<p>A modified anaerobic baffled reactor (MABR) integrated with three sequential hybrid constructed wetlands (HCW) was developed to treat domestic wastewater from small and medium enterprises outside industrial parks and clusters in Southwestern Vietnam. In an on-site experiment of 12&#xa0;months, the 15 m³/day -MABR-HCW system had a total wetland area demand of 4.5 m²/PE and received 3 m³/day of domestic wastewater from a distribution warehouse. In HCW and in order, the vertical and horizontal sub-surface flow CWs were planted with <i>Phragmites australis</i> and the free water surface flow CW was planted with <i>Typha angustifolia</i> L. The results showed that the removal efficiencies of total dissolved solids (TDS), total suspended solids (TSS), biological oxygen demand (BOD₅), chemical oxygen demand (COD), ammonia nitrogen (NH₄⁺-N), total nitrogen (TN), orthophosphate (PO₄³⁻-P) and total coliforms (TC) reached average values of 42.9, 94.7, 92.1, 92.4, 95.2, 87.7, 68.3 and 99.7%, respectively, while the effluent concentrations of the study system complied with the limits for discharge into the receiving water source without disinfection. The MABR-HCW system designed in this study provided a good solution for rural, decentralized domestic wastewater treatment with low wastewater flow rates in low-income regions.</p> Graphical Abstract <p></p>