Environmental Project, 899 – Degradation af estrogens in sewage treatment processes

Degradation of Estrogens in Sewage Treatment Processes

1 Introduction

1.1 Background

During the last few years, there has been a growing scientific and public interest and concern about the possible impacts of female hormones (estrogens) and other so-called endocrine disruptors that are emitted to the aquatic environment where they can cause disturbances in the sexual differentiation of fish and amphibians (typically feminisation). Public sewage treatment plants (STPs) are believed to be a major source of estrogen release into the aquatic environment.

The Danish Minister of Environment recognises the need for more information and generation of new knowledge within this field and, therefore, the Danish Environmental Protection Agency (DEPA) has funded and initiated a number of studies on the occurrence, fate and impacts of estrogenic substances in the (aquatic) environment, e.g. a review on feminisation in fish (DEPA 2002) and a study on the occurrence and levels of estrogens in influents and effluents of selected Danish STPs (DEPA 2003a).

A number of studies have been published internationally during the last approximately five years, which document the presence of natural and synthetic estrogens in raw sewage as well as in the effluents from STPs and, in very low concentrations, in receiving water bodies. However, detailed studies of the fate of these substances on their way through the different stages of sewage treatment are still sparse and need to be understood better if estrogen removal at Danish STPs is to be improved.

1.2 Objectives

The objective of the present project is to generate more knowledge about the fate of natural and synthetic estrogens during traditional treatment processes employed at common municipal Danish STPs for urban sewage.

The results of the investigations will provide knowledge about the ability of the key treatment processes to remove estrogens from the sewage. This knowledge can form the basis e.g. for later estimation of the discharges of estrogens from the STPs to the aquatic environment and/or be used to assess how the design and operation of STPs can be optimised in terms of removal of these substances and thereby minimisation of the load on the environment.

1.3 Organisation

The project has been carried out in collaboration between the Danish Pharmaceutical University (DFU) and COWI A/S. COWI has been responsible of the project management and co-ordination, and of general descriptive and editing activities while DFU has been in charge of the experimental investigations.

The following persons have participated in the project:

DFU	Bent Halling-Sørensen (scientifically responsible at DFU) Henrik R. Andersen Martin Hansen Flemming Ingerslev
COWI:	Frank Stuer-Lauridsen (PM until 31 October 2003) Jesper Kjølholt (PM from 1 November 2003) Thomas Dueholm Blicher

Line W. Hollesen was the project responsible person at DEPA (Office of wastewater and water supplies), and, further, a steering committee was formed for which - in addition to DEPA, COWI and DFU - the following external persons were appointed:

Bo Neergaard Jacobsen, DANVA (Danish Water and Waste Water Association)
Gunnar Tholstrup, Office of Environment, Århus Municipality
Thomas Plesner, County of Århus.

The project was initiated in August 2003 with a kick-off meeting between DEPA, COWI and DFU. In mid September 2003 a status and progress report outlining the remaining experimental activities was forwarded and approved by DEPA. The steering committee discussed the work and the results hereof at a meeting on 25 November 2003, and has afterwards commented on the draft final report.

The Municipality of Århus has kindly placed the Egå STP at the project team's disposal for sludge sampling and is greatly acknowledged for providing resources and transport in relation to the sampling in the autumn of 2003.