Acomb Minewater Treatment Scheme

Site History - There were two coal seams mined at Acomb in the 19^th and 20^th centuries, with the workings being closed in 1952. The discharge occurs to the east of Acomb Drift via an old pipe and is known to have been present prior to reclamation of the colliery area. Discharge occurs into the Red Burn, approximately 1000m above its confluence with the River Tyne and impacted severely due to the highly visible nature of the burn in the village.

Water Chemistry - The minewater at Acomb is net alkaline with a total Iron concentration in the region of 25 to 40mg/l. There had been reports of high levels of lead, copper, nickel and zinc (no data) these levels may indicate connections with local metal mines. The average flow of the discharge is 10l/s with a pH value of 6.6.

Site Design - The treatment required at Acomb was simple aeration and settlement to remove the iron from solution. Construction work commenced in August 2001.

The minewater is pumped from the top of the drift into an aeration tower. Once the water is aerated then it passes out of the tower into two irregular shaped lagoons, these are approximately 2.5m deep and have a total area of 750m². These lagoons have some peripheral planting to improve the aesthetics of the scheme. The water then passes into two reed beds in sequence, these are planted with Typha, and Scirpus and have a combined area of 1200m². The site has also been landscaped with woodland, shrub and waterside planting together with fencing, footpaths and picnic areas.

The construction costs for Acomb were in the region of £350,000.