Licence conditions for pollution studies and reduction program


  

Licence conditions for pollution studies and reduction programs

Summary
 
Licence number: 2504
Title: Assessment of Residual Toxicity in Discharges from Points 24 and 40
Start date: 30 Nov 2023
 
Licence Condition
Pollution Study – Assessment of Residual Toxicity in Discharges from Points 24 and 40 Background The licensee completed works required under condition E1.1 - Installation of a water treatment plant at Appin North and modification of the Appin West water treatment plant.  Reverse osmosis technology was adopted by the licensee to meet the discharge performance criteria in table 2 of condition E1.1. Condition E2.1 required monitoring of the toxicity of discharges from points 24 and 40 for a period of up to 2 years following commencement of operation of the water treatment plants. In response a report was submitted to the EPA titled ‘Ecotoxicity assessment of LPD 24 from Appin Colliery WTP, 8 June 2023’.  The report found that the discharge from point 24 did not meet the toxicity assessment criterion in condition E2.2 for 4 out of 7 months that were monitored.  The criterion exceeded was EC10 reproduction >100% sample for the Ceriodaphnia dubia test species. This EPA considers that additional work is required to assess residual toxicity in LDP 24 and 40. Requirement The Licensee must engage a suitably qualified and experienced person to undertake an investigation into toxicity in discharges from licence discharge points 24 and 40. The investigation must include consideration of the following as a minimum. •  Identification of the cause(s) of toxicity using laboratory analysis and techniques such as toxicity identification evaluation. •  An assessment of whether the discharges are likely to cause an in-stream environmental impact following discharge, and estimation of the downstream level and extent of any impact. •  Treatment processes or other management options to meet the toxicity assessment criteria “EC10 reproduction >100% sample for the C. dubia test species” in the receiving environment.  (These options should not significantly compromise treated water quality or lead to exceedances of licence limits for points 24 and 40). •  If necessary, a program with an indicative timeframe to reduce the toxicity to meet the assessment criteria and a monitoring program to demonstrate that discharges from points 24 and 40 are not toxic following completion of the program. By the due date, the licensee must submit a report to the EPA containing the findings of the investigation. Due Date:  30 April 2024