Evaluation of removal efficiency of human antibiotics in wastewater treatment plants in Bangkok, Thailand

Abstract

This study aimed to investigate the antibiotic concentration at each stage of treatment and to evaluate the removal efficiency of antibiotics in different types of secondary and advanced treatment, as well as the effects of the location of their discharge points on the occurrence of antibiotics in surface water. Eight target antibiotics and four hospital wastewater treatment plants in Bangkok with different conventional and advanced treatment options were investigated. Antibiotics were extracted by solid phase extraction and analysed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The antibiotic with the highest concentration at influent was cefazolin at 13,166 ng/L, while the antibiotic with the highest concentration at effluent was sulfamethoxazole at 1,499 ng/L. The removal efficiency of antibiotics from lowest to highest was sulfamethoxazole, piperacillin, clarithromycin, metronidazole, dicloxacillin, ciprofloxacin, cefazolin, and cefalexin. The adopted conventional treatment systems could not completely remove all antibiotics from wastewater. However, using advanced treatments or disinfection units such as chlorination and UV could increase the antibiotic removal efficiency. Chlorination was more effective than UV, ciprofloxacin and sulfamethoxazole concentration fluctuated during the treatment process, and sulfamethoxazole was the most difficult to remove. Both these antibiotics should be studied further regarding their contamination in sludge and suitable treatment options for their removal.

Distribution and persistence of cephalosporins in cephalosporin producing wastewater using SPE and UPLC–MS/MS method

“…The LOQs of the cephalosporins in the current study were comparable to the LOQs of cephalosporins in municipal wastewater and hospital wastewater previously reported in the literature (Diwan et al, 2010;Gomez et al, 2007;Sinthuchai et al, 2016;Wang et al, 2011).…”

“…Diwan et al (2010) detected no cephalosporin in both hospital wastewater influent and effluent samples. Sinthuchai et al (2016) investigated the presence of cephalosporin in four hospital wastewater treatment plants and reported that the cephalosporin concentrations ranged from 861.11 μg/L to 13,338.66 μg/L in influent samples and from below the detection limit to 26.99 μg/L in effluent samples. The cephalosporin concentrations surveyed in CPWW were comparable to those in hospital wastewater as investigated by Diwan et al (2009) and Gomez et al (2007).…”

Where Did They Come from—Multi-Drug Resistant Pathogenic Escherichia coli in a Cemetery Environment?

“…Activities, such as the discharge of untreated or poorly treated sewage into receiving water bodies [ 11 ], use of sewage sludge in agriculture [ 12 ] and use of animal faeces as fertiliser [ 13 ], have been linked to the increased detection of antibiotics and antibiotic-resistant bacteria in the environment. Despite their effectiveness in removing bacteria from wastewater, wastewater treatment works, for example, are unable to completely remove antibiotics from wastewater, thus resulting in the discharge of these metabolically active compounds into the environment [ 14 ]. It has been suggested that microbial exposure to these sub-lethal doses of antibiotics leads to the development of resistance to the antibiotics in bacteria [ 15 , 16 ].…”

Antibiotic residues in the environment of South East Asia

“…From human consumption, conservative estimates suggest that nearly half of consumed antibiotics are released, in active form, through excretion. 2 Studies from South East Asia 7 8 report residues of several antibiotics in hospital wastewater. However, it should be noted that the majority of antibiotics are used in the community, and this also contributes to environmental residues.…”

“…15 16 However, another study from Thailand showed residues for roxithromycin, sulfamethazine, and sulfamethoxazole even with advanced treatment. 8 Effluent from a treatment plant serving drug manufacturers in India contained up to 31 000 μg/L of ciprofloxacin. 5 Ampicillin up to 21 μg/L was detected in effluent from a treatment plant serving community wastewater in an Indian city.…”