Treatment of High-Ammonia-Nitrogen Wastewater with Immobilized Ammonia-Oxidizing Bacteria Alcaligenes sp. TD-94 and Paracoccus sp. TD-10

Abstract

In this study, modified granular activated carbon (GAC) and immobilized cells were used to improve the biological efficiency of high-ammonia-nitrogen wastewater treatment using microorganisms. The results showed that using sodium-hydroxide-modified activated carbon (NaOH-GAC) greatly increased the immobilized numbers of the ammonia-oxidizing bacteria Alcaligenes sp. TD-94 and Paracoccus sp. TD-10. Using NaOH-GAC increased the number of immobilized cells by 63.27% over GAC. Compared with free cells, those immobilized on modified activated carbon were more effective in the removal of high ammonia nitrogen levels from wastewater. In wastewater with an ammonia nitrogen concentration of 100 mg·L−1, the ammonia nitrogen removal efficiencies of NaOH-GAC-immobilized cells and free cells within 24 h were 100% and 4.17%, respectively. After 45 cycles, NaOH-GAC-immobilized cells maintained an ammonia nitrogen removal efficiency of 79.24%. After 70 days of storage at 4 °C, the ammonia nitrogen removal efficiency was still as high as 100%. The removal efficiencies of ammonia nitrogen (NH4+-N), total nitrogen (TN), and chemical oxygen demand (COD) in high-ammonia-nitrogen wastewater from petrochemical enterprises reached 99.27%, 88.39%, and 69.85%, with removal rates of 75.21, 69.43, and 1117.40 mg·L−1·d−1, respectively. The findings demonstrated that NaOH-GAC improved the capacity of the biological treatment to remove ammonia nitrogen from wastewater and provide a practical option for the remediation of environmental pollution.