Distillery Stillage: Characteristics, Treatment, and Valorization

Abstract

Distilleries are among the most polluting industries because ethanol fermentation results in the discharge of large quantities of high-strength liquid effluents with high concentrations of organic matter and nitrogen compounds, low pH, high temperature, dark brown color, and high salinity. The most common method of managing this wastewater (distillery stillage) is to use it for soil conditioning, but this requires thickening the wastewater and may cause soil pollution due to its high nitrogen content. Therefore, treatment of distillery stillage is preferable. This review discusses individual biological and physico-chemical treatment methods and combined technologies. In addition, special attention is paid to valorization of distillery stillage, which is a valuable source of polysaccharides and volatile fatty acids (VFAs), as well as natural antioxidants, including polyphenols and other bioactive compounds of interest to the pharmaceutical, cosmetic, and food industries. New directions in improvement of valorization technologies are highlighted, including the search for new eutectic solvents for extracting these compounds. Such technologies are essential for sustainable development, which requires the use of management and valorization strategies for recovery of valuable compounds with minimal disposal of waste streams.

Evaluation of Organic Loading Rate and Chemical Oxygen Demand Removal: A Coupled Anaerobic-aerobic Treatment Approach for Molasses Distillery Stillage Treatment

“…The best COD removal (68%) in the process was attained in just eight hours. In fact, the nal corrected COD after aerobic degradation is still around 2278 mg/L; however, it is far better when compared to the removal of the same, which was obtained from prior studies and of course that is far better than the same COD measured after the AD was completed 28 . During the aerobic test, the least COD measured is attained within four days.…”

“…Though there are emerging AD techniques for an improved stillage COD reduction 25 , still they are applied at a reduced COD feed concentration. Consequently, most investigations end up concluding on the importance of integrated stillage treatment, which include feed pretreatment, AD and aerobic degradation [26][27][28] . Therefore, the objective of the current study is to evaluate the effect of stillage pretreatment on the Organic Loading Rate (OLR) and the subsequent COD removal under continuous AD process.…”

An Integrated Approach for the Assessment of Environmental Sustainability in Agro-Industrial Waste Management Practices: The Case of the Tequila Industry

“…While the physicochemical characteristics of vinasses from other alcoholic production processes (molasses, sugarcane, sugar beet, etc.) are well documented (España-Gamboa et al, 2011;Christofoletti et al, 2013;Chowdhary et al, 2018;Mikucka and Zielińska, 2020), there is a lack of information regarding tequila vinasses because most of the existing reports on the physicochemical characteristics have been obtained from single production units and thus fail to represent the variability in vinasse characteristics resulting from a wide variety of productive processes used across the state (Íñiguez-Covarrubias and Peraza-Luna, 2007;López-López et al, 2010).…”

“…Several other practices have been proposed globally for the management of vinasses, in addition to the ones proposed in the previously discussed scenarios. Some examples include use as animal feed, treatment by electrocoagulation, coagulation-flocculation and advanced oxidation (Ozone) as well as biorefinery approaches using either bacteria, fungi, or algae for the simultaneous treatment and recovery of metabolites, biomass or energy (Waliszewski et al, 1997;López-López et al, 2010;España-Gamboa et al, 2011;Christofoletti et al, 2013;Mikucka and Zielińska, 2020). Several novel processes have been developed on a laboratory scale that may offer new alternatives with promising effects on the quality of generated vinasses, as they use hydrolytic enzymes to increase substrate fermentability and decrease the discarded vinasses organic load (Ávila-Fernández et al, 2009;Waleckx et al, 2011).…”

A dual perspective (conventional and solar-enhanced) on advanced oxidation processes for the treatment of Agave cocui vinasses

“…Effluents from the production of Cocuy pecayero are refractory to biological treatments, meaning that a wastewater treatment technique must be applied to achieve a higher degree of efficiency in related biochemical processes, e.g., degradation of stable substances of low degradability such as unfiltered Agave fibers, yeast biomass, residual sugars, acids, esters, higher alcohols, phenols, and pigments [5]. Wastewater treatments must also be appropriate to issues including economic factors (especially in relation to circular economies), operation in an industrial environment, low influence over efficiency, and safe discharging.…”