Enrichment and adaptation yield high anammox conversion rates under low temperatures.

This study compared two anammox sequencing batch reactors (SBR) for one year. SBR was kept at 30 °C while temperature in SBR was decreased step-wise from 30 °C to 20 °C and 15 °C followed by over 140 days at 12.5 °C and 10 °C.

Methods for assessing biochemical oxygen demand (BOD): a review.

The Biochemical Oxygen Demand (BOD) is one of the most widely used criteria for water quality assessment. It provides information about the ready biodegradable fraction of the organic load in water. However, this analytical method is time-consuming (generally 5 days, BOD5), and the results may vary according to the laboratory (20%), primarily due to fluctuations in the microbial diversity of the inoculum used.

Comparison of five integrative samplers in laboratory for the monitoring of indicator and dioxin-like polychlorinated biphenyls in water.

This study aimed at evaluating and comparing five integrative samplers for the monitoring of indicator and dioxin-like polychlorinated biphenyls (PCBs) in water: semi-permeable membrane device (SPMD), silicone rubber, low-density polyethylene (LDPE) strip, Chemcatcher and a continuous-flow integrative sampler (CFIS). These samplers were spiked with performance reference compounds (PRCs) and then simultaneously exposed under constant agitation and temperature in a 200 L stainless steel tank for periods ranging from one day to three months. A constant PCB concentration of about 1 ng·L(-1) was achieved by immersing a large amount of silicone rubber sheets ("dosing sheets") spiked with the target PCBs.

Development of a diagnostic tool: the wastewater collection network odour wheel.

The assessment of nuisance odour problems and the application of an effective odour management programme for the associated industrial activity may be achieved using a representative odour wheel and Odour Profile Analysis methodology. The odour wheel is a very useful tool for conducting odour quality control monitoring and developing a constructive dialogue regarding nuisance odours with the public. Previously, odours from wastewater treatment plant activities have been identified and described with a dedicated odour wheel.

Energy efficiency in membrane bioreactors.

Energy consumption remains the key factor for the optimisation of the performance of membrane bioreactors (MBRs). This paper presents the results of the detailed energy audits of six full-scale MBRs operated by Suez Environnement in France, Spain and the USA based on on-site energy measurement and analysis of plant operation parameters and treatment performance. Specific energy consumption is compared for two different MBR configurations (flat sheet and hollow fibre membranes) and for plants with different design, loads and operation parameters.

Odours in sewer networks: nuisance assessment.

As odour nuisance can affect the quality of life, the population is more and more demanding and in many cities sewers are a critical source of odours. Both factors can lead to increasing numbers of complaints due to the odour nuisance perceived by the residents, affecting also the public image of the sewer management companies. Odours associated with sewer networks are very heterogeneous, in as much as the different 'types of odours' encountered are sewer site specific.

The role of MBR technology for the improvement of environmental footprint of wastewater treatment.

This paper aims to demonstrate the relevance of membrane bioreactor (MBR) technology for the reduction of the environmental footprint of wastewater treatment in terms of removal of microbial and organic trace pollutants with increased reliability of operation. The application of a holistic approach using failure mode analysis, life cycle analysis (LCA), water quality fingerprints and environmental impacts underlines the lower environmental footprint of MBRs compared with conventional activated sludge. Several elements of this empirical approach can be included to upgrade the existing LCA tools in order to include the reduction of eco-toxicity, better human health protection and water reuse.

A new empirical model for stormwater TSS event mean concentrations (EMCs).

An empirical model for TSS event mean concentrations in storm weather discharges has been derived from the analysis of data sets collected in two experimental catchments (Chassieu, separate system and Ecully, combined system) in Lyon, France. Preliminary tests have shown that the values of TSS EMCs were linked to the variable X =TP ×ADWP (TP rainfall depth, ADWP antecedent dry weather period) with two distinct behaviours under and above a threshold value of X named λ: EMCs are increasing if X < λ and are decreasing if X > λ. An empirical equation is proposed for both behaviours.

Calibration of stormwater quality regression models: a random process?

Regression models are among the most frequently used models to estimate pollutants event mean concentrations (EMC) in wet weather discharges in urban catchments. Two main questions dealing with the calibration of EMC regression models are investigated: i) the sensitivity of models to the size and the content of data sets used for their calibration, ii) the change of modelling results when models are re-calibrated when data sets grow and change with time when new experimental data are collected. Based on an experimental data set of 64 rain events monitored in a densely urbanised catchment, four TSS EMC regression models (two log-linear and two linear models) with two or three explanatory variables have been derived and analysed.

Pilot-scale anaerobic digestion of screenings from wastewater treatment plants.

The anaerobic digestion of screenings from a municipal wastewater treatment plant was studied in a 90 L pilot-scale digester operated at 35 degrees C under semi-continuous conditions. In the first 4 weeks, a dry solids residence time of 28 days was applied, but the installation of inhibitory conditions was observed. Feeding was therefore suspended for 4 weeks to allow the digester to recover from inhibition, and then progressively increased up to a constant load of 6 kg of raw waste per week, corresponding to an average residence time of about 35 days of dry solids.

Characterization of screenings from three municipal wastewater treatment plants in the Region Rhône-Alpes.

The objective of this study was to analyze the composition of the screenings sampled from three municipal wastewater treatment plants (wwtp) located in the Region Rhône-Alpes, France. The plants were equipped with multi screening stages with gap sizes ranging from 60 to 3 mm. Waste production flows from each plant were monitored over at least 48 hours in each sampling campaign in order to calculate average production rates.