Introduction
Micropollutants are increasingly talked about, often with some confusion. These substances found in water at infinitesimal quantities — microgram or nanogram per litre — have a real, documented impact on aquatic ecosystems and potentially on human health.
Pharmaceuticals, pesticides, PFAS, endocrine disruptors, cosmetics, industrial residues: the sources are multiple, the molecules number in the thousands, and conventional treatment plants are not designed to remove them. France has structured its response through the National Micropollutants Plan, while the EU has considerably tightened its regulatory requirements.
I. What is a micropollutant?
A micropollutant is a substance present at very low concentrations (µg/L or ng/L) capable of harming living organisms and ecosystems. Main families: pharmaceutical residues, pesticides and biocides, PFAS ("forever chemicals"), endocrine disruptors, heavy metals, microplastics, and personal care products.
Conventional WWTPs are designed for carbonaceous organic pollution: between 30 and 90% of micropollutants pass through them, with PFAS passing almost entirely through classical treatment trains.
II. The regulatory framework
France’s National Micropollutants Plan targets source reduction and improved treatment performance. The Water Framework Directive lists 45 priority substances (since Directive 2013/39/EU) subject to Environmental Quality Standards. A revision adopted by the Council of the EU in February 2026 adds new substances, including PFAS, bisphenols, pharmaceutical residues and pesticides, and tightens several existing standards.
The new Urban Wastewater Treatment Directive, Directive (EU) 2024/3019, adopted at the end of 2024 and to be transposed by July 2027, requires a fourth level of treatment (4T) for all WWTPs of 150,000 PE and above by the end of 2045 (20% of plants by 2033, 60% by 2039), and for plants above 10,000 PE discharging into at-risk areas by the same deadline. It also introduces extended producer responsibility: pharmaceutical and cosmetic manufacturers will fund at least 80% of quaternary treatment costs. For industrial operators, ICPE emission limit values evolve regularly based on BAT Reference Documents.
III. Priority substances to monitor
Local authorities (urban WWTPs): pharmaceutical residues (antibiotics, hormones), PFAS, urban pesticides, microplastics.
Food industry: biocide residues, process-specific organic compounds.
Chemical and pharmaceutical industries: active pharmaceutical ingredients, chlorinated solvents, PFAS, metals.
IV. How to prepare concretely
Step 1 — Discharge diagnostic: extended analytical monitoring programme beyond standard parameters (BOD, COD, TSS).
Step 2 — Source reduction: substitute hazardous substances, optimise processes, treat concentrated streams separately before dilution.
Step 3 — Complementary treatment: activated carbon, ozonation, nanofiltration — see our dedicated article on available technologies.
Step 4 — Anticipate regulations: operators who anticipate reduce their costs and risks.
V. Nomado supports you
Nomado intervenes on micropollutant issues through diagnostic and monitoring programmes, design of tertiary and quaternary treatment solutions in compact modular units, regulatory compliance support, and the WaaS model for operators wishing to outsource treatment and compliance guarantees.
FAQ
1. Which micropollutants are most regulated in France? The 45 WFD priority substances. The list has just been extended (revision adopted in early 2026) to include PFAS and pharmaceutical residues.
2. Are small rural WWTPs affected by the 4T requirement? Not directly: the obligation targets WWTPs of 150,000 PE and above, and plants above 10,000 PE discharging into at-risk areas, by the end of 2045. Smaller plants must still anticipate, particularly on PFAS.
3. How do I know if my discharges contain micropollutants? Through a specific analytical programme using accredited laboratories capable of measuring concentrations at the ng/L scale.
4. Who finances micropollutant treatment investments? Water Agencies, producers of pharmaceuticals and cosmetics (at least 80% of quaternary treatment costs under the new UWWTD), and European Green Deal funding.
5. Can Nomado intervene in existing WWTPs? Yes — modular complementary treatment units adaptable without full reconstruction.
