Peristaltic pumps supplied by Watson-Marlow Bredel are delivering trouble-free, 24-hour operation of lime slurry dosing for Yorkshire Water at the Blackmoorfoot WTW near Huddersfield.
The WTW at Blackmoorfoot was the first full-size three-stage water treatment works to be built by Yorkshire Water and serves over 400,000 people.
Pumping around 30 megalitres of water a day, the three-stage process involves flotation and first-stage filtration followed by manganese and chlorine removal.
The 3-stage process has been successful in treating upland Pennine waters and, as a result, water quality throughout the area has improved.
A critical aspect of the water treatment process at Blackmoorfoot is the addition of lime slurry to control the pH of the water.
Water enters the treatment facility with a pH of around 6, at which point it is dosed with ferric sulphate and brought to a pH of 3.5.
Lime is then added to aid flocculation at the first stage of filtration, bringing the water to a pH level of 4.2 before more lime is dosed to raise the level to pH 6.8.
At the second stage of filtration before the water leaves the site, alkaline lime slurry is metered to the supply in order to maintain the required pH level.
The lime raises the pH to around 9.2, which assists in the removal of naturally occurring manganese.
According to Joe Kelly, Process Engineer at the Blackmoorfoot Works, peristaltic technology offers distinct advantages over other types of pumps.
He says that Watson-Marlow Bredel peristaltic pumps have been used onsite for at least seven years, and have delivered trouble-free operation.
He comments that peristaltic pumps from other well known suppliers installed on various sites have not performed as well and are often prone to failure, particularly the inverters and motors resulting in unnecessary downtime and high maintenance costs.
The process control engineers at Blackmoorfoot WTW use six separate Watson-Marlow Bredel SPX 40 hose pumps to handle the lime dosing.
While three of these pumps run 24 hours a day, the remaining pumps are used as duty/ standby units.
The Watson-Marlow Bredel SPX 40 pumps are part of their family of SPX direct-coupled hose pumps, offering a maximum flow of 6000 l/h and discharge pressure of 16 bar.
Providing all of the performance, reliability and ease-of-maintenance benefits of bareshaft (long-coupled) designs with the compact advantages of close-coupled pumps, the SPX peristaltic pumps are available in sizes ranging from 10mm to 100mm.
Unlike close-coupling, the Watson-Marlow Bredel patented direct-coupled design permits the drive to be removed and replaced without the need to dismantle the pumphead.