Expansion of sugarcane crops may have contributed to the increased contamination of native habitats in Brazil. Several species of amphibians inhabit ponds formed in flooded farmlands, where pesticide concentrations are usually high. This study evaluated the ecotoxicological effects of the sugarcane pesticides fipronil and 2,4-D, as well as the fertilizer vinasse (isolated and mixed), on physiological responses of Leptodactylus fuscus and Lithobates catesbeianus tadpoles. In situ assays were conducted in mesocosms with concentrations based on the doses recommended by the manufacturer. Vinasse (1.3% dilution) caused 100% tadpoles’ mortality immediately after its application. Fipronil and/or 2,4-D altered antioxidant and biotransformation responses, induced neurotoxicity and changed lipid contents in tadpoles. A multivariate approach indicated that the mixture of pesticides induced most of the sublethal effects in both tadpole species, in addition to the isolated fipronil in L. fuscus. Fipronil alone increased glucose-6-phosphate dehydrogenase (G6PDH) activity, decreased acetylcholinesterase (AChE) and total lipid contents, and altered some individual lipid classes (e.g., free fatty acids and acetone-mobile polar lipids) in L. fuscus. The interaction between fipronil and 2,4-D in this species were more evident for lipid contents, although enzymatic alterations in G6PDH, AChE and glutathione-S-transferase (GST) were also observed. In L. catesbeianus, the mixture of pesticides reduced triglycerides and total lipids, as well as increased GST and decreased AChE activities. The detoxifying enzyme carboxylesterase was reduced by 2,4-D (alone or in mixture) in both species. Isolated pesticides also modulated specific lipid classes, suggesting their disruptive action on energy metabolism of tadpoles. Our study showed that fipronil, 2,4-D, and vinasse, individually or mixed, can be harmful to amphibians during their larval phase, causing mortality or impairing their functional responses.

Co-digestion between sugarcane vinasse (Vn) and water hyacinth (WH) at various mixing ratios of 0:1, 1:0, 1:3, 3:1, and 1:1 was carried out under thermophilic conditions (55 °C) for 60 days. The effect of various mixing ratios on the pH changes, soluble chemical oxygen demand (sCOD) reduction, and cumulative biogas production was investigated. The first order, modified Gompertz, and logistic function kinetic models were selected to fit the experimental data. Model discrimination was conducted through the Akaike Information Criterion (AIC). The study revealed that co-digestion shows better performance compared to the mono-digestion of both substrates. Vn:WH mixing ratio 1:1 with inoculum to substrate ratio (ISR) of 0.38 g VSᵢₙₒcᵤₗᵤₘ/g VSₛᵤbₛₜᵣₐₜₑ is the most favorable ratio, achieving sCOD reduction efficiency and cumulative biogas production of 71.6% and 1229 mL, respectively. Model selection through AIC revealed that ratio 1:1 was best fitted to the logistic function kinetic model (R² = 0.9897) with Yₘ and K values of 1232 mL and 31 mL/day, respectively.

Sugarcane vinasse, also known as distillery wastewater, is a key by-product of the ethanol industry. Vinasse characteristics and their huge volume pose environmental concerns about the choice of treatment method. Microfiltration (MF) has been efficiently applied to vinasse clarification; however, it has been underexplored in the literature. In this context, the present study investigated the application of coagulation and cross-flow MF for vinasse clarification. To maximize the process efficiency, operational parameters were optimized using the one-factor-at-a-time method in batch tests. The optimal values were Superfloc C492 concentration of 5 mg L⁻¹, backpulsing frequency of 10 min, and vinasse temperature of 45 °C, which showed a removal of 35.0, 86.0, and 99.9% for chemical oxygen demand (COD), color, and turbidity, respectively. The optimization process significantly improved the vinasse flux but did not show any influence in the permeate quality. Optimal parameters were successfully applied to the continuous mode in the MF system, which operated during 164 h at an average flux of 21.6 L h⁻¹ m⁻². High removals were reached for color (79.3%) and turbidity (99.6%), and low removal was found for COD (31.6%), which are in agreement with the batch mode tests. This work showed the importance of operational optimization, and the results provide valuable support for establishing practical guidelines for vinasse clarification in the ethanol industry. Graphical Abstract

Inorganic anion monitoring is essential for bioreactor operation and is related for pollution control or energy and products recovery. However, there is a lack of studies validating methods for inorganic anions analyses in conditions compatible to those in bioreactor operations treating different types of wastewater. This paper provides a systematic statistical study and matrix-effect assessment for sugarcane vinasse, leachate, sewage and synthetic sewage. Sample preparation consisted of only a filtration and sample dilution. Cl⁻, NO₂⁻, NO₃⁻, PO₄³⁻ and SO₄²⁻ were determined in a Dionex ICS 5000® equipped with a chemical conductivity suppressor. Calibration curves were linear and well-adjusted between 2.5 and 50 mg L⁻¹ for all the anions in all the tested matrices, except PO₄³⁻ and SO₄²⁻ in vinasse. A calibration range for PO₄³⁻ in all tested matrices was 5.0 to 100 mg L⁻¹, whereas a range from 5.0 mg L⁻¹ to 50 mg L⁻¹ was obtained for SO₄²⁻ in vinasse. All the anions yielded recoveries in the range of 85–115% for all the tested matrices. Relative standard deviations lower than 10 and 2% were achieved for peak areas and retention times, respectively. A signal enhancement was observed for all the tested matrices and all the anions. The matrix effect level varied from −1.7 (NO₂⁻ in vinasse) to −33.9% (Cl⁻ in leachate). Sewage was the less affected matrix, while leachate gave higher matrix effects. Validation results and the matrix effect assessment showed that a simple sample preparation is suitable for multi-elemental analyses of inorganic anions for complex environmental samples.

Studies on ion movement in soil profiles associated to the application of vinasse are scarce. The objective of this study is to assess the quantity of inorganic and organic ions in the profile of the soil under sugarcane. The study was realized in a commercial sugarcane cultivar in the municipality of Ponta Pora, MS, Brazil in the harvest year of 2010/2011. The soil in the experimental area was classified as Haplorthox clay. The experimental design was randomized blocks, with four repetitions, two depths, and four harvest periods, after application of a 350 m³ h⁻¹ vinasse dosage. Twenty-four soil solution extractors were installed at a distance of 4 × 4 m from each other in the areas under vinasse treatment. Vinasse was chemically characterized by the inductively coupled plasma atomic emission spectrometry method. The extracted solution samples were determined for ionic chromatography. Elevated concentrations of lactic, butyric, citric, tartaric, succinic, formic, and acetic acids were found up to 1 m of depth up to 29 days after application. After 63 days, no traces of those anions were found in the soil. There was a rise in nitrate and a decline in the content of chloride and sulfate.

Sugar industry produces a variety of organic byproducts causing disposal as well as environmental issues. This study investigated the safe use of these byproducts in assessment of soil physicochemical properties and metal accumulation in rice. A field experiment was performed with following treatments: control only NPK (CF), NPK + sugarcane bagasse (SB), NPK + press mud (PM), NPK + sugarcane vinasse (SV), NPK + SB + PM (SB + PM), NPK + SB + SV (SB + SV), NPK + PM + SV (PM + SV), NPK + SB + PM + SV (SB + PM + SV). Total byproduct input was (1.25 t ha⁻¹) as recommended for organic inputs in the local area. The results indicated that integrated use of these amendments with chemical fertilization improved soil properties and rice yield. Organic matter was significantly improved in SB + SV (191.3%), SB + PM + SV (164.4%), and SB + PM (150.9%). Total N was significantly enhanced in SB + SV (193%), SB + PM + SV (166%), and SB + PM (152.5%); extractable P was high in SB (103%), PM + SV (89.7%), and SB + PM (51%); extractable K was significantly improved in PM (39.6%) and SB (33.4%); extractable Zn was significantly enhanced in SB (1172.8%), SV (829.2%) and PM (819.1%) in soil. Rice grain yield was significantly enhanced in SB (213.1%) and PM (208.8%) while combined application also improved the yield with reference to the CF. The application of SB + PM improved N (58.7%), P (27.4%), K (11.5%), and Zn (166.4%) concentration in grain, while metal accumulation was within the permissible limit. Zn concentration was significantly enhanced in SB + PM (166.4%) whereas the concentration of Cd and Pb was significantly reduced with the application of byproducts. Health assessment results showed no harmful effects for humans. Results conclude that these byproducts are good nutrients source and improve soil physicochemical properties without any health hazards.

The aim of this study was to evaluate and compare three species of ligninolytic fungi (Trametes versicolor, Bjerkandera adusta, and Phanerochaete chrysosporium) in laboratory-scale columns with respect to their efficiency for the treatment of raw tequila vinasse, in order to assess the feasibility of incorporating this type of fungi in vertical flow treatment wetlands. The following parameters were analyzed at the inlets and outlets of the columns: total suspended solids (TSS), total dissolved solids (TDS), chemical oxygen demand (COD), biological oxygen demand (BOD₅), pH, electrical conductivity (EC), true and apparent color, total nitrogen (TN), nitrites (NO₂⁻), nitrates (NO₃⁻), and total phosphates. The performance of the 3 fungi was very similar (p > 0.05), although T. versicolor showed a trend towards higher efficiencies for the removal of TSS, TN, total phosphates, and COD. The removal efficiencies of TSS were 73.1%, 80.2%, and 78.8% for B. adusta, T. versicolor, and P. Chrysosporium, respectively; for TN removal, the efficiencies were 64.7%, 65.7%, and 60.6%, respectively. The higher removal percentage for COD (10.2%) was obtained in the column with T. versicolor. These results demonstrate the tolerance of the fungi to raw tequila vinasse, their role in reducing pollutant concentrations, and the feasibility of incorporating them into vertical flow treatment wetlands to increase the efficiency of these systems for the treatment of tequila stillage.

The replacement of synthetic surface-active compounds (SACs) by their microbial counterparts is carving out a niche for themselves in the field of bioremediation. However, the high cost of microbial products has limited their application at a realistic scale. In the current study, several hydrocarbon-degrading microorganisms were assayed as potential SAC producers in low-cost liquid media. Only the strain CC10, placed within the class Actinobacteria, was able to produce emulsifying molecules by using a combination of sugarcane vinasse or crude glycerol (as cheap carbon substrates) with urea or peptone (as nitrogen sources). The emulsifying activity of the supernatants and the stability of emulsions formed with motor oil depended on the carbon and nitrogen sources. However, the biodegradability of these metabolites was only associated with the carbon substrate, and it was always higher than the two tested synthetic surfactants, sodium dodecyl sulfate and Triton X-100. Also, a positive linear association between emulsifying and lipase activities of the CC10 supernatants was detected (r = 0.781; p = 0.219), with the maximum activities detected in the glycerol-peptone supernatant. Interestingly, this supernatant was able to emulsify different oily substrates, a property that could be used to increase the efficiency of the treatment of effluents with high fat content.

The mutagenic and genotoxic activity of vinasses collected from a fuel alcohol plant, located in the municipality of Frontino, Northwestern Colombia, were evaluated. Two samples obtained from an 82-L capacity hybrid reactor (UASB-anaerobic filter (AF)-UASB) were studied under laboratory conditions after being treated with biological oxidation, the first, and the second with Fenton reaction consecutively. Mutagenicity was evaluated in vitro by the Ames test using strains TA98 and TA100 with and without S9 metabolic activation. The genotoxic analysis was conducted using the Allium cepa roots assay where chromosomal aberrations were used as clastogenic or aneugenic response markers, and micronuclei as mutagenic response. The Ames test results showed a strain-dependent positive linear association with the vinasse sample concentration before treatment (dose–response effect). Unlike TA100, strain TA98 showed a mutagenic effect in both the presence and absence of metabolic enzymes. After the biological oxidation treatment, vinasse mutagenicity significantly decreased. Finally, after Fenton treatment, the sample did not induce any mutagenic event. Genotoxic activity was observed in all three samples, but there was a higher frequency in the vinasse sample before treatment. Concerning the frequency of micronuclei, no clear association was observed with either the concentration or the type of sample.