Biochar-Based Solutions for Urban Artificial Landscape Water Bodies: Mitigating Eutrophication and Enhancing Visual Aesthetics

This study examines the efficacy of biochar in improving water quality in urban artificial landscape water bodies. Three biochar types—wood biochar, coconut shell biochar, and apricot kernel biochar—were systematically evaluated, along with the purification effects of varying biochar dosages on landscape water. Water quality parameters were quantified using a multiparameter water quality meter, while the enhancement of visual aesthetics was validated through online questionnaires distributed to citizens. The findings include the following: All biochar types significantly reduced eutrophication indices and enhanced visual quality metrics, with coconut shell biochar demonstrating the most pronounced effects. The purification effect correlates with initial water quality and biochar dosage. Water bodies with poorer initial quality tend to show better purification results. While optimal biochar dosage improves water quality parameters, excessive application leads to decreased performance and potential water quality deterioration. Questionnaire analysis of visual preferences for the purified water showed that among biochar types, coconut shell biochar was most preferred (53.2%), followed by apricot kernel biochar (22.8%) and wood biochar (17.2%), while untreated water received the lowest preference (6.8%). When evaluating coconut shell biochar dosages, the 10 g/L treatment achieved the highest preference (67.4%), followed by 5 g/L (18.2%), while both the 15 g/L treatment and untreated water received notably lower preferences (7.1% and 7.3%, respectively). These findings highlight biochar as a promising tool for enhancing both the ecological and aesthetic qualities of urban water bodies, provided its application is carefully tailored to variable environmental conditions.