Lean Gas Instead of High-Temperature Flare at the Blomenhof Landfill, Neumarkt i.d.OPf. - Climate Protection Through Landfill Remediation

The Blomenhof landfill in the district of Neumarkt i.d.OPf. is a clear example of how modern technology and strategic planning can go hand in hand to effectively reduce environmental pollution.

Landratsamt Neumarkt i.d.OPf. - Kommunaler Umweltschutz, Abfallwirtschaft

Landfills are seen as a legacy of past disposal strategies. Particularly in view of the climate crisis, they remain relevant even decades after their closure. Considerable quantities of landfill gas - a mixture of carbon dioxide and methane, the latter of which has a particularly high global warming potential - are still produced in the landfill bodies. The controlled handling of these emissions is therefore a key area of action for modern environmental and climate protection policy. 

1. Initial Situation

Important foundations for sustainable aftercare were already laid there between 2002 and 2005. During this period, the district had extensive construction measures carried out for surface and base sealingin order to ensure the continued operation of the landfill beyond 2005. As part of the project, both TASi-compliant surface sealing and improvements to the base sealing were realised. ia GmbH was responsible for the planning and tendering of the construction work - from the approval and implementation planning to the preparation of the specifications, tender processing and construction supervision.

However, sealing the landfill surface is no substitute for long-term management of the landfill gas produced by biological decomposition processes. Over the years, it became apparent that the existing plant technology - a combined heat and power plant (CHP) and a high-temperature flare - was increasingly reaching its technical limits. Due to the natural decline in biological activity in the landfill body, the methane concentration in the gas fell steadily, meaning that the gas engine could only be operated a few days a week. Continuous operation was no longer possible, which increased the risk of uncontrolled methane emissions.

2. Funding from the National Climate Initiative (NKI)

In order to develop a sustainable solution, a landfill gas potential study was commissioned in 2021, prepared by ia GmbH.

The aim was to make a well-founded decision on the future direction of gas utilisation based on reliable data.

The study also formed the basis for a successful funding application as part of the National Climate Initiative (NKI). This initiative specifically supports innovative measures to reduce climate-damaging emissions in municipalities, companies and other areas of society.

The analysis confirmed that there was an urgent need to adapt the utilisation technology, particularly through the use of a so-called lean gas treatment plant, which also works reliably at low methane concentrations (from 6 - 12% by volume).

3. Implementation and Realisation

With this knowledge, the district decided to implement this project. In February 2024, the existing plant technology - combined heat and power plant and emergency flare - was completely replaced by a modern lean gas treatment plant.

The fact that thermal treatment is now also possible for landfill gases with a very low methane content is a significant improvement on the previous technology. An exhaust gas heat exchanger was also installed so that the heat generated can continue to be used to heat and provide hot water for the plant building. The plant was commissioned in March 2024 as an important contribution to the system's energy efficiency.

4. Results After the First Year of Operation (03/2024 - 02/2025)

The results after the first year of operation (March 2024 to February 2025) impressively confirm the effectiveness of the measure. The availability of the new system was over 95 per cent, which means almost continuous operational readiness. In total, over 220,000 standard cubic metres of landfill gas with an average methane content of 21% by volume were treated. This means that the gas capture rate was increased by a factor of 6.5 compared to the average of the previous five years - a significant improvement. It should be noted in particular that the old CHP plant could only be used to a very limited extent due to the low methane concentrations, meaning that the comparison shows a particularly clear increase in efficiency.   Effect at GWP 100 The mass treated in the first year of operation was 66.8 tonnes of methane, which - based on the global warming potential of methane (GWP100 = 28) - corresponds to an avoidance of around 1,870 tonnes of COâ‚‚ equivalents per year. In addition, 7,800 kilowatt hours of useful heat could be recovered through heat recovery and used for the company building - a practical side effect that further improves the ecological balance of the project. Effect with GWP 20 As methane only has a lifetime in the atmosphere of 12.5 years, it is now becoming increasingly common to use the Global Warming Potential over 20 years (GWP 20) as an alternative, which shows the short-term effect over 20 years with a factor of 84 and corresponds to an avoidance of around 5,611 tonnes of COâ‚‚ equivalents per year. These figures illustrate the concrete contribution that technical aftercare measures at old landfills can make to climate protection.

5. Outlook

The Blomenhof landfill site is an impressive example of how environmental problems of the past can be solved effectively and sustainably using today's resources. The combination of responsible planning, innovative technology and targeted funding can make an effective contribution to climate protection - in terms of municipal sustainability.