Fender Minewater Treatment Scheme

Site History - The discharge at Fender is from both deep and drift mines, and is also both an historic discharge and the results of post pumping water table rebound.

Water Chemistry - The minewater at Fender is net alkaline and the discharge comes from deep and outcrop mines. The discharge occurs on the bank of the River and is collected and pumped to the wetland treatment scheme. The receiving stream - Barlow Brook, was previously stained by ochre but since pumping started in July 2000 the stream has cleaned up considerably. The total iron concentration in the water is 10mg/l and the pumping rates are between 25 and 26 l/sec. The average inflow pH is 6.6.

Site Design - The wetland at Fender comprises four cells in series, the cells are planted with Phragmites, Juncus and Scirpus. Water collected in a concrete sump near the adit mouth and is pumped via a rising main to the treatment site. The inflow to the first cell is through gabion baskets. But blockages to this arrangement due to ochre accretion have led to a simpler open pipe arrangement being implemented. There was an initial problem with cell one when the Iron loading was far greater than expected and the plants in cells one became smothered with precipitated ochre. The first cell was to be replanted with Scirpus that shows a greater tolerance to Iron loading.

Inflow to each of the other three beds is through separating weir walls but plastic pipes along the top of the dividing walls are provided. These pipes are used as a bypass system so that maintenance and cleaning may be carried out on any of the other cells.

Outflow from the wetland series is via three concrete outflow structures in the fourth bed with subsequent discharge into the river. The cost of the scheme at Fender was £385,000.