Anaerobic treatment of sugar cane vinasse: treatability and real‐scale operation

Abstract

BACKGROUND Vinasse is a wastewater from bioethanol production with a very high concentration of organic matter, usually from 40 to 80 gCOD L‐1. These features make this wastewater attractive for treatment in an anaerobic system. Anaerobic processes allow the valorisation of this highly polluting wastewater as an energy resource in an environmentally friendly way. RESULTS A multiscale approach was followed, using batch tests, continuous bench scale reactors, and a full‐scale upflow anaerobic sludge bed (UASB) reactor. Potential inhibition due to high potassium concentrations was evaluated. Using batch tests, the IC50 potassium concentration was determined to be around 6 g L‐1, but continuous reactors could adapt the biomass to this concentration level without removal efficiency decay. A load of 20 gCOD L‐1 d with chemical oxygen demand (COD) removal efficiencies between 60% and 80% were reached in bench scale UASB and expanded granular sludge bed (EGSB) reactors. Finally, a 100 m3 UASB reactor located in a distillery was tested under industrial conditions. A load of 0.6 kgCOD kg‐1VSS d‐1 was achieved with a COD removal efficiency of 78%. CONCLUSION Although potassium was inhibitory for the inoculum, the sludge from a continuously operated reactor can be adapted to high potassium concentrations without affecting its performance. The real possibility of working with undiluted vinasse was also verified. For distilleries like the Uruguayan case, which produces 18 000 m3 of bioethanol per year, 5x10 m3 of biogas per year, with 68% methane, could be expected, representing an energy potential of about one‐third of the main fuel produced. © 2017 Society of Chemical Industry

Preliminary analysis ofChloroflexipopulations in full-scale UASB methanogenic reactors

“…The relative abundance of Chloroflexi in reactors AL and SR increased after operation day 280, moment where an increase in the granulation was detected (Fernández ; López et al . ).…”

“…Reactors AL and SR were previously studied by López et al . () and Fernández (), respectively. Reactor MO was previously studied by Borzacconi et al .…”

Evaluación de la producción de metano de vinazas mediante digestor anaerobio tipo batch.

“…En la figura 2 se puede contrastar el aumento del volumen de metano (L) generado por tratamiento a medida que disminuye la cantidad de DQO (g/L). Se determina que la producción de metano acumulado es equivalente a la DQO que ha sido degradada por tratamiento aplicado, a partir de las condiciones iniciales (López, Borzacconi y Passeggi, 2017). De acuerdo con Sánchez et al (2016), esto se debe a que tanto los SV, como la DQO, son proporcionales a la materia orgánica que puede ser convertida a biogás.…”

“…consecuencias importantes en los costos asociados al volumen del reactor y a la necesidad de contar con este recurso para dilución (Chernicharo, 2007;López, Borzacconi y Passeggi, 2017). Lo que sí debe resaltarse es la elección del agente neutralizante, pues en el presente trabajo se usó hidróxido de sodio, pero existen otros tipos de menor costo y fácil acceso.…”

“…Puede afirmarse que la vinaza puede ser tratada por reactores anaerobios, y que la biomasa puede aclimatarse y trabajar con sus niveles altos de concentración(López, Borzacconi y Passeggi, 2017).Por otra parte, pese que el inóculo ha pasado por un proceso de adaptación, la dilución con agua que se aplicó en algunos de los tratamientos hace que disminuya la concentración de SV, lo que influye en el crecimiento de los microorganismos; por lo cual se considera una de las razones del menor aumento microbiológico(Mundhenke, Müller y Schwedes, 2001), así como de la producción de biogás y metano.…”