Aeration influence on synergistic effects of hybrid water hyacinth and moving bed biofilm reactor in polishing low-strength synthetic wastewater

Abstract

The hybridizing water hyacinth (WH) with a moving bed biofilm reactor (MBBR) offers a nature-based polishing strategy, in which aeration plays a key role in determining oxygen availability, biofilm stability, and pollutants removal performance. Aeration is critical part to MBBR performance, however operational guidelines for plant–biofilm hybrids remain insufficiently underdeveloped. This study investigates the effects of aeration on NH₃-N and COD removal performance that sustains the integration of macrophytes and biofilms. A two-phase laboratory scale study was conducted using WH–MBBR hybrid system to treat domestic wastewater. Phase I was operated without aeration, while Phase II was operated with continuous aeration at 2.5 L min⁻¹ with 72 h performance monitoring. The results showed that NH₃-N removal achieved 88 % at 72 h without aeration, whereas with aeration it reached 95–99 %. In addition, COD was completely removed within 28 h under aerated conditions, indicating accelerated reaction rates and improved effluent quality. Aeration is the primary factor influencing WH–MBBR polishing. Continuous low-intensity aeration enables near-complete nitrogen and organic pollutant removal. These findings provide a comparative assessment that demonstrates the role of aeration in macrophyte–MBBR performance, supporting design standards and the selection of appropriate DO range for polishing.