SADE won two long-term work orders in Pont-d’Ain and Chavanoz, which began in May 2022 and are scheduled for completion in the second half of 2023. SADE is carrying out the sizing, execution plans, operation management, networks and all equipment, including electricity and automations.
The aim is to inaugurate the Pont d’Ain on 8 September 2023!
The task is to build a brand new 5000PE treatment plant and demolish the existing facilities located in the immediate vicinity. The mayor of the commissioning municipality set the inauguration of the new WWTP for 8 September 2023.
The goal is thus clear, and given the scale of works and their launch in May 2022, the teams will have to be particularly efficient, specifically in terms of supply lead times for electrical and electronic equipment.
Building impressive facilities
In this new activated sludge WWTP, the effluent enters via a pre-treatment facility consisting of a screen, grit chamber and grease trap, and flows into a 3-zone (contact /anaerobic/aerobic) aeration basin, a 16m-diameter, 6m-deep concrete structure with a useful capacity of 1,230m³.
Following pre-treatment, the water continues on its path to a degasser, then an 800m3, 16m-diameter clarifier equipped with a scraper bridge. It ends its journey via a tertiary membrane filter, a UV channel and a metering duct before its discharge into the Suran, which joins the River Ain a few hundred metres further along. To prevent the risk of flooding on the site, due to a 100-year floodplain, most of the facilities are above ground and located at a height.
As the discharge zone is located in the immediate vicinity of a protected area, the treatment process is specifically adapted for reinforced nitrogen and phosphor treatment. The sludge extracted from the clarifier will be treated in a spinner prior to evacuation and recycling.
Chavanoz, two years of works
The Lyon Saint-Exupéry en Dauphiné Community of Districts (LYSED) entrusted the extension of its activated sludge wastewater treatment plant (27,000 to 40,000PE) and the rehabilitation of existing facilities, without service stoppage, to the consortium led by SADE. This represents a two-year project in a sensitive environment with a high level of co-activity alongside the site operator, Veolia.
Imposing new facilities
The specifics of the 2 main facilities to be built in the context of this extension are enough to realise the vast scale of this project, the plans for which were produced by SADE Engineering. The 3600m³ aeration basin, equipped with 4 surface turbines, measures 32m x 32m. The circular clarifier, equipped with a sucking/ scraping bridge, measures 35m in diameter for a volume of 3000m³. Added to these structures are numerous networks and associated facilities, in particular a collector system for residue sludge.
Service continuity is a key element in the organisation of this project. Nothing must interfere or compromise the quality of effluent treatment. Operations are subject to precise phasing determined in association with the operator, who issues the work permits.
2 high points
The two high points of this project will be the commissioning of the new facilities with stoppage of the existing one for its rehabilitation, followed by the connection of all built and rehabilitated facilities to form a high-performance ensemble capable of treating 10,400m³ per day in rainy weather, with a top flow rate of 950m³ per hour.