Table 5.11 Criteria, controls and monitoring to mitigate turbidity hazards in relation to the stages of risk assessment impacting on receiving assessment Residual risk assessment environment (operational) Source water for • Low risk of mobilising recharge <1 NTU • clays or other colloids from aquifer into Confirmation of Maximal and • Acceptance groundwater precommissioning precommissioning criteria Low risk of recovered • residual risk assessment residual risk water and aquifer criteria based on assessment turbidity beyond the validation monitoring attenuation zone not Low risk of meeting required • purge water environmental values and waste stream simplified If solids are accumulating • Preventive in aquifer, monitoring and measures investigations to define the level of residual risk Validation monitoring na Refer to Section 6.1 Refer to Section 6.1 • • na na Monitor turbidity and flow of recharge and recovery to obtain a • Determine turbidity of Verification recharge and recovered monitoring water, supported by volumetric inputs and outputs Determine turbidity of recharge and • • recovered water, and at observation well at edge of attenuation zone verification Operational monitoring above monitoring Maintain records of • management of clogging and their effectiveness Estimate • • or measure annual injection and recovery volumes na = not applicable; NTU = nephelometric turbidity unit. 5.7 Radionuclides Radioactive materials (eg uranium, thorium, potassium-40) occur naturally in the environment, and risk of human exposure to radiation is predominantly from natural sources.
Table 5.11 Criteria, controls and monitoring to mitigate turbidity hazards in relation to the stages of risk assessment Acceptance criteria and simplified assessment • Source water for recharge <1 NTU Maximal and precommissioning residual risk assessment • Low risk of purge water waste stream impacting on receiving environment • Low risk of mobilising clays or other colloids from aquifer into groundwater • Low risk of recovered water and aquifer turbidity beyond the attenuation zone not meeting required environmental values Residual risk assessment (operational) • Confirmation of precommissioning residual risk assessment criteria based on validation monitoring Preventive measures Validation monitoring na • Refer to Section 6.1 • Refer to Section 6.1 na na • Monitor turbidity and flow of recharge and recovery to obtain a • If solids are accumulating in aquifer, monitoring and investigations to define the level of residual risk Verification monitoring • Determine turbidity of recharge and recovered water, supported by volumetric inputs and outputs • Determine turbidity of recharge and recovered water, and at observation well at edge of attenuation zone Operational monitoring • Estimate or measure annual injection and recovery volumes • verification monitoring above • Maintain records of management of clogging and their effectiveness na = not applicable; NTU = nephelometric turbidity unit. 5.7 Radionuclides Radioactive materials (eg uranium, thorium, potassium-40) occur naturally in the environment, and risk of human exposure to radiation is predominantly from natural sources.