Enhancing wastewater treatment efficiency: A hybrid technology perspective with energy-saving strategies

[Display omitted] •Pure moving bed reactor turned into a hybrid without extra sludge inoculation.•The effect of various intermittent aeration regimes on energy use was investigated.•Activated sludge presence improved efficiencies of denitrification and P removal.•Significant drop in energy consumption for aeration was noted after hybrid formation.•The high nitrification efficiency could be attributed to heterotrophic nitrifiers. The study aimed to investigate how hybrid technology, combined with various intermittent aeration (IA) strategies, contributes to reducing the energy costs of wastewater treatment while simultaneously ensuring a high treatment efficiency. Even with IA subphases lasting half as long as those without aeration, and oxygen levels reduced from 3.5 to 1.5 mg O2/L, pollutants removal efficiency remains robust, allowing for a 1.41-fold reduction in energy consumption (EO). Hybrid technology led to a 1.34–fold decrease in EO, along with improved denitrification efficiency from 74.05 ± 4.71 to 81.87 ± 2.43 % and enhanced biological phosphorus removal from 35.03 ± 4.25 to 87.32 ± 3.64 %. The high nitrification efficiency may have been attributed to the abundance of Pseudomonas, Acinetobacter, and Rhodococcus, which outcompeted the genera of autotrophic nitrifying bacteria, suggesting that the hybrid system is favorable for the growth of heterotrophic nitrifiers.