Conference on Environmental Science and Technology

The rising demand for effective wastewater treatment solutions and technologies has become vital due to increasing industrial activities and the associated environmental and public health risks posed by industrial effluents. Propylene Glycol Methyl Ether (PGME), an organic solvent widely used in semiconductor manufacturing, ink, paint production as a coating agent, contributes to high-pH wastewater, presenting challenges to treatment methods. This study investigates the degradation potential of an alkaliphilic bacterial isolate, initially labeled as SBR-02, cultivated from long-term acclimated SBR set-up in the reduction of chemical oxygen demand (COD) of distillate-derived strong alkaline wastewater (D-DSAW) from PGME processes (pH = 13.5) through batch experiments. A response surface methodology (RSM) using the Box-Behnken Design (BBD) in Design Expert 13 software was employed to examine the effects of initial COD concentration, initial pH, and inoculum size on biodegradation efficiency. The results indicated that SBR-02 effectively reduced COD, achieving an optimal removal efficiency of 68.33% observed under conditions of 3000 mg/L initial COD concentration, pH 10 and 25% v/v inoculum size. ANOVA confirmed the significant influence of these parameters on the degradation performance with initial pH and inoculum size showing the most significant interaction effects (F-value= 72.57, p-value = 0.0001). 16S rRNA gene sequencing identified the bacterial strain as closely related to Halalkalibacter krulwichiae strain AM31D with 95.08% identity and 100% query cover, a member of the Bacillaceae family known for its enzymatic degradation capabilities. The findings suggest that alkaliphilic bacteria hold promise for industrial wastewater bioremediation, providing insights into microbial-based treatment approaches for highly alkaline waste streams.