An innovate two-stage Nature-Based Solution for Optimization Leachate Reuse, Water Quality Compliance and Biodiversity Enhancement in European Greenhouse Agriculture. Project 101293832 — LIFE25-ENV-ES-LIFE BIOWET

BIOWET tackles a major challenge in European agriculture: nitrate and phosphorus pollution from intensive greenhouse production. The rapid expansion of greenhouses, especially in Spain,  Italy, and the Netherlands, has increased nutrient leaching into water bodies, causing eutrophication, biodiversity loss, and declining water quality. Hydroponic systems, though efficient, generate nutrient-rich leachates that are seldom reused due to salt build-up, nutrient imbalances, and pathogen risks. Current treatment options are costly, energy-intensive, or unsuitable, highlighting the need for sustainable, affordable, and scalable solutions consistent with the Nitrates Directive and the Water Framework Directive. The project proposes a two-stage, nature-based system combining woodchip denitrification bioreactors with constructed wetlands. It removes over 80% of nitrates and up to 70% of phosphates while reducing pathogens, enabling safe water reuse in fertigation, compliance with standards for alternative uses, or secure discharge when reuse is not feasible. The modular, scalable system will be demonstrated on two pilot farms in southeastern Spain. Circular economy principles are applied through sustainable materials, gravity-driven flow, and renewable energy, minimizing energy demand and carbon footprint. It will provide key benefits: improved water quality in Nitrate Vulnerable Zones, reduced fertilizer use and freshwater abstraction, controlled nutrient losses, creation of wetland habitats that foster biodiversity, optimized water management, and increased farm profitability. Knowledge transfer via training, workshops, and demonstration events will support uptake. With replication potential across 200,000 hectares of greenhouse agriculture, BIOWET shows high scalability. An ambitious communication strategy will ensure EU-level visibility, policy alignment, and long-term sustainability.