Yuan, et al (2024) Recycling crayfish shell and waste activated sludge as biochar to in-situ enhance antibiotics removal from wastewater: Linking structure properties and reaction kinetics. Journal of Water Process Engineering. https://doi.org/10.1016/j.jwpe.2024.105517

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Tackling Antibiotic Contamination in Aquatic Environments

Antibiotic pollution in water bodies, especially from aquaculture, poses a significant threat to human health and ecological stability. Intensive aquaculture practices, particularly in countries like China, have led to increased antibiotic usage to manage diseases in overcrowded fish and shellfish farms. Consequently, a wide range of antibiotics, including tetracycline and ciprofloxacin, often exceed safe levels in these environments, creating a need for effective treatment solutions.

Innovative Use of Biochar for Antibiotic Removal

Researchers have developed an innovative approach using biochar derived from crayfish shells and waste activated sludge to address this issue. Biochar, a carbon-rich material produced through pyrolysis, is known for its high porosity and large surface area, making it suitable for adsorbing contaminants. This study focuses on enhancing the efficiency of biochar in removing antibiotics from aquaculture wastewater.

The Study’s Approach and Findings

The research team explored the effectiveness of biochar made solely from crayfish shells (C-BC) and a combination of crayfish shells and sludge (CS-BC) in adsorbing antibiotics like tetracycline and ciprofloxacin. They discovered that CS-BC significantly outperformed C-BC, achieving a 50.3% to 77.1% increase in adsorption efficiency.

Several key findings emerged from the study:

1. Enhanced Surface Properties: The incorporation of waste activated sludge into the biochar increased its surface area and pore volume. This structural enhancement provided more active sites for antibiotic adsorption.
2. Shift in Adsorption Mechanisms: While C-BC primarily relied on physical pore filling for adsorption, the addition of sludge introduced chemical adsorption mechanisms. This shift was attributed to the presence of more oxygen-containing functional groups and increased hydrogen bonding on the CS-BC surface.
3. Minimal Impact of Ammonia: The presence of ammonia, a common component in aquaculture wastewater, had little effect on the antibiotics removal efficiency, making CS-BC a robust solution in varied water conditions.

Practical Implications for Waste Management and Pollution Control

This research not only provides a promising method for addressing antibiotic contamination but also offers a sustainable way to manage organic waste. Annually, China generates approximately 1.4 million tons of crayfish shell waste and 11.2 million metric tons of dry sludge. Traditional disposal methods like incineration and landfilling are energy-intensive and environmentally problematic. By converting these wastes into biochar, the study presents an eco-friendly, cost-effective alternative that mitigates pollution and repurposes waste materials.

Broader Environmental and Economic Benefits

The dual benefits of this approach extend beyond pollution control. The enhanced biochar can be utilized in various wastewater treatment applications, potentially reducing the operational costs of treatment facilities. Additionally, the efficient disposal of crayfish shells and sludge alleviates the environmental burden associated with their traditional management methods.

The study underscores the potential of biochar derived from crayfish shells and waste sludge as a viable solution for removing antibiotics from aquaculture wastewater. This innovative approach not only tackles a pressing environmental issue but also promotes sustainable waste management practices. As aquaculture continues to grow, such advancements are crucial in ensuring the health of our water bodies and the communities that depend on them.