The pollution that flows into a wastewater treatment plant (TP) is the sum of the flows from all connected demand site (DS) return flow links and catchment (Catch) runoff links.
TreatmentPlantPollInflowTP,p = DSReturnLinkPollOutflowDS,TP,p + CatchmentRunoffLinkPollOutflowDS,TP,p
Treatment can be specified by two different methods: removal rate or outflow concentration
Some fraction of the pollution will be removed by the plant (entered as data--see Water Quality\Wastewater Treatment), and the rest will flow out. Note that if the plant's inflow exceeds its capacity, not all of the inflow will be treated.
TreatmentPlantPollOutflowTP,p = (1 - RemovalRateTP,p x FractionTreatedTP) x TreatmentPlantPollInflowTP,p
The concentration of the outflow will be as specified in the outflow concentration data (see Water Quality\Wastewater Treatment). Note that if the plant's inflow exceeds its capacity, the treated effluent at the specified concentration will be mixed with the untreated overflow.
TreatmentPlantPollOutflowTP,p = OutflowConcentrationTP,p x TreatmentPlantOutflowTP x FractionTreatedTP + TreatmentPlantPollInflowTP,p x (1 - FractionTreatedTP )