Modern technologies can reliably deliver acceptable effluent quality in a way that is economical and practical. Therefore, for some lower-risk wastewater treatment plants (WWTPs), a standardised approach can be applied to developing discharge requirements. This makes it simple to understand what effluent quality is acceptable, and easier to plan upgrades to achieve this effluent quality.
The Emission Limit Guidelines for Sewage Treatment Plants that Discharge Pollutants in Fresh and Marine Waters June 2001 (ELGs) describe this standardised approach.
Emission Limit Guidelines for Sewage Treatment Plants that Discharge Pollutants into Fresh and Marine Waters, June 2001 (65Kb)
The ELGs apply to WWTPs that:
- receive less that 500 kL of wastewater per day;
- discharge effluent into fresh or marine waters, because sustainable full reuse has been assessed and is not feasible;
- discharge into receiving waters where the lowest seasonal median flow offers a dilution factor of at least 80; and
- do not discharge into a pristine environment, or a lake, or a wetland.
Based on these criteria, the ELGs apply to nearly half of the Level 2
(EPA-regulated) WWTPs in Tasmania and to all Level 1 (council-regulated) WWTPs that discharge to waterways. All WWTPs to which the ELG applies must achieve the given effluent quality standards within reasonable timeframes.
The EPA must be consulted where the ELGs do not apply, to determine site-specific effluent quality requirements.
The ELGs for WWTPs were developed by the EPA as a requirement of the State Policy on Water Quality Management 1997 (SPWQM).