|SETIER project||The setier is an ancient measure of capacity, of variable value depending on the times, the regions, and the nature of the goods measured. The word comes from the Latin sextarius, which means sixth part (sixth part of the conge, measure of capacity for liquids, about 3 liters, or 1⁄48 of an amphora). (Source: https://fr.wikipedia.org/wiki/Setier )|
|Project initiator: INRAE-UR REVERSAAL||Responsible REVERSAAL :
AERMC, INRAE, IGE
|The development of open-source electronics and low-cost, miniaturized and portable sensors makes physico-chemical measurements (conductivity, pH, turbidity, COD, temperature, redox, dissolved O2, energy) more accessible (Guyard et al., 2017; Spinelli and Gottesman, 2019). Their development opens up new perspectives in terms of monitoring and control of wastewater treatment and recovery facilities thanks to more detailed spatio-temporal characterization (meter, minute). This type of approach, known as the “SMART Project”, is developing considerably in other fields of environmental applications, for example in air pollution (Al-Haija et al., 2013) and hydrology (Clement et al., 2018; Guyard et al., 2017). The main advantage of these open-source tools is that they offer a very high flexibility (choice of measurements, number of sensors, measurement frequency).
Usually, a worse metrological quality (but not always) of these sensors is compensated by the multiplication of measuring points allowing to increase the amount of information.
To date, there is no experienced feedback (reliability, uncertainties, constraints) on the measures applied to the problem of wastewater treatment and recovery. One can imagine the interest of such sensors in the sustainable management of the implemented channels, whether intensive or extensive. The multiplication of sensors would allow:
· To improve the knowledge of the processes (their dynamics and resilience), by accessing precisely with the help of sensors the spatial and temporal variability of the parameters of interest;
· To propose accessible and continuous monitoring sensors to help steering the systems and thus allow a quicker action of operators in case of failure of operations ;
· To provide new information on the characteristics of processes and channels such as operating limits in relation to maximum load, the non-homogeneity of flows and its impact on treatment performance, the adaptation of the energy expenditure of the various consumer stations, the adaptation of emissions according to the quality of the receiving environment, etc…
For example, in an aeration tank, the interest would be to increase the density of parameter mapping: within reactors and from one reactor to another (possibility of intermediate measurements). For small communities and for extensive processes, these sensors would offer the possibility of continuous monitoring at an a priori acceptable cost-effectiveness, improving reactivity in case of malfunction, in order to secure the operation of treatment plants and the quality of water discharged into the natural environment. On-line energy measurement would also make it possible to compensate for the lack of monitoring, in order to optimize the energy consumption
The objective of the project is to optimize the performance of new low-cost sensors, to define their limits and their strategy of use in the field of wastewater treatment and recovery.
The specific objectives are to:
· Make an inventory of the measurement requirements according to the size of the wastewater treatment plant and identify the overlapping parameters taking into account the needs on the sampling frequency to establish a specification. This specification will take into account the regulatory parameters and additional parameters that could be interesting to measure;
· Define an evaluation protocol to characterize the sensors, in collaboration with the RMC Water Agency, according to the needs;
· Collect feedback :
o To test the efficiency and the difficulty of implementation of these sensors by a metrological approach (uncertainties, limits of quantification, response time);
o Propose the simplest possible sensor/acquisition station design, including optional remote data transmission possibilities;
o Test these sensors and acquisition units on semi-industrial pilots or even on field sites, over a defined period, to be studied with the Water Agency depending on the duration of the project.
Propose a methodological guide for the implementation of these sensors with recommendations and points of vigilance, as well as notions of “cost-effectiveness”, for the benefit of partners and public and private operators, and for different objectives.