Revista Ambiente & Água - An Interdisciplinary Journal of Applied Science

1-15

Authors: Alanna Maria do Nascimento Bezerra; Marcos Henrique Gomes Ribeiro; Artur Paiva Coutinho; Ana Emília Carvalho de Gusmão da Cunha Rabel; Elizabeth Amaral Pastich Gonçalves

Jean laundering generates significant effluent flows with a high organic load, color, and other pollutants, making it difficult to adjust effluent releases within legal limits. Slow Sand Filters (SSF) with downflow were tested for seven days (bench scale), to propose an after-treatment of effluents from an Effluent Treatment Plant of a jean laundry. The research evaluated the removal of the following parameters: color, turbidity, chemical and biochemical oxygen demand, conductivity, ammonia, total phosphorus and salinity of the textile effluent. The experimental apparatus had four SSF: the first filter was fed with distilled water, while the other three filters (triplicates) were fed with effluent. The filters had, on average, the following removal efficiencies: 91% for ammonia, 61.24% color, 89.43% turbidity, and 83.54% for phosphorus. Regarding the removal of organic matter, 98.11% for BOD and 81.17% for COD, demonstrating that SSFs were efficient in removing particulate, dissolved materials and organic matter.

1-11

Authors: Cristiane Patrícia Kist; Claudio Eduardo Scherer; Marlene Soares; Marcio Barreto Rodrigues

Pleurotus fungi are basidiomycetes that stand out in the degradation of recalcitrant organic compounds such as lignin derivatives and phenolic compounds. The aim of this study was to make a comparative evaluation of the capacity of the Pleurotus ostreatus POS 560 and Pleurotus floridae PSP1 fungi in the degradation of 2,4 and 2,6-dinitrotoluene (DNTs) in effluent from an explosive factory. The characterization of the effluent indicated 318 mg L-1 of DNTs, 246 mg L-1 of COD and toxicity factor for Daphnia magna corresponding to 8. The conduct of a multivariate study estimated the influence of the variables pH (5.0 and 6.0), co-substrate concentration (10 and 20 g L-1 of glucose) and species of the fungus Pleurotus (ostreatus and floridae) on the degradation of DNTs, indicating that the variables Fungus and [Glucose] were significant (p <0.05) presenting effects in the order of + 4.45 ± 0.26 and -1.14 ± 0.26, respectively. The reproduction of the best efficiency conditions (P. floridae; pH 6.0 and 10 g L-1 of glucose) in agitated flasks (100 rpm, 26oC) was able to carry out, within 14 days of treatment, the removal of organic matter and toxicity factor in levels on the order of 55 and 50%, respectively, in addition to the complete degradation of DNTs which occurred in the first 120 hours of treatment. In this period, the maximum activity of the peroxidase and Mn-peroxidase enzymes was also characterized, suggesting high potential of the bioprocess under study for remediation of effluents contaminated with nitroaromatic compounds.

1-10

Authors: Eduardo José Ludwig; Ubirajara Russi Nunes; Osmar Damian Prestes; Lovane Klein Fagundes; Tiéle Stuker Fernandes; Nathália Saibt

This study evaluated the physiological quality and quantified the efficiency of polymer in reducing the loss of phytosanitary products by leaching from soybean seeds of different diameters and in different treatments. Two lots of seed and two types of treatments were tested: polymers associated with seed treatment, and polymer application in layers after the seed treatment. For that, the following treatments were analyzed: Control= no seed treatment; Treat+pol= seed treatment + polymers in the mix; Treat/pol= seed treatment + polymers applied in layers; Treat= seed treatment. To evaluate seed treatment retention by the polymers, extraction equipment was employed and leaching of the active ingredient thiamethoxam was quantified. Evaluation of physical quality was conducted with tests of germination rate, first count, emergence rate, accelerated aging, seedling length, seedling dry mass and moisture content. Polymer application associated with seed treatment was efficient in reducing losses by leaching, reducing product loss by 20%. No significant differences in retention and physiological quality were found when different methods for polymer application were compared. Bigger seeds presented greater vigor, but the germination rate was unaffected.

1-12

Authors: Julia Aoki Domingues; Nelson Consolin Filho; Luiz Augusto Gomes de Souza; Flávia Vieira da Silva Medeiros

The use of natural coagulants is a promising alternative to replace or assist chemical coagulants due to its numerous advantages. This paper evaluates the effectiveness of a natural coagulant in water treatment. The coagulant was extracted from the Zygia cauliflora (Willd.) Killip seed in saline solutions and defatted using 95% ethanol. The tests were conducted using different concentrations of the coagulant (0.1, 0.5, 1.0, 2.0, 3.0, and 4.0 g L-1) and of NaCl (0.0 M, 1.0 M, and 5.0 M). The results showed that the use of 2 g L-1 of coagulant and 1.0 M of the salt achieved an effectiveness of 20% and 70%, respectively, of color and turbidity removal. The analysis showed an effectiveness of 70% and 30%, respectively, when removing the UV254 compound and DOM (dissolved organic matter). The mechanism for turbidity removal by the coagulants prepared with aqueous solution and with saline solution at 1.0 M of NaCl is supposed to be adsorption and charge neutralization, respectively, following the Freundlich and Langmuir models. However, the coagulant prepared with saline solution at 5.0 M of NaCl tends to form a netlike structure followed by turbidity removal through a sweep coagulation mechanism. Future papers should therefore focus on the use of Zygia cauliflora (Willd.) Killip as an alternative for replacement or use as an auxiliary chemical coagulant.

1-15

Authors: Francisco Wellington Martins da Silva; Cleiton da Silva Silveira; Antônio Duarte Marcos Junior; João Dehon de Araujo Pontes Filho

The Brazilian energetic matrix is predominantly based on hydroelectric plants and its planning is very sensitive to climate variability in different time scales. Natural Affluent Energy (NAE) is an established planning tool to project different scenarios of possible energy production, especially in an integrated system. This work aims to fill a gap between short-term (seasonal/ interannual) and long-term (climate change) planning scales by realizing NAE medium-term projections for the Brazilian National Interconnected System basins. The historical NAE series provided by the National System Operator was used for the years 1931 to 2014. The series was divided into two periods: from 1931 to 2003 for verification, and from 2004 to 2014 for calibration. The Wavelets Auto-Regressive (WAR) model was applied from low- and medium-frequency bands. The band signal was analyzed and the NAE was projected for the years 2014 to 2024. A relationship of the NAE variability with the Pacific Decadal Oscillation (PDO) climate index and the Atlantic Multidecadal Oscillation (AMO) was verified.

1-10

Authors: Érica Aparecida Batista; Luane Ferreira Garcia ; Antonio João Carvalho de Albuquerque; Nara Ballaminut; Paulo Sérgio Scalize; Eric Souza Gil

The chemical and pharmaceutical industries are the main generators of residues, such as phenolic microcontaminants, including catechol, resorcinol, p-nitrophenol and 4-chlorophenol. Therefore, this work aims to identify these microcontaminants through an emerging contaminant biosensor by means of an enzymatic biosensor constructed with an enzymatic extract from the fungus Marasmiellus colocasiae. Based on the differential pulse voltammetry electrochemical technique, the biosensor was used to analyze the patterns of catechol, resorcinol, p-nitrophenol and 4-chlorophenol. The analysis of a sample prepared with these standards in water from the public supply network was also carried out. As a result, it was possible to verify that the biosensor developed in this study is more sensitive than conventional methods and has a greater affinity for catechol. In the sample prepared with the standards, it was possible to qualitatively identify the presence of 4-chlorophenol, resorcinol and catechol. The proposed biosensor was sensitive and has potential for application in the analysis of microcontaminants in the environment with the detection limit = 0.17 µmol L-1, and the quantification limit = 0.52 µmol L-1.

1-11

Authors: Kessia Caroline Dantas da Silva; Miriam Cleide Cavalcante de Amorim; Renan Santana Galvão; Yandra Beatriz de Oliveira Gonçalves; Paula Tereza de Souza e Silva; Eduardo Souza Costa Barros

The grape industrialization process produces large volumes of solid organic waste, with the grape bagasse being the main waste generated in the winemaking process. Anaerobic digestion can be used to treat and dispose of agro-industrial biomass waste. The objective of this study was to evaluate the effect of the inoculum/substrate ratio on the Biochemical Methane Potential (BMP) of grape marc. The experiment was performed in laboratory scale through a system of reactor bottles in batches, removing a set of triplicate flasks for sampling and analysis every 48 hours, with the test lasting 12 days. The reactors contained residue, inoculum and 20% of nutritive solution, maintaining 20% of headspace. The reactors were incubated in an incubator at a mesophilic temperature (35 ± 2°C) and shaken manually every 24 hours. Three different inoculum/substrate (I/S) ratios of 0.75, 1.5 and 3 were used to evaluate the methane yield, organic removals and at the end of degradation the morphology of the bacterial community was evaluated by means of scanning electron microscopy. The I/S 3 ratio provided the best results for loading anaerobic systems, indicating that grape marc presents potential for biological treatment through anaerobic digestion.

1-14

Authors: Magno dos Santos Pereira ; Alisson Carraro Borges* ; Gustavo Lopes Muniz ; Fernanda Fernandes Heleno ; Lêda Rita D'Antonino Faroni

The objective of this study was to evaluate the efficiency of dissolved ozone flotation (DOF) in comparison to dissolved air flotation (DAF) for treatment of milk industry wastewater (MW). In the first phase of the experiment, a synthetic milk wastewater (SMW) was used to evaluate DOF and DAF, with and without addition of hydrogen peroxide, at pH 4.0 and pH 11.4. In the DOF tests, the concentration of ozone was equal to 19 (± 0.5) mg L-1 and in the tests with addition of hydrogen peroxide, the H2O2/O3 ratios tested were 0.5, 1.0 and 1.5. In the second phase, tests were performed using three MW from three different industries to validate the results obtained and to determine the DOF system's ability to treat this type of effluent. The parameters tested during validation were turbidity, total suspended solids, oils and greases (O&G), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total nitrogen (TN) and total phosphorus (TP). It was observed that the efficiency of the treatments was better at pH 4.0. The results showed a reduction of the efficiency with the use of DOF. The addition of H2O2 in DAF and DOF also resulted in reduced system efficiency. The results obtained with SMW only approximated those obtained with the MW from one of the industries that contained the largest traces of milk and cheese.

1-10

Authors: Cleiton Fernando Barbosa Brito; Varley Andrade Fonseca; Marcelo Rocha dos Santos; Sérgio Luiz Rodrigues Donato; Alessandro de Magalhães Arantes; Aloísio José dos Santos

Studies determining physiological characteristics of field-grown pineapples irrigated with low-quality water are lacking. This work evaluated the photochemical efficiency of ‘Pérola’ pineapple irrigated with saline water in the semiarid region of Bahia, Brazil. The experiment was carried out in randomized blocks with five treatments consisting of the following irrigation depths: 100% of ETc using water with electrical conductivity (ECw) of 0.75 dS m-1; and 50, 75, 100 and 125% of ETc using water with ECw of 3.6 dS m-1. Chlorophyll a fluorescence measurements were made over the course of 13 months using a pulse-modulated fluorometer, in all treatments. Quantum efficiency (Fv/Fm) fluctuated throughout the cycle of the pineapple with values below the ideal, especially at the end of the crop cycle. Quantum yield of photosystem II (Yield), photochemical quenching (qP), non-photochemical quenching (NPQ) and chlorophyll fluorescence decrease ratio (RFd) were not influenced by irrigation depths. Therefore, energy used for photosynthetic processes in pineapple plants is not affected by irrigation using saline water with electrical conductivity of 3.6 dS m-1.

1-12

Authors: Alailton dos Reis Guaralde; Daniela Almeida de Souza; Celso Luiz Possas Guimarães Júnior; Rafael Soares Guimarães; Victor Barbosa Saraiva; José Augusto Ferreira da Silva; Marcos Massao Murata; Renato Matos Lopes; Rachel Ann Hauser-Davis; Manildo Marcião de Oliveira

In Brazil, malacoculture is developed mainly in the state of Santa Catarina, followed by São Paulo and Rio de Janeiro. In the course of the development of Brazilian mariculture, legislation has addressed the sanitary requirements necessary for bivalve commercialization. However, monitoring phycotoxins is a challenge, due to often costly reference methods. In this context, this study evaluated the use of alternative ecotoxicological and bioanalytical methods using Artemia franciscana (brine shrimp) lethality assessments. The results confirm that, although correlations between the reference mouse assay and the brine shrimp assays were not high, the alternative brine shrimp assay may be incorporated into phycotoxin monitoring programs, as hepatopancreas methanolic extracts of mussel (Perna perna) containing DSP resulted in high lethality rates. Therefore, further methodological adjustment studies and the inclusion of other enzymatic and toxicological models are required to further assess these differences, and associations between ecotoxicological methods as early-alarm methods are encouraged.

1-14

Authors: Gabrielle de Oliveira Xavier; Tati de Almeida; Carlos Magno Moreira de Oliveira; Petronio Diego Silva de Oliveira; Victor Hugo Barros Costa; Larissa Moreira Alves Granado

The goal of this study was to assess the temporal dynamics of an accumulation reservoir in an accessible and accurate way. The study was conducted on the Serra da Mesa Dam (GO) using orbital images. To estimate the flat area of the dam surface, Landsat TM and OLI images for the period 1998 to 2018 were used. The images were processed using the Google Earth Engine platform (GEE) in order to obtain the dam surface area (km²) and relate it to the flow, altimetric height and volume of the reservoir over the years. The dam showed constant variation of water since its inception, with a decreasing trend. The highest values of the reservoir measurement metrics were observed in the years coincident with the largest areas of the dam, and inversely proportional to the years of the appearance of new dams upstream. More than 90% of the altimetric height variation of water could be explained by the flat area of the dam. The processing platform using the GEE is effective to provide extensive temporal analysis using a large volume of data in a short time, with accurate and robust results.

1-11

Authors: Walter Javier Cuadrado Campó; María Custodio; Carmela Emperatriz Vicuña Orihuela; Richard Pavel Peñaloza Fernández

The phytosorption potential of metals of Hydrocotyle ranunculoides was evaluated for the mitigation of water pollution in the high Andean wetlands of Peru. The plants were selected from 10 wetland sites in the community of Pomachaca- Tarma and were washed with potable water, dried, ground, weighed, chemically digested and read with Varian AA 240 atomic absorption equipment. The plant showed copper concentrations in the root (12.08 ± 1.67 mg/kg) greater than the stem (7.37 ± 1.00 mg/kg), followed by the leaves (7.37 ± 1.56 mg/kg). Lead concentration in the root was 0.228 ± 0.711 mg/kg, but was not found in the stem or leaves. The highest zinc concentration was in the root (67.52 ± 12.57 mg/kg) to the stem (53.30 ± 0.61 mg/kg), followed by the leaves (43.99 ± 8.49 mg/kg). Finally, iron was higher in the root (5571.28 ± 693.94 mg/kg) than in the leaves (342.76 ±122.09 mg/kg), followed by the stem (291.94 ± 54.84 mg/kg). Surrounding water had pH between 7.2 and 7.6; no copper and lead were found, zinc was 0.005 ± 0.012 mg/L and iron was 0.009± 0.007 mg/L. In the sediment, copper was 26.12 ± 0.65 mg/kg, lead 28.25 ± 2.41 mg/kg, zinc 85.98 ± 11.38 mg/kg and iron 26111.89 ± 614.37 mg/kg. These results indicate that this plant absorbs metals in the order of Fe>Zn>Cu>Pb and is an alternative for the development of phytotechnology, oriented to the treatment of effluents with metals that contaminate water in wetlands.

1-13

Authors: Shirlei Almeida Assunção; Marcos Gervasio Pereira; Denilson Dortzbach; Eduardo Carvalho da Silva Neto

Phosphorus (P) is an essential element for vineyard productivity. This study assessed the influence of parent material on organic P fractions in vineyard soils of basaltic and rhyodacitic origin. The experiment was conducted in four municipalities located in mountainous regions in Santa Catarina, Brazil: Urubici, São Joaquim, Campos Novos, and Água Doce. Disturbed soil samples were collected between grapevine rows at depths of 0.00–0.05, 0.05–0.10, 0.10–0.20, and 0.20–0.40 m. Soil chemical attributes (pH in H2O, Ca2+, Mg2+, Al3+, P, K+, and H + Al), total organic carbon (TOC), available and residual P, labile P (extracted with sodium bicarbonate), moderately labile P (extracted with sulfuric acid), and moderately resistant P (extracted with sodium hydroxide) were determined. Soil parent material influenced the dynamics of phosphorus in vineyard soils. Both P forms (available and solution equilibrium P) and P organic fractions (labile, moderately labile, and moderately resistant P), are affected by the parent material. Basaltic soils had higher TOC, available and residual P, and moderately labile and moderately resistant P, whereas rhyodacitic soils showed higher labile P. The high levels of moderately labile and moderately resistant P fractions in basaltic soil were attributed to its high TOC, available P, and residual P contents. Parent material was found to influence organic P fractions in vineyard soils.

1-13

Authors: Nelize Lima Santos; Maria da Conceição Rabelo Gomes; José Ângelo Sebastião Araújo dos Anjos; Fernanda Gonçalves Cunha

This study employed multivariate analysis techniques to identify and evaluate the chemical variables responsible for the contamination of the urban area of Boquira, Bahia, due to the abandonment of the tailings basin of Pb-Zn mining, in order to assist in the environmental management of the area. Factor analysis was performed on main and grouping components. The factor analysis allowed grouping the variables into two main factors for street sediment samples, adding up to 72% of the total accumulated variance, and three factors for house dust samples, which explained 77% of the total variance. The variables have a strong correlation with the composition of the tailings basin. Cluster analysis classified the samples according to the concentration of metals in the area, where the influence of the tailings basin and the natural background of the region's rocks in the contamination distribution can be identified.

1-22

Authors: Andres Paladines Andrade; Marley Vellasco; Karla Figueiredo; Francisco Gerson Araújo; Christina Wyss Castelo Branco

The complexity of evaluating the quality of an aquatic environment with its numerous variables has resulted in several quality indexes to synthesize all information in a single value. However, most of these indexes are based on few environmental variables, losing information from other relevant variables. This article presents a new model capable of representing the quality level of a tropical oligo-mesotrophic reservoir on a numerical scale, considering the subjectivity implicit in the concept of quality, and involving several physical, chemical and biological variables. The proposed model, called "Fuzzy Indices for Water Quality Assessment and Biotics" (FUZZY-WBQAI), is based on fuzzy inference systems, providing a way to deal with the uncertainty between the quality categories. A computational tool was developed, which automatically assesses the quality of water, considering different methodologies that depend on the stratification conditions and the longitudinal zone of the reservoir. The model calculates two indices: one for water quality and one biotic that uses metrics from the fish assembly. The model was effective in revealing the decrease in water quality in summer months with higher temperature and precipitation. The effect of the mixture of the stratified reservoir in winter in decreasing the water quality in an area of fish cultivation was highlighted. The biotic index was sensitive to spatial changes in the environmental quality of the reservoir. The results were considered satisfactory, in agreement with the specialized knowledge, and can provide a rapid diagnosis of water conditions in oligo-mesotrophic reservoirs in the tropics.

1-10

Authors: Camila Peitz ; Claudia Regina Xavier

The pulp industry uses more than 40 m3 of water per ton of pulp produced, generating high effluent flows. In general, it presents high concentrations of organic matter, color and ecotoxicity. The most widely used effluent treatment systems in the pulp industry are biological, including moving bed biofilm systems that are efficient in removing biodegradable organic matter. This work evaluated the removal of organic matter, total phenolic compounds, color and lignin derivatives in the treatment of Kraft cellulose effluent using the moving bed biofilm reactor (MBBR), and also evaluated the support media biofilm development by solid analysis and scanning electron microscopy. The parameters evaluated during treatment were: BOD5, COD, color, total phenolic compounds, lignin derivatives, and solids, with tests performed on organic loads from 0.7 and 8.9 kgCOD m-3 d-1. Organic matter removal remained stable, being over 80% to BOD5 and over 42% to COD. The color and the total phenolic compounds were removed up to approximately 7 and 28%, respectively. Over 19% removal of derivatives of lignin compounds was observed in both organic load rates. In the MBBR, biofilm was confirmed and enabled this biological system to treat the cellulose effluent in a stable way.

1-12

Authors: Cristian Epifanio Toledo; João Carlos Mohn Nogueira ; Alexandre de Amorim Camargo

The objective of this work was to propose and evaluate a model to estimate transit water losses and surface runoff in a Brazilian semi-arid basin, fundamental components in the hydrological studies of the region, such as in the verification of hydrological connectivity. The study area was the Orós Reservoir Basin, located in the state of Ceará. The modeling of transit water loss and surface runoff were developed based on the work of Araújo and Ribeiro (1996) and Peter et al. (2014). In the proposed model, the parameter of loss in transit (k) was estimated at 0.027 km-1 for a section of the river basin, and when simulated for other stretches it provided good flow results at the end of the stretch, obtaining an NSE of 82%. The value of the runoff coefficient was estimated at 3% and when evaluating a spatial variation of this coefficient in the basin, the values varied from 2% to 12%, and the use of specialized runoff coefficient (RC) values promoted a higher NSE in the discharge simulation in the basin. It is concluded that the proposed model to estimate transit water losses and surface runoff demonstrated a high efficiency in the simulation of hydrological processes. The basin of Orós reservoir presented a high variability of the coefficient of surface runoff, justifying the need for a greater spatiality of this coefficient in heterogeneous environments.

1-11

Authors: Guilherme Henrique Expedito Lense ; Rodrigo Santos Moreira ; Taya Cristo Parreiras ; Derielsen Brandão Santana ; Talyson de Melo Bolelli ; Ronaldo Luiz Mincato

Water erosion is the principal degradation process of tropical soils, and its effects can be measured by modeling techniques. Erosion models provide a diagnosis of the soil loss intensity and can support the planning of soil conservation practices. Models with low data requirements, such as the Revised Universal Soil Loss Equation (RUSLE) and, more recently, the Erosion Potential Method (EPM), are mainly applied in Brazil. Thus, the objective of this work was to estimate water erosion soil-loss rates using the EPM and RUSLE models on a tropical subbasin, followed by a comparison of their outcomes. The models’ application considered soil physical parameters, edaphoclimatic conditions of the area, land use, and subbasin management practices. The accuracy of the methods was verified using total transported sediment and water discharge data. We compared the models using Pearson's correlation analyses, considering a 5% of significance. We found a predominance of moderate-intensity erosion with average soil loss of 1.17 and 1.46 Mg ha-1 year-1, measured by EPM and RUSLE, respectively. The EPM model underestimated soil losses by 15.27%, and RUSLE overestimated by 19.08%, indicating a higher percentage of areas with high erosion rates (4.60%). The models presented results with a different order of magnitude, but with significant correlations, indicating that both methods pointed out similar zones of intense and light-erosion rates.

1-10

Authors: Allan Remor Lopes; Marcio Antonio Vilas Boas; Felix Augusto Pazuch; Diane Aparecida Ostroski; Marta Juliana Schmatz

This study monitored a drip irrigation system with different hydraulic heads, using control charts. The study included 25 tests, and was conducted at the Experimental Nucleus of Agricultural Engineering of the State University of Western Paraná, located in the municipality of Cascavel, Paraná. The drip irrigation system was operated by gravity, and had four hydraulic heads (10, 11, 12 and 15 kPa). The uniformity of the system was determined based on uniformity distribution. Uniformity monitoring was performed using Shewhart and exponentially weighted moving-average (EWMA) control charts. An increase in the hydraulic head increased uniformity. The use of 12 and 15 kPa hydraulic heads yielded good performance, whereas 10 and 11 kPa yielded regular performance. The use of control charts proved to be efficient; the Shewhart control chart was more robust, whereas the EWMA control chart, which indicated trends and deviations not shown by Shewhart control charts, was more sensitive.

1-31

Authors: Gabrielle Nunes da Silva; Letícia Delduque Alves; Isabella Escobar dos Santos; Daniele Maia Bila; Alfredo Akira Ohnuma Júnior; Sérgio Machado Corrêa

This study evaluates the rainwater harvesting system to determine the chemical quality of the water and allocate it for use. Samples were collected in the city of Rio de Janeiro at the points of Direct Precipitation (DP), First Flush (FF) and Reservoir (RR). The methodology involved carrying out an analysis of Ca, Cd, Cu, Na, Ni, Fe, K, Mg, Pb, Zn, conductivity, turbidity, pH and chloride. The R language was used for the principal component analysis, Pearson coefficient correlation, hierarchical cluster analysis, Tukey test and boxplot. The results show that when there is no interference from the catchment surface (DP), the rainwater has a low concentration of metals, although the first millimeters of rain have a concentration above what is permissible in the guidelines issued by the Ministry of Health (Ordinance n° 05/2017). The disposal system (FF) reduced the concentration of pollutants in the RR, but not enough to comply with legislation. It was noted that Ca, K and Na are the main metals found in rainwater. During the dry period, there were significant correlations between the physico-chemical and meteorological parameters. The high concentration of metals in the wet period suggests that rain assists the cleaning of the atmosphere and that most metals are present in the form of aerosols or fine particles suspended in the air. The findings reveal significant indications of acid rain and pre-treatment is recommended to ensure rainwater can be used safely for more mundane purposes.

1-10

Authors: Fernán Chanamé-Zapata; María Custodio; Christian Poma-Chávez; Alex Huamán-De La Cruz

The study assessed the trophic state of three lakes used as fish farms in the region of Junín-Peru, under different hydrological conditions. Surface water samples were collected from three points at each lake in 2018 during the rainy (March-April) and dry (June-July) seasons. Total phosphorus, turbidity, and chlorophyll-a (Chl-a) were measured. Trophic indexes (TSI Chl-a, and TSI TP) were also computed. The water trophic state categorization was performed by adapting and calculating the Trophic State Index (TSI). The TSI (TP) classified the three lakes in both seasons (rainy and dry) as mesotrophic (30 < TSI ≤ 60). Pomacocha and Tipicocha were classified as eutropic (60 < TSI ≤ 90) in the two seasons according to TSI (Chl a), while Tranca Grande was classified as mesotrophic (also two seasons). The results for TSI showed a predominance of eutrophic and mesotrophic conditions in all lakes used as fish farms.

1-15

Authors: Fernanda Neves Ferreira; Hebe Morganne Campos Ribeiro; Vítor Abner Borges Dutra

We investigated the application of economic instruments in the management of Brazilian water resources as mechanisms to stimulate the rational use of water and to recognise its economic value. We analysed water-charge scenarios at the national and international levels as a methodology to provide an economic estimate of environmental services related to water resources. Through bibliographical and documentary research, we identified the economic instruments applied to Brazilian water-resource management, describing the methodologies and values used Brazilian water charges and in some member states of the Organization for Economic Cooperation and Development. We identified how economic valuation methods of environmental resources could contribute to the improvement of water charges, considering the environmental services offered by a healthy river basin. In the Brazilian and the international scenarios, water charge methodologies include the volumetry of abstracted or consumed water, associating some elements that indicate the pollution level. The prices per cubic meter of water are still very low in all the scenarios. Environmental valuation techniques can be an essential tool for rethinking the methodologies and costs applied in water charges, increasing the potential of water’s rational use through economic instruments.

1-12

Authors: Adriana Maria Güntzel; William Marcos da Silva; Eliana Aparecida Panarelli

The Taquari River is one of the most important tributaries of the Paraguay River, whose sediments are carried and deposited on the plain forming the largest alluvial fan in the world, known as Pantanal. In the floodplain, the course of the river has been modified by the sedimentation process, resulting in lakes with different degrees of connectivity with the river. This study assessed the influence of connectivity on the physical and chemical characteristics of water along a hydrological cycle in oxbow lakes of the Taquari River floodplain, in Mato Grosso do Sul, Brazil. Sampling was carried out monthly, from May 2005 to June 2006.The physical and chemical data of the water and the variables of river level and rainfall intensity were correlated by Principal Component Analysis (PCA). Limnological differences resulted from distinct degrees of connectivity between the oxbow lakes and the Taquari River. Variations in the dry and rainy seasons established a gradient that extends over a space-time continuum and generates greater environmental heterogeneity and, consequently, greater biodiversity. Thus we conclude that this mosaic of lakes and the surrounding landscape requires protection and preservation because of its importance for biodiversity conservation.

1-11

Authors: Adriana Mendonça Gallotti; Hélio Fernandes Machado Júnior; Arlene Gaspar

In the Armed Forces' campaign activities, large troops may be exposed to serious health risks even before war itself. In 2010, for example, the Brazilian Army sent nearly 2,000 men to join the United Nations peacekeeping mission in Haiti, which was experiencing a cholera epidemic. This work therefore investigated the water quality and sanitation of the various types of reservoirs used in four field-training activities of a Brazilian Army Unit located in the state of Rio de Janeiro. Physicochemical and microbiological analyses of the water were carried out, and visual inspections and swab samples were collected from the inner surface of these reservoirs for counting coliform bacteria and counting mesophilic aerobic microorganisms. Physicochemical and microbiological analyses of water from different types of reservoirs revealed a lack of conformity with American Public Health Association and Ordinance Number 518, of 03/25/04, of the Brazilian Ministry of Health . It was observed that 50% of the collective and individual reservoirs did not have the desirable minimum levels of Free Residual Chlorine. In addition, in 35.7% of the total collective and individual reservoirs evaluated there was growth of coliform group bacteria and in 28.57% of them the number of heterotrophic bacteria exceeded the maximum recommendation. According to the swabs performed on the inner surfaces, results of the total viable mesophilic aerobic counts were above the recommended levels in 78.57% of the total evaluated reservoirs. Besides that, in the Lyster bags of activities 1 and 2, there was growth of coliforms, or 14.28% of the total evaluated reservoirs. It was concluded that there were failures in the management of multiple barriers during storage and / or distribution, as well as in the maintenance of disinfection to prevent or eliminate microbial contamination, indicating the need for corrective measures.

1-12

Authors: Jair Juarez João; Cíntia Souza da Silva ; José Luiz Vieira ; Milena Felipe da Silveira

Pork production involves the generation of wastewater containing a high pollutant load. Although the biological systems show satisfactory efficiency for the treatment of these effluents, they demand an elevated area for installation and high production of biological sludge. Alternatively, oxidative processes are an alternative for treating such effluents, requiring minor areas and increasing the efficiency of the treatment. We studied the Fenton process assisted with ultrasound for the treatment of swine slaughterhouse wastewater. Nails used in civil construction were used as the iron source. We evaluated the influence of pH, contact time, nail mass, and hydrogen peroxide concentration on color removal, turbidity, chemical oxygen demand (COD) and biochemical oxygen demand (BOD5). The removal of nutrients and oils and greases was also evaluated. The best results using the ultrasound-assisted Fenton process were obtained at pH 3, hydrogen peroxide concentration 90 mg L-1, and a nail unit (2.7g). In these conditions, color, turbidity, COD, and BOD5 removal of 98, 98.2, 84.6, and 98%, respectively, were achieved. The reduction in the other parameters evaluated was above 70%. Catalytic activity maintained above 90% until the sixth cycle of use. In general, the ultrasound-assisted Fenton process using the nail as a catalyst would be an alternative for the treatment of swine slaughterhouse wastewater. This alternative is responsible for the higher removal of organic load and nutrients in a shorter time when compared with biological systems.

1-11

Authors: Jhones da Silva Amorim; Rubens Junqueira ; Vanessa Alves Mantovani; Marcelo Ribeiro Viola; Carlos Rogério de Mello; Nicole Lopes Bento

Maximum and minimum streamflow are fundamental for water resource management, especially for water rights. However, lack of monitoring and scarce streamflow data limit such studies. Streamflow regionalization is a useful tool to overcome these limitations. The study developed models for regionalization of the maximum and minimum reference streamflows for the Mortes River Basin (MRB) (Water Resources Planning and Management Unit - GD2), Southern Minas Gerais State. The study used long-term streamflow historical series provided by the Brazilian National Water Agency (ANA). Previous exploratory analysis was performed, and it was observed that the streamflow series are stationary according to the Mann-Kendall test. The estimation of the streamflow for different return periods (RP) was performed by fitting Probability Density Functions (PDFs) that were tested by the Anderson-Darling (AD) test. The Generalized Extreme Values (GEV) and Wakeby were the most appropriate PDFs for maximum and minimum streamflows, respectively. The streamflow models were fitted using a power regression procedure, considering the drainage area of the watersheds as inputs. The fittings reached the coefficient of determination (R2) greater than 0.90. Thus, the streamflow regionalization models demonstrated good performance and are a potential tool to be used for water resource management in the studied basin.

1-12

Authors: Diogo Botelho Correa de Oliveira; Willames de Albuquerque Soares; Marco Aurélio Calixto Ribeiro de Holanda

Effluent collection and stormwater management make use of different drainage systems, which should remain unconnected with one another. If stormwater drains into sewage collection systems, it often causes changes in effluent quality indicators at sewage treatment plants. This study sought to quantify the changes caused by rain in a Wastewater Treatment Plant (WWTP) located in Paulista, PE, which uses the activated sludge system. Accordingly, changes in pH, temperature, BOD, and treatment efficiency at the inlet and outlet, as well as inlet flow were analyzed on dry and rainy days at the plant, which has a sewage capacity of 400 L s-1. The input volume was found to be greater than the design flow of the station, about 25%. With this, some relevant operational controls were identified, such as temporarily shutting down sewage pumping stations in order to maintain full operation of the system and avoid overload. The pH increases slightly in alkalinity, about 0.3, but this does not interfere with the treatment process. The temperature of the influent on rainy days is about 3 to 5 degrees cooler, depending on the intensity of the event. Using the T and Z tests, it was possible to identify that BOD concentrations in the influent and the effluent were not significantly different (uneq. var. t: 1.18 > 0.26 and uneq var. z: 0.71 > 0.48, respectively), and the organic load removal efficiency was maintained, contrary to what is expected with other, more simple types of treatment.

1-16

Authors: Isabela Pires da Silva; Gabriela Barbosa da Costa; João Gabriel Thomaz Queluz; Marcelo Loureiro Garcia

This study evaluated the effect of hydraulic retention time on chemical oxygen demand (COD) and total nitrogen (TN) removal in an intermittently aerated constructed wetlands. Two horizontal subsurface-flow constructed wetlands were used: one without aeration and the other aerated intermittently (1 hour with aeration/7 hours without aeration). Both systems were evaluated treating domestic wastewater produced synthetically. The flow rate into the two CWs was 8.6 L day-1 having a hydraulic retention time of 3 days. The results show that the intermittently aerated constructed wetland were highly efficient in removing COD (98.25%), TN (83.60%) and total phosphorus (78.10%), while the non-aerated constructed wetland showed lower efficiencies in the removal of COD (93.89%), TN (48.60%) and total phosphorus (58.66). These results indicate, therefore, that intermittent aeration allows the simultaneous occurrence of nitrification and denitrification processes, improving the removal of TN in horizontal subsurface-flow constructed wetlands. In addition, the use of intermittent aeration also improves the performance of constructed wetlands in removing COD and total phosphorus.

1-16

Authors: Elisa Flávia Luiz Cardoso Bailão; Leovigildo Aparecido Costa Santos; Sara dos Santos Almeida; Patrícia Lima D’Abadia; Ronny José de Morais; Túlio Natalino de Matos; Samantha Salomão Caramori; Cleide Sandra Tavares de Araújo; Carlos de Melo e Silva Neto; Luciane Madureira Almeida

Low-order streams located near urban areas usually receive domestic, industrial, and agricultural wastewaters that negatively affect river water quality. Additionally, water pollution is associated with land-use variations around the river, which is characterized by unplanned urbanization, intense agricultural activities, and deforestation. This work correlated land-use patterns with physicochemical quality and genotoxic potential of water at four points (P1 to P4) along the Extrema River, located in an industrial and agricultural area of Central Brazil. Physicochemical analyses indicated that the water collected from the Extrema River is inappropriate for human consumption. Using the Allium cepa model, no evidence of cytotoxicity was observed at any point; in contrast, the genotoxic potential of these water samples was observed. The correlation of these results with land use showed that the water collected at P3 was the most contaminated; this is probably due to the inflow of wastewater from municipal, industrial, and agriculture activities. Different results were observed for P2 and P4, where land-use analysis attributed the water quality to forest burns. We concluded that differential use of the land changed the characteristics of the associated river water, and A. cepa parameters were more related to land-use characteristics than to physicochemical parameters. This study highlighted the importance of associating land use with the cyto genotoxic potential of water.

1-10

Authors: Emanoelly Barbosa Sacramento ; Caroline de Almeida Azevedo ; Saulo Tavares Abreu ; Helcio Resende Borba ; Viviane Moreira de Lima

The public water supply of the Rio de Janeiro metropolitan region is highly dependent on transposition from the Paraíba do Sul River: 70% of the water is diverted to the Piraí River and then passes through a series of other rivers and reservoirs, finally discharging in the Guandu River. During this path, the water is exposed to many sources of pollution. This makes the quality of the raw water that reaches the Guandu Treatment Station (WTS) highly vulnerable. This article reports the analysis of the cytogenotoxic potential of water samples collected at four different points along the Piraí River downstream from the transposition point, utilizing the Allium cepa test system. The samples were collected in two periods, the dry and wet seasons. The water at all four collection points presented some level of cytogenotoxicity, with the presence in the test cells of large nucleoli, multiple nucleoli, nuclear buds, lagging chromosomes, sticky chromosomes, karyorrhexis, cytoplasmic shrinkage and changes of the mitotic index. The samples collected during the dry season had a larger number of cells with alterations, indicating that the cytogenotoxic potential varies in function of the time of year, depending on the volume of contaminated effluents. The results obtained along with data from the Rio de Janeiro State Environmental Institute (INEA) for the same period reveal the importance of monitoring along with proper sanitation and sewage treatment, and that the presence of pollutants not only hampers water treatment, but also poses risks to organisms at different trophic levels, including humans.

1-15

Authors: Tatiana Candeia da Silva Fortunato ; José Antonio Tosta dos Reis; Antonio Sérgio Mendonça; Fernando das Graças Braga da Silva

This study simulated nitrogen-compound concentration changes in rivers, taking into account uncertainty analysis carried out by the Monte Carlo Method. The study area is the final stretch of the Piracicaba River, located in Minas Gerais, Brazil, which is an important Doce River tributary. The uncertainty analysis took into account random generation of hydrodynamic variables, initial water quality conditions and kinetic constants. Different variation percentages for the organic nitrogen decay kinetic constants random generation did not influence considerably the ammonia or organic nitrogen maximum concentration extreme values. In the simulations, maximum organic nitrogen concentrations were most frequently between 0.20 mg.L-1 and 0.22 mg.L-1 (42%), maximum ammonia nitrogen between 0.28 mg.L-1 and 0.30 mg.L-1 (30%), maximum nitrite between 0.05 mg.L-1 and 0.07 mg.L-1 (49%) and maximum nitrate between 0.46 mg.L-1 and 0.50 mg.L-1 (37%). Estimated maximum concentrations for ammonia nitrogen, nitrite and nitrate did not exceed the environmental quality standards established by Brazilian CONAMA Resolution 357/2005 for Class 2 watercourses. Random generation of kinetic constants that regulate ammonia and nitrite decay produced significant ammonia nitrogen, nitrite, and nitrate peak concentrations value frequencies, histograms and forms changes, when considering variation percentages equal to or greater than 50%. Some simulation results showed more inhibition of oxidized nitrogen forms production.

1-13

Authors: Alessandra Bosso; Adriana Aparecida Bosso Tomal; Lucas Caldeirão Miranda; Josemeyre Bonifácio da Silva; Hélio Hiroshi Suguimoto; Raul Jorge Hérmaz Castro-Gomez

This study sought to create a better fermentation medium to maximize lactase production by Saccharomyces fragilis IZ 275 using different carbon sources, including reconstituted powdered cheese whey. A factorial design 24 was applied to evaluate the significant effects of variables which compose the fermentation medium. Then, a steepest descent-ascent design was applied to obtain the maximum activity. A Rotational Central Composite Design (RCCD) 24 was made to optimize the fermentation medium. We verified that the cheese whey, a by-product of the dairy industry, can be employed as an excellent fermentation medium by yeast, within the bioeconomy concept and used by the dairy industry as product with additional value. The employed methodology is an efficient tool in the optimization process for β-galactosidase production. In the optimized fermentation medium, the maximum production of β-galactosidase (54.68 U/mL) by S. fragilis IZ 275 is obtained with 14 g/L sucrose, 17.7 g/L reconstituted powdered cheese whey, 5.14 g/L yeast extract and 8.85 g/L peptone.

1-12

Authors: Dione Richer Momolli* ; Huan Pablo de Souza ; Mauro Valdir Schumacher ; Aline Aparecida Ludvichak ; Claudiney do Couto Guimarães ; Angélica Costa Malheiros ; José Mateus Wisniewski Gonsalves

The chemical composition of rainfall is influenced by natural or anthropogenic factors; the amount of nutrients deposited is increased by the amount of rainfall. This work sought to estimate the amount of nutrients deposited by precipitation in the Pampa biome, the seasonal variation of the chemical composition of rain water, and the origin of nutrients found in the water. Precipitation collectors were installed in the open area to measure precipitation volumes biweekly over 2 years, and the samples were chemically analyzed. Concentrations of nutrients in the rain water increased over winter; however, since there was less precipitation, the total deposition was similar to the other seasons. Correlation analysis using the Pearson coefficient showed a negative correlation between rain volume and ion contents, indicating a dilution effect. The total amount of nutrients from precipitation during the study was 72.7 kg ha-1, representing an average of 36.3 kg ha-1 year-1. The Ca2+ and K+ ions are predominantly of litholical origin, whereas the SO42- and NO3- ions were of anthropogenic origin. The balance between the sum of cations and the sum of anions was shown to be unitary, indicating excellent data validation. The input of these nutrients occurs gradually, avoiding excessive losses, increasing the stock in the soil.

1-10

Authors: Mateus Marques Bueno; Ricardo Valcarcel; Marcos Gervasio Pereira; Felipe Araújo Mateus

The differentiated effects of the provision of environmental services in a watershed are due to the capacity of regularization of outflows in its mouth. In impacted areas, this environmental function is affected, and in some situations, it ceases to exist completely. This study characterized the soil and the production of sediments in anthropic watersheds, with the purpose of describing and evaluating the environmental services offered by a watershed undergoing anthropic transformation. The analyses show that the water flow in the remaining watersheds was preferably horizontal in the transmission zone, and these areas represent almost all areas. The values of hydraulic conductivity suggest that the infiltration decreases with soil depth; this fact is corroborated by the values of bulk density. The natural regions of water accumulation, the floodplains or outcrops zones, are small and do not have direct contact with the main floodplain present in the Guandu River Basin, making it impossible to recharge through other areas. Even so, water balance shows that the set of measures implemented ensured that the deficit water demand was supplied during the years of operation, even in times of water deficit. Likewise, the retention of solids in the settling tanks and in the drainage system prevented some 29,000 t of sediment from being carried between the years of 2012 and 2015.

1-11

Authors: Enzo Luigi Crisigiovanni; Elynton Alves do Nascimento; Rodrigo Felipe Bedim Godoy; Paulo Costa de Oliveira-Filho; Carlos Magno de Sousa Vidal; Kelly Geronazzo Martins

Considering the current importance watercourses quality conservation, it is important to establish relationships between parameters that enable evaluation of the origins of changes in water quality, allowing actions to mitigate them. However, it is important to improve the association of different variables and to take sufficient samples. This study associates usual techniques and parameters to analyse the water quality of an urban river from Paraná State, Brazil. For this, we used biological indicators (aquatic macroinvertebrates), physical-chemical (temperature, turbidity, true colour, pH, DO and BOD5,20) indicators and microbiological (faecal and total coliforms) indicators. These indicators were related to land use and occupation classes obtained from high resolution QuickBird 2 images. For this association, the surroundings (450 meters buffer) of three distinct points of the river were considered: I. Near the spring; II. In the downtown city; and III. In a residential neighbourhood. Different values of physical, chemical and microbiological variables were detected along the river, showing evident relationships between them and with the use and occupation of the urban and peri-urban space in the characterization of surface waters. The association design was able to detect the landscape effect on water quality in a coherent way and that these connections were mainly related to suppression of the riparian forest present in the surroundings, further demonstrating the importance of this vegetation for the maintenance of watercourse quality.

1-15

Authors: João Henrique Gaia Gomes; Marcos Gervasio Pereira; Márcio Rocha Francelino; João Pedro Bessa Larangeira

Soil is a fundamental natural resource for subsistence and development of humanity, exploited mainly for agriculture. Agricultural practices, though, are improperly performed, compromising edaphic conditions and favoring erosive processes, which mainly culminate in the loss of soil and nutrients. Water erosion represents the main form of soil degradation, given that the impact of raindrops on the soil results in the detachment of particles, a process favored by factors such as climate, relief, soil vegetation and use and occupation. The objective of the study was to classify four gullies based on their evolutionary turns and to judge the physical-chemical classifications of the soil at the internal and external faces of the gullies. The morphology of the gullies was classified by aerial images generated by drones. The gullies were mapped using Google Earth images from 2016. The qualitative assessment was performed using the digital field-elevation curvature (MDESC) model with field validation. Deformed samples were collected at depths of 0-10 and 10-20 cm, while non-deformed samples were collected at depths of 0.0-0.10 cm to evaluate their chemical and physical attributes. A nonparametric 5% Kruskal-Wallis statistical analysis was performed on the resulting data. The chemical and physical attributes of the soil differed according to the evolutionary stage of the surfaces (internal and external) at depths of 0 to 10 cm, while the faces showed differences in depth of 10 to 20 cm.

1-13

Authors: Suymara Toledo Miranda; Antonio Teixeira de Matos ; Mateus Pimentel Matos; Claudéty Saraiva

The present work evaluated the influence of filling substrate material (crushed PET bottles or fine gravel) on the efficiency of pollutant removal in horizontal subsurface flow constructed wetlands (HSSF-CWs). They were cultivated with a consortium of elephant grass cv. Napier (Pennisetum purpureum Schum) and Tifton 85 (Cynodon spp.) to treat wastewater from a common milk cooling tank (WWMT). For this, six HSSF-CWs were used which had dimensions of 0.6 m tall x 1.0 m wide x 2.5 m long. In order to investigate possible efficiency loss in the removal of pollutants from the system, operation was divided into two periods: Period I (from April to December 2015) and Period II (April to December 2016). Thus, the removal efficiencies of BOD5, solids and total nitrogen (TN), total phosphorus (TP), potassium (K) and sodium (Na) from WWMT were statistically compared. Results indicated that the efficiency of the HSSF-CWs for removing pollutants increased or remained similar after one year and nine months of their operation; and PET bottles were a viable alternative substrate in HSSF-CWs based on the efficient removal of pollutants from WWMT during the one year and nine months of monitoring. Crushed PET bottles constitute a viable substrate for filling HSSF-CWs. Altering the cultivation positions of the plant species did not change pollutant removal efficiencies, but indicates the importance of species arrangement to maximize system performance.

1-11

Authors: Everton Luis Butzen ; Gabriel Capellari Santos; Sandrini Slongo Fortuna ; Vandré Barbosa Brião

Malls concentrate a large number of people in a relatively small area, and thus generate concentrated urban wastewater. This study evaluated the performance of a membrane bioreactor (MBR) as an alternative for the treatment of mall wastewater. Wastewater samples without any previous treatment were collected from a medium-size mall and showed a high chemical oxygen demand (COD) near 2,000 mg L-1. The MBR operated with a constant pressure of 40 kPa during 60 days with a sludge age of 30 days. Concentration of biomass was 3,738±930 mg L-1 and average permeate flux was 7.0 L h-1 m-2. The MBR was able to remove 91.2% and 97.2% of color and turbidity, respectively. Furthermore, COD removal was approximately 90% and biochemical oxygen demand (BOD) 88%. In addition, the MBR produced a phosphorus removal near 50%, and for nitrogen, 80%. The MBR system proved to be an efficient process for the removal of the pollutants, remaining stable even with the oscillation of the characteristics of the raw sewage, presenting great potential for application in the treatment of sewage from malls and effluents with high organic loads.

1-15

Authors: Pedro Fialho Cordeiro; Fernando Figueiredo Goulart; Diego Rodrigues Macedo; Mônica de Cássia Souza Campos ; Samuel Rodrigues Castro

The water hyacinth (Eichhornia crassipes) is listed among the 100 worst invasive plants and was ranked as the 11th worst invasive species in Europe, being a threat to aquatic biodiversity and water-provision. Predicting species distribution is the first step to understanding niche suitability, forecasting the invasion impact and building resilience against this species. In this study, we used a potential distribution model to assess the global risk of water hyacinth invasion by overlapping maps of highly suitable areas for water hyacinth occurrence and areas of biological importance and water scarcity. The MaxEnt - Maximum Entropy algorithm was used in the construction of the model and included five global bioclimatic layers and one of urbanized areas. Among the variables used, occurrence is mainly explained by urban areas, highlighting the importance of cities as a source or dispersion mechanism of the water hyacinth. Global biodiversity hotspots are predominantly situated in high suitability regions for the species. Ramsar sites and global protected areas are at a lower risk level compared to hotspots; however, future climate change and urban growth scenarios could put these areas at higher risk for invasion. Threats posed by the water hyacinth are possibly more acute in regions suffering from current or chronic drought. The results suggest that niche models that do not consider anthropic variables may be underestimating potential distribution of invasive species. Furthermore, the ecological plasticity of the water hyacinth and its close association with cities increase the concern about the impact of this species on the environment and on water security.

1-11

Authors: Blanca Lisseth Guzmán Barragán; Manuel Alejandro Gonzalez Rivillas; Manuel Salvador Cuero Villegas; Jose David Olivar Medina

Chemical contamination of the water supply system caused by anthropic activities can cause adverse health effects. This study determined the presence of toxic metals, organic substances, pesticides and trihalomethanes in the water supply systems of the urban area of Ibague City. The economic and sanitary activities located in the 25 surface streams of the 32 water supply systems of the municipality were characterized. A total of 25 water samples were taken from the surface streams, and 35 samples in the water network of each drinking water service provider for the identification of pesticides (carbamates, organochlorines, organophosphorus), mercury, arsenic, cyanide, lead, cadmium, antimony, cobalt, selenium, silver, nickel and hydrocarbons. The presence of trihalomethanes was sampled after the treatment process given. A total of 775 economic and sanitary activities were detected in the surface streams of the water supply systems, highlighting the human settlements, agricultural and tourist activities impact on the water sources. Organochlorine pesticides (0.009-0.109 mg/L), mercury (0.001-0.004 mg/L) were identified in the water supply system in concentrations higher than those permitted by local regulation. Concentrations of trihalomethanes (0.064-1.260 mg/L) were detected in 68.7% of the water supply systems with treatment. The presence of chemical contaminants occurs mainly in communities with water supply systems of low complexity with high anthropic affectation. It is necessary to strengthen the assessment of hazards and risk by health surveillance, as well as intersectoral intervention for the protection of water sources and the improvement of water treatment technologies.

1-13

Authors: Emmanuel Bezerra D'Alessandro; Ina de Souza Nogueira; Nora Katia Saavedra del Aguila Hoffmann

Density of phytoplankton in stabilization ponds influences treatment performance. The study hypothesized that the phytoplankton community structure varies according to local and temporal changes and consequently influences the treatment of the effluent. Phytoplankton community structure in facultative and maturation ponds in central Brazil was analyzed to provide guidance on system operation and maintenance. Further, species density, abundance, diversity, richness, dominance and beta diversity were measured. The efficiency of the treatment was evaluated based on Biochemical Oxygen Demand (BOD). Additionally, a Canonical Correspondence Analysis (CCA) was used to investigate how physical and chemical variables influenced the composition of the most abundant species in the dry and rainy seasons and the microalgae that were most related to the removal of BOD. One hundred and sixty-eight taxa were recorded, and the most abundant classes in both ponds were Chlorophyceae and Cyanophyceae (40% potentially toxic). The maturation pond had greater adaptability in the rainy season, while the facultative pond was more flexible in the dry season. The best period of growth varied among species. In both ponds, Chlorella minutissima was the one which most contributed to the optimization of the treatment. Thus, identifying phytoplankton species and relating them to water quality parameters and weather can help to understand the ecological dynamics of wastewater treatment and provide useful information for the operation and maintenance of stabilization ponds.