RESIDUE - Risk reduction of chemical residues in soils and crops – impact due to wastewater used for irrigation

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Reclaimed wastewater use in agriculture has become a solution for feeding a global population pressure allied to climate change, and rising demand for food, what made fresh water for agricultural purposes an increasingly scarce resource. Arid and semiarid regions across the globe progressively rely on reclaimed wastewater for crop irrigation. Reclaimed wastewater makes up over 50% of the total irrigation-water used in Israel, 17% in Spain and 6% in California. The benefits of reutilizing wastewater include water conservation and an alternative source of organic matter and nutrients for the agro-environment. However, safety concerns regarding the use of reclaimed wastewater for crop irrigation have also been raised. For years, there was a concern about the contamination of ecosystems and arable land with organic pollutants such as endocrine-disrupting compounds, pharmaceuticals and other synthetic chemicals. In a recent report we have seen for the first time that active pharmaceutical residues have penetrated the food chain, which emphasizes the health concerns for the population as well as an urgent need of developing techniques to minimize risks associated with irrigation with treated wastewater. The main goal of the project is to improve the safety of agricultural products grown in countries which are obliged to use waste materials for irrigation and fertilization in agriculture. The concept of the project is not to set limits for this practice but to develop a technology with significantly reduced risks of transfer of organic contaminants into the agricultural products. The new technology will be based on i) the improvement of soil functions to enhance in situ the removal and detoxification of introduced organic pollutants, (ii) new production procedures for safe soil amendments and iii) a clear discrimination of non-bioavailable organic pollutants introduced

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Period of Implementations

Aug 1, 2020 - Jul 31, 2024

Total Budget

EUR 1.363.968,00



The goal of the project is to enhance food quality/security by an evaluation of the risks associated with agricultural techniques, using sewage sludge for soil fertilization and treated wastewater for irrigation. Associated contaminants may reach the soils and plants, representing a risk to the consumer. In the project, we develop an improved treatment of waste materials prior to spreading based on biochar techniques. We study the fate and distribution of selected relevant contaminants from treatment of the waste materials until crop harvest. 14C-radiolabelled contaminants allow an advanced evaluation to extend the risk assessment for transformation products and bound residues. As an integral part of the project, soil qualities and sustainable use of waste materials in agriculture will be an important result of the study. To ensure practical relevance of the project, advancement will be pursued by the involvement of stakeholders (farmers’ cooperatives, trade associations) to evaluate the applicability of the proposed technologies. A user manual will be prepared that can serve as guidance on how to implement the research results in agricultural practise. As countries like Israel have no choice to use waste materials in agriculture, the project will support the Israel export agricultural business. In Spain and Italy basically the same applies: the high rate of treated sewage sludge and wastewater used in agriculture raises the same concerns. For Germany, the results will be of high value for the safety and quality assessment of sewage sludge application in agriculture. It may find a broader application again if the risk for contamination decreases, because they bring valuable organic matter and plant nutrients to soil. This makes the project of extreme importance, because it will provide new insights into the risk associated to this agricultural practice, as related to chemical pollution and food-safety issues.


The objectives of this project are directly linked to the Topic 2.1.2. “Management of low-quality waters under water scarcity and climate change conditions” in the “Management of water” Call of Section 2 of the PRIMA Program. The objectives are linked directly with the fields of the topic. Water limitation is one of the most important factors for agriculture in most PRIMA countries. This is specially applicable to Israel, where, to take advantage of all available water sources, the effluent from wastewater treatment plants (WWTPs) is used widely for irrigation of fields. In this country, over 50% of the irrigation is done with treated wastewater. Recent reports indicate that the treated wastewater used for irrigation still contains organic pollutants. Some characterization with regard to heavy metal content and nutrients is actually done but monitoring of organic contaminants is missing completely. This lack of information constitutes a potential risk, because, for example, as in the case of other developed countries (with e.g. an up-to-date medical care), significant residues of pharmaceutical active ingredients occur in WWTP effluents. There is very little knowledge on the fate of these organic contaminants in irrigated soils and whether there is a risk for plant uptake after spreading onto agricultural fields. This is an important information for risk assessment on both environmental and consumer health. Further, in Israel 63.7% of the total sewage sludges produced are used for fertilization of agricultural soils. The fertilization issue is considered more important than the contamination risk, even if it is well-known that the sludges may be contaminated. In order to reduce the contaminant loading, all sludges have to be composted before spreading onto soils. However, there is usually no information on whether the composting process

Impact Pathway

The major innovation of this project is that, for the first time, it will convene experts from PRIMA countries on the environmental fate and metabolism of chemicals, soil functions, bioavailability, composting and biochar production (see proposal sections 3.3. - consortium as a whole- and 4.1. -Participants), to consider how wastewater and sewage sludge can be sensibly incorporated into agricultural practice under water scarcity. This can only be achieved in a collaborative PRIMA project scheme. The work described in this RESIDUE proposal is anticipated to open new market opportunities for agriculture in the areas of soil fertilization and irrigation. The use of sewage sludge and wastewaters in this context is widespread but not devoid of associated risks at present. We anticipate that the safe and knowledge-based use of these materials will optimize the performance of agricultural practices under water scarcity, what will be of tremendous interest under the current challenges caused by climate change and the growing world population. This will help to overcome a number of conceptual and technical problems found in the use of sewage sludge and wastewaters that limit the agricultural current applicability of this technology. The RESIDUE project will foster the safe use of wastewater in irrigation by focusing on three key issues: (i) The improvement of soil functions that lead to a minimized impact from irrigated wastewater by enhancing in situ the removal and detoxification of introduced organic pollutants. (ii) New production procedures for safe soil amendments based on sewage sludge, through biochar addition and composting. (iii) A clear discrimination of non-bioavailable organic pollutants introduced into soil through irrigated wastewater and treated sewage sludge, that are not taken up by plants and, therefore, do not constitute a risk for agriculture. The output from this project will be a ‘laboratory’ of interdisciplinary work that links water scarcity and agriculture. It is anticipated that the novel benefits of this RESIDUE proposal will be the development of a framework for the safe use of wastewater for irrigation. This process will enable (i) a more pragmatic approach to water management under water scarcity, (ii) cost reductions in water treatment through residue revalorization and reconsideration of wastewater depuration targets, and (iii) a more effective and sustainable agriculture.

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