the Phase 1 guidelines). This is because the enrichment or addition of salts from natural or anthropogenic processes in water transported through a rural or urban catchment increases its salinity levels. Salinity levels in groundwater range from fresh to highly saline. Infiltration of shallow saline groundwater into leaky sewers can substantially increase the salinity and sodicity of sewage effluent, rendering it unfit for recycling via managed aquifer recharge unless it is treated or blended. 5.3.3 Management of salinity and sodicity Management controls include preventive measures such as: catchment water-quality management and source control (to minimise salt export and remove • or mitigate point sources of salinity, where viable) source water selection • site selection to target aquifers that minimise risk • pretreatment or post-treatment (desalination) • shandying of recovered water with alternative, lower salinity sources (shandying is the • addition of one water source to another). 5.3.4 Mitigation of salinity and sodicity hazards in relation to stages of risk assessment General criteria for assessing the appropriate level of management for salinity and sodicity hazards are provided in Table 5.7. Table 5.7 Criteria, controls and monitoring to mitigate salinity and sodicity hazards in relation to the stages of risk assessment assessment Residual risk Low anticipated mixing • assessment Source water for leading to acceptable • (operational) recovery efficiencies recharge <500 mg/L Low risk of mobilising TDS As per • • Acceptance salt stored in the soil Source water of better precommissioning • criteria quality than ambient profile or in aquifer residual risk groundwater mineral deposits assessment criteria, Entry-level Low probability of based on validation • assessment undesirable off-site monitoring during Maximal and impacts and commissioning and precommissioning simplified further modelling residual risk assessment Preventive measures na Refer to Section 6.2 Refer to Section 6.2 • •
the Phase 1 guidelines). This is because the enrichment or addition of salts from natural or anthropogenic processes in water transported through a rural or urban catchment increases its salinity levels. Salinity levels in groundwater range from fresh to highly saline. Infiltration of shallow saline groundwater into leaky sewers can substantially increase the salinity and sodicity of sewage effluent, rendering it unfit for recycling via managed aquifer recharge unless it is treated or blended. 5.3.3 Management of salinity and sodicity Management controls include preventive measures such as: • catchment water-quality management and source control (to minimise salt export and remove or mitigate point sources of salinity, where viable) • source water selection • site selection to target aquifers that minimise risk • pretreatment or post-treatment (desalination) • shandying of recovered water with alternative, lower salinity sources (shandying is the addition of one water source to another). 5.3.4 Mitigation of salinity and sodicity hazards in relation to stages of risk assessment General criteria for assessing the appropriate level of management for salinity and sodicity hazards are provided in Table 5.7. Table 5.7 Criteria, controls and monitoring to mitigate salinity and sodicity hazards in relation to the stages of risk assessment Acceptance criteria Entry-level assessment and simplified assessment • Source water for recharge <500 mg/L TDS • Source water of better quality than ambient groundwater Maximal and precommissioning residual risk assessment • Low anticipated mixing leading to acceptable recovery efficiencies • Low risk of mobilising salt stored in the soil profile or in aquifer mineral deposits • Low probability of undesirable off-site impacts Residual risk assessment (operational) • As per precommissioning residual risk assessment criteria, based on validation monitoring during commissioning and further modelling Preventive measures na • Refer to Section 6.2 • Refer to Section 6.2
water-recycling-guidelines-mar-24.docx