Tequila vinasses is a mixture made from up to six still distillation two-stage process residual effluents. First stage fractions: residual must (60%), heads (0.9%) and tails (20.0%); second stage fractions: non-evaporated (8.0%), heads (0.1%) and tails (1.0%); the result is a more complex effluent for its treatment or biorefining. The objectives of this study were to: (a) characterize the five still distillation volatile streams in the Tequila 100% Agave processing; compounds: methanol, ethanol, acetaldehyde, ethyl acetate, sec-butanol, n-propanol, iso-butanol, n-butanol, iso-amyl, n-amyl, and ethyl lactate were detected by gas chromatography; calculated chemical oxygen demand from chemical composition had very high values (53,760–1,239,220 mg/L); measurement of pH (3.24–4.80), color (38.6 UC Pt-Co max), turbidity (46.1 max), electrical conductivity (3.30–172.20 μS/cm), and solid content (0 mg/L) was also made; (b) report an energy analysis (2.02 × 10⁹ KWh) and CO₂ production (429 × 10⁶ kg) in the Tequila industry during 2019; (c) up to date residues (365.2 × 10⁶ kg agave bagasse, 1146.1 × 10⁶ kg agave leaves and 3300.0 × 10⁶ L agave vinasse) in 2019; (d) economic analysis, current tequila vinasses treatment price is 16.00 USD/m³ but could reach a considerable fraction value if is bio-refined, a break down component analysis reach for five volatile streams $51.23–$140.00 USD/m³.

In this paper, the production of biomass, pigments, lipids, and carbohydrates and the elimination of ammonium and orthophosphate by the microalgae Chlorella vulgaris, grown in synthetic wastewater (SWW), were studied under different light intensities (3000–10,000 lux), pH (7.5–9.5) and daily illumination time (8–16 h). The best conditions for the autotrophic culture of microalgae were predicted using response surface methodology (RSM). The results showed that the adaptation of the microalgae for this nutrient source was effective. The best conditions for the cultivation of Chlorella vulgaris in SWW were 8.44 pH and a light intensity of 8433 lux in the daily illumination time of 16 h. Under optimal conditions, the production of microalgal biomass, chlorophyll-a, chlorophyll-b, carotenoids, lipids and carbohydrates was 0.534 g/L, 7.46 mg/mL, 3.53 mg/mL, 2.01 mg/mL, 21.40% and 28.46%, respectively. The removal efficiencies of ammonium and orthophosphate from SWW were 97.66% and 58.78% in autotrophic cultures. This investigation introduces a new aspect by verifying the optimized cultivation conditions with real municipal wastewater, indicating that the procedure could be utilized for sustainable production of bioproducts and efficient treatment of municipal wastewater.

Tequila production occurs in Mexico's designated area of origin, principally in the Jalisco State. Its residues are a challenge in treatment and tracking due to a lack of technology, non-economic treatments available, low environmental consciousness and incipient control from authorities. In 2021, average production was close to 1.5 million tequila litres per day with an estimated residue yield of 10-12 litres of stillage (tequila vinasses) per tequila litre produced, including volatile fractions. This research aims to reduce organic matter by electrooxidation (EO) from 5 distillation volatile residual effluents (two-stage still distillation) from three tequila distilleries, first and second-stage heads and heads and tails and second-stage non-evaporated fraction. Round 3 mm titanium (grade-1) electrodes (one anode and one cathode) were used, with fixed voltage to a value of 30 VDC at 0, 3, 6, 9 and 12 hours with 75 experiments. Gas chromatography was used to analyze methanol, ethanol, acetaldehyde, ethyl acetate, n-propanol, sec-butanol, iso-butanol, n-butanol, iso-amyl, n-amyl, and ethyl lactate content. Treatment shows positive results, reducing organic matter content in all effluents in a Chemical Oxygen Demand COD range of 580-1880 mg/L.h, particularly useful in the second-stage non-evaporated fraction for water recovery. GRAPHICAL ABSTRACT

Response surface methodology was investigated to determine the operational parameters on the degradation of Congo red dye (CR) and chemical oxygen demand (COD) in two electrochemical systems evaluated individually on effluent pretreated by an up-flow anaerobic sludge blanket (UASB) reactor. The UASB reactor was fed with 100 mg L⁻¹ of CR and was operated for 12 weeks at different hydraulic residence times (HRTs) of 12 h, 10 h, and 8 h. Once stabilized at an HRT of 8 h, the effluent was collected, homogenized, and independently treated by electrooxidation (EO) and electrocoagulation (EC) cells. On both electrochemical systems, two electrode pairs were used; solid for EC (Fe and stainless-steel) and mesh electrodes for EO (Ti/PbO₂ and Ti), and the effect of intensity (A), recirculation flow rate (mL min⁻¹), and experimental time (min) was optimized on response variables. The maximum efficiencies of sequential systems for COD degradation and CR decolorization were 92.78% and 98.43% by EC and ≥99.84% and ≥99.71% by EO, respectively. Results indicate that the coupled systems can be used in textile industry wastewater treatment for the removal of dyes and the decolorized by-products.

Las aguas residuales provenientes del proceso de nixtamalización representan un reto por su composición compleja y altamente alcalina. El presente trabajo tiene como objetivo potenciar la producción de metano mediante la digestión anaeróbica de nejayote con materiales conductores a base de carbón modificado con hierro. A través de dos fases experimentales, los resultados más significativos muestran que la carga metálica en el carbón activado granular (CAG) no estimula la transferencia de electrones en un medio como el nejayote. Por otro lado, cuando el pH se mantiene en valores neutros, se obtiene una reducción del 88% en la DQO y altos valores de metano acumulado. El estudio describe la relación entre el uso del CAG y el nejayote como promotor de metano en la digestión anaeróbica, lo que puede ser una alternativa sustentable.

This study evaluated the effect of particle size and concentration of granular activated carbon (GAC) and temperature (30, 37, and 45 °C) on methane production from the anaerobic digestion of swine wastewater separated into solid-liquid fractions. The culture with the liquid fraction (LF) and GAC with a particle size of 75-150 µm and 15 g/L increased 1.87-times the methane production compared to the control without GAC. Generally, the cultures with GAC at 75-150 µm showed low lag phases and Rmax higher than those with GAC at 590-600 µm. The cumulative methane at 45 °C with the raw effluent (RE) + GAC was 365 mL, representing a volume 7.4-fold higher than the control test. Moreover, with the culture LF + GAC (6.0-fold) and SF + GAC (2.0-fold), the increments compared to the controls were also considerably at 45 °C. The GAC addition also influenced the production of volatile fatty acids and ammonium.