Tropical-based EBPR process: The long-term stability, microbial community and its response towards temperature stress

Temperature is known to influence the operational efficiency of enhanced biological phosphorus removal (EBPR) systems. This study investigated the impact of thermal stress above 30 degrees C on the properties of an EBPR community established with tropical inoculum. The results confirmed the stability of the 30 degrees C EBPR system with high P-removal efficiency over 210 days. Accumulibacter was abundant in the community. When the EBPR sludge was subjected to a sudden temperature increase to 35 degrees C under multiple cycles of anaerobic-aerobic phases, each lasting 4 h, high P-removal was maintained over 2 days, before gradually failing when the Competibacter appeared to outcompete Accumulibacter. These data suggested that the EBPR capacity is robust when subjected to occasional thermal stress. However, it could not be maintained even for a short time under temperature stress at 40 degrees C. Thus, the threshold temperature for tropical EBPR failure is between 35 degrees C and 40 degrees C. Practitioner Points EBPR was stably maintained at 30 degrees C with Accumulibacter being dominant. Good EBPR activities persisted for a short period at 35 degrees C. EBPR was deteriorated at 40 degrees C. The threshold temperature for tropical EBPR failure is between 35 degrees C and 40 degrees C.

Automated summary

This study investigated the effect of temperature on tropical inoculated EBPR systems, concluding that the system remained stable at 30 degrees Celsius with high P-removal efficiency. However, the system deteriorated at 40 degrees Celsius and the threshold temperature for tropical EBPR failure was found to be between 35 and 40 degrees Celsius.