Types of Mine Water Treatment

Active:

Active treatment is the enhancement of water quality by methods which require the pumping of minewater and/or (bio)chemical reagents (hydrogen peroxide, caustic soda). Examples of active treatment schemes are Ynysarwed mine water treatment scheme, South Wales and Horden mine water treatment scheme, Durham.

Fully active minewater treatment schemes are not the Authority's preferred way of treating water from abandoned coal mines. Active schemes have a high visual impact and do not increase the biodiversity of the area in any way. Active schemes are expensive to purchase and maintain and require a high level of maintenance to work effectively. Active plant is used as a short term solution or when the required land area for a passive scheme is not available.

Passive:

Passive treatment is the deliberate up grade of water quality using only naturally available energy sources (e.g.gravity), in systems which require infrequent maintenance in order to operate effectively over the entire system design life. Examples of passive treatment schemes are Morlais mine water treatment, South Wales and Blaenavon mine water treatment scheme also in South Wales.

The preferred form of treatment for the Authority. Totally passive schemes are fed by gravity so expensive pumping arrangements are not required. There is very little maintenance required.

Active / Passive:

Schemes can have both active and passive elements with the need for pumping and dosing at the start of the process, whilst still passing the water through reed bed cells for final polishing. Built examples include Six Bells mine water treatment scheme, South Wales and Acomb mine water treatment scheme, Northumberland.