Pool Farm Mine Water Treament Scheme

The polluting minewater discharge that currently discharges into the Dippool Water, is considered by SEPA to be a high priority for remediation. Proposals for the construction of a minewater treatment system, designed by consultants Mouchel Parkman, include diversion of the Dippool Water, construction of a minewater collection chamber, two wetland treatment areas with distribution structures, access roads and landscaping works.

The untreated minewater emerges from an exisiting culvert. A short selection of the culvert pipe was replaced with polyethylene pipe to enable the inlet transfer structure to be attached. The minewater flows through the transfer structure to a headwall from which the minewater is passed to an areation cascade. The cascade comprises an upper chamber into which the minewater flows and a concrete channel 1.9m wide descending over a set of three concrete steps, each with a vertical height of 0.25m, the aerated minewater passes from the cascade into the conditioning/settlement pond.

The settlement pond is approximately 1.4m deep and has a surface area of 700m2. Following oxidation iron ochre sludge is expected to fall to the bottom of this pond. The pond has a retention time of 4hrs.

The water then flows into the Reedbed section of the scheme; operating in series, the reedbeds have a total surface area of 4,300m2. The reedbeds are planted with Typha Latifolia and Phragmites Australis. Flows of the minewater are conveyed between wetland ponds by concrete channels; these channels can be adjusted to control the level of the water in the upper reedbed.

The treated minewater is discharged into the Dippool water through a dedicated outfall structure.