Rehabilitation Plan
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Appendix O – Rehabilitation Plan GHD | Report for Latrobe City Council –Hyland Highway Landfill Extension, 3136742 Latrobe City Council Hyland Highway Landfill – Rehabilitation Plan Prepared By: Chandana Vidanaarachchi - Latrobe City Council Reviewed By: John Nolan - Nolan Consulting Pty Ltd 1 INTRODUCTION Hyland Highway Landfill is owned and operated by Latrobe City Council under the licence 25565 as amended on 17 August 2018 and issued by Environmental Protection Authority (EPA) Victoria. The landfill is licenced to accept putrescible waste, solid inert waste, asbestos waste of domestic origin and tyres shredded into pieces <250 mm into Cell 4 and Cell 5. The landfill is located at 64 Hyland Highway Loy Yang. It consists of 6 cells on a footprint of 8.2 Ha, with approved capacity of 960,000 cu.m. Landfill Cells 1, 2, 3A and 3B have been completely filled, Cell 4 is partially filled and waste is currently being accepted in Cell 5. Cell 6 is the final cell under the existing works approval. It is yet to be constructed. 2 STATUTORY REQUIREMENT 2.1 LICENCE CONDITION EPA Licence Condition LI_L22 states that You must implement a rehabilitation plan for the landfill. The plan must: a) be revised after each cell is full, if necessary; b) meet the requirements of Section 8 of Best Practice Environmental Management (BPEM), Siting, Design, Operation and Rehabilitation of Landfills (EPA Publication 788.3, released August 2015); c) set timeframes for placement of final capping of all completed cells, calculated from the date that the cell became full; and d) set timeframes for the progressive capture and treatment of landfill gas and leachate from each completed cell. This Rehabilitation Plan addresses the above licence requirement including the Section 8.1.1 of the BPEM Requirement that the plan should include: • the potential afteruses of the site, taking into consideration current and likely future land use in the area surrounding the site • operational requirements, to ensure that the capping is designed to suit the intended afteruse • surface contours before and after settlement • specifications and materials to be used in the final cap • Preservation/installation of environment performance control or monitoring features. 3 AFTERUSE The likely afteruse of the site, taking into consideration current and likely future land use in the area surrounding the site is public open space. This would become available when the landfill is closed and the land is revegetated with native species. The site which includes the landfill footprint is owned by Latrobe City Council and is approximately 100 Ha. Due to steep slopes and landfill gas infrastructure the landfill footprint will be fenced off as it is unsuitable for public access. This would be reviewed once the obligations under any post closure pollution abatement notice are compiled with. Beyond the site the adjacent motor cycle club is used for racing events. 4 SURFACE CONTOURS BEFORE AND AFTER SETTLEMENT The before settlement contour plan across all cells is that provided in Schedule 1C of the licence. It is the top of waste pre-settlement contour plan (PSCP) and is given in Appendix A with cross sections. As the landfill is considered to be well compacted, the settlement is expected to range from 10% to 20%. An after settlement contour plan will be prepared upon landfill closure which would allow for a projection from the settlement that would have occurred by that time. 5 REHABILITATION COMPLETED The progressive rehabilitation of the landfill commenced in the 2014/15 financial year with the Stage 1 cap. This involved the capping of the western two thirds of Cells 1 and 2. The 1.2 Ha capped area is shown as Stage 1 capping in the attached plan. The rehabilitation works which was completed by June 2015 included the construction of a BPEM compliant cap and installation of landfill gas management system. The Stage 1 landfill gas management system included 14 landfill gas extraction bores and a gas flare. The constructed Stage 1 cap consisted of (from bottom up): Gas collection trench Sub-grade GCL Geomembrane Cushion Geotextile Sand Drainage Layer 300 mm thick Subsoil minimum 700 mm thick Topsoil Vegetation Figure1 : Stage 1 Cap Profile The Stage 2 capping works commenced in the 2016/17 financial year and were completed in July 2017. This involved the completion of the capping of Cells 1 and 2 and 90% of Cell 3. The works involved construction of BPEM compliant cap and the installation of 11 landfill gas extraction bores and connect them to the existing gas flare. The constructed Stage 2 cap consisted of (from bottom up) Gas collection trench Sub-grade GCL Geomembrane Geocomposite Subsoil Topsoil Vegetation Where the cap slope exceeded 5%, Geogrid was placed to improve the sub-soil stability. 6 TIMEFRAMES FOR THE PLACEMENT OF FINAL CAPPING The tentative timeframe for future landfill capping is shown in below and in Appendix B. The required funding has been allocated for this works in the council’s long term financial plan. Table 1: Landfill Capping Schedule Capping Landfill Cell Expected time Expected time of Expected Time of stage of filling Rehabilitation Gas Infrastructure completed commenced Installation 3 Cell 3 Jun 2018 Sep 2019 Jul 2019 Remaining 10% 4 Cell 4 Sep 2021 Jul 2021 Jul 2021 5 Cell 5 Sep 2023 Jan 2024 Jan 2024 6 Cell 6 Sep 2024 Jan 2025 Sep 2024 Each stage of capping will consist of a BPEM compliant cap and the installation of additional landfill gas extraction bore connected to a flare with adequate flaring capacity. Stage 3 capping works are proposed to commence in the 2019/20 financial year. When stage 3 capping is completed the cells 1, 2 and 3 will be entirely capped. Cell 4 will be ready for capping when waste acceptance in Cell 5 ceases. The timetable for capping presented in Table 1 assume site operational requirements allow Cell 5 to be completely filled by September 2023. If this is not possible Cell 5 will be capped with Cell 6. 7 MATERIALS TO BE USED IN THE FINL CAP The landfill cap for Stages 3 to 6 will be designed to meet BPEM requirements and also to satisfy overall stability of landfill. The Stage 3 cap will consist of (from bottom up) Gas collection trench Sub-grade GCL Geomembrane Geocomposite Subsoil Topsoil Vegetation Where the cap slope exceeds 5%, Geogrid has been placed to improve the sub- soil stability. Figure 2: Cell 3 Cap Profile (Steep Sections) Figure 3: Cell 3 Cap Profile (General) It is anticipated that the Stage 4, 5 and 6 cap will have a similar material specification. 8 LANDFILL GAS AND LEACHATE MANAGEMENT 8.1 LANDFILL GAS MANAGEMENT A plan showing the landfill gas management system is shown in Appendix C. The gas management system will be expanded with the landfill capping program. The gas wells will be installed simultaneously with the landfill capping of each completed cells. 8.2 LEACHATE MANAGEMENT All the landfill cells (current and future) have/will have a leachate collection system with network of leachate collection pipes, 300 mm thick drainage aggregate layer, a sump, riser pipe and submersible pump and will comply with the leachate related licence conditions. This setup can handle leachate over a period of time until leachate load become negligible. The collected leachate will always be appropriately treated. 9 MONITORING Monitoring of Groundwater, Surface water, Landfill Gas and Leachate will be continued as per the verified monitoring program during the operational period and aftercare period. Any changes to monitoring requirement will be made in consultation with Environmental Auditor and EPA. 10 REVISIONS This rehabilitation plan will be revised after each cell is full, as if necessary, and after any future extension of the landfill following a works approval. APPENDIX 1 SURFACE CONTOURS BEFORE SETTLEMENT LANDFILL FORM – Cross Sections E&F APPENDIX 2 HYLAND HIGHWAY LANDFILL – CAP CONSTRUCTION STAGES CELL 1&2 CELL 3 CELL 1&2 ff, §: O' Qj,'! ' IS' , ° ()'0/ '-0 1:', CELL 4 �.' /1 � ... �� Cap Stage boundaries Cell boundaries Stormwater c:::::::::J Stage 1 capping completed in 2015 Jun Pond c:::::::::J Stage 2 capping completed in Jun 2017 c:::::::::J Stage 3 capping � Cell 4 capping c:::::::::J Cell 5 capping c:::::::::J Cell 6 capping s APPENDIX 3 HYLAND HIGHWAY LANDFILL LANDFILL GAS INFRASTRUCTURE Latrobe City Council Hyland Highway Landfill – Rehabilitation Plan Prepared By: Chandana Vidanaarachchi - Latrobe City Council Reviewed By: John Nolan - Nolan Consulting Pty Ltd 1 INTRODUCTION Hyland Highway Landfill is owned and operated by Latrobe City Council under the licence 25565 as amended on 17 August 2018 and issued by Environmental Protection Authority (EPA) Victoria. The landfill is licenced to accept putrescible waste, solid inert waste, asbestos waste of domestic origin and tyres shredded into pieces <250 mm into Cell 4 and Cell 5. The landfill is located at 64 Hyland Highway Loy Yang. It consists of 6 cells on a footprint of 8.2 Ha, with approved capacity of 960,000 cu.m. Landfill Cells 1, 2, 3A and 3B have been completely filled, Cell 4 is partially filled and waste is currently being accepted in Cell 5. Cell 6 is the final cell under the existing works approval. It is yet to be constructed. 2 STATUTORY REQUIREMENT 2.1 LICENCE CONDITION EPA Licence Condition LI_L22 states that You must implement a rehabilitation plan for the landfill. The plan must: a) be revised after each cell is full, if necessary; b) meet the requirements of Section 8 of Best Practice Environmental Management (BPEM), Siting, Design, Operation and Rehabilitation of Landfills (EPA Publication 788.3, released August 2015); c) set timeframes for placement of final capping of all completed cells, calculated from the date that the cell became full; and d) set timeframes for the progressive capture and treatment of landfill gas and leachate from each completed cell.