Papaya seed extract as coagulant for potable water treatment in the case of Tulte River for the community of Yekuset district, Ethiopia

Abstract

The high cost of chemical coagulants for water treatment makes most people in rural community to resort to readily available surface water which are usually of low quality exposing them to different water-borne diseases. It is in this light, this research was conducted to assess the effectiveness of Papaya seed extract for the removal of turbidity and total coliform in raw water sampled from Tulte River which serves as potable water for the society. Jar test experiment was carried out via locally available Papaya seed as coagulant for treatment of high (392.7NTU) & medium (94.2NTU) turbidity level to obtained optimum operation condition of dose, pH and mixing time plus suitable extraction method. Those optimized parameters were then applied in household level of water treatment through manual coagulation (coagulation by hand) in order to qualify its effectiveness. The three extraction method used for coagulation/flocculation were Aqueous crude extract, salt crude extract and defatted salt extract which were gave best result at dosage of 20 ml,acidic condition of 6.0 and 60 min of agitation time. Coagulation test revealed that, superior total coliform removal of 96.32% was achieved through Defatted salt extract and gave residual turbidity of 4.25NTU which is acceptable based on WHO standard of drinking water. Its removal efficiency was good for all pH range especially at neutral and slightly basic pH condition. Overall, finding of this research suggest the potential of using Papaya seed as bio-coagulant for raw water treatment.