Increasing attention has been given to the treatment of livestock and poultry wastewater because of its high ammonium nitrogen (NH₄⁺-N) content and low carbon/nitrogen ratio (C/N). Ceramic filter medium (CFM) and dewatered aluminum sludge (DAS), which are products from cast-off materials, are used as small-scale combined biological filters (CFM-DAS) for wastewater treatment. The high and stale removal efficiency of chemical oxygen demand (COD), NH₄⁺-N, and total nitrogen (TN) in the DAS filter indicate that DAS plays a major role in pollutant removal. Although significant differences are found between the composition of nitrifying bacteria in CFM and DAS, the structures of nitrifying communities are evenly distributed in each layer of CFM or DAS irrespective of the running time. Microbial compositions are attributed to the comprehensive effect of various environmental factors such as pH and TN at effluents. In the DAS, Nitrosospira shows significant negative correlation with the concentrations of NH₄⁺-N in effluents, whereas it has positive correlation with NO₃⁻-N, and Nitrososphaera has a significant negative correlation with NO₃⁻-N in effluents. Pearson correlation test reveals that certain genera may be used in estimating or predicting NH₄⁺-N consumption and NO₃⁻-N accumulation in CFM-DAS for treating sewage with a high NH₄⁺-N content.

Perfluorooctanoic acid (PFOA) is an emerging environmental pollutant that has attracted widespread attention. In this study, water samples were collected from the Wanggang River in the eastern coastal area of China, and the PFOA and dissolved organic matter (DOM) levels were measured. The results show that the PFOA concentration in the water bodies ranges from 3.2 to 52.9 ng·L⁻¹, and the average value is 27.1 ± 13.4 ng·L⁻¹, indicating an intermediate level. Two protein-like (C2, C3) and two humus-like (C1, C4) DOM components in the Wanggang River are attributed to rainfall and human activities. Differences are observed in the DOM components before and after the flood season. The humus-like components are higher in the post-flood season, and are one of the factors affecting PFOA distribution and concentration in the Wanggang River. The results provide data support for monitoring and evaluating PFOA in rivers and help formulate PFOA pollution management strategies. In future research, it might be better to define the interaction between DOM and emerging organic pollutants by using 17 PFASs as subjects.