Removal of endocrine disruptors by tertiary treatments and constructed wetlands in subtropical Australia

Abstract

The controversial topic of endocrine disrupting chemicals (EDC) in aquatic environments is of international and Australian significance with the need for sustainable management of water resources increasing. The issues have been highlighted on the major continents of Europe and North America but so far have received less attention in Australia. A major source of these compounds has been identified as sewage effluent, which is treated prior to release to the environment with a primary focus on pathogen and nutrient removal. Sewage effluent is a complex mixture, which can contain many organic and inorganic compounds some of which may remain after treatment processes. More recently, technologies such as ozonation, UV treatment and advanced filtration have improved the quality of effluent discharged to the environment but there are still unresolved issues relating to poorly understood chemistries relating to EDCs in effluent discharges and the possible impacts in aquatic environments and to human health. This paper reports on an investigation of the removal from sewage effluent of selected chemicals that are known or suspected environmental endocrine disruptors (EEDs) by sand filtration, ozonation and UV treatment at the Landsborough Water Reclamation Plant in Queensland, Australia. Compounds detected in the raw effluent included pesticides, herbicides, some heavy metals and the human hormones 17bestradiol and estrone. Most of these were removed by the advanced treatments at the water reclamation plant, with only trace concentrations of some compounds present in the final effluent. Removal of toxicants by a free water surface wetland is also reported on. Some of the constraints of direct chemical measurements are discussed and some solutions proposed.