title: Simultaneous removal of nanosilver and fullerene in sequencing batch reactors for biological wastewater treatment.
abstract: Increasing use of engineered nanomaterials (ENMs) inevitably leads to their potential release to the sewer system. The co-removal of nano fullerenes (nC60) and nanosilver as well as their impact on COD removal were studied in biological sequencing batch reactors (SBR) for a year. When dosing nC60 at 0.07-2mgL(-1), the SBR removed greater than 95% of nC60 except for short-term interruptions occurred (i.e., dysfunction of bioreactor by nanosilver addition) when nC60 and nanosilver were dosed simultaneously. During repeated 30-d periods of adding both 2 mg L(-1) nC60 and 2 mg L(-1) nanosilver, short-term interruption of SBRs for 4d was observed and accompanied by (1) reduced total suspended solids in the reactor, (2) poor COD removal rate as low as 22%, and (3) decreased nC60 removal to 0%. After the short-term interruption, COD removal gradually returned to normal within one solids retention time. Except for during these "short-term interruptions", the silver removal rate was above 90%. A series of bottle-point batch experiments was conducted to determine the distribution coefficients of nC60 between liquid and biomass phases. A linear distribution model on nC60 combined with a mass balance equation simulated well its removal rate at a range of 0.07-0.76 mg L(-1) in SBRs. This paper illustrates the effect of "pulse" inputs (i.e., addition for a short period of time) of ENMs into biological reactors, demonstrates long-term capability of SBRs to remove ENMs and COD, and provides an example to predict the removal of ENMs in SBRs upon batch experiments.
authors.affiliation: School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, Arizona 85287-5306, United States. Electronic address: yu.yang.2@asu.edu.
authors.forename: Yu
authors.initials: Y
authors.lastname: Yang
authors.affiliation: School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, Arizona 85287-5306, United States.
authors.forename: Yifei
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Polytechnic School, Arizona State University, Mesa, Arizona 85212, United States.
authors.forename: Kiril
authors.initials: K
authors.lastname: Hristovski
authors.affiliation: School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, Arizona 85287-5306, United States.
authors.forename: Paul
authors.initials: P
authors.lastname: Westerhoff
mesh_terms: D057919:Biological Oxygen Demand Analysis; D018533:Biomass; D019149:Bioreactors; D037741:Fullerenes / Q000032:analysis / Q000302:isolation & purification*; D016014:Linear Models; D053768:Metal Nanoparticles / Q000032:analysis*; D012834:Silver / Q000032:analysis / Q000302:isolation & purification*; D062065:Wastewater / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D037741:Fullerenes; D012834:Silver; D062065:Wastewater
keywords: Nano fullerene; Nanosilver; SBR; Waste water treatment