The research efforts of the UR 1468-REVERSAAL Unit, entitled “Reduction, Reuse and Recovery of Residual Water Resources” are intended to raise the level of knowledge on processes for recovering and treating urban effluent, i.e. residual water (both raw and treated), urban discharges during rainfall events and sludge. These types of wastewater give rise to a resource pool (water, matter and energy) capable of being harnessed through the reuse of treated wastewater, power generation and material recovery.

Our research work yields informational documents, along with relevant and innovative guidelines in terms of design, sizing, operations and optimization of urban water treatment facilities. Against this backdrop, we develop: methods, innovative tools that are both experimental and numerical, plus a set of decision-making aids applicable to field actors whether representing the public or private sector.

The advances achieved within the scope of the research conducted by this unit will enable not only water treatment plants to transition into water resource recovery stations, but for the urban environment to incorporate nature-based solutions in the aim of improving water management techniques.

Our ambition

The unit is focused on managing the flows of water and matter with greater feedback loops at the regional scale. The unit’s emphasis thus entails laying out the treatment plant of the future through an assembly of technological building blocks that are:

• Innovative: using urban water resources to produce energy, water for various potential uses, safe materials relying less on natural resource extraction
• Adapted: enabling more decentralized uses in order to both limit waste collection costs and identify water reuse options at the local level
• Economical: reducing energy consumption, in addition to mitigating atmospheric emissions (greenhouse gases) and discharges into the ground
• Intelligent: featuring sensors whose connectivity contributes to a predictive system geared around real-time production and sustained inclusion on the source-network-plant-river continuum.

The following illustration highlights these various anticipated uses in order to manage flows with effective feedback loops.

Research topics

Our research has been structured around four topics:

Topic 1: Environmental emissions abatement	Topic 2: Water reuse	Topic 3: Resource restoration and recovery	Topic 4: Digital innovations
Leader: Nicolas FORQUET	Leader: Rémi LATUNE	Leader: Florent CHAZARENC	Leader: Rémi CLEMENT
Measure, model and control the transfers and transformations of both effluent and sludge pollutants within the treatment processes and protocols Evaluate, develop and optimize new processes Adapt the design and operations	Devise and oversee the processes and protocols for producing water adapted to various uses Configure decentralized approaches to manage urban waters for resilient cities	Expand the knowledge bridge between organic matter composition and energy production capacity Maximize energy recovery and production via the processes introduced Further develop recovery processes	Integrate innovative connected sensors for monitoring and regulation, including a “Low-Tech” strategy Enhance data reliability, applicability (the FAIR approach), and design process performance optimization strategies - Develop decision-making aids in the design and management of both processes and protocols

Originality of this research set-up

The materials (organic, nutriments, metals and organic chemical molecules) and their transformation, along with the flows and transfer steps occurring within treatment and reuse processes, lie at the heart of the REVERSAAL research unit’s activities.

Our research approach is based on a coupling between experiments conducted at various scales (from laboratory prototypes to industrial systems), which often wind up being associated with modeling efforts. We are highly capable of analyzing actual systems, in addition to engaging in field campaigns to enable working at the pilot or semi-industrial scale and full-scale installations (industrial complexes). Unit researchers and engineers define, plan and coordinate the set of research tasks and projects, some of which combine distinct scientific disciplines. A six-person technical committee is responsible for supervising the measurement campaigns, prototype building and installation of the pilot plants needed for the projects. The unit is endowed with a number of experimental facilities (at the La Feyssine Research Complex in Craponne) and technical equipment at the La Doua site. This infrastructure is available for consultation via information sheets and videos.

We are recognized specialists in many treatment processes involving urban effluent and sludge (below is a non-exhaustive list of such processes):

• Primary treatment: coagulation-flocculation with reagents
• Secondary treatment: free suspension processes (activated sludge, extended high-load aeration, SBR, BRM), fixed-bed biofilm reactors (biofiltration, botanical filters with or without forced aeration) or fluidized-bed reactors (MBBR, IFAS), nature-based solutions
• Separation equipment: sedimentation basins, clariflocculators, floaters, rotary sieves
• Tertiary treatment: sorption (activated charcoal, alternative materials), chemical oxidation (O₃, H₂O₂), photooxidation (UV), soil treatment, plant discharge zones
• Anaerobic digestion of sewage sludge
• Sludge treatment: reed beds

Dissemination of the knowledge acquired

From a historical perspective, REVERSAAL staff publish on a very regular basis scientific and technical articles in peer-reviewed journals (roughly a dozen per year), as well as project reports and deliverables. Moreover, they are tasked with providing some 50 hours of instruction annually in the field of wastewater treatment and reuse within the scope of initial training (university, engineering schools) and continuing education. Over the past several years, staff output has also encompassed Web applications and databases, open-source hardware tools (notably in geophysics) and open-source modeling codes, along with coordinated sanitation planning tools.

Unit personnel

The REVERSAAL Research Unit was created in 2018 following an internal scientific and technical reorganization. The unit’s total staff size has reached forty, currently broken down as follows: 18 permanent personnel, some 12 PhD students and post-docs, 5 contractors and 3 guest scientists. Also hosted are roughly 10 student interns a year (as part of their Master’s or Engineering degree programs).

The unit’s organizational chart features a Director and Deputy Director, a leader of the Technical Committee plus 4 individual theme manager, and a supervisor of the various platforms. Cross-disciplinary missions set up to overlap with the specific scientific department or center are overseen by some staff members, namely: Prevention Assistant, Head of Operational Data, Communications Supervisor, and Metrology Supervisor.