Treated wastewater can be added by entering nutrients using the Fertiliser > Organic > ‘Other organic material’ dialog and water as the depth of irrigation water applied on a monthly basis. You will need to know the volume of wastewater applied (as mm equivalent) and the average concentration of nutrient applied, including organic nitrogen in the wastewater each month.
‘Other organic material’ can be highly variable, and hence there are no defaults. More reliable results are obtained if there has been a laboratory analysis of the material. Enter an appropriate amount (in Tonnes), and enter the DM content if the amount is a wet weight, or 100% if the amount is a dry weight. Nutrient contents are on a dry weight basis. The “Percentage of N in inorganic material” should be estimated from laboratory results as N - nitrate and ammonium divided by total N. This value affects the proportion of material that is treated as slow-release material.
Specify the irrigation system type that best describes the irrigation system used, and when specifying nutrient concentrations in irrigation water, select Block specific and then enter the minimum possible concentration (0.1 ppm) for a nutrient not of interest, say Ca. Now enter the volume of water applied to the block as a depth (mm/month) using the Application depth option. Do this for each month.
If the treated wastewater only contains inorganic N, then the option of using irrigation management strategy and user-defined irrigation nutrient concentrations, where the enter concentration is the water concentration as ppm or ug/ml, can be used.