Overall bi-plot of PCA data showing top 10 OTUs. All OTUs were used for analysis. The key clusters of Activated sludge - AS (inoculum Ag+, and control overlap), Feed, and Anaerobic Digestion (AD) are shown. Arrows show shift from control and Ag+ to AgNP communities. Note that AD Inoculum is right-shifted on PC1 compared to the control and Ag+ samples.