Summary #
AMD typically contains dissolved metals such as iron, aluminum, and manganese. Removing these metals from water involves precipitation reactions that are influenced by pH, oxygen levels, and the specific metals present. This page introduces the chemistry of metals removal. For treatment systems, see the Removing Metals section under AMD Treatment.
Removing metals
AMD usually contains dissolved metals, such as iron, aluminum, and manganese. These dissolved metals decrease the tolerance of aquatic life to non-neutral pH. Dissolved metals also corrode man-made structures, such as bridges and wells, and cows will not drink water if it is high in iron, distressing milk production.*
Because most dissolved metals in AMD are likely to precipitate eventually after exiting the mine, most passive treatment systems try to hasten the process before the mine drainage reaches a stream or river. This generally requires merely keeping the AMD calm in a settling pond (http://amrclearinghouse.org/Sub/AMDtreatment/SettlingPonds.htm) for a while, but sometimes pH is increased to precipitate metals faster. Some systems also use sulfate-reducing bacteria (http://amrclearinghouse.org/Sub/AMDtreatment/SulfateReducingBioreactors.htm) to cause metals to remove metals.
* Dairy Reference Manual, 1995. Third Edition. College of Agricultural Sciences, Pennsylvania State University & Northeast Regional Agricultural Engineering Service, 293p.
Sources/Links (as provided in the source text):
- http://amrclearinghouse.org/Sub/AMDtreatment/SettlingPonds.htm
- http://amrclearinghouse.org/Sub/AMDtreatment/SulfateReducingBioreactors.htm
Related Pages #
- Neutralizing Acid (Chemistry Concepts) — Raising pH to precipitate metals
- Ferrous and Ferric Iron — Iron oxidation states and precipitation
- Settling Ponds (AMD Treatment) — Where metals precipitate
- Aluminum (Chemical Monitoring) — Measuring aluminum
Source and Last Reviewed #
Source: AMR Clearinghouse (amrclearinghouse.org). Migrated to AML-Connect. Last Reviewed: 2026-03-13.
[Admin note: Some external links in this article may be outdated. Verify before relying on them. Flag dead links for removal or replacement.]
Tags: amd, metals, monitoring, education
