Design of an Environmental Management Software Tool
Using MS Excel, FT has developed a landfill gas management model for South Dublin County Council (SDCC) at Arthurstown landfill. The landfill, which received up to 600,000 tonnes of waste per annum, has a large landfill gas utilisation plant comprising eight engines as well as two 2,500 m³/hr enclosed flares.
The gas utilisation plant is owned and operated by a third party, with SDCC owning and operating a number of flares on site to control landfill gas from uncapped areas.
Typical landfill gas management practice prior to the commissioning of this project was to balance landfill gas extraction in relation to available methane and oxygen. This was to facilitate the operating criteria for utilisation plant and the flaring units, but often resulted in odour problems.
FT was retained by SDCC to:
1. Carry out an audit of the landfill gas collection system, the utilisation plant and the flaring plant.
2. Develop an alternative extraction philosophy to manage and balance extraction of landfill gas from landfill site to mitigate odour nuisance.
3. Develop a MS Excel model to aid the on-site auditing and management of landfill gas extraction.
4. Provide training for on-site staff in the operation and management of landfill gas extraction using the bespoke landfill gas management model.
The MS Excel model aids on-site staff in the management of landfill gas extraction and balancing by structuring inputs to:
• Define operating criteria in relation to gas flow rates, quality and allowable variance.
• Review infrastructural extraction requirements over the lifetime of the landfill.
• Enter data from gas surveys that is presented on aerial photographs of the site.
• Input gas model predictions from “LandGem”, “GasSim” or other models over the lifetime of the landfill.
• Monitor gas extraction in relation to model predictions and altering model predictions by a factor adjustment
• Review system performance of flares, manifolds and engines.
• Review well characteristics in relation to CH4, CO2, O2, CO, N2, flow and pressure.
• Review data from other landfill related monitoring as required.
• Carrying out trend analyses of historical survey results.
• Facilitate decision making in relation to balancing requirements.
• Monitor the impacts of balancing exercises carried out on the waste body.
Processes 600,000 tonnes of waste per annum
Total of 8 engines across the site
2 enclosed flares developed