The focus of the project is to identify and quantify the minor energy losses over the entry and exit during gas flow through biofilter materials. The investigation, of minor loss dependency on biofilter medium characteristics and flow conditions, was carried out using five different laboratory scale biofilter units.

For this purpose the gas pressure variation across the different filter units were measured for a range of different gas flow velocities, before the inlet, inside and after the outlet of the filter units.

The measurements showed that filter material characteristics such as pore size and pore orientation have a significant impact on the pressure variation across the filter units.

In addition the variations in gas energy level across the filter units was measured and successfully modelled.

The modelling confirmed that both pore size and pore orientation have a significant influence on the minor energy losses over the inlet of the filter.

Additional measurements of pressure loss were carried out on a full scale biofilter unit located at a pig production facility.

The result showed that the presence of a biofilm inside the biofilter material can have a very significant impact on the pressure loss. In general pressure loss increase rapidly with increasing biofilm thickness. The results also showed that biofilm density within the biofilter material varies with location, but is generally higher near the inlet.

In conclusion this project shows that there exist minor pressure and energy losses over the inlet and outlet of biofilter media (something that has not previously been documented) and that it is possible to model these losses.