Rotting trash controls whether metal pollutants escape landfills
Ye L, Wang Z, Chen F, Xing X, Zeng C
Soil Health
The same chemistry that governs how decomposing food scraps and yard waste release acids and dark organic compounds in a landfill is the same process at work in your backyard compost bin, shaping which minerals stay locked in soil and which leach away.
Landfills often mix old coal ash with household organic trash, and that ash contains rare metals used in electronics and magnets. As the organic waste rots, it produces acids that pull those metals out of the ash, but once the mix settles into a more neutral, stable state, decomposed organic matter grabs onto the metals and holds them in place on the trash's surfaces. It's basically the same push and pull between acidity, decay, and mineral surfaces that happens in a compost pile, just on a bigger, dirtier scale.
Key Findings
Early-stage organic waste decomposition dropped pH and increased release of rare earth elements from exchangeable, acid-soluble, and reducible fractions of coal ash.
As pH recovered to neutral-alkaline levels, dissolved organic matter (especially fulvic-like compounds) became the main driver of rare earth element binding, via carboxylic, polysaccharide, amide, and phenolic functional groups.
New organo-mineral surfaces formed on coal ash particles during decomposition, increasing retention of rare earth elements during leachate recirculation.
chevron_right Technical Summary
Scientists built mini landfill systems to track how rare earth metals from coal ash move into landfill liquid and solid waste as it breaks down, finding that decaying organic matter first pulls these metals out through acidity, then locks them back onto mineral surfaces as conditions turn neutral. The work could help engineers recover valuable metals from landfills instead of losing them to leachate.
Abstract Preview
Original paper
Release and Redistribution of Rare Earth Elements from Coal Ash in Simulated Landfill Systems.
Municipal landfills have historically co-disposed coal ash (CA) and other solid wastes containing rare earth elements and yttrium (REY). However, REY mobility and their dynamics between residues an...
open_in_new Read full abstractAbstract copyright held by the original publisher.
Was this useful?
Want to tell us more? (optional)
Thanks for the note!
Something went wrong — please try again.
Too many submissions. Try again in an hour.
Ancient Amazonian forests were planted and tended by Indigenous farmers
Forests and fruits we romanticize as wild — including many plants now in our kitchens and gardens — may exist in their current abundance precisely because an...
Composting is the controlled decomposition of organic materials—such as plant waste, food scraps, and manure—into a nutrient-rich amendment that improves soil fertility and structure. For plant science, compost is significant because it enhances soil microbial communities, increases nutrient
arrow_forward Explore topic