Head is the summation of static and friction head. In waste water treatment if waste water flows by gravity then a difference of top water level makes waste water flow from one unit to other. Generally the difference is between 100 to 300 mm. The MBBR does not add any extra head loss. I can share more information with you. Please write me on sarafrv@virajenvirozing.com
Head loss is defined as pressure loss due to flowing liquid and is usually emerged when the hydrodynamic system is more dominant than the hydrostatic.
In the MBBR process, the water flow will pass reactor tank where hydrostatic system is more dominant, therefore it’s unusual to discuss head loss within hydrostatic condition. You need to separate head loss calculation between water flow before reactor tank and after reactor tank while you ignore head loss in the MBBR reactor tank.
Pipe flow expert the good program for waste water flow,head of pump design. The volume in MBBR is less and the amount of Media in cluding MO. For my opinion I will try on the site the collect the data which be so close for application design.