87.28. Effluent of a tertiary treatment system with phosphorous removal: The effluent of a tertiary treatment system with phosphorous removal that cannot be carried towards a leaching field that complies with Division XV.4 may be discharged into any watercourse whose dilution rate in dry periods is over 1:300.
The outlet pipe through which the effluent is discharged into the watercourse must be located at all times below the surface of the receiving water.