Municipal wastewater treatment by biofiltration: comparisons of various treatment layouts. Part 2: assessment of the operating costs in optimal conditions.

This work aims to compare the operation costs (energy, reagents, waste management) for the three layouts usually used in wastewater treatment plants incorporating biofilters, using technical and economical data acquired during 10 years of operation of a Parisian plant (Seine Centre, 240,000 m(3) d(-1) -800,000 equivalent inhabitants). The final objective is to establish general economical data and tendencies that can be translated from our study to any biofiltration plant. Our results evidenced the savings achieved through the treatment process combining upstream and downstream denitrification.

Municipal wastewater treatment by biofiltration: comparisons of various treatment layouts. Part 1: assessment of carbon and nitrogen removal.

One of the largest wastewater treatment plants in the Paris conurbation (240,000 m(3)/d) has been studied over several years in order to provide technical and economical information about biological treatment by biofiltration. Biofiltration systems are processes in which carbon and nitrogen pollution of wastewater are treated by ascendant flow through immersed fixed cultures. This paper, focused on technical information, aims: (1) to compare performances of the three biological treatment layouts currently used in biofiltration systems: upstream denitrification (UD), downstream denitrification (DD) and combined upstream-downstream denitrification (U-DD) layouts; and (2) to describe in detail each treatment step.

Contribution of treated wastewater to the microbiological quality of Seine River in Paris.

Urban part of Seine River serving as drinking water supply in Paris can be heavily contaminated by Cryptosporidium spp. and Giardia duodenalis. In the absence of agricultural practice in this highly urbanized area, we investigated herein the contribution of treated wastewater to the microbiological quality of this river focusing on these two parasites.

New tools for modelling water quality of hydrosystems: an application in the Seine River basin in the frame of the Water Framework Directive.

The implementation of the European Water Framework Directive requires new tools for predicting the effect of expected measures taken in the watershed on water quality at the scale of large regional river systems. In the Seine basin, four models, developed in a research context, have been chained to each other to simulate water quality and biogeochemical functioning of the hydrosystem from headwater streams to the coastal marine area. All four models are based on a similar deterministic approach and share a common description of the biogeochemical processes, allowing them to exchange information.

Modelling the impacts of Combined Sewer Overflows on the river Seine water quality.

To achieve the objectives of the European Water Framework Directive (EWFD), the Seine basin Water Authority has constructed a number of prospective scenarios forecasting the impact of planned investments in water quality. Paris and its suburbs were given special attention because of their impact on the river Seine. Paris sewer system and overflow control is of major concern in future management plans.