The development of bio-coagulants from Moringa oleifera seeds for sewage wastewater treatment has been investigated. The prepared bio-coagulant was treated with distilled water, HCl, NaOH, and NaCl to surface-functionalize the M. oleifera seed powder (MOSP). The bio-coagulant performance was investigated by monitoring the reduction of turbidity, EC, pH, TS, BOD, and COD from the wastewater. SEM, EDAX, and FTIR characterized the native and functionalized MOSP bio-coagulants. The HCl treated MOSP was found to be effective and have good coagulation activity (∼90%) compared to natural and other MOSPs. The turbidity removal by all the MOPS conformed to the WHO acceptable limit of finished water. Hence, maximum turbidity reduction was recorded in HCl > NaCl > NaOH > Natural (distilled water) treated MOSP. The pseudo-first and second-order kinetics rate also showed the effectiveness against turbidity reduction in municipal sewage water. Hence, the prepared MOSP bio-coagulants could be suitable for primary water treatments.