Recent Advances in Distillery Waste Management for Environmental Safety

Vineet Kumar, Pankaj Chowdhary, Maulin P Shah

• Publisher: CRC Press
• Year: 2021
• ISBN:
  9781000422306
• Edition: 1
• Topic: Physical Sciences
• Subtopic: Chemistry
• Index: Chemistry

The safe disposal of distillery waste into the environment, as well as its recycling and management, has become a hot topic in developing countries including India. This gross misconduct creates serious environmental and public health hazards. Thus, adequate management of waste has become a priority of environmental engineers and biotechnologists for environmental safety and sustainable development.

Recent Advances in Distillery Waste Management for Environmental Safety covers specific, advanced, and updated knowledge on various developed individual and/or innovative, green, and emerging plant-microbe-based technologies' uses for the management and recycling of distillery waste in an environmentally friendly and cost-effective manner for sustainable development. Moreover, this book provides comprehensive, state-of-the-art information on the physicochemical properties, chemical composition, and environmental risks associated with distillery waste. Furthermore, the book also discusses various existing methods and technologies; up-gradation of existing technologies; the advent of newer technologies for the treatment, processing, and disposal of distillery waste; and focus areas for further development. This broad and unique coverage allows treatment firms and regulatory authorities to determine and develop appropriate treatment strategies for site-specific problems of distillery waste remediation.

Features:

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• Provides practical solutions for the treatment and recycling of distillery waste illustrated by specific case studies

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• Focuses on recent industry practices and preferences, along with newer approaches for wastewater treatment

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• An instructive compilation of treatment approaches, including advanced physicochemical and integrated/sequential methods

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• Covers biocomposting of sludge and effluent, and biodiesel production from distillery waste for recycling and sustainable development

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• Emphasizes the relationship of metagenomics with organometallic compounds of distillery waste

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• Discusses the role of ligninolytic enzymes and bioreactors in distillery wastewater treatment

This book serves as an accessible reference to assist engineering consultants, industrial waste managers, policy makers, environmental engineers, government implementers, researchers, scientists, and a wide range of professionals responsible for regulating, monitoring, and designing industrial wastewater treatment techniques, who aspire to work on the reclamation, recycling, and management of distillery waste or wastewater pollutants for environmental safety and sustainable development.

1 Introduction

DOI: 10.1201/9781003029885-1

1.1 Brief Background

The worldwide demand for energy, uncertainty of natural resources, and concern about global warming have led to the environment-friendly development of alternative liquid biofuels. Ethanol is regarded as one of the excellent candidates since it reduces dependence on fossil-fuel reserves and it is also cleaner burning and thus better for air quality. India is the fourth largest producer of ethanol after Brazil, the United States, and China, and the 5% blending of petrol/motor fuel is mandatory all over the country, which helps in reducing import of crude oil, thereby saving foreign exchange. Currently, the 5% blending is applicable only in ten states and three union territories and it requires about 410 million liters of anhydrous ethanol. Apart from its use in petro fuel, beverages, medicines, pharmaceuticals, and flavoring compounds, ethanol is an important feedstock for the manufacture of various chemicals like acetic acid, butanol, butadiene, acetic anhydride, polyvinyl chloride, etc., which are being used in the production of rubber, drugs, solvents, and pesticides. Due to its high demand in global market, distilleries are growing at an alarming rate in the world (Kumar and Sharma 2019). However, distilleries are widely regarded as one of the most polluting industries in more than 130 countries, especially in developing countries including India, Mexico, Brazil, and Japan, as 88% of its raw materials are converted into waste and discharged as a large volume of high-strength effluent (Kumar and Chandra 2020a). According to one estimate, for every liter of ethanol that is produced during sugarcane-molasses-based fermentation and distillation processes, about 10–15 L of recalcitrant, troublesome, and complex liquid as an effluent, also called spent wash, stillage, vinasses, mosto, and raw distillery effluent, is generated (Chandra and Kumar 2017a). Sugarcane molasses, a natural sweetener obtained as a by-product during the processing of refined sugar from sugarcane (Saccharum officinarum) juice, contain 45–50% of residual sugars (i.e., glucose, fructose, and sucrose), 15–20% of non-sugar organic substances, 10–15% of ash (minerals), and about 20% of water. The majority of distilleries are located in tropical and subtropical regions of the world using sugarcane molasses as a feedstock (Chandra and Kumar 2017b). About 90% of the molasses produced in cane sugar manufacture is consumed in ethanol production. Moreover, some distilleries are using various substrates as a feedstock such as cereal malt (i.e., rice, barley, wheat, and maize) and grapes for ethanol fermentation. It has been reported that spent wash produced in sugarcane-molasses-based distilleries has a high organic load as compared to other raw material used for ethanol production (Chandra et al. 2018a). India has a large network of distilleries of varying capacity that are distributed throughout the country (Kumar and Chandra 2018a). A recent report suggests that there are 397 molasses-based distilleries in India producing 8,679 million liters of alcohol and generating 3.5 × 10¹³ kL of spent wash as a liquid waste annually (Kumar and Chandra 2020b). Depending on the sugarcane origin and the subsequent fermentation and distillation processes for ethanol production and waste treatment, the volume and intrinsic composition of generated high-strength spent wash can vary significantly (Kumar 2021). Spent wash is a dark brownish color effluent characterized by a specific obnoxious odor, high ash content, high biological oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC), total dissolved solids (TDS), total soluble solids (TSS), and organic matter and refractory organic compounds such as a variety of sugar decomposition products, phenolics, steroids, anthocyanins, tannins, furfurans, melanoidins, androgenic-mutagenic compounds, and endocrine-disrupting compounds (EDCs), that are highly toxic in nature and resistant to biodegradation in an open environment (Chandra and Kumar 2017a; Chandra et al. 2018a). In addition, a high mineral load was also reported due to the presence of sulfate (SO₄²⁻), potassium (K⁺), phosphorous (PO₄²⁻), calcium (Ca²⁺), and sodium (Na⁺). Moreover, spent wash also contains a large concentration of numerous heavy metals (HMs) such as iron (Fe), zinc (Zn), nickel (Ni), manganese (Mn), lead (Pb), mercury (Hg), copper (Cu), and chromium (Cr) (Kumar et al. 2020a). The intense color in spent wash is mainly due to the existence of a dark brown polymeric pigment compound known as melanoidin, which is formed by Maillard reaction (MR), a non-enzymatic browning reaction between amino and sugar compounds. Melanoidin possesses antioxidant, antimicrobial, and antihypertensive activity properties. Therefore, the presence of these antimicrobial compounds and the removal of color in spent wash together pose a major challenge to scientists, environmentalist, and researchers for efficient and sustainable development (Kumar and Sharma 2019). It has been reported that melanoidins have net negative charges; hence, different heavy metallic ions such as Cu²⁺, Cr⁶⁺, Cd²⁺, Fe²⁺, Zn²⁺, and Ni²⁺ strongly bind with melanoidins to form organometallic complex in distillery spent wash (Hatano et al. 2016; Kumar and Chandra 2020b). A few adequate uses for spent wash management have been identified and it is used in large-scale operations, such as recycling to fermentation streams, energy production, animal feed production, and ferti-irrigation practices, i.e., utilizing it as a liquid fertilizer for sustainable agriculture and reducing the water input for plant growth (Kumar and Chopra 2012; Kumari et al. 2016). However, ferti-irrigation practices usually have negative effects on soil and groundwater quality in long term due to accumulation of their low pH and organic and inorganic contents (Kumari et al. 2009; Kumari et al. 2012). Furthermore, some studies have indicated that spent wash also negatively affects the microbial flora of soil (Chowdhary et al. 2018a). In addition to spent wash generation during ethanol production, a huge amount of solid waste as a yeast sludge is formed in the distilleries, that cause pollution when it is disposed into the environment without adequate treatment. However, yeast sludge is rich in protein and contains a considerable amount of essential amino acids, and drying sludge grains are marketed as livestock feed and make it the best source for the production of single-cell protein. Figure 1.1 outlines the ethanol production processes, generation of liquid and solid waste and their treatment by different physicochemical, integrated, and biological approaches, and impact of discharged wastes on the environment.

FIGURE 1.1The production of ethanol from fermentation of sugarcane-molasses, generation of effluent and sludge as a waste by-products and their treatment by various physicochemical, biological, and integrated approaches, and impact of disposed wastes into the environment.

The organic and inorganic pollutants present in the effluent of different nature are reacting to each other and make the effluent more toxic and complex (Zhang et al. 2017; Kumar and Chandra 2020b). Due to high pollution nature of spent wash, the Ministry of Environment, Forest, and Climate Change (MoEF&CC), Government of India, has listed ethanol industries at the top among the “Red Category” industries. In accordance with the environmental protection act and rules of the MoEF&CC and Central Pollution Control Board (CPCB), Government of India, it is mandatory for distilleries to treat hazardous spent wash before it is disposed into the environment. According to Indian government rules, every industry has an effluent treatment plant. However, the plants are not generally operated because of the high cost involved in treating effluents; as a result, they discharge the untreated effluent to the outside environment, which ultimately negatively affects human beings. In many instances, industries dilute the spent wash by mixing with raw water before discharge in order to meet the set waste disposal standard. This dilution, even though accepted in some regions, is of great environmental concern as it does not reduce the absolute pollution load of the spent wash. Thus, Indian government's policies on pollution prevention have forced distilleries to look for cost-effective and sustainable technology for decreasing the characteristics of the final discharged spent wash.

Distillery spent wash treatment is being carried out generally by four routes in the industry: (i) concentration followed by incineration, (ii) direct oxidation by air at a high temperature followed by aerobic treatment, (iii) anaerobic digestion with biogas recovery followed by aerobic polishing, and (iv) reverse osmosis. Out of four routes, anaerobic digestion, also known as biomethanation, is the most attractive and the best possible treatment method for decolorization and detoxification of spent wash in developing countries such as Japan, India, and Mexico, due to its low-cost, easy operation, and eco-friendly technique besides its energy generation potential in the form of biogas (biomethane, CH₄), which is utilized for running steam boilers for the generation of electricity (Malik et al. 2019a). The effluent received from distilleries after anaerobic digestion, called as biomethanated spent wash or biomethanated distillery effluent, is required to further cope with environmental standards (Mohana et al. 2007; Ravikumar et al. 2011; Reis et al. 2019). Biomethanated spent wash is characterized by an extremely higher level of BOD, COD, TDS, total Kjeldahl nitrogen (TKN), SO₃²⁻, Na⁺, and PO₄³⁻, with alkaline pH and dark brown color (Saner et al. 2014; Shinde et al. 2020). Moreover, biomethanated spent wash retains a high amount of various toxic metals, namely, Ni, Mn, Fe, Zn, Cu, Pb, and Cd, along with melanoidins and various recalcitrant organic pollutants (ROPs) (Singh et al. 2010; Sharma et al. 2011; Wagh and Nemade 2018).

Since the anaerobic digestion is reported to remove about 40–50% COD, 60–65% BOD, and color of spent wash converts darker with higher TDS after anaerobic digestion due to complexation of organic and inorganic pollutants (Chandra et al. 2018a). This means that spent wash after anaerobic digestion still contains some organic load and is not safe for discharge into the environment (Kumar et al. 2021a). In India, the existing full-scale distillery effluent treatment system includes the combination of anaerobic digestion and a two-stage extended aeration process. Although, the primary aerobic and anaerobic conventional treatment systems can easily remove sugars, volatile organics, and other easily biodegradable compounds that constitute BOD, the color and COD constituted by melanoidin pigment remain unchanged after treatment due to its antioxidant and antimicrobial nature, and these treatments are found ineffective to degrade the color compounds at high concentrations. Besides effluent, sugarcane-molasses-based distilleries also produce a huge amount of solid sludge as a by-product during anaerobic digestion of spent wash, which contributes significantly toward the contamination of environments (Chandra and Kumar 2017b, c; Mahaly et al. 2018). Different approaches to distillery sludge management such as incineration, landfilling, and composting are reported in scientific literature by a various group of researchers (Suthar and Singh 2008; Singh et al. 2014). Some research works evaluated the potential of composting of distillery sludge, also mixed with other substrates, for its utilization in agriculture as a fertilizer; the main concern related to this option is the fate of heavy metals and organic chemicals contained in distillery sludge and their effects on plant growth and soil quality. Sludge discharged after anaerobic digestion of spent wash enriched with a high concentration of Fe and other metals have adverse effects on the environment (Chandra and Kumar 2017c; Kumar and Chandra 2020b). Plants growing in the metalliferous soils may have the ability to cope with high metal concentrations. The sludge produced in the anaerobic digestion process is normally used as a substitute of the compost after drying or it is mixed with press mud and then converted into the compost. Preliminary s...

Table of contents

• Cover Page
• Half-Title Page
• Title Page
• Copyright Page
• Dedication Page
• Contents
• Preface
• Acknowledgments
• About the Authors
• 1. Introduction
• 2. Distillery Waste Generation and Characteristics
• 3. Colorants of Distillery Waste and Their Properties
• 4. Environmental Impacts and Health Hazards of Distillery Waste
• 5. Treatment Approaches of Distillery Waste for Environmental Safety
• 6. Ligninolytic Enzymes in Degradation and Detoxification of Distillery Waste
• 7. Bioreactors in Distillery Wastewater Treatment
• 8. Phytoremediation: An Eco-Sustainable Green Technology for Remediation and Restoration of Distillery Waste Contaminated Environment
• 9. Recycling and Reuse of Distillery Waste by Vermitechnology
• 10. Sequential Treatment: A Novel Approach for Biodegradation and Detoxification of Distillery Effluent for Environmental Safety
• 11. Microbial Fuel Cell Technology in Distillery Wastewater Treatment and Bioelectricity Generation
• 12. Biodiesel Production from Distillery Waste: An Efficient Technique to Convert Waste to Biodiesel
• 13. Rules, Policies, and Laws Made by Government of India for Recycling, Reuse, and Safe Disposal of Distillery Waste into the Environment
• 14. Emerging Issues, Challenges, and Future Outlook of Distillery Waste Management
• 15. Concluding Remarks
• References
• Index