Circular Valorization and Biochar Based Treatment of Agro-Industrial Effluents: Insights from the VALCARB ProjectSihem BenAli, Tebra Triki, Samir Tlahig, Faiza Bousorra, Hanen Zaeir, Nidhal Marzougui, Walid Chmingui, Mouzeina Bettaieb, Monia Guiza and Ferdaous GuasmiE3S Web Conf., 697 (2026) 00004DOI: https://doi.org/10.1051/e3sconf/202669700004