Design and documentation of Bairnsdale regional landfill - Cell 3 Johnston’s Road, Bairnsdale

Abstract

This project was aimed to develop the preliminary design concept for a future landfill cell (Cell 3 of 5) at the Johnston’s Road Landfill site, situated on the outskirts of Bairnsdale in East Gippsland, Victoria. The project was completed on behalf of East Gippsland Shire Council, with the expectation that this project will then form the basis of the complete design and documentation for the landfill cell. The concept created has an operational capacity of three years, including waste and daily/weekly cover requirements and meets or exceeds the minimum best practice guidelines as set out in the EPA Victoria publication 788, Siting, Design, Operation and Rehabilitation of Landfills. All elements of the landfill system were examined, these included: • Siting Conditions and environmental assessment – identification of need, buffer distances, groundwater, surface water, flora and fauna, existing infrastructure, geology and land ownership; • Site layout – examine suitability of existing and future requirements, as well as existing access issues;• Landfill liner system – minimum or recommended liner types and methods, sub-base requirements, clay liner, geo-membrane and protection layer and finally, the drainage layer and geo-textile use; • Water management – Storm water management and existing issues, groundwater management, leachate generation rates and modeling using a HELP package; • Landfill gas; • Odour and noise impacts; and • Site security and fencing The landfill Cell was designed as an extension to the previous Cell (Cell 2), and has the capacity to hold 175,163m3 of waste, placed in six 2m thick layers, with each layer separated by 0.3m of cover materials. The finished height was designed to match with the previous cells, which allows for a uniform and useful area once landfill activities are complete. The overall footprint of the landfill is approximately 2.2 ha, with a base size of 120m x 84m, and uses 3:1 batters on the Cell walls. The proposed leachate system utilizes a number of 110mm Class 16 HDPE pipes, spaced at 15m intervals. These pipe diameters were based upon inspection and maintenance access requirements as opposed to flows, as the HELP modeling results indicated that leachate volumes generated were not overly large (0.036 L/sec) Once the preliminary design concept was established, the focus of the project moved towards preparation of the documentation, namely construction specifications. This specification will eventually form part of the design package sent to the EPA, and selected environmental auditor for approval, prior to advertising a tender for construction of the Cell