One of Europe’s largest smoked salmon facilities is compliant with tighter local trade effluent discharge regulations thanks to a new effluent treatment plant. Farne Salmon & Trout Ltd in Berwickshire had previously discharged effluent from its factory to a foul sewer, but increased production, together with tighter trade discharge consent criteria set by Scottish Water, required the company to find an alternative solution.

The company’s search for the right effluent treatment plant prompted a visit to a trade exhibition. Martin Smith, Farne’s Project & Site Services Manager said ” At the exhibition we discussed our requirements and were confident the DAF solution could meet our needs.”

Working closely with Farne and Scottish Water from an early stage to design and supply a suitable energy-efficient solution, which is odour-controlled and creates minimal visual impact. As part of its comprehensive product and service package, we sampled effluent from the factory in order to calculate the correct chemical dosing regime.

Effluent is collected in a 100,000 litre balance tank and mixed with air to prevent it from 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) treatment system. 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 chemical dosing, Farne may be able to sell this by-product to a local composting facility. 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.

We also considered energy consumption in the plant’s design and used 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, Technical Director explains: “We 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. The company has also significantly reduced its sewer discharge costs.”

Since it was set up, 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.

WPL and Atana are now a part of WCS Environmental Engineering

WCS Environmental Engineering is a part of the WCS Group, which has the in-house skills and expertise in place to deliver full turnkey solutions from influent to effluent, with the capability to close the loop with water reuse.