Hospitals discharge considerable amounts of chemicals and microbial agents in their wastewaters. Problem chemicals present in hospital wastewater belong to different groups, such as antibiotics, X-ray contrast agents, disinfectants and pharmaceuticals. Many of these chemical compounds resist normal wastewater treatment. They end up in surface waters where they can influence the aquatic ecosystem and interfere with the food chain. Humans are particularly exposed by the drinking water, produced from surface water. Microbial agents of special concern are multi-resistant microbial strains. The latter are suspected to contribute to the spread of antibiotic resistance. Hospital wastewater constitutes a major discharge of chemicals, but it is not unique in this respect. Residues of pharmaceuticals can be found in all wastewater treatment plant (WWTP) effluents, due to their inefficient removal in the conventional systems. Besides recalcitrant and potent chemicals, hospitals discharge plenty of undesired potentially pathogenic propagules, e.g. antibiotic resistant bacteria, viruses and maybe even prions, etc.
Increased biodegradability of cephalosporine, penicillin and quinolone after ozonation or O3/H2O2 treatment have been observed. Ozonation is very effective in removing carbamazepine and diclofenac, decreased bezafibrate and primidone concentration levels considerably.