Haith supply wash water clarification & slurry dewatering plant for Kimco DeKimpe Cool. Haith supply wash water clarification & slurry dewatering plant for Kimco DeKimpe Cool. Haith supply wash water clarification & slurry dewatering plant for Kimco DeKimpe Cool. Haith supply wash water clarification & slurry dewatering plant for Kimco DeKimpe Cool.
 

Haith supply wash water clarification & slurry dewatering plant for Kimco DeKimpe Cool.

22nd January 2010

Kimco SA is one of the largest carrot processing companies in Europe. Each year the company grows hundreds of acres of carrots in Belgium and the Netherlands including onions, garlic and shallots for Belgium and other countries.

Overall, three subsidiaries and forty permanent staff manage an annual production of over 40 million pounds of carrots and 8 million pounds of onions!

From June to December, the carrots are harvested and transported from the field to the processing unit located in Dendermonde.

To maintain carrot supply throughout the year, large quantities are harvested and stored in central refrigeration Fernelmont in late autumn. These are then transported as required to Fernelmont Dendermonde where they are then delivered to different destinations.

With years of experience working within a stringent selection criteria Kimco have provided vegetables that not only meet, but surpass the quality standards of EurepGap. To further ensure the end product is of the highest quality, Kimco has a BRC certificate proving that their quality system meets the BRC Global Standard ensuring a healthy and optimal production process, both in terms of logistics, traceability and storage methods.

Following an order from their Dutch agent Murre Techniek B.V., Haith Industrial who specialise in waste and water treatment have designed, manufactured and commissioned a new wash water clarification & slurry dewatering plant for Kimco DeKimpe Cool.

As efficient water process and waste water management plays a key role in any vegetable production process Haith conducted several consultation processes and were subsequently successful in designing and manufacturing a new primary screening and silt removal thickening and dewatering system for the client.

The new primary treatment system provides solids/liquids separation from the washing and polishing carrot lines providing a dewatered cake suitable for stacking in a trailer and subsequent disposal off site in a trailer, allowing for all year round disposal back to land.

By removing the vast majority of the suspended solids and an element of the BOD/COD this process complies with the current Belgium environmental legislation discharge consent - to the adjacent watercourse which is a small land drain/ brook.

Production process.

With the wash water  flumed from the washer and polishing lines at approximately 120m/hr Haith manufactured and designed a purpose collection sump which is  fitted out with a Haith vertical shaft agitator and a dry mounted clarifier feed duty /standby pump which delivers to a 10mm Haith Aquabelt' scraper screen.

This is followed by further fine screening down to 3mm utilizing a Haith paddle screen (provides a higher capacity and capable of producing dryer screenings) prior to discharge of the wash water via launder into the central stilling well of a Haith 13 metre diameter deep cone upward flow clarifier.

The resulting silt and clay fines are then subjected to a suitable coagulant and flocculent mix which is automatically prepared with correct dosage application from the Haith powder and liquid polymer make-up systems. The dosage rate is controlled automatically by a Haith Autofloc' polymer optimization unit. Located on the top of the thickener this unit adjusts the rate according to the amount of suspended solids, thereby minimising the flocculent consumption.

This addition of flocculent is required to achieve solids liquid separation within the clarifier giving rise to a thickened slurry underflow being discharged at its base.

The Haith deep cone thickener is fitted with a torque limiter positioned on the thickener rake. The cone compresses the silt and at a specific torque on the rake sends a signal to operate the underflow pump which in turn discharges the thickened slurry from the thickener into a 45m slurry buffer tank.

The thickener provides a uniform pre-thickened slurry of approx 40%DS wht/wht which in due course reports to a 1.5 metre Haith multi-roll belt press for further conditioning with additional flocculent and dewatering to up to 70-75% DS wht/wht.

This dewatered cake is then transported by a Haith traversing belt conveyor onto a stockpile for off site disposal. 

Any overflow from the thickener (which is significantly free of suspended solids) is discharged into an existing concrete storage tank. From this tank it is then re-circulated and has the advantage of been re-used in low hygiene areas; for example the first fill of the pre-soak and also the washers in the carrot packaging plant.

The installation and subsequent commissioning was a complete success.