Evaluation of bacterial diversity in a swine manure composting system contaminated with veterinary antibiotics (VAs).

Composting has become an alternative for the treatment of organic effluents, due to its low cost, easy handling, and a great capacity for treating swine manure. As it is a biological process, many microorganisms are involved during the composting process and act in the degradation of organic matter and nutrients and also have the ability to degrade contaminants and accelerate the transformations during composting. The objective of this work was to identify microorganisms present in the swine effluent composting system, under the contamination by most used veterinary drugs in Brazil. The composting took place for 150 days, there was an addition of 200 L of manure (these 25 L initially contaminated with 17 antibiotics) in 25 kg of eucalyptus wood shavings. The microorganisms were measured at times (0 until 150 days) and were identified by the V3-V4 regions of the 16S rRNA for Bacteria, by means of next-generation sequencing (NSG). The results show seven different bacterial phyla (Proteobacteria, Bacteroidetes, Firmicutes, Acidobacteria, Actinobacteria, Spirochaetota and Tenericutes) and 70 bacterial genera (more than 1% significance), of which the most significant ones were Pseudomonas, Sphingobacterium, Devosia, Brucella, Flavisolibacter, Sphingomonas and Nitratireductor. The genus Brucella was found during mesophilic and thermophilic phases, and this genus has not yet been reported an in article involving composting process. With the results obtained, the potential for adaptation of the bacterial community was observed, being under the influence of antibiotics for veterinary use.

Preparation of alumina-supported Fe-Al-La composite for fluoride removal from an aqueous matrix.

Using groundwater for human consumption is an alternative for places with no nearby surface water resources. Fluoride is commonly found in groundwater, and the consumption of this water for a prolonged time in concentrations that exceed established limits by WHO and Brazilian legislation on water potability (1.5 mg L-1) can cause harmful problems to human health. For this reason, fluoride removal is an important step before water consumption. In this work, activated alumina was impregnated with Fe-Al-La composite and employed for the first time as an adsorbent for fluoride removal from an aqueous environment. XRD, SEM/EDS, FT-IR, and point of zero charge were used to characterize the prepared adsorbent. The adsorptive performance of adsorbent material was investigated by employing a 23-central composite design (CCD), and the obtained experimental conditions were pH = 6.5 and adsorbent dosage = 3.0 g L-1. A maximum adsorption capacity of 8.17 mg g-1 at 298 K and pH = 6.5 was achieved by Langmuir isotherm to describe the adsorption. The kinetic model that better described experimental data was Avrami, with the kav parameter increasing with the initial concentration from 0.076 to 0.231 (min-1)nav. The nature of adsorption was found to be homogeneous, and it occurs in a monolayer. The fluoride removal performance for the prepared adsorbent was higher than granular activated alumina, showing that supporting Fe-Al-La at the alumina surface increased its fluoride adsorption capacity from 16 to 42% at the same experimental conditions. Finally, the influence of co-existing ions Cl-, SO42-, and NO3- was evaluated in fluoride adsorption, and the material presented great selectivity to fluoride. Thus, Fe-Al-La/AA adsorbent is a promising material for fluoride removal from water.

Transformation of Residual Açai Fruit (Euterpe oleracea) Seeds into Porous Adsorbent for Efficient Removal of 2,4-Dichlorophenoxyacetic Acid Herbicide from Waters.

Brazil's production and consumption of açai pulp (Euterpe oleracea) occur on a large scale. Most of the fruit is formed by the pit, which generates countless tons of residual biomass. A new purpose for this biomass, making its consumption highly sustainable, was presented in this study, where activated carbon (AC) was produced with zinc chloride for later use as an adsorbent. AC carbon formed by carbon and with a yield of 28 % was satisfactorily used as an adsorbent in removing the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). Removal efficiency was due to the highly porous surface (Vp = 0.467 cm3 g-1; Dp = 1.126 nm) and good surface área (SBET = 920.56 m2 g-1). The equilibrium data fit the Sips heterogeneous and homogeneous surface model better. It was observed that the increase in temperature favored adsorption, reaching a maximum experimental capacity of 218 mg g-1 at 328 K. The thermodynamic behavior indicated a spontaneous, favorable, and endothermic behavior. The magnitude of the enthalpy of adsorption was in agreement with the physical adsorption. Regardless of the herbicide concentration, the adsorbent displayed fast kinetics, reaching equilibrium within 120 min. The linear driving force (LDF) model provided a strong statistical match to the kinetic curves. AC with zinc chloride (ZnCl2), created from leftover açai biomass, is a potential alternative as an adsorbent for treating effluents containing 2,4-D.

Use of the CuFe2O4/biochar composite to remove methylene blue, methyl orange and tartrazine dyes from wastewater using photo-Fenton process.

In this study, CuFe2O4 ferrite was supported on biochar produced from malt biomass residues as a photocatalyst for degradation of methylene blue (MB), methyl orange (MO), and tartrazine (TZ) dyes. XRD, FT-IR, and FE-SEM were used to characterize the crystallinity and morphology of the samples. The characterization showed that the ferrite was uniformly supported on the surface of the biochar, confirming the formation of the composite. Degradation tests showed that CuFe2O4 degraded approximately 50, 47, and 62% of MB, MO, and TZ dyes, respectively, after 60 min of reaction. On the other hand, the CuFe2O4/biochar composite showed a significant increase in dye degradation, ~ 100%, for all three dyes. This increase in degradation efficiency may be due to less agglomeration of supported particles and due to decreased recombination of electron/hole pairs. Thus, results showed that the photocatalyst composite produced in this study is an effective alternative for removing dyes from wastewater.

Performance of an electrocoagulation-flotation system in the treatment of domestic wastewater for urban reuse.

Domestic wastewater is an important alternative source of water in the face of a growing discrepancy between water availability and demand. The use of techniques that enable the urban reuse of treated sewage is essential to make cities more sustainable and resilient to water scarcity. The main goal of this study was to evaluate the performance of an electrocoagulation-flotation system in the treatment of domestic wastewater for urban reuse. The study was performed using raw domestic wastewater samples. The electrocoagulation-flotation system was a cylindrical reactor with aluminum electrodes. The treatment conditions involved agitation at 262.5 rpm, electrical current of 1.65 A, electrolysis time of 25 min, an initial pH of 6, and inter-electrode distance of 1 cm. Overall, the electrocoagulation-flotation system was highly efficient for removal of apparent color (97.9%), chemical oxygen demand (82.9%), turbidity (95.8%), and orthophosphate phosphorous (> 98.2%). The electrocoagulation-flotation system had a consumption of electrical energy ranging from 9.5 to 13.3 kWh m-3, electrode mass from 294.7 to 557.0 g m-3, and hydrochloric acid from 4.3 to 6.6 L m-3. Sludge production in the system ranged from 1,125.7 to 1,835.7 g m-3. Treated wastewater had a satisfactory quality for several urban reuse activities. The electrocoagulation-flotation system showed potential to be used for domestic wastewater treatment for urban reuse purposes.

Degradation of ramipril by residues from the brewing industry: A new carbon-based photocatalyst compound.

This study is a pioneer in the use of hydrochar as a support for photocatalytic oxide and its application and evaluation as a catalyst in degradation reactions of ramipril. Novel composites were easily prepared by the support TiO2 or ZnO nanoparticles on the malt bagasse hydrochar. The preparation of the hydrochar requires low synthesis temperature (250 °C), generating the energy savings of the process. The production of the new composites was well supported by different analytical techniques XRD, FTIR, SSA, SEM, EDS, and reflectance diffuse. The effect of different proportions of TiO2 or ZnO on the composites was investigated on the degradation efficiency of the pharmaceutical ramipril, without pH adjustment. Composites with a 5:1 hydrochar/TiO2 or ZnO ratio (MH5T and MH5Z, respectively) showed degradations of 72 and 98% of ramipril at 120 min. This remarkable performance may be associated with the decrease in band gap energy and the electron-hole recombination rate. In addition, the composites were more efficient than metal oxides pristine, and this may be related to the fact that hydrochar have a high concentration of phenolic, hydroxyl, and carboxylic functional groups on their surface. Radical identification tests indicated that h+, O2•-, and •OH were the reactive species involved in the degradation. The proposed mechanism was studied via LC-MS/MS indicated that the ramipril molecule degrades into low m/z intermediates in the first 60 min of reaction using the MH5Z.

Toxicity of acrylamide after degradation by conjugated (UV/H2O2) photolysis in microalgae.

Acrylamide (AA) is routinely used in laboratories and industries, and its disposal is always a problem; consequently, offering an alternative for their treatment contributes to conducting research in a responsible way. Therefore, in this work, acrylamide solutions were degraded by ultraviolet radiation and hydrogen peroxide (H2O2), and their toxicity was evaluated using a Desmodesmus quadricauda microalgae growth assay. The AA solutions were exposed to different dosages of H2O2 and different exposure times to UV radiation. The degradation was evaluated by liquid chromatography, which allowed the identification of the acrylamide peak and subsequent by-product peaks. A 100% degradation of the 1.5 mg L-1 AA solution with UV/H2O2 (0.034 g L-1) was achieved in just 10 min. The by-products formed did not inhibit the growth of D. quadricauda microalgae. The number of D. quadricauda individuals that grew in acrylamide solutions exposed to 20 and 30 min of UV radiation, with 0.034 g L-1 of H2O2, was very similar to the number of individuals that grew in the control solution. Thus, the treatment proposed in this work using H2O2 combined with ultraviolet radiation degraded acrylamide into by-products with reduced toxicity.

Occurrence and fate of pharmaceuticals in effluent and sludge from a wastewater treatment plant in Brazil.

A wide variety of pharmaceuticals are discharged in water courses on a daily basis due to their incomplete removal from effluent in treatment plants. The aim of the current study was to assess the occurrence, fate and removal of pharmaceuticals from effluent and sludge samples collected in the biggest sanitary sewer plant in Southern Brazil. In total, 13 pharmaceuticals were detected in the influent through UHPLC-MS/M - paracetamol and caffeine recorded the highest concentrations, 137.98 and 35.29 µg L-1, respectively. The treated effluent presented 11 compounds. Antibiotics were the class recording the widest diversity; metronidazole showed the lowest concentration (0.023 µg L-1) and sulfamethoxazole presented the highest concentration (1.374 µg L-1) in influent samples. Seven pharmaceuticals were absorbed by the sludge; among them, one finds caffeine, ciprofloxacin and ofloxacin, which were quantified both in the effluent and in the sludge. On the other hand, doxycycline, fenbendazole, norfloxacin and tetracycline were only detected in sludge samples - their concentrations ranged from 0.026 to 5.034 mg kg-1. Clindamycin, oxytetracycline, sulfathiazole and trimethoprim concentrations increased throughout the treatment. There were high paracetamol and caffeine removal rates (>97%), and it may have happened due to degradation, photodegradation or chemical reaction. Ciprofloxacin and ofloxacin removal rate exceeded 83% mainly due to their sorption by sludge. Finally, the mass balance analysis highlighted high pharmaceutical loads (511.466 g d-1) discharged into recipient waterbodies. This outcome demands broadening the removal of these pharmaceuticals from sewage.

Optimization of an electrocoagulation-flotation system for domestic wastewater treatment and reuse.

The risks inherent to the inadequate domestic wastewater disposal, allied to the water growing demand, scarcity, and pollution problems, have highlighted the importance of adopting treatment techniques that not only target the sewage discharge, but also its reuse. For this reason, the objective of this study was to evaluate the best conditions of an electrocoagulation-flotation system for domestic wastewater treatment and urban reuse. To achieve this, an effects study followed by two rotatable central composite experimental designs 2² was performed, considering: agitation, electrical current, electrolysis time, inter-electrodes distance, and initial pH. The electrocoagulation-flotation system was composed of a cylindrical acrylic reactor with a working volume of 1 L, with two aluminium electrodes connected to a direct-current power supply. Results showed that electrical current and electrolysis time were the most influent operational parameters on domestic wastewater treatment in the electrocoagulation-flotation system. The initial pH adjustment was also important due the pH increase tendency observed in the results. The best conditions of agitation, inter-electrodes distance, electrolysis time, electrical current, and initial pH for domestic wastewater treatment and urban reuse were 262.5 rpm, 1 cm, 25 min, 1.65 A, and 6, respectively. Under these conditions, turbidity and colour removals higher than 98% and 92% were reached respectively, as well as residual turbidity lower than 6 NTU and final pH of 8 were achieved, following the Brazilian standards and guidelines for urban reuse. Thus, the electrocoagulation-flotation system studied was effective for domestic wastewater treatment and reuse for urban supply purposes.

Antibiotic resistance in wastewater treatment plants: understanding the problem and future perspectives.

Antibiotics residues (AR), antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARG) are a new class of water contaminants, due to their adverse effects on aquatic ecosystems and human health. Contamination of water bodies occurs mainly by the excretion of antibiotics incompletely metabolized by humans and animals and is considered the main source of contamination of antibiotics in the environment. Given the imminent threat, the World Health Organization (WHO) has categorized the spread of antibiotics as one of the top three threats to public health in the twenty-first century. The Urban Wastewater Treatment Plants (UWWTP) bring together AR, ARB, ARG, making the understanding of this peculiar environment fundamental for the investigation of technologies aimed at combating the spread of bacterial resistance. Several methodologies have been employed focusing on reducing the ARB and ARG loads of the effluents, however the reactivation of these microorganisms after the treatment is widely reported. This work aims to elucidate the role of UWWTPs in the spread of bacterial resistance, as well as to report the efforts that have been made so far and future perspectives to combat this important global problem.

Potential environmental toxicity of sewage effluent with pharmaceuticals.

Sewage effluent effects on the biochemical parameters of Astyanax bimaculatus organs were investigateted. Treated sewage was collected in a treatment plant; 43 compounds, among them, pharmaceuticals and hormones, were investigated. Caffeine, ciprofloxacin, clindamycin, ofloxacin, oxytetracycline, paracetamol, sulfadiazine, sulfamethoxazole, sulfathiazole and tylosin waste was detected in the collected material. Fish were divided into four groups: control, TSE (treated sewage effluent), TSE + P (TSE with increased concentration of five pharmaceuticals) and PTSE (TSE + P post-treated with O3/H2O2/UV). Biochemical parameters were evaluated in different organs after 14-day exposure. TBARS levels increased significantly in the brain of animals in the TSE and TSE + P groups in comparison to the control. There was significant reduction in TBARS levels recorded for the liver, muscle and gills of animals in the PTSE group in comparison to those of animals in the other groups. AChE activity reduced in the muscle of animals in the groups showing the highest pharmaceutical concentrations. CAT activity in the liver of animals in groups exposed to pharmaceutical effluent was inhibited. GST activity increased in brain of animals in the TSE + P and PTSE groups, whereas reduced levels of this activity were observed in liver of animals in the TSE group. Increased GST activity was observed in the brain of animals in TSE + P and PTSE groups. Based on integrated biomarker response values, the TSE + P group presented greater changes in the analyzed parameters. Results point out that pharmaceutical waste can cause oxidative stress, as well as affect biochemical and enzymatic parameters in Astyanax sp. Post-treatment can also reduce damages caused to fish, even in case of the likely formation of metabolites. Based on these results, these metabolites can be less toxic than the original compounds; however, they were not able to fully degrade the pharmaceutical waste found in the sewage, which can interfere in fish metabolism.

Removal of microorganisms and antibiotic resistance genes from treated urban wastewater: A comparison between aluminium sulphate and tannin coagulants.

The presence of antibiotic resistant-bacteria (ARB) and antibiotic resistance genes (ARG) in treated effluents of urban wastewater treatment plants (WWTP) may represent a threat to the environment and public health. Therefore, cost-effective technologies contributing to minimize loads of these contaminants in the final effluents of WWTP are required. This study aimed at assessing the capacity of coagulation to reduce the ARB&ARG load in secondary treated urban wastewater (STWW), as well as the impact of the process on the structure and diversity of the bacterial community. Coagulation performance using aluminium sulphate, a synthetic substance, and tannins, a biowaste, was compared. Samples were analysed immediately before (STWW) and after the coagulation treatment (Alu, Tan), as well as after 3-days storage in the dark at room temperature (RSTWW, RAlu, RTan), to assess possible reactivation events. Both coagulants decreased the turbidity and colour and reduced the bacterial load (16S rRNA gene copy number, total heterotrophs (HET), and ARB (faecal coliforms resistant to amoxicillin (FC/AMX) or ciprofloxacin (FC/CIP) up to 1-2 log immediately after the treatment. Both coagulants reduced the load of intl1, but in average, aluminium sulphate was able to decrease the content of the analysed ARGs (blaTEM and qnrS) to lower levels than tannin. Reactivation after storage was observed mainly in RTan. In these samples the load of the culturable populations and qnrS gene prevalence increased, sometimes to values higher than those found in the initial wastewater. Reactivation was also characterized by an increment in Gammaproteobacteria relative abundance in the bacterial community, although with distinct patterns for RTan and RAlu. Curvibacter, Undibacterium and Aquaspirillum were among the most abundant genera in RAlu and Aeromonas, Pseudomonas and Stenotrophomonas in RTan. These bacterial community shifts were in agreement with the variations in the culturable bacterial counts of HET for RTan and FC/CIP for RAlu. In summary, the overall performance of aluminium sulphate was better than that of tannins in the treatment of treated urban wastewater.

Ecotoxicological Analysis of Acrylamide Using a Microalga as an Indicator Organism.

Aquatic ecosystems are very prone to contamination. The fast and accurate assessment of the toxicity of water is an important tool for environmental safety. The aim of this study was to assess the possible toxic effects of acrylamide on physiological parameters of the Chlorophyceae Desmodesmus quadricauda. Cells in exponential growth phase were exposed for 72 h to different concentrations of acrylamide. Light microscopy analysis documented cell density, number of cells per coenobia, cell dimensions, and biovolume; chlorophyll a concentration was also determined. Result show that EC50 of acrylamide for D. quadricauda is 5.88 mg/L. Significant morphological changes were also observed for phenotypic plasticity and cellular dimensions. The most noticeable changes were the significant increase in one-celled coenobia over 24 and 48 h of exposure to EC50. These findings demonstrate that acrylamide may affect aquatic life, not only through growth inhibition, but also inducing phenotypic plasticity and also be problematic when used in high concentrations for water supply.

Comparison between coagulation-flocculation and ozone-flotation for Scenedesmus microalgal biomolecule recovery and nutrient removal from wastewater in a high-rate algal pond.

The removal of nutrients by Scenedesmus sp. in a high-rate algal pond, and subsequent algal separation by coagulation-flocculation or flotation with ozone to recover biomolecules, were evaluated. Cultivation of Scenedesmus sp. in wastewater resulted in complete NH3-H removal, plus 93% total nitrogen and 61% orthophosphate removals. Ozone-flotation obtained better water quality results than coagulation-flocculation for most parameters (NH3-N, NTK, nitrate and nitrite) except orthophosphate. Ozone-flotation, also produced the highest recovery of lipids, carbohydrates and proteins which were 0.32 ±â€¯0.03, 0.33 ±â€¯0.025 and 0.58 ±â€¯0.014 mg/mg of biomass, respectively. In contrast, there was a low lipid extraction of 0.21 mg of lipids/mg of biomass and 0.12-0.23 mg of protein/mg of biomass in the coagulation-flocculation process. In terms of biomolecule recovery and water quality, ozone showed better results than coagulation-flocculation.

Revisiting Coiled Flocculator Performance for Particle Aggregation.

This work summarizes recent studies evaluating the torsion and curvature parameters in flocculation efficiency using a hydraulic plug flow flocculator known as a Flocs Generator Reactor (FGR). Colloidal Fe(OH)3 and coal particles were used as suspension models and a cationic polyacrylamide was used for the flocculation. The effectiveness of the aggregation process (in the distinct curvature and torsion parameters, and hydrodynamic conditions) was evaluated by the settling rate of the Fe(OH)3 flocs, and flocs size by photographic analysis. As a result of curvature, a secondary flow is induced and the profiles of the flow quantities differ from those for a straight pipe. Results showed that the differences in the flocculator design influences the Fe(OH)3 flocs size and settling rates, reaching values of about 13 and 4 m/h, for the coiled and straight pipes respectively. Coal flocs generation was also shown to be dependent on the flocculator design and shear rate. Results showed that turbulent kinetic energy increases because of curvature when the torsion parameter is kept constant (pitch close to zero), enhancing the flocs formation.