Performance evaluation of Synthetic and Bio-organic coagulants for removal of Natural Organic Matter from Drinking Water

Mihret Mersha Haileselassie; Nigus Gabbiye Habtu; Getachew Dagnew Gebreeyessus; Agegnehu Alemu; Million Mulugeta Habtegebrel

doi:10.20372/pjet.v2i1.1717

Mihret Mersha Haileselassie Addis Ababa Water and Sewerage Authority, Water quality department, P.O.Box- 1505, Addis Ababa, Ethiopia
Nigus Gabbiye Habtu Faculty of Chemical and Food Engineering, Bahir Dar Institute of Technology, Bahir Dar University, P. O. Box 26, Bahir Dar, Ethiopia
Getachew Dagnew Gebreeyessus Kotebe Universityof Education, P.O.Box 31248, Addis Ababa, Ethiopia
Agegnehu Alemu College of Science, Department of Chemistry, Bahir Dar University
Million Mulugeta Habtegebrel Kotebe Universityof Education, P.O.Box 31248, Addis Ababa, Ethiopia

DOI: https://doi.org/10.20372/pjet.v2i1.1717

Keywords: Enhanced coagulation, bio coagulant, NOM, Synthetic coagulant, TOC, Turbidity removal.

Abstract

Surface water sources contain a high amount of natural organic matter (NOM), which results from natural and anthropogenic activities. The NOM could react with chlorine to produce disinfection by-products (DBPs) that pose public health risks and are environmentally unfriendly. This study examined the effectiveness of synthetic and bio-coagulants for the removal of NOM and the associated turbidity from raw drinking water. Water samples were collected from Legedadi water treatment plant during the months of April (dry season) and July (Wet seasons) 2021. Jar test was performed to test the coagulants' effectiveness for removing turbidity and microbial community. The results revealed that the optimum coagulant doses were 70 & 30 mg/LforPACl, 110 & 90 mg/Lfor Aluminum sulfate, and 140 & 120 mg/Lfor MOS for the dry and wet seasons, respectively. Enhanced coagulation experiments were carried out to evaluate the efficiency of the coagulants in removing the TOC and turbidity. The enhanced coagulation removal of TOC and UV₂₅₄ followed an order of PACl> Aluminum Sulfate > MOS. Coagulant dose, type and pH, have significant(p< 0.05) effect on TOC and turbidity removal from the raw water. The result obtained in this study indicated that synthetic and bio-organic coagulants can be viable options in thetreatment of water to remove NOM and reduce the formation of DBPs.