As we preach the gospel of Agriculture in Nigeria and Africa at large we should also look at the horizontal effects of increased agricultural activities. High agricultural activities lead to large agricultural waste generation.
Agricultural waste if not well managed can pollute the environment, though only for a while because it is biodegradable. But it is important to note that before degrading, agricultural wastes can cause significant damage to our environment and health.
There is a new technology that involves the use of agricultural waste to manage environmental pollution. It is important that we look into this cheap and new technology.
Agricultural wastes have been used as mature in farms and in recent times, some are being used to make biofuel. With Biosorption technology, before agricultural wastes are used as manure and biofuel some can be used to manage environmental pollution from poisonous metals (e.g. lead, chromium. Mercury, etc.), dyes and other organic wastes resulting from military, industrial and agricultural activities.
Heavy metals are often assumed to be highly toxic or damaging to the environment. Some are, while certain others are toxic only if taken in excess or encountered in certain forms. Lead for instance is a very toxic heavy metal, and its target organs are bones, the brain, blood, kidneys, and the thyroid glands, so heavy metals and toxic organic wastes must be removed from our waters and rivers.
There are many methods available for the removal of heavy metals and toxic organic wastes from water but they come with several disadvantages such as generation of huge poisonous by-products, high capital costs and are mostly not eco-friendly.
The search for better methods lead to the discovery of the use of biological substances to remove heavy-metals through a process called biosorption which is due to the metal binding capacity of various biological materials to metals, dyes and other wastes.
Many biological materials and agricultural wastes have been discovered to absorb metals and organic wastes from water. These include hyacinth, coconut, copra meal, sea weed, legume pods, moss, water leaf, peanut shell, pineapple peals, rice husk, banana peels, water melon peels, kiwi peels, tangerine peels etc.
How does biosorption works?
The biosorption process involves a solid phase (sorbent: biological material e.g chaff, husk, peels etc.) and liquid phase (sorbate: the water containing metals). Due to the high attraction of the chaff or husk to the metals, dyes or other organic wastes in the water, they will bind to each other. The metals, dyes and other wastes bonded to the chaff/husk in the water is afterwards removed from the water leaving the water unpolluted.
Advantage of the use of biosorption using agricultural waste
The major advantages of biosorption over conventional treatment methods include:
- the low-cost of the process and the materials used (mostly wastes from homes and farms),
- the high-efficiency of the method in removing metals from water,
- the minimization of chemical or biological sludge which in most cases are toxic and can become pollutants,
- the regeneration of the biological materials (biosorbents) and possibility of recovering the metal from the biological materials used after the process.
- agricultural waste materials are abundant and easy to source.