Snail Shells as Circular Biofilm Carriers for the Continuous Treatment of Real Cooperative Dairy Effluent: Performance and Biofilm Age Effect

Amal Aitcheikh; Meriem Mahmoudi; Ikrame Charef; FatimaZahra Boutaleb; Bouchaib Bahlaouan; Mohamed Bennani; Said El Antri; Nadia Boutaleb

doi:10.63095/NBSEH.25.913332

Authors

Amal Aitcheikh Hassan II University of Casablanca (https://ror.org/001q4kn48), Laboratory of Biotechnology, Agri-Food, Materials and Environment, Team: Biotechnologies, Resource Valorization, Quality, Health and Ecotoxicology, Faculty of Science and Technology Mohammedia, BP 146, Mohammedia 20650, Morocco.
Meriem Mahmoudi Hassan II University of Casablanca (https://ror.org/001q4kn48), Laboratory of Biotechnology, Agri-Food, Materials and Environment, Team: Biotechnologies, Resource Valorization, Quality, Health and Ecotoxicology, Faculty of Science and Technology Mohammedia, BP 146, Mohammedia 20650, Morocco
Ikrame Charef Hassan II University of Casablanca (https://ror.org/001q4kn48), Laboratory of Biotechnology, Agri-Food, Materials and Environment, Team: Biotechnologies, Resource Valorization, Quality, Health and Ecotoxicology, Faculty of Science and Technology Mohammedia, BP 146, Mohammedia 20650, Morocco
FatimaZahra Boutaleb Hassan II University of Casablanca (https://ror.org/001q4kn48), Laboratory of Biotechnology, Agri-Food, Materials and Environment, Team: Biotechnologies, Resource Valorization, Quality, Health and Ecotoxicology, Faculty of Science and Technology Mohammedia, BP 146, Mohammedia 20650, Morocco
Bouchaib Bahlaouan Higher Institutes of the Nursing Professions and Techniques of Health (ISPITS) (https://ror.org/007h8y788), Laboratory of Care, Health and Sustainable Development 2S2D, Casablanca 22500, Morocco
Mohamed Bennani Institut Pasteur Casablanca Morocco, Laboratory of Physico-Chemical Analysis of Water, Food and Environment, Casablanca 20250, Morocco
Said El Antri Hassan II University of Casablanca (https://ror.org/001q4kn48), Laboratory of Biotechnology, Agri-Food, Materials and Environment, Team: Biotechnologies, Resource Valorization, Quality, Health and Ecotoxicology, Faculty of Science and Technology Mohammedia, BP 146, Mohammedia 20650, Morocco
Nadia Boutaleb Hassan II University of Casablanca (https://ror.org/001q4kn48), Laboratory of Biotechnology, Agri-Food, Materials and Environment, Team: Biotechnologies, Resource Valorization, Quality, Health and Ecotoxicology, Faculty of Science and Technology Mohammedia, BP 146, Mohammedia 20650, Morocco

DOI:

https://doi.org/10.63095/NBSEH.25.913332

Keywords:

Biofilm, Carriers, Natural, Dairy, Wastewater, Treatment

Abstract

The rapid growth of Morocco’s dairy sector has led to the discharge of high-strength effluents, particularly from cleaning and cooling operations. In the face of water scarcity and limited access to conventional infrastructure, this study proposes a novel, plastic-free treatment strategy using snail shells as circular biofilm carriers in a moving bed biofilm reactor (MBBR). Real effluent was collected directly from a cooperative dairy outlet and treated under continuous flow conditions. The system was inoculated with Aspergillus niger, a filamentous fungus known for its biofilm-forming ability. Snail shells achieved higher pollutant removal rates than industrial Kaldnes K3 carriers: 92.9% COD, 84.75% BOD₅, 88.7% TKN and 82.9% total phosphorus within 72 hours of biofilm maturation. Their porous and hydrophilic surface supported faster colonization (16 h start-up) and improved biofilm stability. This is the first study to evaluate the effect of biofilm age and shell surface characteristics in the continuous treatment of real dairy wastewater using natural carriers. In addition to reducing reliance on synthetic polymers, this low-cost approach promotes biodegradability, circular resource use, and enhanced ecological performance. These findings support the replacement of plastic media with nature-based alternatives in decentralized wastewater treatment systems.

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