An intensive sampling campaign has been carried out in a municipal wastewater treatment plant (WWTP) to assess the dynamics of the influent pharmaceutical active compounds (PhAC) and musks. The mass loadings of these compounds in wastewater influents displayed contrasting diurnal variations depending on the compound. The musks and some groups of PhACs tended to follow a similar diurnal trend as compared to macropollutants, while the majority of PhACs followed either the opposite trend or no repeatable trend. The total musk loading to the WWTP was 0.74±0.25gd⁻¹, whereas the total PhAC mass loading was 84.7±63.8gd⁻¹. Unlike the PhACs, the musks displayed a high repeatability from one sampling day to the next. The range of PhAC loadings in the influent to WWTPs can vary several orders of magnitude from one day or week to the next, representing a challenge in obtaining data for steady-state modelling purposes.

We report the isolation of a new bacterium species (named as DN-06) that degrades pyridine, a model compound containing both carbon and nitrogen, from the aerobic activated sludge in a coking wastewater treatment plant. DN-06 was identified as Achromobacter sp. using 16S rDNA sequence analysis. In batch culture, more than 95% of pyridine (500 mg/L) was degraded within 18 h by DN-06 grown at 35°C and pH 8 with agitation at 170 rpm. Degradation experiments of pyridine at different initial concentrations (50–4,300 mg/L) revealed that pyridine was an inhibitory substrate, and that neither yield coefficient Y nor endogenous decay coefficient K d was a constant. The values of Y and K d were 0.55–0.74 and 0.0032–0.0057 h−1, respectively. Five kinetic models (Haldane, Yano, Aiba, Webb, and Monod) were fitted to the experimental growth kinetic data. Models of Haldane and Yano (correlation coefficient R 2 = 0.929) were the most suitable models. For Haldane kinetic model, the values of μ max, K s, and K i were 0.161 h−1, 142.6 mg/L, and 4234.8 mg/L, respectively. The large values of Y and K i indicated that DN-06 had good tolerance against high pyridine concentrations. These results indicated possible future applications of Achromobacter sp. DN-06 in removing pyridine from industrial wastewaters, as well as in destroying pyridine in concentrated solutions during further treatment of trial water coupling with adsorption technology.

The number of chemical compounds in sewage and consequently their release into the environment is increasing. Some of them are toxic and many of them are considered endocrine disrupters. Here, the capacity of three wastewater treatment plants (WWTPs) to remove caffeine, hormones and bisphenol-A was investigated. Bisphenol-A and caffeine are highly water-soluble compounds, as opposed to hormones (estradiol, estriol, and ethynilestradiol) which are hydrophobic compounds. In the Sewage Treatment Plant (SWT)1 the sewage is treated by activated sludge process, in the second plant, SWT2, sewage is treated by upflow anaerobic sludge blanket reactors followed by dissolved air flotation, and in the third, SWT3 sewage is treated by stabilization lagoons. The first lagoon is 3.5 m deep, thus facultative and polishment processes occur. It was speculated that there was a difference in efficiency between the three plants in removing micropollutants. Small differences were found in the amounts removed, probably accounted for by retention time. The caffeine and bisphenol-A were almost completely removed, higher than 90% for both compounds (bisphenol-A and caffeine) in all WWTPs. The hormones, however, had a smaller rate of removal, between 70% and 87%. It is suspected that retention time is essential for removal efficiency, together with type of treatment. In fact, the hormones, caffeine, and bisphenol-A found in the environment definitely come from untreated sewage.

The capability of environmental microorganisms to biodegrade simazine—an active substance of 2-chloro-s-triazine herbicides (pesticide waste since 2007)—was assessed. An enormous metabolic potential of microorganisms impels to explore the possibilities of using them as an alternative way for thermal and chemical methods of utilization. First, the biotope rich in microorganisms resistant to simazine was examined. Only the higher dose of simazine (100 mg/l) had an actual influence on quantity of bacteria and environmental fungi incubated on substrate with simazine. Most simazine-resistant bacteria populated activated sludge and biohumus (vermicompost); the biggest strain of resistant fungi was found in floral soil and risosphere soil of maize. Compost and biohumus were the sources of microorganisms which biodegraded simazine, though either of them was the dominant considering the quantity of simazine-resistant microorganisms. In both cases of periodic culture (microorganisms from biohumus and compost), nearly 100% of simazine (50 mg/l) was degraded (within 8 days). After the repeated enrichment culture with simazine, the rate of its degradation highly accelerated, and just after 24 h, the significant decrease of simazine (20% in compost and 80% in biohumus) was noted. Although a dozen attempts of isolating various strains responsible for biodegradation of simazine from compost and biohumus were performed, only the strain identified as Arthrobacter urefaciens (NC) was obtained, and it biodegraded simazine with almost 100% efficiency (within 4 days).

BACKGROUND, AIM, AND SCOPE: Fishery wastewater treatment can be compromised due to seasonal production. The use of sequencing batch reactors is not completely successful, despite flexibility being one of the principal advantages. Most research on activated sludge is performed using synthetic wastewater to ensure a stable and constant feed. The current work compared biomass morphology and settling ability using image analysis of synthetic and real fishery wastewaters, with and without NaCl addition. RESULTS: The final effluent presented higher turbidity for both wastewaters after NaCl addition, and lower SVI values. For synthetic wastewater, NaCl addition led to the total aggregates' area (TA) increase from 1.46 to 2.09 mm2/μL, alongside the growth of intermediate aggregates into larger aggregates. The addition of NaCl to the fishery wastewater led to a decrease of the TA from 4.43 to 1.72 mm2/μL. The biomass composition decreased in larger and intermediate structures, opposite to the smaller aggregates' area percentage increase. DISCUSSION: NaCl addition to synthetic wastewater incited flocculation increasing sludge settling ability. A slight aggregate disruption was responsible for a turbidity increase. A strong deflocculation was identified in fishery wastewater with NaCl from the decrease of intermediate and large aggregates. This contrasted with pinpoint flocs release, which increased the turbidity levels. CONCLUSIONS, RECOMMENDATIONS, AND PERSPECTIVES: It could be established that synthetic wastewater biomass flocculation and fishery wastewater biomass deflocculation, observed during 0.5% NaCl experiments, were related to sludge settling and effluent turbidity changes. Furthermore, the biomass changes obtained with synthetic wastewater cannot be extrapolated to fishery wastewater.

INTRODUCTION: This study investigated the effect of copper on chemical oxygen demand (COD) removal efficiency and on the properties (mainly settling and dewatering) and the composition of extracellular polymeric substances (EPS) when 20 mg/L Cu(II) was continuously dosed to a sequencing batch reactor (SBR) inoculated with activated sludge. MATERIALS AND METHODS: The results showed that the continuous addition of 20 mg/L Cu(II) seriously inhibited the removal of sodium benzoate (provided as a model organic pollutant) by activated sludge in a SBR. RESULTS AND DISCUSSION: After 40 days of acclimation, the removal efficiency presented a slight but unsteady recovery and the settling and dewatering properties improved, indicating that sludge bulking had been inhibited. Additionally, the proportion of loosely bound EPS in the total EPS increased with time and the relative composition of the total organics was polysaccharide > humic substances > protein > DNA. CONCLUSION: The effects of copper on the composition of EPS and the settling and dewatering properties of bulking activated sludge were also discussed for the first time in this paper.