Removal of pharmaceuticals in biological wastewater treatment plants

Providing sufficiently clean water to the public has become a challenging issue worldwide as the quality of water sources increasingly deteriorates.¹ As a consequence, treated wastewater has attracted attention as an alternative water resource, provided appropriate treatment can be applied.² Therefore, the removal of microcontaminants, such as pharmaceuticals and personal-care products, in wastewater is critical because many of these compounds survive conventional treatment.³ In general, these compounds are present at parts per billion (ppb) levels or less in wastewater.^4,5 Although these concentrations are much lower than the levels of traditionally known organic pollutants (such as the persistent organic pollutants DDT, PCBs, and the like) the potential long-term effects of these compounds to humans and wildlife cannot be neglected. For example, several studies have shown that even parts per trillion (ppt) levels of ethinyl estradiol (the active ingredients of birth control pills) and natural estrogens can disrupt the hormone system of aquatic species.^6,7 In addition, low levels of antibiotics from the effluents of wastewater treatment plants (WWTPs) can promote antibiotic resistance in microorganisms that are exposed constantly to these compounds.^8–10