Evaluation of the proposed EU regulation on minimum requirements for water reuse for irrigation

Reuse of domestic waste water for irrigation could play an important role in water resource management. Waste water is already often indirectly reused in agriculture by irrigating with surface water in which treated waste water is discharged and diluted. In direct water reuse, waste water is treated to such an extent that it is suitable for irrigation. The European Commission has published a proposed regulation for direct water reuse for irrigation with the aim to support responsible reuse of waste water for irrigation purposes by harmonized minimum quality requirements and risk management. The proposed regulation also specifies processes related to permits and obligations on the sharing of information on reuse. Researchers from KWR Watercycle Research Institute have evaluated the performance of the proposed regulation in the Dutch context, focusing on microbial and chemical risks, and the performance of the
regulation for water reuse in the Netherlands. It is concluded that the proposed regulation is very generic The minimum quality requirements that are specified focus only on general quality and public microbial health. Specific comments are made about these minimum requirements and where they might fall short to adequantely protect human health. No minimum requirements for chemicals are specified. The Water Reuse Risk Management Plan, which is a multidisciplinary and exhaustive task, should determine if/which minimum requirements for specific chemicals in specific settings are needed to manage public health and environmental health risks. However, this is costly and requires expertise that likely exceeds that of the responsible stakeholders. The reference situation for irrigation of crops in the Netherlands is the use of groundwater or surface water. Especially the latter that can be impacted by discharges of urban waste water treatment plants. Intentional reuse generally offers better control and management possibilities than such de facto reuse. However, intentional reuse conforming to the proposed regulation asks for a detailed understanding of the benefits and risks of reuse for agricultural practices. As this requires specific expertise and is costly, the proposed regulation might unintendedly stimulate indirect reuse. Our main recommendation is to provide more (supra)national guidance information to support operators and regulators to efficiently prepare Water Reuse Risk Management plans that are sufficiently protective for human and environmental health.