Diplazium esculentum leaf extract as coagulant aid in leachate treatment

Abstract

The use of extracts from Diplazium esculentum leaves as coagulant and coagulant aid has not been discussed in literature. In this research, the capability of extracts from D. esculentum leaves, namely, D. esculentum aqueous (DEaqs) and D. esculentum powder (DEpowd), to act as coagulant aid in combination with polyaluminum chloride (PACl) was evaluated using stabilized leachate from the Kuala Sepetang Landfill Site (KSLS) and the Kulim Landfill Site (KLS) through a Jar test. Identified as polymers with high molecular weight, DEaqs (221 kDa) and DEpowd (275 kDa) act as anionic coagulants and are capable of promoting the coagulation process in leachate saturated with negative particles. The main functional groups that induce the coagulation–flocculation process by DEaqs and DEpowd are carboxyl, hydroxyl, and amine groups, which all contain hydrogen in their molecules. Jar test results were analyzed based on the removal efficiency (RE) of suspended solids (SS), turbidity, colour, chemical oxygen demand (COD), and ammonia-N. A 50% reduction in the volume of PACl from its optimum dosage, with the DEaqs and DEpowd dosages below 1000 mg/L, exhibited a synergic effect of all the measured parameters in KSLS leachates.