Oral Presentation Society of Environmental Toxicology and Chemistry Australasia 2021

Assessing impacts from effluent and biosolids wastewater discharges on a marine receiving environment, a multiple lines of evidence approach (#14)

megan N priestley 1 , Zoe Rogers 1 , Daniel Livingston 1 , Katie Newton 2 , Harry Houridis 2 , Brett Miller 3
  1. Hunter Water, Newcastle, NSW, Australia
  2. Advisian, Newcastle, NSW, Australia
  3. Water Research Laboratory (WRL) UNSW, Sydney, NSW, Australia

A weight of evidence approach is a robust approach for water quality management including assessing impacts from wastewater discharges on receiving environments (ANZG, 2018).  Conceptually, potential impacts on aquatic environments from wastewater discharges are via pathways of alterations to water and/or sediments via nutrients, dissolved oxygen, pathogens, toxicants (both ‘traditional’ and emerging contaminants of concern) and particulate matter.  Whether impacts will occur from wastewater discharges is not only dependent on the quality of wastewaters but also the complexity of the receiving waters, so understanding hydrodynamics and other inputs is also very important. Burwood Beach Wastewater Treatment Works (WWTW), is located in Newcastle, NSW.  It is designed to provide preliminary and secondary (biological and UV) treatment of wastewater for an estimated population of 220,000.  Discharges of secondary effluent and biosolids are into the Pacific Ocean via 1.5km outfalls at a depth of ~22m.  Multiple studies have now been undertaken over the past decade to assess potential impacts from effluent and biosolids discharges on the marine receiving environment using a weight of evidence approach.  In particular, Marine Environment Assessment Programs (MEAPs), were completed in 2011-2013 and 2017-2019, in line with the WWTW Environmental Protection License (EPL) and NSW EPA regulatory requirements.  The MEAPs were based on a multi-disciplinary approach including hydrodynamic modelling and integration with studies on water and sediment quality, subtidal reef, fish and benthic infauna ecology, ecotoxicology and bioaccumulation.   This presentation will give an overview of the MEAP findings and other studies to date.