Characterizing a novel in-situ oxygen delivery device for establishing controlled redox zonation within a high infiltration rate sequential biofilter

Fate and Transport of Viruses within a High-Rate Plug-Flow Biofilter Designed for Non-Membrane-Based Indirect Potable Reuse Applications

“…During the experiments conducted in 2018, including the second spiking test and monitoring of indigenous virus concentrations, high feedwater DOC concentrations caused suboxic conditions after the infiltration trench, characterized by DO concentrations below the detection limit of 0.05 mg/L and limited nitrate reduction (<0.5 mg N/L) (see Table and ref ). Observed pH values (7.5–7.8) were stable and representative of secondary effluent qualities during both experimental periods.…”

“…Schematic flow diagram of the SMART plus -based advanced water treatment train for IPR. Modified from ref with permission. Copyright 2020 Elsevier.…”

“…In the SMART plus bioreactor, the high-rate infiltration trench technology is combined with a horizontal biofilter filled with highly uniform porous media with a larger effective size ( d 10 = 0.75 mm) than typical slow sand filters ( d 10 = 0.15–0.45 mm), which results in rapid deep-bed filtration (effective flow velocity of 0.58 m/h) under controlled plug-flow conditions . To adjust redox conditions, oxygen can be delivered in situ into the saturated porous media by gas–liquid membrane contactors, avoiding additional pumping and maintaining controlled hydraulics without any flow disturbances . While the desired flow and redox conditions as well as high biological activity have been successfully established and their effects on the TOrC attenuation were studied, to date, virus log reduction performance of the novel pilot-scale SMART plus bioreactor has not been assessed.…”

Removal of Trace Organic Chemicals during Long-Term Biofilter Operation

“…Around 63000 BVT, the influent water quality composition began to change due to operational problems at the WWTP, resulting in high NH 4 + -N concentrations that subsequently altered the redox conditions in the columns. Despite in-line H 2 O 2 dosing into the RSF in attempts to mitigate NH 4 + -N concentrations to <1 mg/L, oxic conditions in the columns could not always be maintained . Additionally, the high turbidity in the RSF/Dynasand effluent was mitigated by dosing a coagulant (FeCl 3 ) prior to RSF/Dynasand between 76000 and 80000 BVT, and the precipitation of iron hydroxide species also affected the back pressure of the filters.…”

“…Despite in-line H 2 O 2 dosing into the RSF in attempts to mitigate NH 4 + -N concentrations to <1 mg/L, oxic conditions in the columns could not always be maintained. 23 Additionally, the high turbidity in the RSF/Dynasand effluent was mitigated by dosing a coagulant (FeCl 3 ) prior to RSF/Dynasand between 76000 and 80000 BVT, and the precipitation of iron hydroxide species also affected the back pressure of the filters. All operational issues encountered due to chemical and mechanical disruptions are summarized in Table SI + -N concentrations from the WWTP to <1 mg/L, the water quality disturbances likely affected the growth and composition of the column biomass, because DO was rapidly consumed in the biofilters during periods of high NH 4 + -N concentrations.…”