The operation and control of whey protein concentrating ultrafiltration plants seems, at times, to be difficult. These problems can cause plants to be less efficient due to losses in product quality and throughput. With the general rise in the size of the dairy industry and the subsequent increase in whey protein concentrate production it would seem important to solve these operation and control problems.

This thesis presents work that has been done investigating these problems. The work can be divided into three areas. Firstly the development of suitable models for the description of UF whey concentrating plants. Secondly the use of these models to study the operation and control of UF plants in order to solve the problems mentioned above. Thirdly the study of the UF plant process from a state space perspective in order to determine the underlying reasons for the results found.

The model developed for the simulation of UF plants was found to be qualitatively correct and applicable for the modelling of these plants. It showed that the control of UF plants is very closely linked with their operation. The main effect being the diafiltration ratios used in the operation of the plant. The results found, for the operation and control of UF plants, where confirmed and explained using state space analysis.

The conclusions for the operation and control of UF plants are listed in section 5. 5 of chapter. This section shows an itemised list of the conclusions of chapter 5 which contains all the conclusions for the operation and control of UF plants.