By using membrane technology to re-concentrate juice solids from rinsewater, full strength juice can be recovered.
During orange juice processing, changes of product or periodic cleaning of the plant often leaves significant volumes of partly diluted juice purged from vessels and lines. This juice may be slightly diluted to say 10.3% solids, compared to full strength juice at 12.25% solids and has no commercial value (or even a negative value as a pollution load).
By using membrane technology to increase the concentration of solids and remove some of the water, full strength juice can be recovered. Here is an example of the economics.
Firstly, the juice is treated by Ultrafiltration (UF) to remove the suspended solids and the filtrate or permeate is then concentrated by Reverse Osmosis (RO) to remove some of the water and so increase the solids.
The concentrates from both the UF and RO processes are added together to re-form a full strength orange juice which then has significant commercial value.
|Potential payback time for orange juice processing plant = 7.9 months
- £90,000 = Capital cost of automatic UF system
- £100,000 = Capital cost of automatic RO system
- 10% allowed for installation of systems
- £79/day allowed for operating costs of both membrane systems (8 hours/day)
- 24p /litre wholesale price for full strength orange juice
- 4,820 litres / 8 hour day diluted juice at 10.3% SOLIDS
- 4,005 litres / 8 hour day at 12.25% solids recovered juice
- £961/day recovered juice value at 12.25% solids
- £882/day recovered juice value after operating costs allowed
Payback time for membrane system =
(£90,000 + £100,000) / £882 x 1.1 = 7.9 months