Energy recovery performance of Klebsiella pneumoniae in high-rate contact and stabilization process

Abstract

This study investigates the identification and characterization of cultivable microbial species within the sludge of a high-rate contact stabilization (HRCS) process. A specific emphasis was on Klebsiella pneumoniae, which was employed as the sole inoculum for the purpose of enhanced organic matter recovery. K. pneumoniae, isolated from HRCS sludge, exhibited a rapid growth rate with a doubling time of 2.4 h. This rate is significantly faster than that of conventional microbial consortia used in wastewater treatment. A comparative analysis was conducted between the conventional HRCS system and the HRCS-K system, which was inoculated with K. pneumoniae. The objective was to evaluate the performance of both systems in terms of organic matter removal and methane production. Although the HRCS-K system demonstrated reduced efficacy in the removal of total organic matter, nitrogen, and phosphorus in comparison to the HRCS system, it achieved superior performance in soluble COD removal. Additionally, the HRCS-K demonstrated a significantly enhanced sludge yield and exhibited efficient anaerobic digestion, which resulted in a carbon recovery rate of 0.567 ± 0.130 g-CODCH4/g-CODinf. This represents a 48 % improvement over the conventional HRCS system. The increased methane production capacity of the HRCS-K system presents a promising approach to energy recovery and the sustainable treatment of wastewater. © 2024