PROJECT Next-generation electrochemical technology for the treatment of hospital wastewater: electrogenerated sulfate radicals for complete destruction of persistent pollutants


FP7-PEOPLE - Specific programme 'People' implementing the 7FP. MC-IIF - International Incoming Fellowships.




Catalan Institute for Water Research (ICRA)


Mira Petrovic


Jelena Radjenovic



Hospital wastewater effluents have been identified as the primary sources of DNA-damaging compounds, and are considered as the major source of antibiotic resistance in the environment. They exhibit significantly higher pollution, up to 3,500 mg/L of chemical oxygen demand, compared to municipal sewage (i.e., 100-500 mg/L).

There is no established technology for the treatment of hospital wastewater. Biological treatment is incapable of degrading more persistent contaminants, e.g., organohalogens, cytostatics, and antibacterial agents. Reverse osmosis membranes are very energy intensive, and generate large amounts of retentate that requires further treatment. The major constraint of chemical oxidation processes is the requirement for high chemical dosages for heavily polluted hospital wastewater.

This project proposes a next-generation technology for the treatment of contaminated hospital wastewater, based on the electrochemical generation of sulfate and hydroxyl radicals. Highly oxidizing sulfate and hydroxyl radicals are formed by applying current to an anode at atmospheric temperature and pressure. Sulfate radicals react mainly through electron transfer and hence are less subject to scavenging by the background matrix, which allows their accumulation in the solution and drastically enhances the oxidation efficiency.

The process offers several important advantages over existing oxidation technologies as it does not generate secondary pollution, has no pH limitations and does not require any external activators (e.g., iron). The project will develop a novel, clean platform technology for hospital wastewater remediation, yet applicable to the treatment of other types of contaminated waste streams, e.g., industrial wastewater.

The main research objectives of this project are:

(i) Evidencing the electrogeneration of sulfate radicals using probe compounds and radical scavengers.
(ii) Investigation of electro-oxidation for the removal of target pollutants – comparison of hydroxyl and sulfate radical oxidation kinetics.
(iii) Fundamental understanding of electro-oxidation pathways of target pollutants induced by hydroxyl and sulfate radical, and study of the effects of hospital wastewater constituents on the process performance.
(iv) Determination of optimum process design in terms of contaminants removal and low energy consumption in the onsite hospital wastewater treatment.


1. Ali Farhat, Jürg Keller, Stephan Tait, and Jelena Radjenovic. Removal of Persistent Organic Contaminants by Electrochemically Activated Sulfate, Environmental Science and Technology, 2015, in press, DOI: 10.1021/acs.est.5b02705.

2. Jelena Radjenovic and David L. Sedlak. Challenges and Opportunities for Electrochemical Processes as Next-Generation Technologies for the Treatment of Contaminated Water, Environmental Science and Technology, 2015, 49 (19), 11292–11302.

Conference presentations:

1. Jelena Radjenovic, Ali Farhat and Mira Petrovic. Degradation of iodinated contrast media and other persistent organic contaminants by electrochemically activated sulfate, 9th IWA Specialist Conference on Assessment and Control of Micropollutants and Hazardous Substances in Water, 22-25 November, 2015, Singapore. 2 2
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