18. Distillery Wastewater: A Major Source of Environmental Pollution and Its Biological Treatment for Environmental Safety

Distillery industries are one of the major sources of environmental pollution because these industries discharge a huge volume of dark-colored wastewater into the environment. The wastewater discharged contains high biological oxygen demand (BOD), chemical oxygen demand (COD), total solids (TS), sulfate, phosphate, phenolics, and toxic heavy metals. On terrestrial region, distillery wastewater at higher concentration inhibits seed germination, growth and depletion of vegetation by reducing the soil alkalinity and Mn availability, whereas in aquatic region, it reduces sunlight penetration and decreases both photosynthetic activity and dissolved oxygen content damaging the aquatic ecosystem. The large volume of dark-colored wastewater acts as a major source of soil and water pollution and thus requires adequate treatment for its safe discharge into the environment. Therefore, the removal of pollutants and color from distillery wastewater is becoming increasingly important for the environment and sustainable development. Thus, this chapter provides the detailed information on the generation, characteristic, toxicity as well as various biological methods employing bacteria, fungi, microalgae, etc. for the treatment of distillery wastewater. In biological treatment approaches microalgae have a number of applications over the conventional approaches as it is useful in wastewater treatment, CO₂ sequestration, cost-effective, sanitation and also in the production of renewable energy sources such as methane gas, biodiesel, biofuel, glycerol, hydrogen gas, biofertilizers, etc. Furthermore, the merits and demerits of existing processes have been also summarized in this chapter.