Ozonation of hospital raw wastewaters for cytostatic compounds removal. Kinetic modelling and economic assessment of the process

- 17 cytostatic compounds were analysed and 4 detected by SPE-LC/MS-MS.
- The ozonation is 100% effective on the removal of the detected cytostatics.
- The kinetics of cytostatic ozonation reaction is modeled by competitive kinetics.
- The economic cost of the treatment of hospital wastewater was assessed.

The kinetics of the ozone consumption for the pretreatment of hospital wastewater has been analysed in order to determine the reaction rate coefficients between the ozone and the readily oxidisabled organic matter and cytostatic compounds. The wastewater from a medium size hospital was treated with ozone and peroxone methodologies, varying the ozone concentration, the reaction time and the hydrogen peroxide doses. The analysis shows that there are four cytostatic compounds, i.e. irinotecan, ifosfamide, cyclophosphamide and capecitabine, detected in the wastewaters and they are completely removed with reasonably short times after the ozone treatment. Considering the reactor geometry, the gas hydrodynamics, the mass transfer of ozone from gas to liquid and the reaction of all oxidisable compounds of the wastewater it is possible to determine the chemical ozone demand, COzD, of the sample as 256 mg O3 L− 1 and the kinetic rate coefficient with the dissolved organic matter as 8.4 M− 1 s− 1. The kinetic rate coefficient between the ozone and the cyclophosphamide is in the order of 34.7 M− 1 s− 1 and higher for the other cytostatics. The direct economic cost of the treatment was evaluated considering this reaction kinetics and it is below 0.3 €/m3 under given circumstances.

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