Potential acute effects of suspended aluminum nitride (AlN) nanoparticles on soluble microbial products (SMP) of activated sludge

The study aims to identify the potential acute effects of suspended aluminum nitride (AIN) nanoparticles (NPs) on soluble microbial products (SMP) of activated sludge. Cultured activated sludge loaded with 1, 10, 50, 100, 150 and 200 mg/L of A1N NPs were carried out in this study. As results showed, A1N NPs had a highly inverse proportionality to bacterial dehydrogenase and OUR, indicating its direct toxicity to the activated sludge viability. The toxicity of A1N NPs was mainly due to the nano-scale of A1N NPs. In SMP, A1N NPs led to the decrease of polysaccharide and humic compounds, but had slight effects on protein. The decrease of tryptophan-like substances in SMP indicated the inhibition of A1N NPs on the bacterial metabolism. Additionally, AIN NPs reduced obviously the molecular weight of SMP, which might be due to the nano -scale of A1N. (C) 2017 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.