Case Study – Potato Peel Dewatering

When potatoes are peeled in abrasive peelers a large amount of potato fibre and grey starch is generated that is too wet for storage and disposal. Attempts have been made in the past to screen this material with parabolic screens but the best this can achieve is a thick soup consistency and the screen underflow water will still contain suspended solids that, unless clarified in some way, will ultimately end up at the effluent treatment plant.

Centri-Force are experts in the use of high speed industrial centrifuges for continuous processing, recovering starch in plants across the UK. The decanter centrifuge separates the solids from the water and produces a dry friable material with a moisture content of less than 60% which is suitable for storage and disposal as animal feed.

The liquid phase will have had the bulk of the solids removed and consequently there is a dramatic reduction in load on the sewer and substantial savings in trade effluent charges.

The illustration shows dewatered solids discharging from a decanter centrifuge.

This picture shows a close up of the solids discharge area of the centrifuge discharging dewatered solids onto a conveyor. The only other equipment required is a feed pump to deliver the peel water to the centrifuge and probably a macerator to prevent pump blockage. All of this equipment is easy to operate and runs continuously without supervision. There is no need for complex installations and the whole process can be up and running in a few weeks.

Centri-Force supply a complete range of factory refurbished centrifuges from leading manufacturers that are a cost effective solution ideal for this application. The application itself is now well proven and has been shown to be non aggressive, resulting in low servicing costs and good durability.

A typical maintenance cost is less than 5% per annum of the capital cost.

The principal benefit is economic. Quite simply it saves money, frequently with dramatic pay back potential, particularly if the dewatered peelings can be sold on. No one particularly “wants” to invest in effluent treatment because there are always prior demands from the mainstream processes. However with rapid payback, or consent issues even the most hardened Finance Directors are having to listen to the arguments.

Of course all companies have to think about how they interact with the environment and reducing the pollution that goes down the drain is an obvious benefit to all concerned. There is also a possibility for reusing the clarified wash water which is certainly worth investigating.