Heterocyclic pharmaceuticals—those chemical compounds whose structure includes a ring with at least one atom other than carbon—are increasingly recognised as contaminants of emerging concern in water and soil systems. Recent reviews highlight their persistence, toxicity and the challenges posed for treatment, monitoring and safe reuse of reclaimed water.
Why this is relevant for NEWater
In the Mediterranean and semi-arid agricultural regions addressed by NEWater, the reuse of treated wastewater for crop irrigation and other non-potable applications presents an opportunity to save freshwater and recover nutrients. At the same time, ensuring such reuse is safe means we must account for “hard-to-remove” contaminants such as heterocyclic pharmaceuticals.
These compounds add complexity to the design of our low-energy, nature-based or hybrid treatment trains, because:
- They often resist conventional secondary treatment and can persist in effluents.
- Their presence may require additional polishing steps, such as adsorption, soil-filtering or constructed wetland units, which must be evaluated from a techno-economic and risk-perspective (linked to NEWater’s modelling & sustainability work).
- They pose potential risks to soil fauna, crop uptake, groundwater infiltration and hence to the overall sustainability and acceptability of reuse solutions.
Key technical challenges
- Persistence and pathways: Heterocyclic structures often degrade slowly, sorb to soils or sediments, or are transformed into metabolites that may still be active. sciencedirect.com
- Monitoring and prioritisation: Identifying which heterocyclic pharmaceuticals are most relevant for irrigation reuse sites (occurrence, toxicity, mobility) is a prerequisite for designing effective control measures.
- Polishing treatment design: For NEWater’s natural-based/low-energy systems to meet safety thresholds, we must test whether additional polishing is required for heterocyclic pharmaceuticals and under what conditions (soil type, crop, climate).
- Integration into decision-support: The modelling and sustainability tool-chain in NEWater must include removal efficiencies, cost impacts and risk metrics specific to heterocyclic pharmaceuticals in reuse scenarios.
Implications and next steps for NEWater
- Our outreach and stakeholder engagement will emphasise the need for monitoring and safe reuse criteria that account for emerging contaminants such as heterocyclic pharmaceuticals in reclaimed water.
- Our sampling campaigns at the pilot sites will now include targeted analyses of heterocyclic pharmaceutical compounds in addition to the priority pharmaceuticals already selected.
- The design of polishing units will test materials and nature-based systems (biochar, volcanic ash, constructed wetland beds) for their capacity to remove heterocyclic pharmaceuticals under irrigation reuse conditions.
- Data on removal rates, cost, energy use and residual concentrations will be fed into WP5 (Modelling, Social & Economic Benefit) to provide realistic treatment-chain scenarios for reuse across Mediterranean agroecosystems.
Reference
Baaloudj O., Scrano L., Bufo S.A., Modley L.-A.S., Lelario F., Zizzamia A.R., Emanuele L., Brienza M. (2025).
Environmental Fate, Ecotoxicity, and Remediation of Heterocyclic Pharmaceuticals as Emerging Contaminants: A Review of Long-Term Risks and Impacts.
Organics, 6(1), 1.
DOI: 10.3390/org6010001