Structure of the Microbial Community of the Biological Wastewater Treatment Plant of a Pig Farm and Storage Pond

Abstract

A primary study of the quality of wastewater treatment and the composition of the microbial community of the activated sludge of the treatment plant and the storage pond of a pig farm is carried out. Activated sludge is widely represented by nitrogen-cycle microorganisms, including denitrifying and nitrifying bacteria (Nitrosomonas (4%), Nitrospira (8%), as well as, to a lesser extent, anammox microorganisms (Candidatus Kuenenia (0.2%)). Phosphorus is removed by phosphate-accumulating bacteria, primarily Thauera (5%) and Candidatus Accumulibacter (1%). Two-stage aerobic treatment has a very high degree of chemical oxygen demand (97%) and ammonium (99.7%) removal. At the same time, a rather high concentration of nitrates (569 mg/L) and phosphates (75 mg/L) in the treated water probably caused the dramatic development of purple sulfur bacteria of the genus Thiolamprovum in the storage pond, coloring the water a red-burgundy color (“borscht” color). To improve the quality of treatment, reduce energy costs, obtain an energy carrier in the form of biogas, as well as solve the problem of water bloom in the storage pond, a scheme for anaerobic-anoxic-aerobic wastewater treatment of the pig farm is proposed.