Comparative performance and statistical analysis of DEGBR and EGSB reactors for treating high-strength poultry slaughterhouse wastewater

High-rate anaerobic bioreactors (HRABs) are increasingly employed for treating high-strength wastewaters due to their ability to handle elevated organic loading rates (OLRs) at reduced hydraulic retention times (HRTs). This study compares the performance of two HRAB configurations the up-flow Expanded Granular Sludge Bed (EGSB) and the down-flow Expanded Granular Bed Reactor (DEGBR) for poultry slaughterhouse wastewater (PSW) treatment. Both systems included a biological pre-treatment stage and post-treatment with a membrane bioreactor (MBR). The DEGBR consistently outperformed the EGSB, achieving COD, TSS, and FOG removals of 87%, 92.5%, and 89.4%, respectively, versus 53.9%, 68.4%, and 66.9% for the EGSB. When integrated with pre-treatment and MBR polishing, the DEGBR-based system achieved > 99% removal across all parameters. Statistical analysis confirmed the significance of these differences (p < 0.05). These results demonstrate the DEGBR–MBR system’s robustness, stability under variable loading, and suitability for decentralised PSW treatment in resource-limited settings, offering a scalable and energy-efficient solution for broader industrial wastewater applications.