Modelling the effect of water recycling on the quality of potato products

Purifying and recycling process water is a way to minimize the use of potable water and the production of wastewater in the food industry. Water recycling should, however, never affect the quality of the final products. Therefore, a model has been developed to investigate the possibilities of water recycling in a potato factory. One problem that could arise in a water recycling system is the accumulation of dissolved components, such as salts, in the process water loop, which would affect the product quality. Therefore, the quality of the potato products can be related to the amount of chloride ions present in the final product. The model described in this article is based on mass balances and transient diffusion theory is used to calculate the amount of chloride ions present in the process water and in the final product. The calculations show that chloride ions do accumulate in the water and in the potatoes during recycling, because of the addition of salts to the system. The approach used proved to be useful to obtain quantitative information on the process and to find critical points in the system.