Wairau/Awatere Resource Management Plan Quality of Effluent Effluent that is suitable for application to a surface irrigation system shall comply with the following criteria: • 90% of the samples shall have a BOD less than or equal to 20 mg/L with no5 samples greater than 30 mg/L. • 90% of the samples shall have total suspended solids less than or equal to 30 mg/L with no sample greater than 45 mg/L. • 90% of the measurements of dissolved oxygen in the aerobic chamber shall be equal to or greater than 2 mg/L. • The samples taken on each day shall have a thermotolerant coliform count (determined by either multiple tube dilution or membrane filter technique) not exceeding a median value of 10 organisms per 100 mL with four out of five samples containing less than 20 organisms per 100 mL. • The free residual chlorine concentrations shall be greater than or equal to 0.5 mg/L in all four samples under the maximum 30 minute flow. App O - 2