Trond Mæhlum
Research Scientist
Biography
Education
PhD from NMBU (1998) in use of constructed wetlands for water pollution control in cold climates. Cand.agric. in mangagement of water resources fram NMBU (1991)
Key qualifications
Environmental engineering, specialising in water protection management hydrogeology and aquatic chemistry. Experience in planning, design and monitoring of nature based systems for treatment of point sources and diffuse pollution. Landfill leachates, domestic wastewater, urban runoff, agricultural wastewaters and runoff. Particular interest in treatment wetlands, ponds, soil infiltration and biological filters. Investigation of filter media and treatment processes - in laboratory, mesocosm and full-scale systems. University lecturer and examiner in environmental engineering and water resource management.
Abstract
Landfilling remains a widely used and economically viable waste disposal method, particularly in regions with limited access to advanced treatment technologies. However, once these sites reach capacity and are closed, their long-term environmental management becomes a critical concern for municipalities and stakeholders. This study explores post-closure landfill management strategies by examining three closed landfill cases in Norway. A literature review was conducted to establish a baseline understanding of current practices and gaps. Despite previous research on landfill gas utilization and waste-to-energy technologies, there is a lack of empirical, site-specific studies addressing the long-term aftercare and post-closure management of closed landfills in European contexts. Therefore, this study addresses this gap by providing a case-based assessment of closed landfill management practices in Norway. Findings were synthesized using a SWOT (Strengths, Weaknesses, Opportunities, Threats) analytical framework to assess both internal and external influencing factors. The results highlight key strengths, including existing gas monitoring systems and recycling efforts, as well as critical weaknesses, such as infrastructure instability and limited historical assessment data. Opportunities are found in areas such as methane mitigation, circular economy integration, and land reuse planning, while threats include financial constraints and long-term maintenance concerns. Drawing on these insights, the study emphasizes the importance of developing integrated aftercare strategies that incorporate environmental monitoring, risk assessments, and cost-benefit analyses tailored to site-specific conditions. These insights are valuable for stakeholders, including municipalities, policymakers, landfill owners, national authorities, industries, and waste management companies, in shaping future initiatives for repurposing landfills.
Authors
Trond MæhlumAbstract
Rapporten oppsummer resultater fra miljøovervåking av Spillhaug avfallsdeponi for driftsåret 2025. Data vurderes mot rensekrav og tidligere undersøkelser. Deponiet er etablert i et tidligere sandtak uten etablert bunntetting. Vannet strømmer 2-300 m gjennom sand, avgrenset av fjell, før sigevannsforurenset grunnvann pumpes til et behandlingsanlegg. Renseparken omfatter to brønner med pumpe, luftebasseng og tre tilplantede våtmarksbasseng. Sigevannsmengde til behandling er i 2025 målt til 30 379 m3, som er på nivå med tidligere år i forhold til årsnedbøren (768 mm). Beregnet ut fra endring i vannkvalitet fra deponiet og til resipienten Sandbekken, har rensegraden vært: 97% for jern, 25% for KOF, 56% for nitrogen (tot-N) og 84% for ammonium-nitrogen. Nivået av miljøgifter i utløpet av renseanlegget er lavt, og konsentrasjoner av tungmetaller i utløpsvannet er under nivåer som anses å være skadelige. Sandbekken mottar renset vann og diffus innlekking via grunnvann og overvann. Sandbekken påvirkes av sigevann, med økte konsentrasjoner av konduktivitet og nitrogen, men har liten endring for de andre analyserte parameterne. Årlig utslipp av PFAS-forbindelser er ca. 3,5 gram. Overvåkningen gir grunnlag for å fastslå at renseanlegget virker tilfredsstillende. Det er derfor ikke foreslått spesielle tiltak for å bedre rensingen i 2026. NIBIO foreslår at luftet lagune og sedimenteringstanker tømmes for slam. NIBIO foreslår at driftsoppfølging og overvåkning i 2026 ligger på samme nivå som 2025.
Authors
Trond MæhlumAbstract
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