|  | Public Health Safety | Environmental Health

What Are Slurry Ponds?

Slurry ponds are open pits in which waste products are stored. The two most common types of slurry ponds are those that hold sludge from coal mines and the slurry ponds that temporarily store animal waste in agriculture. In agriculture, the lagoons store manure until the farmers are able to spread it on the fields. Sludge in coal slurry ponds, however, can remain much longer. Some eventually become abandoned, raising environmental concerns.

  1. Slurry Ponds in Farming

    • Most slurry ponds, or manure lagoons, used in farming have a concrete bottom and walls, although older versions may be an earthen pit. Manure is generally pushed into grates at the end of a cattle barn, where the manure flows down a short, wide drain into the slurry pond. The manure collects there until the farmer is able to spread it on the fields using slurry tanks. Most slurry ponds have to be able to hold at least 90 days of manure storage, according to law.

    Coal Slurry Ponds

    • Half of the coal processed in the United States is worked in a way that produces a wet coal slurry byproduct. This slurry is collected in large ponds--sometimes 70 to 80 acres--where the solids are meant to settle out from the liquid. There are at least 700 coal slurry ponds in the United States, the majority of them located in Kentucky, West Virginia and Pennsylvania. The slurry contains not only coal dust, but chemicals from the processing plant.

    Environmental Concerns with Manure Slurry Ponds

    • The main concern with slurry ponds in agriculture is their production of methane gas. The anaerobic fermentation of manure produces methane, a gas known to contribute to global warming. To alleviate this problem closed manure lagoons are sometimes used, although this adds a significant expense to the farmer, who may already be operating within tight financial margins. Anaerobic manure digesters are being more frequently used with manure slurry ponds to harvest the methane gas and create renewable energy.

    Environmental Concerns with Coal Slurry Ponds

    • The major fear of coal slurry ponds is the threat of contaminating the surrounding watershed. Heavy rains or flooding can fill the ponds over their embankments and cause them to spill into the environment. There is also the danger of the dam or enclosements breaking. In 2000, a 72-acre coal slurry pond in Kentucky collapsed into the mine below it and eventually flooded into the river, poisoning the water and animal life in the valley. There have been other documented instances of coal slurry ponds leaking or breaking.

Environmental Health - Related Articles