Addressing wastewater reuse challenges in rural decentralized areas: Implementation of a solar chlor-photo-Fenton demonstration plant

Solar chlor-photo-Fenton (SCPF) proved to be an emerging process for reclaiming rural wastewater, effectively addressing the inherent variability in its complex composition. Successfully scaled up in a wastewater treatment plant (WWTP) for the first time, SCPF marks a significant step forward, representing the beginning toward a sustainable water reuse for crop irrigation in rural communities with small WWTPs. A 37-m 2 raceway pond reactor for SCPF was operated at 10-cm liquid depth and 1-h hydraulic residence time (HRT) treating 3.40 m 3 /h for two consecutive days during summer and winter. The performance of the technology was conducted in continuous mode under mild oxidation conditions (0.1 mM of ferric nitrilotriacetate, 0.73 mM of hydrogen peroxide and 0.13 mM sodium hypochlorite). The photoreactor design reduced mixing times, enabling short HRTs and thereby increasing process efficiency. SCPF achieved up to 60 % organic microcontaminant removal and produced water quality Class B according to the European Regulation for water reuse with undetectable levels of disinfection by-products (DBPs). The concentrations of trihalomethanes and haloacetic acids (< 1.8 and 8.3 μg/L, respectively) were well below the levels stipulated in the regulations (30 and 60 μg/L, respectively). The results highlight the commercial potential of the treatment providing confidence in the scalability and broader application for integration into decentralized water reuse systems. • A sustainable solution for wastewater reclamation in rural areas is proposed. • The technical viability of solar chlor-photo-Fenton was assessed at demonstration scale. • Solar chlor-photo-Fenton proved resilience in reclaiming rural wastewater. • Reclaimed water quality Class B was produced with ≈60 % microcontaminant removal. • Disinfection by-products mitigated, remaining well below regulatory thresholds.