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 multiresistant microbial strains. The latter are suspected to contribute to the spread of antibiotic resistance. In this paper, we will discuss the different approaches towards hospital wastewater treatment. The principle of uncoupling hospitals from public sewers warrants indepth evaluation by technologists and ecotoxicologists as well as public health specialists.

INTRODUCTION

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 (Ku¨ mmerer 2001; Kolpin et al. 2002; Petrovic et al. 2003; Snyder et al. 2003; Carballa et al.
2004). It is difficult to distinguish between pharmaceuticals which originate from hospitals connected to the sewer and
from household users. For substances such as iodinated X-ray contrast media, which are used for X-ray imaging of
soft tissues, the hospital source is obvious. Non-prescription drugs are mainly used in hospitals (Kolpin et al., 2002), but
in households as well. Besides recalcitrant and potent chemicals, hospitals discharge plenty of undesired potentially pathogenic propagules, e.g. antibiotic resistant bacteria, viruses and maybe even prions, etc. There may arise situations where a total exclusion of emission from the hospital is required, for instance in the case of multiple antibiotic-resistant strains (MARS).