Effects of ZnO nanoparticles on high-rate denitrifying granular sludge and the role of phosphate in toxicity attenuation.

The increasing release of engineered nanoparticles (NPs) from consumer products has raised great concerns about their impacts on biological wastewater treatment. In this study, the widely-used ZnO NP was selected as a model NP to investigate its impact on high-rate denitrifying granular sludge in terms of sludge properties and community structure. A hormesis effect was observed during short-term exposure, in which the specific denitrification activity (SDA) was stimulated by 10% at 1 mg L ZnO NPs, but inhibited by 23% at 5.

Evaluating the effects of Zn(II) on high-rate biogranule-based denitrification: Performance, microbial community and sludge characteristics.

High-rate denitrification is a popular and efficient process for treatment of nitrate-rich wastewater. Knowing the effect of heavy metals on denitrification is essential for industrial development. In the present study, the long-term impacts of Zn(II) on denitrifying granular sludge were investigated.

Deciphering the evolution characteristics of extracellular microbial products from autotrophic and mixotrophic anammox consortia in response to nitrogen loading variations.

Extracellular microbial products (EMP) in biological wastewater treatment systems vary with operational conditions and in turn indicate the metabolic status of functional bacteria. In this study, the response of EMP from autotrophic and mixotrophic anammox consortia (AAC and MAC) to the variation of total nitrogen loading rates (TNLR) were investigated as well as their correlations with the community evolution. The variation of TNLR showed a significantly negative correlation with the production of bound microbial products (BMP) but a significantly positive correlation with the production of soluble microbial products (SMP).

Achieving completely anaerobic ammonium removal over nitrite (CAARON) in one single UASB reactor: Synchronous and asynchronous feeding regimes of organic carbon make a difference.

At least 11% of total nitrogen (TN) remains in the anammox effluent, making it difficult to meet increasingly stringent discharge standards. To overcome this bottleneck, an innovative process to achieve completely anaerobic ammonium removal over nitrite (CAARON) in one single up-flow anaerobic sludge blanket reactor was proposed in this study. The synchronous feeding of acetate at a C/N (nitrite) ratio of 0.

The revolution of performance, sludge characteristics and microbial community of anammox biogranules under long-term NiO NPs exposure.

Given the increasing applications of NiO nanoparticles (NPs) in battery products, the potential effects of NiO NPs on anaerobic ammonium oxidation (anammox) systems were studied for the first time. The results showed that the anammox system performance obviously differed under the stresses of different NiO NPs concentrations. After the withdrawal of NiO NPs, the nitrogen removal performance of the anammox reactor returned to nearly that of the initial phase within 35 days.