Relation Between Conductivity and Ion Content in Urban Wastewater

Wastewater conductivity has been monitored for extended periods of time by in situ probes and on grabbed samples in four communities (from 1,000 to 350,000 PE). In parallel, the concentrations of the main ionic contributors, such as calcium, sodium, potassium, magnesium, ammonium, ortho-phosphate, chloride and sulphate have been measured and their variations with respect to time compared to human activity patterns. It appears that sodium, potassium, ammonium and ortho-phosphate, which contribute to about 34% to wastewater conductivity, exhibit diurnal variations in phase with human activity evaluated by absorbance at 254 nm. However calcium (≈ 22% of wastewater conductivity) is out‑of-phase. This release, ahead of the one of other cations and anions, could be related to sewer concrete corrosion or to groundwater infiltration. The combination of these different ionic contributions creates a conductivity pattern which cannot be easily related to human activity. It makes difficult to integrate conductivity in a monitoring system able to detect ion-related abnormalities in wastewater quality.Les variations de la conductivité d’eaux usées urbaines ont été suivies sur de longues durées a l’aide de sondes placées in situ en entrée d’installations de traitement et sur des échantillons prélevés automatiquement. Quatre communautés (entre 1 000 et 350 000 habitants) ont été choisies pour cette étude. On a également dosé sur les échantillons les principaux ions (calcium, sodium, potassium, magnésium, ammonium, ortho-phosphates, chlorures et sulfates). Il apparait que le sodium, le potassium, l’ammonium et les ortho-phosphates contribuent pour 34 % a la conductivité des eaux usées et présentent des variations journalicres en phase avec la pollution carbonée soluble, estimée a partir de l’absorbance a 254 nm. Par contre, le calcium, qui contribue pour 22 % a la conductivité, présente un déphasage qui peut ztre du a son transport dans le réseau d’assainissement du fait de la corrosion des conduites en béton ou a des infiltrations d’eaux claires. Finalement, la combinaison de ces différentes contributions ioniques conduit a une variabilité de la conductivité qu’il n’est pas facile de lier a l’activité humaine, et donc a des rejets accidentels dans le cadre d’un systcme de détection de variation anormale de la qualité des eaux usées

Antibiotic resistance genes in treated wastewater and in the receiving water bodies: A pan-European survey of urban settings

There is increasing public concern regarding the fate of antibiotic resistance genes (ARGs) during wastewater treatment, their persistence during the treatment process and their potential impacts on the receiving water bodies. In this study, we used quantitative PCR (qPCR) to determine the abundance of nine ARGs and a class 1 integron associated integrase gene in 16 wastewater treatment plant (WWTP) effluents from ten different European countries. In order to assess the impact on the receiving water bodies, gene abundances in the latter were also analysed.Six out of the nine ARGs analysed were detected in all effluent and river water samples. Among the quantified genes, intI1 and sul1 were the most abundant. Our results demonstrate that European WWTP contribute to the enrichment of the resistome in the receiving water bodies with the particular impact being dependent on the effluent load and local hydrological conditions. The ARGs concentrations in WWTP effluents were found to be inversely correlated to the number of implemented biological treatment steps, indicating a possible option for WWTP management.Furthermore, this study has identified blaOXA-58 as a possible resistance gene for future studies investigating the impact of WWTPs on their receiving water.COST ActionTekirdag Namık Kemal University-Corlu Faculty of Engineering3203301

Implementing ADM1 for plant-wide benchmark simulations in Matlab/Simulink

The IWA Anaerobic Digestion Model No. 1 (ADM1) was presented in 2002 and is expected to represent the state-of-the-art model within this field in the future. Due to its complexity the implementation of the model is not a simple task and several computational aspects need to be considered, in particular if the ADM1 is to be included in dynamic simulations of plant-wide or even integrated systems. In this paper, the experiences gained from a Matlab/Simulink implementation of ADM1 into the extended COST/IWA Benchmark Simulation Model (BSM2) are presented. Aspects related to system stiffness, model interfacing with the ASM family, mass balances, acid base equilibrium and algebraic solvers for pH and other troublesome state variables, numerical solvers and simulation time are discussed. The main conclusion is that if implemented properly, the ADM1 will also produce high-quality results in dynamic plant-wide simulations including noise, discrete sub-systems, etc. without imposing any major restrictions due to extensive computational efforts

Chronic impact of tetracycline on nitrification kinetics and the activity of enriched nitrifying microbial culture

International audienceThis study evaluated the chronic impact of tetracycline on biomass with enriched nitrifying community sustained in a lab-scale activated sludge system. For this purpose, a fill and draw reactor fed with 100 mg COD/L of peptone mixture and 50 mg N/L of ammonia was sustained at a sludge age of 15 days. At steady-state, the reactor operation was continued with a daily tetracycline dosing of 50 mg/L for more than 40 days, with periodic monitoring of the microbial composition, the nitrifying bacteria abundance, as well as the amoA and 16S TRNA gene activity, using molecular techniques. Changes in the kinetics of nitrification were quantified by modelling concentration profiles of major nitrogen fractions and oxygen uptake rate profiles derived from parallel batch experiments. Activated sludge modeling results indicated inhibitory impact of tetracycline on the growth of nitriflers with a significant increase of the half saturation coefficients in corresponding rate equations. Tetracycline also inactivated biomass components of the enriched culture at a gradually increasing rate with time of exposure, leading to total collapse of nitrification. Molecular analyses revealed significant changes in the composition of the microbial community throughout the observation period. They also showed that continuous exposure to tetracycline inflicted significant reduction in amoA mRNA and 16S rRNA levels directly affecting nitrification. The chronic impact was much more pronounced on the ammonia oxidizing bacteria (AOB) community. These observations explained the basis of numerical changes identified in the growth kinetics of nitrifiers under stress conditions

Valorisation des matières fertilisantes d’origine résiduaire sur les sols à usage agricole ou forestier: Impacts agronomiques, environnementaux, socio-économiques. Résumé de l'expertise scientifique collective

Les effluents d’élevage, boues d’épuration, déchets organiques urbains et effluents industriels – qualifiés de matières fertilisantes d’origine résiduaire (Mafor) - constituent des sources d'éléments fertilisants et de matière organique pour fertiliser ou amender les sols agricoles ou forestiers. L’expertise a fait le point sur les impacts agronomiques, environnementaux et socio-économiques de leur épandage

Use of fertilizing residual materials in agriculture and forestry: Agronomic, environmental and socio-economic effects. Short summary

Les effluents d’élevage, boues d’épuration, déchets organiques urbains et effluents industriels – qualifiés de matières fertilisantes d’origine résiduaire (Mafor) - constituent des sources d'éléments fertilisants et de matière organique pour fertiliser ou amender les sols agricoles ou forestiers. L’expertise a fait le point sur les impacts agronomiques, environnementaux et socio-économiques de leur épandage

Occurrence of eight household micropollutants in urban wastewater and their fate in a wastewater treatment plant. Statistical evaluation

International audienceThe occurrence in urban wastewater of eight micropollutants (erythromycin, ibuprofen, 4-nonylphenol (4-NP), ofloxacin, sucralose, tridosan, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS)) originating from household activities and their fate in a biological wastewater treatment plant (WWTP) were investigated. Their concentrations were assessed in the liquid and solid phases (sewage particulate matter and wasted activated sludge (WAS)) by liquid chromatography-tandem mass spectrometry.The analysis of sewage from two different urban catchments connected to the WWTP showed a specific use of ofloxacin in the mixed catchment due to the presence of a hospital, and higher concentrations of sucralose in the residential area.The WWTP process removed over 90% of ibuprofen and triclosan from wastewater, while only 25% of ofloxacin was eliminated. Erythromycin, sucralose and PFOA were not removed from wastewater, the influent and effluent concentrations remaining at about 0.7 mu g/L, 3 mu g/L and 10 ng/L respectively. The behavior of PFOS and 4-nonylphenol was singular, as concentrations were higher at the WWTP outlet than at its inlet. This was probably related to the degradation of some of their precursors (such as alkylphenol ethoxylates and polyfluorinated compounds resulting in 4-NP and PFOS, respectively) during biological treatment.4-NP, ofloxacin, triclosan and perfluorinated compounds were found adsorbed on WAS (from 5 ng/kg for PFOA to 1.0 mg/kg for triclosan).The statistical methods (principal component analysis and multiple linear regressions) were applied to examine relationships among the concentrations of micropollutants and macropollutants (COD, ammonium, turbidity) entering and leaving the WWTP. A strong relationship with ammonium indicated that some micropollutants enter wastewater via human urine. A statistical analysis of WWTP operation gave a model for estimating micropollutant output from the WWTP based on a measurement of macropollution parameters. (C) 2014 Elsevier B.V. All rights reserved