Biochar as bioretention systems for water quality improvement in Malaysia Anurita Selvarajoo, Darshan Balakrishnan, Aan Mohammad Nusrat Aman and Tuck Wai Yeong E3S Web Conf., 467 (2023) 01032 Published online: 20 December 2023 DOI: 10.1051/e3sconf/202346701032