Phosphorus removal prompts major dosing pump order

Tightening regulatory requirements on phosphorus removal have resulted in the largest ever order of Qdos ReNu chemical metering pumps for Watson-Marlow Fluid Technology Solutions (WMFTS).  

The 240 pumps are required by process specialist Colloide Engineering Systems which has built 115 chemical dosing skids for site upgrades being carried out by Severn Trent Water (STW). Colloide says there are four or five versions of each chemical dosing rig and multiple setups may be required at a single site. In addition, Colloide placed a further order for 40 Watson-Marlow 630 series process pumps for the skid packages. 

The skids are being used in delivery of the UK utility’s phosphorous removal programme for AMP7, the regulatory asset management period 2020-25.  

Phosphorus is a normal part of domestic sewage and new legislation in the European Water Framework Directive requires water utilities to meet much tighter environmental discharge limits to reduce the amount entering rivers and streams. The minimum total phosphorus consent level has been tightened to 0.25mg/litre, which means introducing a range of processes and techniques, and investing in new equipment.  

Chemical dosing is one approach being used by water companies to meet the new phosphorus consent, and equipment needs to be flexible and multi-chemical compatible. This means a range of dosing pumps able to handle different chemicals used in flocculation and coagulation - including ferric, aluminium chloride and polymers - may be required for each skid. 

The order from Colloide includes Qdos peristaltic pumps with three different flow rates – Qdos 30, 60 and 120. These dosing pumps offer repeatable flow up to 120 litres per hour (l/h) and a maximum operating pressure of 7 bar, whilst metering accuracy is assured to ±1 per cent. Unlike traditional diaphragm metering pumps, the flow remains the same whatever the pressure value which provides greater dosing control leading to tangible chemical savings – a key difference to others on the market. 

They are skid-mounted to reduce onsite installation time, with assembly and testing taking place in a controlled factory setting. A reverse function enables the operator to drain the line before maintenance, and once in operation, there is an integral leak detector to reduce the risk of exposure to chemicals.  

The pumps were shipped from WMFTS production plant in Falmouth, Cornwall.  

Colloide project manager Caolan Doyle said, “Colloide has a long-standing partnership with Watson-Marlow for the supply of peristaltic pumps on our chemical dosing rigs. The quality of the pumps provided have impressed both us and the client. Aftercare and support have been thorough.” 

Dale Kavanagh, UK Industrial Sales & Business Development Manager at WMFTS said, “UK water companies are making a huge investment in phosphorus removal to help raise the water quality in river catchments as the environmental regulations require. We are delighted that Qdos chemical metering pumps have a key role to play in carrying out this essential work. 

“The scale of the roll-out of new equipment makes it an ideal time for utilities to consider the whole-life benefit of the chemical dosing equipment they select. Qdos pumps need no supporting equipment and provide accurate and repeatable metering across all conditions. 

“The simple, quick and safe pumphead replacement for Qdos peristaltic pumps is particularly valued by our customers, making them an increasingly popular choice. By working together in close partnership, our expert engineering team can ensure the best solution available, to meet even the most challenging dosing applications.” 

Taxonomy

• Water