Landfills are among major pollution hotspots worldwide. They are seen as sources of air, water and soil pollutants and areas with high emission potential when it comes to greenhouse gases such as methane and CO2. Non-sanitary landfills, especially in developing countries, with little or no waste pre-selection and recycling processes included are left over to nature to take care of. The natural waste disintegration process is long and uncontrolled. Besides being environmentally unfriendly it can also be quite dangerous.
In landfills filled with various communal waste, disintegration in deeper layers without the presence of air can lead to the creation of a flammable mixture of gases. The composition of these gases is majoritarily methane (CH4), alongside carbon dioxide (CO2) and nitrogen (N2). In a process known as anaerobic digestion, these gases, when uncontrolled and unmonitored, usually lead to the formation of so-called “methane pockets”. These methane pockets are huge underground reservoirs of gas, prone to spontaneous combustion and severe explosions.
The only preventative solution against dangerous explosions as a result of waste disintegration is to insert perforated tubes to evacuate methane away from the landfill body and into the atmosphere. However, given the energy value of landfill gas, this solution is both wasteful and presents an environmental hazard and a danger to the ozone layer.
The most efficient way to prevent this waste and to neutralize the pollutants in landfills as well as the dangers is to utilize the methane from landfill gas either in an unrefined state by combusting it in CHP (gas engine) or thermal units or to use it after rafination and deliver it to the end consumers.
Resalta safely diverts landfill gas through extraction wells and pipe it to a landfill-gas-to-energy plant, where it is cleaned before specialized engines convert it to energy for use by the facility and, in many cases, the nearby community.
Resalta has partnered with landfill operators, local municipalities and technology experts to assess the viable solutions for tackling these issues in the region. Our team of engineers has performed in-depth analyses of long term monitoring data of landfill gas from several locations and has created multi-phase methane generation models for several landfills. We have proposed and implemented grids of existing and new methane extraction pipes which are all interconnected to CHP units. We have developed “ready to build” projects that include planning, design, energy and construction permits. Additionally, in close cooperation with our partners in charge of landfill operation and based on their financial preferences we offer financial models which may include project financing based on a loan, repaid from the income generated from the electricity sold to public suppliers or specific tailor-made models.