Co-optimization of sponge-core bioreactors for removing total nitrogen and antibiotic resistance genes from domestic wastewater

TY - JOUR

T1 - Co-optimization of sponge-core bioreactors for removing total nitrogen and antibiotic resistance genes from domestic wastewater

AU - Jong, Mui Choo

AU - Su, Jian Qiang

AU - Bunce, Joshua T.

AU - Harwood, Colin R.

AU - Snape, Jason R.

AU - Zhu, Yong Guan

AU - Graham, David W.

N1 - Funding Information: Authors acknowledge funding support by an UK Engineering and Physical Science Research Council Impact Acceleration Award , entitled “Demonstrating Low-energy Technologies for Decentralised Waste Treatment around the World” ( EP/K503885/1 ); AstraZeneca Global Environment ; and the National Natural Science Foundation of China (Award 21210008 ). Publisher Copyright: © 2018 Elsevier B.V.

PY - 2018/9/1

Y1 - 2018/9/1

N2 - Inadequate sanitation can lead to the spread of infectious diseases and antimicrobial resistance (AMR) via contaminated water. Unfortunately, wastewater treatment is not universal in many developing and emerging countries, especially in rural and peri-urban locations that are remote from central sewers. As such, small-scale, more sustainable treatment options are needed, such as aerobic-Denitrifying Downflow Hanging Sponge (DDHS) bioreactors. In this study, DDHS reactors were assessed for such applications, and achieved over 79% and 84% removal of Chemical Oxygen Demand and Ammonium, respectively, and up to 71% removal of Total Nitrogen (TN) from domestic wastes. Elevated TN removals were achieved via bypassing a fraction of raw wastewater around the top layer of the DDHS system to promote denitrification. However, it was not known how this bypass impacts AMR gene (ARG) and mobile genetic element (MGE) levels in treated effluents. High-throughput qPCR was used to quantify ARG and MGE levels in DDHS bioreactors as a function of percent bypass (0, 10, 20 and 30% by volume). All systems obtained over 90% ARG reduction, although effluent ARG and TN levels differed among bypass regimes, with co-optimal reductions occurring at ~20% bypass. ARG removal paralleled bacterial removal rate, although effluent bacteria tended to have greater genetic plasticity based on higher apparent MGE levels per cell. Overall, TN removal increased and ARG removal decreased with increasing bypass, therefore co-optimization is needed in each DDHS application to achieve locally targeted TN and AMR effluent levels.

AB - Inadequate sanitation can lead to the spread of infectious diseases and antimicrobial resistance (AMR) via contaminated water. Unfortunately, wastewater treatment is not universal in many developing and emerging countries, especially in rural and peri-urban locations that are remote from central sewers. As such, small-scale, more sustainable treatment options are needed, such as aerobic-Denitrifying Downflow Hanging Sponge (DDHS) bioreactors. In this study, DDHS reactors were assessed for such applications, and achieved over 79% and 84% removal of Chemical Oxygen Demand and Ammonium, respectively, and up to 71% removal of Total Nitrogen (TN) from domestic wastes. Elevated TN removals were achieved via bypassing a fraction of raw wastewater around the top layer of the DDHS system to promote denitrification. However, it was not known how this bypass impacts AMR gene (ARG) and mobile genetic element (MGE) levels in treated effluents. High-throughput qPCR was used to quantify ARG and MGE levels in DDHS bioreactors as a function of percent bypass (0, 10, 20 and 30% by volume). All systems obtained over 90% ARG reduction, although effluent ARG and TN levels differed among bypass regimes, with co-optimal reductions occurring at ~20% bypass. ARG removal paralleled bacterial removal rate, although effluent bacteria tended to have greater genetic plasticity based on higher apparent MGE levels per cell. Overall, TN removal increased and ARG removal decreased with increasing bypass, therefore co-optimization is needed in each DDHS application to achieve locally targeted TN and AMR effluent levels.

KW - Antibiotic resistance genes

KW - Denitrification

KW - High-throughput qPCR

KW - Sustainable wastewater treatment

KW - Wastewater bypass

UR - http://www.scopus.com/inward/record.url?scp=85045387173&partnerID=8YFLogxK

U2 - 10.1016/j.scitotenv.2018.04.044

DO - 10.1016/j.scitotenv.2018.04.044

M3 - Article

C2 - 29710641

AN - SCOPUS:85045387173

SN - 0048-9697

VL - 634

SP - 1417

EP - 1423

JO - Science of the Total Environment

JF - Science of the Total Environment

ER -