Bakewell proves the perfect start
A new inlet works designed by Haigh Engineering is being trialled at Severn Trent Water's sewage plant in Bakewell, Derbyshire. Maureen Gaines reports on how the system is reducing screenings
The Series 2 ACE Inlet is designed to handle pumped raw sewage flows. Its performance at Severn Trent is monitored to ensure maximum efficiencies are being achieved, and that the operation is as simple as possible.
The Series 2 Ace Inlet, which is skid-mounted for fixing to a level concrete plinth or high level structure, is capable of handling up to 150l/s pumped raw sewage; serve a 20,000 population; and cope with peak screenings loading of 1.5m3/h.
The inlet comprises a reception tank that allows large stones and debris to settle for manual removal and screenings, small stones and grit to continue with the flow into the approach channel. At the end of this channel, the floor is shaped to feed the grit and stones into an ACE Bandgritter sump, where they are removed and discharged into a skip.
After the Bandgritter, the channel splits into three - the two outer channels feed to the ACE Bandscreeners while the central one feeds to the bypass handrake screen channel. Screenings removed by the Bandscreeners are discharged with the wash water into a launder trough, and flushed into the conditioning tank that has two duty/standby Macipumps mounted.
The duty Macipumps conditions the diluted screenings and delivers them to a distribution tank with a fine grit settlement area and an automatic actuated grit discharge valve, high level overflow and raised discharge bellmouths to feed the diluted or conditioned screenings out to two duty/standby liquid separators.
The separators comprise two integral elements - a Lisep operating at high speed for additional washing and primary dewatering; and a Lipactor for further dewatering and compaction.
The plant is controlled by a motor control centre mounted on the inlet support platform.