Licence conditions for pollution studies and reduction program


  

Licence conditions for pollution studies and reduction programs

Summary
 
Licence number: 4627
Title: Assessment and Management of Hazardous Ground Gases Background
Start date: 31 May 2021
 
Licence Condition
Objectives The licensee will undertake a revised hazardous ground gases risk assessment (“the assessment”) for the land subject to the St Peters Interchange – Landfill Closure Management Plan (LCMP) (4 August 2017). The objectives of the assessment are to: a) Assess the hazards posed by landfill gas at the premises in the form of multi-tiered risk assessments for emissions of landfill gases through sub-surface, surface or in building accumulation in accordance with the NSW Contaminated Land Guidelines: Assessment and Management of Hazardous Ground Gases (2020) and other guidelines made and approved under s105 of the Contaminated Lands Management Act 1997 that are applicable; b) Assess all landfill monitoring data collected both prior to and following the previous hazardous ground gases risk assessment “Construction and Permanent Works Hazardous Ground Gas Risk Assessment” undertaken by Epic in June 2020; and c) Revise the hazardous ground gases risk assessment prepared by Epic in June 2020 to include recent monitoring data and works.
Development of the Hazardous Ground Gases Risk Assessment By 16 March 2022 the licensee must submit a report to the EPA which details the outcomes of the revised hazardous ground gasses risk assessment at the premises. The assessment must: 1. Assess all landfill monitoring data for the land subject to the LCMP which has been collected since the hazardous ground gases risk assessment undertaken by Epic in June 2020. This includes but is not limited to monitoring data collected in accordance with: the LEMP; the “St Peters Interchange Subsurface Gas Management – Contingency Plan” prepared by Golder Associates Pty Ltd (December 2020); “St Peters Interchange Northern Share Path Monitoring” prepared by TfNSW (April 2021); and any other additional monitoring undertaken; 2. Provide an updated Conceptual Site Model (CSM) that identifies all sources, pathways and receptors of hazardous ground gases from the premises; 3. Address all potential sources, pathways and receptors for landfill gas migration. The source assessment should consider the types of wastes, the size of the landfill, the gas generating potential, monitoring results, gas volumes and flow rates; 4. Delineate the extent of migration of hazardous ground gases from the premises and provide a map containing relevant contours including, but not limited to, details such as Lower Explosive Limit (LEL) and Upper Explosive Limit (UPL) concentrations; 5. Assess the risk to human health and the environment for both onsite and offsite receptors; 6. Assess the operational performance of the hazardous ground gas controls and management practices at the premises against best practice; 7. Evaluate additional best practice controls and mitigation measures for hazardous ground gases where identified exceedances are occurring that pose a risk to human health or the environment; 8. Using the evaluation of best practice controls in (6), recommend measures to manage the identified risk including any contingencies should the risk profile change; 9. Provide a timeframe for the implementation of any required additional controls and mitigation measures; and 10. Be reviewed by an EPA accredited Site Auditor who must provide interim site auditor advice regarding the suitability and appropriateness of the assessment and any proposed mitigation or management measures.