Kames Minewater Treatment Scheme

Site History -The receiving watercourse (Garpel Water/ River Ayr) has been impacted by mine water since the early 1970s and the current treatment scheme at Kames was constructed in 2000. There are two shafts, one is capped and has four pipes to allow outflow of water. The other is a former air shaft and has been backfilled. The capping and pipes were installed by the Coal Authority a year or so before the main treatment scheme was constructed.

Water Chemistry - The minewater at Kames is net alkaline and is issuing from deep underground coal mine workings. Iron concentration is in the region of 12 mg/l. The flow is up to 25 l/sec; the design specification for the flow at the site is 36 l/sec. The average inflow value for pH is 7.1.

Site Design - The required treatment scheme at Kames involves aeration and settlement, followed by surface flow aerobic wetland, with re-aeration between the in-series wetland cells.

The minewater flows from the capped shaft straight into a stepped aeration cascade. The water flows from this into two concrete settling tanks working in parallel. The water (still split) flows into the first of two sets of wetland cells in series. There are concrete weir/cascade structures in between the wetland cells. Straw bunds in the wetland cells encourage the water to flow around the system and utilise the full area of the cell. The cells are planted with Typha and Phragmites, however Reed Canary Grass initially smothered these, but they plants have shown signs of regeneration. A grassed bank separates the two parallel wetland systems.

It is estimated that the cells will need to be cleaned annually. The parallel system along with sludge drying beds allows this to happen without disruption to the system. The system at Kames Cost in the region of £600,000.