The transport of NH4 is simulated in a simplified way assuming that NH4 is fully mixed with the flow. Average NH4-N concentrations for dry weather flow (resp. load per inhabitant) and rainwater are needed as input. They are assumed to be constant over time. An initial level of NH4 pollution for the receiving water can be defined by setting the NH4-N concentration for the baseflow. The rainwater from the natural catchment is considered to be unpolluted. The resulting NH4-N concentration in the receiving water is calculated as follows:
c |
NH4-N concentration [g/m3] |
Q |
discharge [m3/s] |
dw |
dry weather part of combined sewer system overflow |
rw |
rainwater part of combine sewer system overflow |
ss |
separate sewer system overflow |
b |
baseflow of receiving water |
n |
rainfall depending discharge of receiving water |
REBEKA 2 considers no other reactions concerning simulation of ammonium.