---
title: Removing Metals Overview
description: "# 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…"
url: "https://aml-connect.org/aml-knowledge-base/removing-metals-overview/"
updated: "2026-01-13"
category: "AML Reclamation & AMD Treatment / AMD Treatment / Passive Treatment / Removing Metals"
---

# Removing Metals Overview

# 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.