Determination and fate of oxytetracycline and related compounds in oxytetracycline production wastewater and the receiving river

Abstract

This study investigated the occurrence and fate of oxytetracycline (OTC) and its related substances, 4-epi-oxytetracycline (EOTC), alpha-apo-oxytetracycline (alpha-apo-OTC), and beta-apo-oxytetracycline (beta-apo-OTC), in a wastewater treatment plant (WWTP) treating OTC production wastewater and a river receiving the effluent from the WWTP using liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS). The percent removal of OTC in the WWTP was 38.0 +/- 10.5%, and the concentration of OTC was still up to 19.5 +/- 2.9 mg/L in the treated outflow. The concentration slightly decreased along the river, from 641 +/- 118 microg/L at site R2 (discharging point) to 377 +/- 142 microg/L at site R4 ( approximately 20 km from site R2), which was still higher than the minimal inhibition concentration of OTC reported ( approximately 250 microg/L). On the other hand, the total amount of its related substances in the treated effluent was less than 5% of OTC. Concentrations of alpha-apo-OTC and beta-apo-OTC increased along the river, from 5.76 +/- 0.63 and 2.08 +/- 0.30 microg/L at site R2 to 11.9 +/- 4.9 and 12.0 +/- 4.6 microg/L at R4, respectively, although EOTC decreased from 31.5 +/- 3.8 to 12.9 +/- 1.1 microg/L, respectively. The mean concentration of beta-apo-OTC in river sediments was 20.8 +/- 7.8 mg/kg, and its ratio to OTC was approximately 0.11, nearly twice the ratio of alpha-apo-OTC and EOTC to OTC (0.058 +/- 0.014 and 0.061 +/- 0.015, respectively).

Microbial community functional structure in response to antibiotics in pharmaceutical wastewater treatment systems

“…Along with the fermentative production of antibiotics, large volumes of antibiotic production wastewater containing antibiotics of up to several mg L À1 are routinely generated (Larsson et al, 2007;Li et al, 2008a), which are much higher than previously reported in other environments (Kü mmerer, 2009). Activated sludge processes, a biological approach utilizing bacterial metabolic functions for the removal of organic nutrients (Seviour and Nielsen, 2010;Wagner and Loy, 2002) have been widely applied for the treatment of antibiotic production wastewater.…”

“…Details of antibiotic analysis and water and sludge characteristics were described previously (Li et al, 2008a(Li et al, , 2008b. All samples were analyzed for chemical properties in triplicate and average values were reported.…”

Response of activated sludge to the treatment of oxytetracycline production waste stream

“…The removal efficiency of OTC antibiotics in the benchscale wastewater treatment system ranged from 35.2 to 64.5 %, which was mainly attributed to biosorption and hydrolysis considering that OTC is refractory to biodegradation (Halling-Sørensen et al 2003;Kim et al 2005;Li et al 2008;. The COD removal efficiency (R COD ) showed a slight decrease (from 64.9 to 51.0 %) when the OTC concentration increased from 121.3 to 620.5 mg/L, perhaps due to the increase in volumetric COD load from 0.28 to 1.36 kg COD m −3 day −1 and to antibiotic concentration.…”

“…The COD Cr was determined every 2-3 days, and MLSS was determined every week according to standard methods (APHA 1998 REF). Concentrations of OTC and its three hydrolysates (4-Epi-OTC, α-Apo-OTC, and β-Apo-OTC) in the influent and effluent were determined under each dilution ratio using high-performance liquid chromatography tandem mass spectrometry (Waters, USA) as detailed in our previous studies (Li et al 2008;Liu et al 2012).…”

“…Mother liquors (ML), which are the waste streams generated after filtration and antibiotic extraction during antibiotic production by fermentation (Environmental Protection Agency 2002; Liu et al 2012), are normally treated using biological processes after dilution (Li et al 2008;Ma et al 2009). Our previous study showed that activated sludge took two strategies to cope with the presence of residual antibiotics during antibiotic production wastewater treatment: preferential growth of functional bacteria possessing antibiotic resistance and preferential growth of fungi, neither of which were susceptible to antibiotics (Deng et al 2011;Li et al 2009Liu et al 2012).…”