superior performance of CW2, which incorporated soil in its substrate, suggests that the composition of the filter medium plays a crucial role in treatment efficiency. This observation opens avenues for future optimizations in CW designs, potentially enhancing pollutant removal capacities, particularly for challenging nutrients like phosphorus.
The effectiveness of this combined system holds significant promise for small rural communities and family agroindustries, offering a low-cost, low-maintenance solution for wastewater treatment. The potential for reducing environmental impact while providing opportunities for water reuse in agricultural irrigation further enhances its appeal as a sustainable technology.
DATA AVAILABILITY STATEMENT
The datasets generated and/or analyzed during the current study are available from the corresponding author upon reasonable request.
REFERENCES
- AMERICAN PUBLIC HEALTH ASSOCIATION (APHA). Standard methods for the examination of water and wastewater 23. ed. Washington, D.C.: APHA, 2017.
-
BALDOVI, Aldrew Alencar; AGUIAR, André Ribeiro de Barros; BENASSI, Roseli Frederigi; VYMAZAL, Jan; JESUS, Tatiane Araujo de. Phosphorus removal in a pilot scale free water surface constructed wetland: hydraulic retention time, seasonality and standing stock evaluation. Chemosphere, v. 266, p. 128939, 2021. https://doi.org/10.1016/j.chemosphere.2020.128939
» https://doi.org/10.1016/j.chemosphere.2020.128939 -
BAWIEC, Aleksandra; PAWĘSKA, Kataryzna; PULIKOWSKI, Krzysztof; KAJEWSKA-SZKUDLAREK, Joanna. Influence of insolation on the efficiency of NO3 removal from wastewater treated in the hydroponic system. Water, Air, & Soil Pollution, v. 229, n. 7, p. 232, 2018. https://doi.org/10.1007/S11270-018-3888-9
» https://doi.org/10.1007/S11270-018-3888-9 -
BUCHADE, J. Y.; KARADGE, B. A. Effect of flooding on the antioxidants in the root and leaves of Vigna aconitifolia (Jacq.) marechal and Portulaca oleracea L. World Journal of Pharmaceutical Research, v. 5, n. 7, p. 723-728, 2016. https://doi.org/10.20959/wjpr20167-6453
» https://doi.org/10.20959/wjpr20167-6453 -
CARRASCOSA, Angel; PASCUAL, Jose Antonio; ROS, Margarita; PETROPOULOS, Spyridon; ALGUACIL, Maria del Mar. Agronomical practices and management for commercial cultivation of Portulaca oleracea as a crop: a review. Plants, v. 12, n. 6, p. 1246, 2023. https://doi.org/10.3390/plants12061246
» https://doi.org/10.3390/plants12061246 -
CASELLES-OSORIO, Aracelly; VILLAFAÑE, Patricia; CABALLERO, Vanessa; MANZANO, Yelena. Efficiency of mesocosm-scale constructed wetland systems for treatment of sanitary wastewater under tropical conditions. Water, Air, & Soil Pollution, v. 220, n. 1, p. 161-171, 2011. https://doi.org/10.1007/s11270-011-0743-7
» https://doi.org/10.1007/s11270-011-0743-7 -
CONFEDERAÇÃO DA AGRICULTURA E PECUÁRIA DO BRASIL (CNA). PIB do agronegócio alcança participação de 26,6% no PIB brasileiro em 2020 CNA, 2021. Available at: https://www.cnabrasil.org.br/storage/arquivos/sut.pib_dez_2020.9mar2021.pdf Accessed on: Oct. 11, 2024.
» https://www.cnabrasil.org.br/storage/arquivos/sut.pib_dez_2020.9mar2021.pdf -
DAHANAYAKE, Kalani; CHOW, Cheuk Lun; HOU, Guo Long. Selection of suitable plant species for energy efficient Vertical Greenery Systems (VGS). Energy Procedia, v. 142, p. 2473-2478, 2017. https://doi.org/10.1016/j.egypro.2017.12.185
» https://doi.org/10.1016/j.egypro.2017.12.185 -
DELL’OSBEL, Naira; COLARES, Gustavo Stolzenberg; OLIVEIRA, Gislayne Alves; RODRIGUES, Lúcia Ribeiro; SILVA, Fagner Pereira da; RODRIGUEZ, Adriane Lawish; LÓPEZ, Diosnel; LUTTERBECK, Carlos Alexandre; SILVEIRA, Elizandro Oliveira Silveira; KIST, Lourdes; MACHADO, Ênio Leandro. Hybrid constructed wetlands for the treatment of urban wastewaters: Increased nutrient removal and landscape potential. Ecological Engineering, v. 158, p. 106072, 2020. https://doi.org/10.1016/j.ecoleng.2020.106072
» https://doi.org/10.1016/j.ecoleng.2020.106072 -
DING, Yi; SONG, Xinshan; WANG, Yuhui; YAN, Denghua. Effects of dissolved oxygen and influent COD/N ratios on nitrogen removal in horizontal subsurface flow constructed wetland. Ecological Engineering, v. 46, p. 107-111, 2012. https://doi.org/10.1016/j.ecoleng.2012.06.002
» https://doi.org/10.1016/j.ecoleng.2012.06.002 -
GAMEIRO, Carla; ZWOLINSKI, Juan; BROTAS, Vanda. Light control on phytoplankton production in a shallow and turbid estuarine system. Hydrobiology, v. 669, n. 1, p. 249-263, 2011. https://doi.org/10.1007/s10750-011-0695-3
» https://doi.org/10.1007/s10750-011-0695-3 -
GUEDES-ALONSO, Rayco; MONTESDEOCA-ESPONDA, Sarah; HERRERA-MELIÁN, José; RODRÍGUEZ-RODRÍGUEZ, Raquel; OJEDA-GONZÁLEZ, Zeneida; LANDÍVAR-ANDRADE, Vanessa; SOSA-FERRERA, Zoraida; SANTANA-RODRÍGUEZ, José. Pharmaceutical and personal care product residues in a macrophyte pond-constructed wetland treating wastewater from a university campus: Presence, removal and ecological risk assessment. Science of the Total Environment, v. 703, p. 135596, 2020. https://doi.org/10.1016/j.scitotenv.2019.135596
» https://doi.org/10.1016/j.scitotenv.2019.135596 -
HERRERA, Luis; SIGCHA, Pavlova; BANCHÓN, Carlos. Boosting BOD/COD biodegradability of automobile service stations wastewater by electrocoagulation. Water Science and Technology, v. 90, n. 9, p. 2399-2412, 2024. https://doi.org/10.2166/wst.2024.357
» https://doi.org/10.2166/wst.2024.357 -
KASENENE, Atwebembela; MACHUNDA, Revocatus; NJAU, Karoli. Performance of inclined plate settler integrated with constructed wetland for high turbidity water treatment. Water Practice & Technology, v. 16, n. 2, p. 516-529, 2021. https://doi.org/10.2166/wpt.2021.009
» https://doi.org/10.2166/wpt.2021.009 -
KAUR, Navneet. Different treatment techniques of dairy wastewater. Groundwater for Sustainable Development, v. 14, n. 24, p. 100640, 2021. https://doi.org/10.1016/j.gsd.2021.100640
» https://doi.org/10.1016/j.gsd.2021.100640 -
MATOS, Mateus; VON SPERLING, Marcos; MATOS, Antonio Teixeira; MIRANDA, Suymara Toledo; SOUZA, Tamara Daiane de; COSTA, Liovando Marciano. Key factors in the clogging process of horizontal subsurface flow constructed wetlands receiving anaerobically treated sewage. Ecological Engineering, v. 106, part A, p. 588-596, 2017. https://doi.org/10.1016/j.ecoleng.2017.06.013
» https://doi.org/10.1016/j.ecoleng.2017.06.013 - METCALF; EDDY. Wastewater treatment and resource recovery 5. ed. Porto Alegre: AMGH, 2016.
- MOURA, Eulina Maria de. Avaliação da disponibilidade hídrica e da demanda hídrica do trecho do rio Piranhas-Açú entre os açudes Coremas-Mãe D’água e Armando Ribeiro Gonçalves Dissertação (Mestrado) – Universidade Federal do Rio Grande do Norte, Natal, 2007.
-
MUCHTASJAR, Bunyamin; HADIYANTO, Hadiyanto; IZZATI, Munifatul; VINCĒVIČA-GAILE, Zane; SETYOBUDI, Roy Hendroko. The ability of water hyacinth (Eichhornia crasipes Mart.) and water lettuce (Pistia stratiotes Linn.) for reducing pollutants in batik wastewater. In: E3S WEB OF CONFERENCES, 2021. Anais […] EDP Sciences, 2021. p. 00010. https://doi.org/10.1051/e3sconf/202122600010
» https://doi.org/10.1051/e3sconf/202122600010 -
NGOMA, Wezzie; HOKO, Zvikomborero; MISI, Shepherd; CHIDYA, Russel. Assessment of efficiency of a decentralized wastewater treatment plant at Mzuzu University, Mzuzu, Malawi. Physics and Chemistry of the Earth, Parts A/B/C, v. 118-119, p. 102903, 2020. https://doi.org/10.1016/j.pce.2020.102903
» https://doi.org/10.1016/j.pce.2020.102903 -
OSCA, José; GALÁN, Felip; MORENO-RAMÓN, Héctor. Rice paddy soil seedbanks composition in a Mediterranean wetland and the influence of winter flooding. Agronomy, v. 11, n. 6, p. 1199, 2021. https://doi.org/10.3390/agronomy11061199
» https://doi.org/10.3390/agronomy11061199 -
PIÑEIRO DI BLASI, Jessica Ingrid; MARTÍNEZ TORRES, Javier; GARCÍA NIETO, Paulino José; ALONSO FERNÁNDEZ, Ramón; DÍAZ MUÑIZ, Cristina; TABOADA, Jaiver. Analysis and detection of outliers in water quality parameters from ‘different automated monitoring stations in the Miño river basin (NW Spain). Ecological Engineering, v. 60, p. 60-66, 2013. https://doi.org/10.1016/j.ecoleng.2013.07.054
» https://doi.org/10.1016/j.ecoleng.2013.07.054 -
RAHMAN, Khaja Zillur; WIESSNER, Arndt; KUSCHK, Peter; VAN AFFERDEN, Manfred; MATTUSCH, Jürgen; MÜLLER, Roland Arno. Removal and fate of arsenic in the rhizosphere of Juncus effusus treating artificial wastewater in laboratory-scale constructed wetlands. Ecological Engineering, v. 69, p. 93-105, 2014. https://doi.org/10.1016/j.ecoleng.2014.03.050
» https://doi.org/10.1016/j.ecoleng.2014.03.050 -
RICART, Aurora; HONISCH, Brittney; FACHON, Evangeline; HUNT, Christopher; SALISBURY, Joseph; ARNOLD, Suzanne; PRICE, Nichole. Optimizing marine macrophyte capacity to locally ameliorate ocean acidification under variable light and flow regimes: Insights from an experimental approach. Plos One, v. 18, 0288548, 2023. https://doi.org/10.1371/journal.pone.0288548
» https://doi.org/10.1371/journal.pone.0288548 -
SANCHEZ, Aline Alves; FERREIRA, Anna Carolina; STOPA, Juliana Martins; BELLATO, Filipe Cardoso; JESUS, Tatiane Araújo de; COELHO, Lúcia Helena Gomes; DOMINGUES, Mércia Regina; SUBTIL, Eduardo Lucas; MATHEUS, Dácio Roberto; BENASSI, Roseli Frederigi. Organic Matter, Turbidity, and Apparent Color Removal in Planted (Typha sp. and Eleocharis sp.) and Unplanted Constructed Wetlands. Journal of Environmental Engineering, v. 144, n. 10, 06018007, out. 2018. https://doi.org/10.1061/(ASCE)EE.1943-7870.0001443
» https://doi.org/10.1061/(ASCE)EE.1943-7870.0001443 -
SILVA, Fagner Pereira da; LUTTERBECK, Carlos Alexandre; COLARES, Gustavo Stolzenberg; OLIVEIRA, Gyslaine Alves; RODRIGUES, Lúcia Ribeiro; DELL’OSBEL, Naira; RODRIGUEZ, Adriane Lawisch; LÓPEZ, Diosnel Antonio Rodriguez; GEHLEN, Günther; MACHADO, Ênio Leandro. Treatment of university campus wastewaters by anaerobic reactor and multi-stage constructed wetlands. Journal of Water Process Engineering, v. 42, p. 102119, 2021. https://doi.org/10.1016/j.jwpe.2021.102119
» https://doi.org/10.1016/j.jwpe.2021.102119 -
SINHA, Amit Kumar; EGGLETON, Michael; LOCHMANN, Rebecca. An environmentally friendly approach for mitigating cyanobacterial bloom and their toxins in hypereutrophic ponds: potentiality of a newly developed granular hydrogen peroxide-based compound. Science of the Total Environment, v. 637-638, p. 524-537, 2018. https://doi.org/10.1016/j.scitotenv.2018.05.023
» https://doi.org/10.1016/j.scitotenv.2018.05.023 -
SRIVASTAVA, Rajani; SRIVASTAVA, Vineet; SINGH, Ajeet. Multipurpose benefits of an underexplored species purslane (Portulaca oleracea L.): A critical review. Environmental Management, v. 72, n. 2, p. 309-320, 2023. https://doi.org/10.1007/s00267-021-01456-z
» https://doi.org/10.1007/s00267-021-01456-z -
YAGHOOBIAN, Neda; SREBRIC, Jelena. Influence of plant coverage on the total green roof energy balance and building energy consumption. Energy and Buildings, v. 103, p. 1-13, 2015. https://doi.org/10.1016/j.enbuild.2015.05.052
» https://doi.org/10.1016/j.enbuild.2015.05.052 -
YOUSAF, Ubaida; VONHOEGEN, Denise; THIELE-BRUHN, Sören. Chemical and microbial mass balances in microbial turnover of two easily degradable carbon substrates. In: EGU GENERAL ASSEMBLY, 2023, Vienna. Anais […]. Vienna: European Geosciences Union, 2023. https://doi.org/10.5194/egusphere-egu23-11989
» https://doi.org/10.5194/egusphere-egu23-11989
Edited by
-
Editor:
Luciano Matos Queiroz https://orcid.org/0000-0001-8390-1274
Publication Dates
-
Publication in this collection
15 Aug 2025 -
Date of issue
2025
History
-
Received
08 June 2023 -
Accepted
24 Apr 2025
Source: elaborated by the authors.