- 著者
- Sulfikar Ryo Honda Mana Noguchi Ryoko Yamamoto-Ikemoto Toru Watanabe
- 出版者
- Japan Society on Water Environment
- 雑誌
- Journal of Water and Environment Technology (ISSN:13482165)
- 巻号頁・発行日
- vol.16, no.2, pp.94-105, 2018 (Released:2018-04-10)
- 参考文献数
- 51
- 被引用文献数
- 16
The influent of municipal wastewater treatment plants (WWTP) can contain micropollutants such as antibiotics, chlorine, detergents, and biocides. In vitro studies have shown that these micropollutants may induce antibiotic resistance in bacteria. Previous studies have reported increases or decreases of antibiotic-resistant bacteria between the influent and effluent of WWTP in an unpredictable manner. Thus, the triggers of resistance induction in WWTP are largely unknown. To investigate the effects of unit operations in WWTP on antibiotic resistance induction, we incubated sixteen strains of Escherichia coli susceptible to amoxicillin or norfloxacin under simulated conditions of the primary sedimentation tank, aeration tank and final sedimentation tank in sterilized and filtered wastewater from each tank at 25°C for 1, 6 and 2 hours, respectively, which are typical hydraulic retention time of each tank. The minimum inhibition concentration towards amoxicillin or norfloxacin was compared before and after incubation to evaluate the occurrence of induction. We found that resistance to both antibiotics was more likely to increase in the aeration tank than in the primary sedimentation tank or final sedimentation tank. The longer contact time with the wastewater and the aeration are factors that appeared to induce antibiotic resistance in an activated sludge process.
- 著者
- Ryo Honda Yuta Teraoka Mana Noguchi Sen Yang
- 出版者
- 日本水環境学会
- 雑誌
- Journal of Water and Environment Technology (ISSN:13482165)
- 巻号頁・発行日
- vol.15, no.1, pp.1-11, 2017 (Released:2017-02-10)
- 参考文献数
- 27
- 被引用文献数
- 23
Treated sewage is a promising source of nitrogen and phosphorus in microalgae biomass production for carbon-neutral biofuel and chemical products. In this study, Chlorella vulgaris was continuously cultivated in membrane photobioreactors (MPBRs) under short hydraulic retention times (HRTs) and with different numbers of submerged membrane modules to investigate potential microalgae productivity when treated sewage was used as a nutrient source. Microalgae biomass concentrations were independent of HRT in MPBRs with one membrane module owing to microalgae biomass deposition on the membrane. Installation of an additional submerged membrane module effectively reduced deposition on the submerged membrane, resulting in increased microalgae biomass concentration and volumetric productivity. Growth kinetics suggested that HRT is the essential parameter influencing the volumetric productivity of microalgae under nutrient-limited conditions, and that optimization of the biomass concentration, which depends on the surface/volume ratio of the photobioreactor and initial light intensity, is critical to maximization of the volumetric productivity under light-limited conditions.