Relationship between bacteria and nitrogen dynamics in wastewater treatment oxidation ponds

BACKGROUND AND OBJECTIVES: The bacterial community plays a crucial role in the nitrogen cycle. Oxidation ponds act as a natural treatment system for wastewater and are designed to promote the growth and activity of certain bacterial species that remove contaminants from the water. The nitrogen cycle in these ponds involves the conversion of nitrogen compounds through biological processes by bacteria. The presence or absence of certain bacterial species can greatly influence the efficiency of the nitrogen cycle in these ponds. This research investigates the relationship between bacteria and nitrogen dynamics, the key components of wastewater treatment, in oxidation ponds. This work aims to identify the bacterial community composition in oxidation ponds, investigate the role of bacteria in the transformation and removal of nitrogen compounds from wastewater in oxidation ponds, and evaluate the impact of environmental factors on the microbial communities and nitrogen dynamics in oxidation ponds. This study was carried out in the oxidation wastewater treatment at the King’s Royally Initiated Laem Phak Bia Environmental Research and Development or LERD Project, in Phetchaburi, Thailand.METHODS: Wastewater samples were collected from the ۱st–۵th oxidation ponds at a depth of ۳۰ centimeter from the water surface and analyzed for various quality parameters including temperature, dissolved oxygen, potential of hydrogen, biochemical oxygen demand, nitrates, ammonia, and total kjeldahl nitrogen. Next-generation sequencing by Illumina Miseq was used to examine the ۱۶S ribosomal ribonucleic acid of bacteria in the collected samples. Correlation test was used for statistical analysis.FINDINGS: The temperature, potential of hydrogen (۱st to ۵th ponds), and dissolved oxygen (۲nd to ۵th ponds) in the oxidation ponds were within the standard value. Fifteen bacterial phyla were identified in the five oxidation ponds, with phylum Proteobacteria accounting for the highest population comprising ۴۷.۵۶% of the total bacterial population.CONCLUSION: Genera Novosphingobium (phylum Proteobacteria), Ammonia-۱۱ (phylum Verrucomicrobiota), and Vicinamibacteraceae (phylum Acidobacteriota) have the strongest relationships with ammonia, nitrate, and total kjeldahl nitrogen (R۲ = ۰.۹۷۱۰, ۰.۹۸۶, ۰.۸۱۲۴). The bacterial population is a crucial factor in nitrogen nutrient and water quality. Novosphingobium is involved in the removal of ammoniafrom wastewater, Verrucomicrobiota act as denitrifiers, and Vicinamibacteraceae increases the total kjeldahl nitrogen levels.

Keywords:

Bacterial Communities , Nitrogen , Nitrogen dynamic , Oxidation ponds and Wastewater treatment