Economic evaluation of the photo-Fenton process. Mineralization level and reaction time: the keys for increasing plant efficiency.

The use of the solar photo-Fenton process is proposed to degrade Paracetamol in water in order to form biodegradable reaction intermediates which can be finally removed with a downstream biological treatment. Firstly, biodegradability enhancement with photo-Fenton treatment time has been evaluated; the minimum mineralization level should be at least 18.6% where Paracetamol has been degraded and biodegradability efficiency is higher than 40%. 20 mg L(-1) of Fe(2+) and 200 mg L(-1) of H(2)O(2) were selected in a lab-scale study looking at Paracetamol's degradation rate and organic carbon mineralization rate. As a result of scaling up the process at a pilot plant, 157.5 mg L(-1) of Paracetamol (∼1 mM) was treated in 25 min of photo-Fenton treatment achieving the desired biodegradability. A further economic evaluation shows how the proposed treatment strategy markedly increases plant efficiency, resulting in an 83.33% reduction in reagent cost and a 79.11% reduction in costs associated with reaction time. Total cost is reduced from 3.4502 €/m(3) to 0.7392 €/m(3).