Lustleigh is a small village with a population of 600 situated in Dartmoor National Park in Devon, England. Lustleigh is often referred to as ‘the prettiest village in Dartmoor’, Lustleigh is a beautiful blend of thatched cottages, narrow lanes and green woodland. Our client, South West Water (SWW), identified it as a site where the ammonia level needed to be improved. Following the successful trials carried out at Cullompton WwTW, SWW decided to use the Advanced Solutions and Technologies Ltd (AS&Tech) MBBR system to reduce the ammonia level at the site.
The first thing that had to be overcome was the restriction in getting any type of plant into the site. Midway down towards the site entrance, there is an old railway bridge which is 2.5 mtrs wide, and the height of the bridge also posed a problem. AS&Tech suggested using a two cell MBBR system, with each cell being separate to the other. This overcame the width restrictions as each cell was 1.5mtrs x 1.5mtrs x 3.3mtrs high, which meant each cell could be delivered on a trailer. A rectangular steel base was constructed off site to ensure the MBBR units had a level base in which to sit. This also helped in lining up the air connections and inlet and outlet connections between each cell.
Since the plant has been installed it has reduced the ammonia (NH3) so SWW meet their required discharge consent. The plant consists one 6mm rotary screen, followed by two rectangular primary settlement tanks. The flow from the primary tanks, now goes to the MBBR plant and following the biological treatment the flow is returned to a final tank for final settlement and polishing via a Copa brush clarifier.
The MBBR is supplied with a GRP kiosk, which houses the duty/standby 3Kw blowers, as well as the electrical controls, for all the MBBR equipment.