InSiTrate

InSiTrate is a technology developed by Eurecat (before CTM Technological Center) in the context of the Life+ program, in collaboration with the companies Amphos21 and Catalana de Perforacions. Catalonia has a large part of the underground water bodies contaminated by nitrates. In this sense, this consortium has developed an in situ nitrate removal technology based on bioremediation.

The results of the pilot plant are promising, reaching percentages of elimination of nitrate concentration above 80%. The on-site treatment plant is automatic and does not generate waste that needs to be treated or disposed of later.

The InSiTrate project is not a management action but is a technological application that requires certain hydrogeological conditions of the aquifer for its correct performance. However, its local approach, low cost and high efficiency make it an interesting reference in the treatment of groundwater

Responsible entity

Eurecat, Technological Centre of Catalonia promotes the competitiveness of companies and the well-being of society through applied research and innovation.

https://eurecat.org/es/ 

Eurecat es the main technology center in Catalonia and the second private organization in Spain in raising funds of H2020. It is an entity specialized in offering services Applied R&D, technological, highly specialized training, technological consulting and professional events for companies from all sectors. Ha participado in more than 200 large national and international R&D&I consortium projects of high strategic value and has 88 patents and 7 spin-offs.

Eurecat develops and optimizes technologies and processes to improve water, soil and air management, as well as associated resources. They carry out research, development and innovation projects with companies from all sectors to improve economic, environmental and social sustainability.

They use advanced modelling and experimentation tools at different scales (laboratory, pilot plant and real scale) to develop and validate new technologies and their applications. It works with a wide range of pollutant treatment technologies to limit their presence in the natural environment, as well as to recover water resources and support the transition to a circular economy.

The experience of the Water, Air and Soil Unit, combined with the capabilities of the different technological units of Eurecat, allows to provide solutions to complex and specific problems in a wide range of sectors: water treatment, chemical, agri-food, pharmaceutical or basic industries and capital goods, among others.
In the water sector, the main objectives are:
Development and optimization of: Water management and associated resources, processes for the elimination of trace and/or recalcitrant compounds, effluent treatment and in-situ and ex-situ treatment technologies

Advanced separation processes, biological treatment, advanced oxidation, electrochemical and disinfection for liquid treatment.
Identification and evaluation of opportunities to improve efficiency and implement a circular economy.
Identification and development of processes for cascade recirculation and reuse in industrial processes.
Recovery of water resources and liquid effluents (nutrients, energy, raw materials).

Tools for monitoring, prediction and quality assurance in distribution networks.
Studies, modelling and simulation of the behaviour and mobility of pollutants in soils and groundwater.
Bioremediation processes with nanoparticles, monitored natural attenuation, reactive permeable barriers, chemical oxidation, stripping, etc.

Recovery of waste / by-products for the improvement of the physicochemical properties of the soil.

Detailed explanation

The most commonly used conventional technologies for nitrate removal first require the extraction of water for further treatment. Ex situ technologies are expensive and can generate unwanted by-products (waste). The Life+ InSiTrate project shows the feasibility of in situ technology based on the process of induced bioremediation.

The objectives of Life+ InSiTrate were:

1. Demonstrate on a pilot scale the feasibility of in situ bioremediation technology of nitrate-contaminated groundwater for the production of drinking water.
2. The development of an innovative design and prediction tool based on a mathematical model that describes the process of in situ bioremediation in any aquifer and helps the design of optimal remediation strategies for other sites.
3. The study of the feasibility of the technology in situ from the technical, environmental and economic point of view, and the comparison of this technology with other existing ones using the same indicators.

Figura 2: Esquema planta piloto de Sant Andreu de Llavaneres. Recuperado de Layman’s Report

4.Promote social acceptance of this technology and encourage the participation of stakeholders and working groups in the development of the technology.

5.The study of the extrapolation of the technology in other specific European sites to demonstrate its potential application.

The process of induced bioremediation consists of the acceleration of the natural process of denitrification by the microorganisms present in the affected aquifer. Nitrates are transformed into nitrogen gas by a sequence of microbial reduction reactions. In this case, theinjection of organic matter (acetic acid) into the aquifer induces bioremediation.

To carry out the project and build the pilot plant, a hydrogeological and chemical characterization of the aquifer (InSiTrate, n.d.) was carried out.
The IST-InSiTrate tool is a useful instrument for decision making, simulates the remediation process under the different injection strategies and hydrogeological characteristics in order to identify the optimal configuration of the denitrification plants (InSiTrate, n.d.), and facilitates the design and remediation strategy of the aquifer, defining the configuration and operating parameters of the plant. (InSiTrate, 2017).

Description ofthe pilot press

The plant has two injection wells (I1 and I2; Figure 2), an extraction well at a distance of 30 m from I1 and I2, and three piezometers (P1, P2 and P3).

The results of the project demonstrate the reduction of nitrate concentration between 80-100% in the monitoring wells and about 30% in the extraction wells.

The main problem was bioclogging that was solved by injecting the organic matter by pulses and performing periodic cleanings.

The social projection to implement innovative technologies was essential. Open approaches and close collaboration of the research groups and social interest groups involved were required, generating a participatory and integrated approach with the social context. The communication and dissemination plan has been structured in a series of tasks aimed at informing citizens of the objectives and developmentof the project in addition to facilitating the results obtained.

The technology at the commercial level requires that the system bescaled, for this the installation of 5 injection wells is required to create the reaction zone where the denitrification will be accelerated (I. Jubany et al 2019).