Ambiente e Agua - An Interdisciplinary Journal of Applied Science

Evaluation of the aerobic process performance for treating tannery effluent in the fungicide presence and ammoniacal nitrogen high concentration

Andressa Corso — 2025-01-10

Leather processing is characterized by the generation of effluents with a high concentration of ammonia nitrogen (N-NH4+) and the presence of fungicides. This study evaluated the interference of these two constituents on the removal of chemical oxygen demand (COD) and N-NH4+. To this end, an aerated reactor operating in a batch system was used. The effects of cycle time, fungicide volume, and initial N-NH4+ concentration on COD and N-NH4+ removal was evaluated using a Centralized Rotational Composite Design. The highest COD removal (45.45%) occurred under the conditions of 72 h, 0.55 mL of fungicide, and 62.5 mg L-1 of N-NH4+, and the lowest removal (8.24%) occurred under the conditions of 24 h, 0.28 mL of fungicide and 84.8 mg L-1 of N-NH4+. The highest removal of N-NH4+ (38.49%) occurred under the conditions of 42 h, 0.55 mL of fungicide, and 62.5 mg L-1 of N-NH4+, and the lowest removal (4.26%) occurred under the conditions of 24.1 h, 0.82 mL of fungicide and 84.8 mg L-1 of N-NH4+. Through statistical analysis, it was possible to obtain mathematical models for the two response variables, which satisfactorily described the removal efficiency of COD and N-NH4+, and through the desirability analysis, it was possible to optimize the treatment process operation with a cycle time of 58.15h, with the addition of 0.62 mL of fungicide and 57.91 mg L-1 of ammoniacal nitrogen. Although the removal of N-NH4+ via nitrification is an efficient technique in industrial effluent treatment, the results obtained in this work indicate that the removal of N-NH4+ was significantly affected by the presence of the fungicide. Keywords: biological treatment, chemical oxygen demand, DCCR, TCMTB.

Optimizing COD reduction in dairy wastewater treatment using magnetic coagulant derived from Moringa oleifera

Rafael Emilio González Cuello — 2025-01-10

In wastewater treatment scenarios, traditional coagulants are becoming increasingly complex and raising environmental concerns. This has led to the exploration of magnetized plant-derived coagulant as an alternative. In this paper, coagulation parameters such as coagulant dosage and pH were optimized through response surface methodology (RSM) based on a central composite design (CCD) employing a magnetic coagulant derived from Moringa oleifera seeds (M. oleifera–CoFe₂O₄). The optimized response variable during the treatment of dairy wastewater was the chemical oxygen demand (COD) reduction. The response surface methodology revealed a statistically significant second-order polynomial model (R² 99.24%) for maximizing COD reduction. The maximum COD reduction achieved was 76.13% under optimal conditions with coagulant dosage of 14.24 g/L and pH of 9.38. The results indicated that magnetic coagulant derived from M. oleifera seeds demonstrated significant potential and can be used in an efficient and eco-friendly process for dairy wastewater treatment.

Keywords: coagulation, dairy wastewater, flocculation, magnetic coagulant, Moringa Oleifera.

Biochar from orange waste as a filter medium for domestic effluent treatment aimed at agricultural reuse

Mariana Paola Cabrini — 2025-01-10

Brazil is the world's leading orange grower, and this agro-industrial sector produces a sizable amount of by-products. Because biochar has the potential to be used as a filtering medium in wastewater treatment systems, it can be advantageous to produce biochar from orange trash as an efficient way to use these resources. The purpose of this study was to assess how temperature affects the synthesis of biochar and to describe the adsorptive qualities of the material for use in filtration systems for agricultural reuse. The produced material was examined for its chemical composition, crystalline structure, morphological changes brought about by the conversion of biomass into biochar, surface area, and average pore size. The pyrolysis temperatures used to produce biochar ranged from 350 to 650°C for 60 minutes. Based on the advantageous physicochemical characteristics for usage as an adsorbent, 550°C was determined to be the ideal temperature. The orange biochar system outperformed the gravel system in terms of macronutrient removal, according to the filtration results using septic tank effluent. The elimination of magnesium (62.09%) and total phosphorus (31.58%) was noteworthy. These findings indicate a promising and long-term wastewater treatment option by indicating that the treated effluent may be suitable for use in some crops.

Keywords: biochar, horizontal flow, sewage treatment, wastewater.

Monitoring deposition and resuspension of the iron ore tailings in the Doce River after the Fundão Dam rupture

Fabricia Benda de Oliveira — 2025-01-10

The Doce River, located in Southeast Brazil, is of great importance in supplying water for urban use, agriculture, fishing and other purposes. It was affected by a disaster that occurred on November 5, 2015 due to the collapse of the Fundão ore tailing dam, in the municipality of Mariana (MG). This disaster generated socio-environmental consequences, as some regions were severely affected due to the waste released in the river, which was considered potentially toxic in the short to long term. This work presents a temporal analysis of images from the Landsat 8 satellite, associating the aspects of rainfall in dry and rainy months, in years before and after the disaster (2014, 2015, 2016, and 2020), together with the Normalized Difference Water Index (NDWI) obtained by image digital processing, to analyze the relation between dry and rainy periods and the spectral response of images. This analysis allowed the understanding of the behavior of the suspended materials, before and after the disaster, to unravel how the dispersion of tailings occurs. Part of the ore tailing that was deposited along the river went into suspension again in the rainy season one year after the disaster and, five years after, the satellite images show no difference compared to pre-disaster conditions. But, seven years after the spill, there are still iron ore tailings deposited and mixed with the river sediments. The fluvial dynamics are incorporating the tailings into the sediments, originating conducive places to provide various types of metals adhered to the particulate matter.

Keywords: iron ore tailings, rainfall, remote sensing.

Morphophysiology of yellow passion-fruit seedlings cultivated with macrophyte (Eichhornia Crassipes) under salt stress

Moisés Wilkson Nunes dos Santos — 2025-01-10

The use of aquatic macrophyte biomass could be a viable alternative for producing substrates. The objective was to evaluate the production of yellow passion fruit seedlings in different macrophyte-based substrates under salinity stress. The experiment was carried out at the Seedling Production Unit in Redenção, Ceará state. A completely randomized design was used, in a 2 × 5 factorial arrangement, with respect to two electrical conductivities of irrigation water (0.8 and 2.5 dS m^-1) and five substrates (S1 = 54% soil + 29. 5% sand + 16% macrophyte; S2 = 34% soil + 33% sand + 33% macrophyte; S3 = 24% soil + 26.5% sand + 49.5% macrophyte; S4 = 20% soil + 14% sand + 66% macrophyte; and S5 = 10% soil + 7.5% sand + 85.5% macrophyte), with 10 replications. Salt stress negatively affected photosynthesis, transpiration, stomatal conductance and internal CO₂ concentration of yellow passion-fruit seedlings. The use of S1 (54% soil + 29.5% sand + 16.5% macrophyte) was more efficient for plant height, leaf area, shoot dry mass, root dry mass, and total dry mass, while S5 (10% soil + 7.5% sand + 82.5% macrophyte) provided higher photosynthesis in yellow passion fruit seedlings. Substrate 1 (54% soil + 29.5% sand + 16.5% macrophyte) and S3 (24% soil + 26.5% sand + 49.5% macrophyte) alleviated salinity stress on Dickson quality index and stem diameter. The use of macrophytes has been shown to be beneficial in the production of passion fruit seedlings, with positive effects on development and gas exchange, and alleviation of salt stress.

Keywords: aquatic plant, Passiflora edulis, salinity, substrate.

Sustainability, social inclusion, and governance: analyzing ESG practices at an urban public university in São Paulo, Brazil

Nadine Sant'Anna Beneton — 2025-01-10

The growing global emphasis on environmental, social and governance (ESG) principles has driven higher education institutions to adopt more sustainable and socially inclusive practices. However, a lack of metrics and regular reporting often limits the ability to assess the true impact of these initiatives. This study critically examined ESG practices at a public urban university in São Paulo, focusing on the Department of Agricultural Sciences (DAS). Using a case study approach, the research employed a systematic literature review, document analysis and on-site observations to assess how ESG principles are implemented. Correspondence Factor Analysis (CFA) and Discursive Textual Analysis (DTA) were used to identify patterns and insights. The findings highlight the University's commitment to sustainability and social inclusion, particularly through initiatives such as the Accessibility Assurance Plan (PGA) and environmental conservation efforts. However, the study also identified the need for structured evaluation metrics and more transparent reporting to better monitor the impact of these initiatives. The research concludes by suggesting that future studies should explore how ESG practices influence students' perceptions of educational quality and examine the financial costs and benefits of these initiatives to guide more strategic implementation in higher education institutions.

Keywords: environment, equity, policies, social inclusion.

Effects of human disturbance gradient on aquatic macroinvertebrate diversity: A study in a river of the Sierra Nevada de Santa Marta

Cristian Granados-Martínez — 2025-01-29

Understanding the environmental factors that shape macroinvertebrate diversity is particularly important because rivers in the neotropics are continuously affected by changes in land use. The main objective of this work was to analyze how environmental variables associated with different levels of human activity shape the macroinvertebrate community in the Ranchería River. Various environmental variables were measured at each of the nine sampling stations distributed across three gradients of human activity in the Ranchería River Basin. The sampling design included three stations in the high elevation zone (P9, P8, P7; 595 to 308 masl), three in the medium elevation zone (P6, P5, P4; 153 to 112 masl), and three in the low elevation zone (P3, P2, P1; 90 to 22 masl). For aquatic macroinvertebrates, five monthly samples were taken from January to May 2010 from these nine stations. A total of 4,615 individuals were collected, distributed across 16 orders, 54 families, and 83 taxa. The taxa with the highest relative abundance were Simulium (Diptera), Melanoides sp. (Thiaridae), and Orthocladiinae (Diptera: Chironomidae), with 20, 11, and 9% respectively. It was found that anthropogenic impacts shape the environmental variables and the structure of macroinvertebrate communities in the Ranchería River Basin.

Keywords: anthropic affectations, canonical correspondence analysis, Hill numbers, Rancheria River, Sierra Nevada de Santa Marta.

Treatment of dairy cattle farming wastewater using constructed wetland system cultivated with rice

Gilda Vieira de Almeida — 2025-01-29

The amount of waste produced each day by dairy cattle is one of the largest problems in intensive management systems. Therefore, disposing of residues from animal facilities has become a challenge for farmers and specialists due to its technical, sanitary, and economic aspects. Organic effluents from confined dairy production systems require proper dairy wastewater treatment before disposal. When discharged into water bodies without adequate treatment, these effluents can cause physical and chemical changes in water sources, posing risks to public health and water supply due to the presence of pathogens and/or toxic elements. This study evaluates the efficiency of a constructed wetland system (CWS) cultivated with rice (Oryza sativa) in removing pollutants from dairy cattle wastewater, while also assessing the crop yield as an integral indicator of the system’s performance. Given the limited number of samples collected, the results presented should be considered as a preliminary analysis, providing insights into the system’s performance and potential for future studies. The constructed wetland system has a surface area of 4 m² and operates with a flow of 500 L dia^-1 and hydraulic retention time of 1.72 days; gravel was used as a support medium. The analyses conducted led to the conclusion that the constructed wetland system, cultivated with rice, demonstrated effective pollutant reduction, particularly excelling in the removal of organic matter (35%), turbidity (43%) and nitrite (36%). Rice cultivation showed adaptation to the constructed wetland system, exhibited satisfactory growth, and showed no signs of nutrient deficiency.

Keywords: biological treatment, cultivated beds, reuse, water resources.

Klebsiella pneumoniae isolated from the intestines of Tenebrio molitor larvae (Coleoptera: Tenebrionidae) that consume expanded polystyrene

Luis Caruajulca-Marin — 2025-02-25

Plastics such as polystyrene are resistant to biodegradation, pollute the environment, and negatively impact the health of living organisms. However, several organisms, such as the larvae of Tenebrio molitor (Coleoptera: Tenebrionidae) and their associated gut microbiome, contribute to its degradation. The aim of this research was to determine the efficiency of degradation of expanded polystyrene (EPS) by gut bacteria isolated from larvae of T. molitor. To achieve this, a set of EPS-degrading bacteria was selected based on the time required to utilize the polymer as a carbon and energy source. Additionally, EPS degradation efficiency was compared, and the most efficient degrading bacterium was identified at the molecular level. Results showed that 95.13% of the bacteria isolated on nutrient agar and 86.57% of those isolated on MacConkey agar were able to grow on EPS. Five selected bacteria were able to degrade the polymer after 36 hours of incubation. The efficiency of EPS degradation, expressed as the percentage of weight loss by the degrading bacteria, ranged from 5.29% to 12.68%, with a reduction rate of 0.0005 to 0.0013 g per day and a half-life of 533.15 to 1386.20 days. Finally, 16S rRNA gene analysis identified the bacterium as Klebsiella pneumoniae. Cultivable gut bacteria from T. molitor larvae have demonstrated potential as candidates for EPS degradation, and biotechnological techniques can further enhance the efficiency of the degradation process.

Keywords: biotechnological techniques, gut microbiome, polystyrene degradation.

Suitable areas for Juçara palm (Euterpe edulis Martius) cultivation in Rio de Janeiro state, Brazil: proposal to encourage agro-ecological practices and non-timber products

Tamíres Partélli Correia — 2025-02-28

The Juçara palm (Euterpe edulis Mart.) is a native species of the Atlantic Forest biome, with high commercial value due to, among other uses, the extraction of the palm heart and pulp. This species has essential ecological interaction with fauna, providing food for many frugivorous species. However, it is on the list of endangered species, mainly due to the disorderly exploration of the palm tree for the extraction of the palm heart, but also due to climate change, habitat fragmentation, and defaunation. In this context, understanding which areas are suitable to grow this species is important for planning and supporting decision-making, as well as delimiting areas environmentally suitable according to the optimal requirements of species and land-use occupation. Our aim was to identify the suitable areas to cultivate Juçara palm in the State of Rio de Janeiro and provide a set of supporting maps and information for this productive sector, to increase agroforestry systems, or even for forest conservation and restoration purposes. Environmental parameters for the species (soil, elevation, air temperature and rainfall), and land use and land cover were assessed in order to perform the mapping of the optimal areas. The results indicate a potential for cultivation of Juçara palm in the State of Rio de Janeiro. All regions of the State have suitable areas, especially the Médio Vale do Paraíba, Centro–Sul, and Baixadas Litorâneas. The most restrictive variables to grow Juçara Palm in Rio de Janeiro State were rainfall and inadequate land use/cover for planting.

Keywords: environmentally suitable areas, geoprocessing, Juçara palm, planning.

Spatial and temporal distribution of potentially toxic elements in the urban area of São Raimundo Basin in Manaus, Brazil

Elissandro Fonseca dos Banhos — 2025-03-11

Contamination of surface water by metallic elements is an environmental concern in cities with industrial parks such as Manaus in Amazonas, Brazil. The concerns are related to the bioaccumulation of these elements and their toxicity, which affect the ecology of aquatic environments and human health. The study evaluated the role of seasonality in the concentrations of potentially toxic metals in the São Raimundo Basin in Manaus. Collections were carried out in June 2021, October 2021 and January 2022 at thirty collection points. The physicochemical parameters were analyzed according to the Methods for the Examination of Water and Wastewater of the APHA/AWWA. The metals were analyzed using optical emission spectrometry with inductively coupled plasma (ICP-OES), and the data using analysis of variance (ANOVA), Pearson correlation and Principal Component Analysis (PCA). All presented values outside those established by Brazilian legislation, with an average of 267.2 ug/L. ANOVA showed role of seasonality in the concentrations of the metals, with the periods of flooding in the basin having the lowest concentrations of metals. Such as Barium (Ba) and Beryllium (Be) with averages close to 0.0 ug/L in the flood period, and dry period with average values of 0.50 ug/L. The correlation showed the relationship of Ba, Be and Titanium (Ti) with the Biochemical Oxygen Demand (BOD). PCA indicated the metals Ba, Be and Ti as the most relevant contaminants in the basin. It was possible to develop a map to identify the sampling points where the concentrations of these metals are the highest.

Keywords: Surface water, toxic metals, urban basin, water contaminants.

Statistical characterization of a capacitive soil moisture probe, integrated into the water balance system in agriculture in a semi-arid region

Juvenaldo Florentino Canja — 2025-03-14

Soil water balance serves as a key indicator of moisture variability across the soil profile. Traditional instrumentation can significantly benefit from advancements in soil moisture monitoring technologies. The sensors can be integrated into precision irrigation systems. This study aimed to assess the water balance in a drainage lysimeter, integrated with a low-cost soil moisture monitoring system using the HD38 sensor. Soil moisture was tracked over a 50 cm depth using four capacitive probes. Environmental variables, including temperature and relative humidity, were monitored using a low-cost DHT11 thermo-hygrometer. Statistical analyses highlighted the dynamics of the water balance and sensor at various depths, with a particular focus on the sensor installed near the soil surface.

Keywords: Arduino, irrigation, Pearson correlation, probe, soil moisture.