Success at Clay Lane WTW

To optimise performance at Clay Lane Water Treatment Works, the peristaltic pumps used for lime dosing over the last 14 years have been upgraded.

The water treatment works at Clay Lane receives water from four reservoirs and following treatment, up to 18 megalitres of water a day feeds into to Bamford Service Reservoir.

An integral part of the treatment process is the addition of lime slurry to control the pH of the water. Water entering the works is dosed with aluminium sulphate and a polyelectrolyte and brought to a pH of around 5.8 in order to facilitate the coagulation and removal of unwanted particles. If the water is lower than this pH, it is dosed with lime to bring it up to the required level. Later in the process, at the secondary filters, Sodium Hypochlorite is added as a disinfectant, while the alkaline lime slurry is pumped into the water just before it leaves the site. This lime dosing raises the pH to around 8/9, assisting in the removal of naturally-occurring manganese.

The Watson-Marlow Bredel pumps used for this purpose were upgraded as part of a £2 million project. ‘The peristaltic pumps previously supplied by Watson-Marlow had been in continuous use for fourteen years. They are very robust, and I was impressed with how well they worked - so when we upgraded the site, I stayed with Watson-Marlow.’ Says Neil Tillery, Process Controller at Clay Lane WTW.

The new pumps are totally automated - making the management of the system much easier. Because peristaltic pumps retain the fluid completely within the hose or tube and have no valves, seals or glands, they handle the viscous lime slurry, without becoming blocked. As the hose or tubing is the only wearing part, and can be quickly replaced without dismantling the pump, maintenance is simple and cost-effective.