Hibiscus rosa-sinensis leaf extract as coagulant aid in leachate treatment

Hibiscus rosa - sinensis is a biodegradable material that has remained untested for flocculating properties. The objective of this study is to examine the efficiency of coagulation–flocculation processes for the removal of color, iron (Fe 3+ ), suspended solids, turbidity and ammonia nitrogen(NH 3 –N), from landfill leachate using 4,000 mg/L alum in conjunction with H. rosa - sinensis leaf extract (HBaqs). Hydroxyl (O–H) and (carboxyl) C=O functional groups along the HBaqs chain help to indulge flocculating efficiency of HBaqs via bridging. The experiments confirm the positive coagulation properties of HBaqs. The Fe 3+ removal rate using 4,000 mg/L alum as sole coagulant was approximately 60 %, and increased to 100 % when 4,000 mg/L alum was mixed with 500 mg/L HBaqs. By mixing, 4,000 mg/L alum with 100–500 mg/L HBaqs, 72 % of SS was removed as compared with only 45 % reduction using 4,000 mg/L alum as sole coagulant.