Diversity of activated sludge system microbiota by environmental and operational parameters: a scientometric analysis

Activated sludge system has diversified microbiota responsible for biochemical reactions of organic matter degradation. The composition and structure of this microbiota depends on different environmental and operational conditions. Therefore, knowledge about activated sludge microbiota is essential to provide improvements in effluent treatment systems. This scientometric review analyzes studies related to the microbiota of activated sludge published in a thirty-year interval, bringing a view of the state-of-the-art and future perspectives. By summarizing the available data in Web of Science, it was possible to verify the relation between microbiota diversity and activated sludge environmental and operational conditions. The terms: activated sludge, microbial community, diversity, and identification were used for the research. Research on the microbiota of activated sludge is frequent in China and the United States of America. The two countries gather the largest amout of data on this issue both individually or in cooperation, distributed in the areas of biotechnology, applied microbiology, and environmental sciences. In the scientometrics performed, no correlation was found concerning the activated sludge microbiota diversity among different geographical locations; microbial communities in each biological system are unique mainly due to seasonality and type of effluent to be treated and its composition in organic matter.