The Effect of Primary, Secondary, and Tertiary Wastewater Treatment Processes on Antibiotic Resistance Gene (ARG) Concentrations in Solid and Dissolved Wastewater Fractions

Abstract

Abstract:Wastewater treatment plants (WWTPs) have been identified as potential sources of antibiotic resistance genes (ARGs) but the effects of tertiary wastewater treatment processes on ARGs have not been well characterized. Therefore, the objective of this study was to determine the fate of ARGs throughout a tertiary-stage WWTP. Two ARGs, sul1 and bla, were quantified via quantitative polymerase chain reaction (qPCR) in solids and dissolved fractions of raw sewage, activated sludge, secondary effluent and tertiary effluent from a full-scale WWTP. Tertiary media filtration and chlorine disinfection were studied further with the use of a pilot-scale media filter. Results showed that both genes were reduced at each successive stage of treatment in the dissolved fraction. The solids-associated ARGs increased during activated sludge stage and were reduced in each subsequent stage. Overall reductions were approximately four log 10 with the tertiary media filtration and disinfection providing the largest decrease. The majority of ARGs were solids-associated except for in the tertiary effluent. There was no evidence for positive selection of ARGs during treatment. The removal of ARGs by chlorine was improved by filtration compared to unfiltered, chlorinated secondary effluent. This study demonstrates that tertiary-stage WWTPs with disinfection can provide superior removal of ARGs compared to secondary treatment alone.

Protease Producers Predominate Cultivable Hydrolytic Bacteria Isolated from Liquid Biomedical Waste

“…Today, newer waste treatment facilities including plasma pyrolysis, encapsulation, inertization have been introduced, to replace older facilities such as incineration as toxic fumes (dioxins and furans) are produced which are harmful to both health and environment. Wastewater treatment plants (WWTP) were also thought to remove the antimicrobial resistance genes during the processing of the waste, which is being generated from the hospitals [5][6][7]. In developing countries, however, wastewater treatment plant is still considered costly [2].…”

Strategic Approach for Prioritising Local and Regional Sanitation Interventions for Reducing Global Antibiotic Resistance

“…Data on the concentrations and removal rates of ARB and ARGs in different waste processing and wastewater treatment processes are varied, depending on the mitigation step, and also the format, type and measurement methods used (see [42][43][44][45][46][47][48][49][50]). For example, limited ARG and ARB reduction data exist on the most basic mitigation options, such as the value of moving from OD to improved basic sanitation.…”

“…The ARGs used for comparisons here were chosen because they are measured in most treatment studies by a common analytical method, quantitative Polymerase Chain Reaction. For our study, we chose specific ARG data from nine manuscripts that examined full-or field-scale systems [42][43][44][45][46][47][48][49][50]. Other manuscripts were considered, but our goal was to contrast ARG conditions and removal rates only in "real" sanitation systems.…”

“…Using Figure 1 as a guide, Figures 2 and 3 were developed based on literature data to compare the relative AR mitigation value and costs of the four main sanitation steps. Figure 2 was developed based on ARG reduction data drawn from nine studies [42][43][44][45][46][47][48][49][50]. In summary, roughly log 4 to 6 ARG reductions occur from OD to improved basic sanitation (although this is hugely variable); improved basic sanitation to primary treatment adds a further 0.0 to 1.0 log reduction in ARGs; primary to secondary treatment provides an additional log 1.0 to 2.0 reduction; and finally, secondary to tertiary treatment adds a further log 1.0 to 3.0.…”

Incidence and molecular characterization of multidrug resistance in Gram‐negative bacteria of clinical importance from pharmaceutical wastewaters in South‐western Nigeria

“…The emergence of antimicrobialresistant bacteria presents a major threat to public health because it reduces the effectiveness of antimicrobial treatment, leading to increased morbidity, mortality, and healthcare expenditure (Lyimo, Buza, Subbiah, Smith, & Call, 2016). Studies have shown the prevalence of antibiotic-resistant pathogens in wastewaters discharged into water bodies (Guardabassi, Petersen, Olsen, & Dalsgaard, 1998;Pruden et al, 2006;Quach-Cu, Herrera-Lynch, Marciniak, & Adams, 2018;Reinthaler et al, 2003), leading to the challenges in antimicrobial therapy. A few authors, in their antibiotic-resistance comparative review using wastewaters from a hospital and a pharmaceutical plant, disclosed that the wastewater from the pharmaceutical plant had increased prevalence of antibiotic resistance among Acinetobacter species (Guardabassi et al, 1998).…”