IN the last year, Welsh company Puffin Produce has seen its water usage reduce by 90% and the electricity used to wash and polish its potatoes decrease by 40%.
The savings are down to a radical restructuring of its Withybush factory, which has seen four production lines replaced with two state-of-the-art lines.
Puffin Produce, which is the largest supplier of Welsh produce in Wales, has worked with vegetable handling equipment specialist Haith Group since the early 2000s and in 2016 Managing Director Huw Thomas asked the company to look at how Puffin could reduce its impact on the environment.
Everything on the new lines is now automated, from receiving and grading through to progress storage and packing.
Before the new lines were installed, none of the water used in the factory was recycled. All of the discharge water was removed from the site by tankers. Today, very little water leaves the site, and 90% of the water used to wash the produce is recycled. The remaining fraction has further treatment prior to discharge with the solids being incorporated into a dry cake that can be returned to land.
After being received and any stones removed, the crop enters a self-cleaning washer which discharges waste water onto a course screen, removing any large particles, skin, haulm and foreign objects. The wastewater is pumped to a finer screen, which sits above a balance tank, where a mixer keeps solid matter in suspension.
Technical Sales Manager Paul Ramplin, who oversaw the design of the water treatment system, said: “We start the primary settlement process in the system by pumping the soil laden water through a serpentine flocculator." This promotes agglomeration of the solids before they report into the settlement tank.
The now flocculated solids accumulate at the bottom of the settlement tank, where and automatic monitoring system starts a slurry removal pump at predetermined setpoints. The slurry is pumped into a storage tank that is continuously mixed to keep the slurry in suspension. A pressure pump feeds the concentrated sludge to a multi-chamber filter press, where dewatering accrues and creates a dry soil cake. It can then be returned to land in a more manageable form.
The 10% of water that cannot be recycled passes through a final biological treatment process before being discharged into the natural watercourse.
Haith also helped Puffin to design all the drainage and the recycled water pumping systems to and from the factory.
Huw said: "It is fantastic that we can operate more efficiently, have the capacity to handle even more produce in the future and can lower both our utility costs and impact on the environment."