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.

The gradual increase in organic loading is a strategy that has been used in reactor operation of wastewater treatment to adapt the microbial community and its metabolic activities. Within this context, the aim of this research was to investigate the microbial community present in an anaerobic chambered reactor (ACR) operating for 270 days treating ethanol distillery stillage. The operation the ACR reactor started with low feed rate which was increased gradually so that the organic load rate (OLR) ranged from 0.5 to 2.5 g COD m⁻³ day⁻¹. Performance monitoring included physicochemical analyses, methane production, microscopy, and biomolecular analyses. The operational data shows satisfactory performance in terms of COD removal, averaging over 92.5%. DGGE analyses revealed that the structure of the microbial community of Bacteria domain is more sensitive to reactor operational conditions than that of the Archaea domain, when the OLR increased. A clear relationship was observed between the microbial diversity and the dominance for Bacteria and Archaea domains to different OLR, indicating adaptation of communities to the operating conditions imposed on the ACR.

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.

Soilless culture systems offer an environmentally friendly and resource-efficient alternative to traditional cultivation systems fitting within the scheme of a circular economy. The objective of this research was to examine the sustainable integration of recycling fertilizers in hydroponic cultivation—creating a nutrient cycling concept for horticultural cultivation. Using the nutrient film technique (NFT), three recycling-based fertilizer variants were tested against standard synthetic mineral fertilization as the control, with 11 tomato plants (Solanum lycopersicum L. cv. Pannovy) per replicate (n = 4) and treatment: two nitrified urine-based fertilizers differing in ammonium/nitrate ratio (NH₄⁺:NO₃⁻), namely (1) “Aurin” (AUR) and (2) “Crop” (CRO); as well as (3) an organo-mineral mixture of struvite and vinasse (S+V); and (4) a control (NPK). The closed chamber method was adapted for gas fluxes (N₂O, CH₄, and CO₂) from the root zone. There was no indication in differences of the total shoot biomass fresh matter and uptake of N, P and K between recycling fertilizers and the control. Marketable fruit yield was comparable between NPK, CRO and S+V, whereas lower yields occurred in AUR. The higher NH₄⁺:NO₃⁻ of AUR was associated with an increased susceptibility of blossom-end-rot, likely due to reduced uptake and translocation of Ca. Highest sugar concentration was found in S+V, which may have been influenced by the presence of organic acids in vinasse. N₂O emissions were highest in S+V, which corresponded to our hypothesis that N₂O emissions positively correlate with organic-C input by the fertilizer amendments. Remaining treatments showed barely detectable GHG emissions. A nitrified urine with a low NH₄⁺:NO₃– (e.g., CRO) has a high potential as recycling fertilizer in NFT systems for tomato cultivation, and S+V proved to supply sufficient P and K for adequate growth and yield. Alternative cultivation strategies may complement the composition of AUR.

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.

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.

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

Brazil is one of the greatest producers of orange and its orange juice processing industry produces large volumes of solid and liquid waste daily. As an efficient use of the residues from citrus industry, production of bioethanol is highlighted. However, the generation of bioethanol produces a liquid effluent as a by-product, known as vinasse. The objective of this study was to evaluate the toxicity of an effluent from citrus industries, orange vinasse, when applied to soil using Allium cepa seeds. The evaluation was performed by means of germination, root growth, and genotoxic and mutagenic parameters. The EC₅₀ (effectiveness concentration) and ½ EC₅₀, defined in the germination test, were used for genotoxicity tests. Toxicity was observed in dilutions above 40%, which was responsible for reducing the germination speed index. Genotoxicity was observed only using the EC₅₀ and mutagenicity was not detected. According to the results, orange vinasse showed toxicity similar to the sugar cane vinasse, so caution is suggested in the disposal of this effluent into the environment.

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.