DIVERSITY AND METABOLIC CHARACTERISTICS OF POLYPHOSPHATE-ACCUMULATING ORGANISMS IN WASTEWATER

Abstract

Efficient phosphorus removal from wastewater has become a critical focus in contemporary environmental safety and sustainable water resource management. Although phosphorus (P) is an essential biological element for living organisms, its excessive discharge into natural water bodies triggers eutrophication, leading to the degradation of aquatic ecosystems. Furthermore, high P concentrations induce oxygen depletion, which ultimately drives a decline in biodiversity. Consequently, mitigating P pollution in wastewater is widely recognized as a pressing challenge for environmental protection and sustainable development. While traditional physical and chemical methods offer certain removal efficiencies, they inherently require substantial chemical reagents, generate secondary sludge, and increase operational costs. To overcome these limitations, enhanced biological phosphorus removal (EBPR) technologies have received significant attention in recent years. The EBPR process has been shown to reduce wastewater P to very low levels without the need for chemical precipitants. This mechanism relies on the capability of polyphosphate-accumulating organisms (PAOs) to take up large amounts of P and store it intracellularly as polyphosphate (РolyP). Under alternating anaerobic and aerobic conditions, PAOs achieve highly efficient P removal. As a result, EBPR technology represents an environmentally friendly, cost-effective, and long-term sustainable system. Thus, leveraging microorganisms to eliminate phosphorus-containing compounds from wastewater stands out as a promising frontier in modern water treatment biotechnology. This approach is expected to protect aquatic ecosystems, enhance wastewater treatment efficiency, and reduce anthropogenic pressure. In this review, we address current knowledge gaps in research regarding the microorganisms employed for P removal, focusing specifically on their phylogenetic diversity and metabolic characteristics.