Developing Hospital Wastewater Treatment Systems to Reduce Antimicrobial Resistance in the Community

Abstract

This action research utilizing a mixed-methods approach was conducted across 18 hospitals in the Chao Phraya River basin. Prior to system improvements, antimicrobial-resistant bacteria (ARB) were detected in 94.44% of the hospitals’ wastewater systems. Statistical analysis revealed no significant correlation (p>0.05) between the detection of ARB and factors such as hospital type or the specific wastewater treatment system used. Instead, the critical factors were treatment and disinfection efficiency, specifically, residual free chlorine levels showed a significant correlation (p<0.05). ARB persisted when chlorine levels fell below 0.5 mg/L. However, maintaining chlorine levels between 0.5–1.0 mg/L with a contact time of at least 30 minutes successfully eliminated key ARB—such as ESBL-producing E. coli, fluoroquinolone-resistant Salmonella, and vancomycin-resistant Enterococci (VRE)—from the effluent. The prototype consisted of five components: 1) suspended solids removal, 2) automated chlorine dosing, 3) plug-flow system management, 4) real-time monitoring, and 5) standard-based control. Following implementation, none of the 18 hospitals showed detectable AMB in wastewater.

The study concluded that this success stemmed from clear policies, executive awareness, and multidisciplinary collaboration. The researchers propose adopting a “multi-barrier approach” within the “One Health” framework and ensuring proper sludge management, as sludge serves as a reservoir for these pathogens.