Haith supply Water Treatment Plant for Batts Combe Haith supply Water Treatment Plant for Batts Combe Haith supply Water Treatment Plant for Batts Combe Haith supply Water Treatment Plant for Batts Combe
 

Haith supply Water Treatment Plant for Batts Combe

14th February 2005


Situated on the edge of Cheddar village, Batts Combe Quarry has been operating since the early 20th century and is owned and operated by Hanson Aggregates. Currently processing 4000 tonnes of limestone per day, one third of which is supplied to an on-site lime kiln, the remainder is sold as coated or dusted aggregates. Recently the company has made a £1 million investment in a new washing plant. Designed to operate at a maximum of 500 tonnes per day the purchase and installation of the plant has been commercially driven and also provides the company with an increased level of health and safety within the site.

Commissioned in January 2005 the new wash plant has provided Hanson with the ability to sell quality materials to its local markets, previously only supplying scalpings the new plant produces a 20-5 material and a good quality sand. The 20-5 can be stocked or supplied to Hanson's own ready-mixed concrete plants; the production of sand has also benefited Hanson as this has allowed them to establish a new local market for this product.

Several companies have been involved with the project including Haith Industrial of Worksop, Notts.
Working closely with other suppliers Haith installed a complete water treatment plant as part of the main aggregate washing plant. Operating under a closed loop system designed to provide clarified water for re-use and a sludge cake for disposal the whole plant is built within a small footprint.

PROCESS.

Effluent emanating from the aggregate washing plant feeds into a plant sump where it is then pumped to the 5 metre wide thickener via a 1metre wide sieve bend. Interlocked with this delivery is a flocculent dosing pump which is connected to an automatic powder grade flocculent preparation system. This addition of flocculent achieves solids liquid separation within the thickener giving rise to a thickened slurry underflow being discharged at the base of the vessel.

Clarified water weiring over the top of the thickener is discharged into a 60m³ clean water storage tank which is fitted with two pumps, one of which provides a supply of treated water for the fully automatic cloth washing system on the filter press and the other pump returns water back to the wash plant.

Thickened slurry from the base of the thickener is pumped to a 20m³ capacity buffer tank, this in turn is fed by a press feed pump to the 1200 x 1200mm x 38-chamber x 32mm cake, automatic side bar filter press at a rate of 4.5 tonnes/hr.

Operating on command from the press PLC delivery to the feed ports of the press is constantly monitored by an in-line pressure switch. On reaching a pre-set line pressure the pump will stop and the press enters its automatic sequence for opening and discharging of the cakes using an electro/hydraulic opening system. Discharge is also aided by an automatic plate and cloth vibration system ensuring fully automatic operation.

After the completion of the cake discharge the press closes and another pressing cycle will automatically start. All filtrate from the press is discharged by gravity into the treated water tank; dirty water generated when the cloth washing system is in operation will flow to a wash water tank fitted with a transfer pump which pumps it to the thickener feed launder. To complete the process the dry filter cake discharged by the press falls by gravity into a three sided concrete bund below.

Haith Industrial also supplied a 9m long x 5m wide x 5m high portal framed building including a galvanized platform and support structure to house the press. All access ladders, platforms and walkways were also pre fabricated and supplied in galvanized steel and conformed to the current health and safety standards.