In solid waste landfills, the same biogas is generated as in biogas plants. The same processes of anaerobic fermentation occur faster in biogas reactors and slower in landfills.
The advantage of processing the organic fraction of solid waste in biogas reactors rather than in landfills is that biogas does not end, even after 30-40 years. As long as fresh waste enters, there is biogas. In landfills, biogas production ends in 3-7 years. However due to its low cost, this method of producing biogas in landfills is also popular.
There are two landfill types in terms of waste collection and gas production: organized and unorganized.
In an organized landfill, horizontal perforated pipes for biogas collection are laid in the body of the landfill at the time of installation. Vertical pipes are laid at the time of laying the landfill or wells are drilled after the landfill is filled. The landfill itself is waterproofed from all sides including from above. In this case, there is no biogas leakage from the landfill resulting in maximum gas output. Landfills are created sufficiently deep 80-100 m. Garbage is collected and documented the logbook which indicates which garbage was put in which part of the landfill and at what time. Biogas from such a landfill can be extracted for as long as 8-12 years.
In an unorganized landfill, waste is dumped without laying horizontal pipes and often even without waterproofing. Vertical wells are drilled, and vertical pipes are laid. The well top is concreted. Wells are drilled at a distance of 15-25 m from one another. The well action range should overlap the zones between the wells. The depth of landfills varies from 20 to 40 m. Biogas is extractable for just 3-7 years.
The biogas is pumped out of the vertical pipes and collected in gasholders. Then the biogas is dried, cleaned of impurities, compressed, and fed to a generator or torch.
Biogas from landfills has a low methane content (30-45%) and a high content of impurities, hydrogen sulfide - up to 3,000-5,000 ppm. Therefore, the installation of high-quality filters is required.
Biogas plants are technically more complicated than landfills. Zorg Biogas has significant experience in the gas preparation of biogas and power generation installations within biogas plant projects. Components for solid waste landfills such as torches and gas blowers were supplied as well. If necessary, Zorg Biogas will carry out drilling projects.
- there are no reactors, old substrates in landfill are not dug up and not mined
- the budget is many times lower than for a biogas plant
- well drilling is required
- gas runs out after 5-7 years of operation