Lindane Removal from Wastewater

Lindane, also known as gamma-hexachlorocyclohexane (γ-HCH), belongs to the class of organochlorine insecticides. It was first synthesised in 1825 and later introduced as a pesticide in the 1940s. Lindane was utilised in various fields such as agriculture, veterinary medicine, and human parasite control due to its potent efficacy against numerous pests.

Farmers used lindane to protect crops from insect infestations, thereby preventing significant yield losses. It was also extensively used to protect wood.

Additionally, the medical field used lindane to combat various conditions such as head lice, scabies, and certain skin conditions.

Lindane was proven very effective against pests. However, it was toxic and remained in the environment. Also, it had the potential to accumulate in the food chain, which caused concerns. Its use is limited in many countries because it harms other organisms and poses health risks to humans.

Lindane contamination in water can lead to severe environmental and health consequences. It can persist in marine environments, rivers, and watercourses for extended periods, making its removal crucial.

Lindane is highly toxic to aquatic organisms, even at low concentrations, and can disrupt the ecological balance of water ecosystems. Brief exposure to water contaminated with lindane can harm fish and other water organisms, causing a decline in population and biodiversity. Long-term exposure may lead to chronic toxicity, affecting reproductive and behavioural patterns of aquatic species.

Lindane can harm humans if consumed in drinking water or by eating contaminated fish and shellfish.

Studies have shown that lindane can persist in water for several months, depending on environmental conditions. Its longevity emphasizes the need for effective and efficient removal methods to protect water quality and aquatic life.

Adsorption, particularly using Granular Activated Carbon (GAC), is an effective method for removing lindane from wastewater.
GAC provides a large surface area and a porous structure, allowing lindane molecules to be trapped onto its surface. The adsorption process effectively removes lindane from the water, leaving behind cleaner effluent.

Pros:
– High removal efficiency for lindane and other organic pollutants.
– Cost-effective compared to other treatment methods.
– Readily available and easy to implement in existing treatment systems.

Cons:
– GAC will eventually reach saturation, reducing its effectiveness and necessitating renewal.
– Requires regeneration or proper disposal of spent carbon to avoid secondary contamination.
– The effectiveness of GAC can be affected by the presence of competing pollutants in water.

Ozone treatment is another of the effective lindane removal methods. Ozone, a powerful oxidant, breaks down lindane into less harmful substances through a chemical reaction. Ozone treatment can be used alone or in combination with other techniques to enhance lindane removal efficiency.

Pros:
– Effective in breaking down lindane and other persistent pollutants.
– No residual chemicals left in the treated water.
– Can improve water quality by removing colour, taste, and odour issues.

Cons:
– The ozone generation process consumes a lot of energy and may be expensive.
– Handling and storing ozone requires careful safety measures due to its toxicity.
– Water may require additional treatment afterwards