Agro-industrial Waste: From Problem to Resource

Agro-industries generate a huge quantity of waste every year due to chips, juice, fruit, oil, and food processing industries. In 2019, crop production worldwide produced more than 2.5 billion tons of crop residues. Waste in agriculture is an alternative source of production for many products such as biogas, biofuel, compost, and many more.

Sustainable Ways to Recycle and Reuse Agro-industrial Waste

Compost:

The most common and effective way to recycle agricultural waste is composting. Crop waste, such as leaves, stems, and fruit peels, can be converted into nutrient-rich biofertilizers. So, this reduces the use of chemical fertilizer, decreases methane emissions through the organic waste decomposition in landfills, and returns the valuable organic matter to the soil.

Advantages:

Raises soil fertility and health by providing vital nutrients to the soil; thus, crop yield rises.

Minimizes the emission of greenhouse gases

Increases water retention capacity

Biofuels (biogas, bioethanol, and biodiesel)

Food processing waste, crop residues, and manure are transformed into biogas, bioethanol, and biodiesel. Biofuel is an alternative to fossil fuels. This is a non-renewable and sustainable source of energy that decreases the pollution of the environment.

Biogas is primarily the anaerobic digestion of organic material in the absence of oxygen. In that process, the microorganisms break down the organic matter and produce biogas, which is composed of methane and carbon dioxide. Biogas can be used in rural villages for cooking purposes, heating purposes, electricity generation, etc. Crop residues like wheat, rice straw, maize stalks, cattle, poultry waste, fruit peels, vegetable waste, and fruit juice waste are used to produce biogas.

Bioethanol: It is primarily used as vehicle fuel, the best alternative for gasoline. Bioethanol is prepared from agricultural waste like sugarcane bagasse, wheat, rice straw, etc.

Biodiesel: Biodiesel is prepared from plant oils, and it minimizes the dependency on petroleum.

Protein-containing feed for animals:

It has been found that India will suffer from a deficiency of dry fodder, green fodder, and concentrates by 2030, due to increased numbers of livestock. On the other hand, large quantities of agro-waste are being generated. However, this type of waste is not adequately recycled as feed for livestock. Brewer spent grains, groundnuts, residues of vegetable oil, wastes of castor crops, etc., are used for preparing animal feed, which is one of the sustainable ways of supporting livestock farming.

Advantages:

Agro-feed furnishes fiber, proteins, and energy to cattle, poultry, and fish. Groundnut cake, sunflower cake, etc.

Provides a source of the alternate conventional ingredients of the feeds with which agricultural resources are highly intensive to generate.

Low-impact activity on agricultural waste is wasteful for the environment; it develops valuable input from waste generation from agriculture.

Biochar:

Biochar is produced through the pyrolysis process. In this process, the agricultural waste is heated in the absence of oxygen, and a byproduct called biochar is produced. The agricultural waste is used for biochar production, such as crop residues, animal manures, and wood chips. The purpose of this biochar is to store carbon in the soil. Reduced greenhouse emissions by storing carbon in the soil.

Benefits:

Improves soil quality through increased nutrient and water retention, thereby increasing crop yield.

Biochar reduces the emission of greenhouse gases through carbon sequestration in the soil. Biochar can store around 2.3-3.1 billion metric tons of carbon globally annually.

Biochar offers a sustainable use of agricultural and industrial waste, which otherwise would have resulted in pollution.

Biochar aids in carbon trading.

Water purification

Shaukat 2022 reported the utilization of agricultural waste as a biosorbent to remove heavy metal ions.

Banana peels, coir shell wastes, tea waste, etc., which suit them for generating activated carbon. Activated carbons are applied to remove pollutants from the water due to their having greater surface areas that accommodate pollutants in the water containing chlorine, heavy metals, odor, taste impurities, etc.

According to WHO 2020, more than 2 billion people lack safe and drinkable water, and more than 57% of the global population will be experiencing problems in accessing safe and drinkable water by 2050.

Advantage:

Tea waste reduces the concentration of pesticides by 60% in contaminated water.

Coconut shell-activated carbon removes 85-95% of dyes from industrial water.

Biosorbent banana peel helps reduce bacterial infection by up to 70%.

Textile manufacturing:

Fiber plants such as sun hemp, jute, flax, and banana stems are used to make environmentally friendly textiles.

Advantage:

These fibers are used in the production of clothing, bags, and other textile products and are encouraging sustainable fashion.

Paper manufacturing:

It leads to direct deforestation, as 410 million tonnes of paper are produced every day with wood; it causes global warming. The chances to increase demand by nearly 2.3% per year have been projected until 2030. Some agro-industrial waste can be used to solve this problem.

Agro waste, like sugarcane bagasse, cereal straw, and cotton lint, is used for making paper production and is the best solution for the wood-based production of paper.

Benefits:

Decrease the use of forest-based paper production and promote sustainable forestry practices; less pollution helps to decrease carbon footprint, reduce agro-waste, and support the circular economy by recycling waste into useful products.

Extraction of essential oil from agro-waste:

Oil-extracted fruit peels, flower petals, herbs, and spices contribute to reducing environmental waste, making sustainable products that help businesses and consumers.

Bioplastic:

Bioplastics are created from sugarcane, maize, sugar beet, potato starch. The sugar present in the plants is converted into plastic. Bioplastics are biodegradable.

World yearly production of plastic exceeds 359 million tons. Based on the European Bioplastic study published in December 2023, the bioplastic production capacity in the world is expected to grow exponentially from around 2.18 M tonnes in 2023 to 7.43 M tonnes in 2028, with an average rate of 82%.

Conclusion:

Agro-industrial waste can be sustainably converted into valuable products. Biogas, biofuel, compost, and biochar are helpful to reduce environmental wastage, develop new industries, and provide economic value. Agro-industrial waste can play an important role in transforming towards a sustainable economy by using recycling and reuse techniques.