March 2009

A new effluent treatment plant designed by WPL is ensuring that Farne Salmon and Trout Ltd in Berwickshire - one of Europe’s largest smoked salmon facilities - complies with tighter local trade effluent discharge regulations, whilst significantly reducing its sewer discharge costs. WPL worked with Farne and Scottish Water from an early stage to design and supply a substantial, energy efficient solution which is odour-controlled and creates minimal visual impact.

Previously, Farne discharged effluent from its factory to a foul sewer, but increased production and staffing levels, together with tighter trade discharge consent criteria set by Scottish Water, required the company to find an alternative. Since it was set up in 1982, Farne has expanded from a workforce of just six to 500 people, rising to 1,000 in the run-up to Christmas to meet seasonal demand for high quality smoked salmon and related products. The company’s search for the right effluent treatment plant prompted a visit to a trade exhibition where they met WPL. “We discussed our requirements with WPL’s team and were confident that they could supply a solution to meet our needs,” says Martin Smith, Farne’s Project & Site Services Manager.

As part of its comprehensive product and service package. WPL sampled effluent from the factory and undertook the design of Farne’s new effluent treatment plant, including calculating the correct chemical dosing regime. Almost all equipment for the system is manufactured in stainless steel and features high quality pumps and controls to ensure reliability in use and a long service life.

Effluent is collected in a 100,000 litre balance tank and mixed with air to prevent it deteriorating and causing an unacceptable odour. The effluent is then pumped to a rotary drum to separate screenings, which fall into a skip, effluent, is then pumped into a coil pipe flocculator for chemical dosing before being transferred to a Dissolved Air Flotation (DAF). Effluent is finally discharged to a V-notch weir for volume monitoring and final pH correction prior to sewer discharge. The residual sludge is transported into a storage tank, and with tight control over control on chemical dosing, Farne may be able to sell this by-product to a local composting facility.

WPL also considered energy consumption in the plant’s design and utilised the power of gravity wherever possible to reduce the number of pumps. In addition, the system is designed with adequate natural ventilation to avoid the use of large extraction units. Andrew Baird, WPL’s Business Development Manager explains: “WPL used its considerable buying power to reduce the cost of this plant and we applied our design expertise to provide a user-friendly operator interface. The result is a simple and cost-effective solution that ensures Farne operates within its local trade effluent discharge consent.”

WPL is an internationally recognised designer and manufacturer of high quality package and turnkey rainwater harvesting, sewage treatment systems and grease management solutions. The company also has ongoing service and support contracts with an extensive customer portfolio comprising the UK’s major water utilities, commercial and industrial users, and all sectors of the domestic market. WPL’s innovative solutions are all designed to exceed existing and proposed standards set by the Environment Agency, SEPA and other regulatory authorities.

For more information regarding products and services, contact Andrew Baird on 023 9224 2607 or andrew.baird@wpl.co.uk