The aim of this Bachelor’s thesis was to optimize the water/product phase in milk, cream and raw milk production lines so that as little usable raw material as possible goes to the sewerage system. On the other hand, it is also important that water is not allowed to go into product tanks. The water in the product tanks would decrease the fat content and the sensory quality of the product.

The thesis was commissioned by Hämeenlinnan Osuusmeijeri (Hämeenlinna Cooperative Dairy) whose product range includes milks, creams and cultured milks. The company has no previous studies on the product/water phase in the production lines between cleaning and production. No changes have been made in the production lines after installation.

The chemical and physical composition of milk and cream were discussed in the thesis as they have an effect on the flow behavior in the pumps and pipeline. The effect of milk processing on the chemical and physical properties of the product were also dealt with. In addition, the theory on flow dynamics and operation of the dairy pumps were applied in the thesis.

First, the amount of product/water phases in the studied lines were monitored for some weeks. The biggest amount of water/product phases was made in milk lines (B5 & B8) and cream lines (B7 & B9). Samples of these water/product phases were taken before and after the changes. The fat and total solid contents were analyzed in the samples. The statistical analysis of the results showed that only changes in the start phases in lines B5 and B9 and start and end phases of line R2 had a statistical significance. Also, the results of dairy waste water monitoring indicate that the changes made in the start and end phases of the production lines had a positive effect. However, it is still possible to adjust the water/product phases even more.