Critical review of the influences of nanoparticles on biological wastewater treatment and sludge digestion

Abstract

Nanoparticles (NPs), with at least one dimension less than 100 nm, are substantially employed in consumer and industrial products due to their specific physical and chemical properties. The wide uses of engineered NPs inevitably cause their release into the environment, especially wastewater treatment plants. Therefore, it is essential to systematically assess their potential impact on biological wastewater treatment and subsequent sewage sludge digestion. This review aims to provide such support. First, this paper reviews the recent advances on the analytical developments and nano–bio interface of NPs in wastewater and sewage sludge treatment. The effects of NPs on biological wastewater treatment and sewage sludge digestion and related mechanisms are discussed in detail. Finally, the key questions that need to be answered in the future are pointed out, which include on-line revelation of the changes of NPs in sewage and sludge environments, in situ assessment of the variations of microorganisms involved in these biological systems after they are exposed to NPs. Differentiation of the contribution of individual toxicity mechanisms to these systems, and the identification of under what conditions the nanoparticle-induced toxicity will be increased or decreased are also considered.

• Activated sludge
• biological wastewater treatment
• nanoparticle toxicity
• sewage sludge digestion
• wastewater treatment plant

Declaration of interest

The authors report no conflicts of interest. This study was financially supported by the project of NSFC (51278354 and 51425802), China Postdoctoral Science Foundation (2014M550249), and National Science Foundation of Jiangsu Province (BK2012253).

Supplementary materials online only - For review only at proofing stage