D Health – Major impact for small population Environment – Potentially lethal to local ecosystem; predominantly but potential for off-site impacts E Severe Health – impact for large population Environment – Potentially lethal to regional ecosystem or threatened species, widespread on-site and off-site impacts Table – Risk rating Consequence Insignificant Moderate Severe Likelihood Almost Certain Medium (5A) High (5B) Very High (5C) Extreme (5D) Extreme (5E) Likely Medium (4A) High (4B) High (4C) Very High (4D) Extreme (4E) Possible Low (3A) Medium (3B) High (3C) High (3D) Very High (3E) Unlikely Low (2A) Medium (2B) Medium (2C) High (2D) Very High (2E) Rare Low (1A) Low (1B) Low (1C) Medium (1D) Very High (1E) Exposure risk levels When determining the of risk, the expected end use should be taken into account to determine the potential level of exposure that end users will have to the recycled water. Common end uses for recycled water are presented in Table 5. Table - Exposure Risk Levels, Classification of Recycled Water, and End Uses Risk Level Class End Uses Extreme A+ Multi-unit dwellings; internal reuse (toilet flushing and dedicated cold water taps for washing machines) or external surface irrigation Agricultural irrigation of food crops consumed raw or unprocessed (hydroponics, salad crops, etc) Very High A Urban surface irrigation with unrestricted access and application Fire fighting Fountains and features Dust suppression Cooling process water High B Urban irrigation with some restricted access and application Commercial food crops
- Communal reuse – flushing toilets and designated cold tap washing machines out by DoH at any time. Ongoing monitoring of coliphages and Clostridia dependant on the outcomes of the validation monitoring. For dual reticulation systems chlorination will be required to provide a measurable residual at the point of use. These will be sampled at the delivery point of the system to ensure a chlorine residual is maintained. Class Type Potential End Uses Ongoing Monitoring Parameter Compliance Value Monitoring Frequency Control Measures A End uses with a high level of human contact, including: Urban irrigation with unrestricted access and application4 - Fountains and features - Dust suppression with unrestricted access - Fire fighting - Cooling tower process water E. coli2 < 10 MPN or cfu/100 mL Weeklya Audit may be required. Plumbing maintenance and alteration audits required once every five years, including backflow and auditing. Random audits may be carried out by DoH at any time. A minimum horizontal distance of 250m is required from the edge of the irrigation area to any bore, dam, rainwater tank or other water storage likely to be used to supply water for human consumption. If using surface irrigation methods, there is to be no overspray of the property boundary, pedestrian paths and walkways. There is to be no surface runoff or ponding of recycled water. Compliance with the requirements of AS/NZS 3500.1, including warning and/or prohibition signs, purple colour coding of recycled water meters, external recycled water fittings and pipes, backflow prevention devices and mechanisms to prevent cross connections. For livestock use, helminth treatment may be required and testing for helminthic eggs may be required. Turbidity < 5 NTU (95%ile)5 Continuous online (or weekly) pH 6.5 – 8.5 Continuous online (or weekly) Disinfection Cl: 0.2-2.0 mg/L residual7 UV: TBA TBA Continuous online (or weekly) Type Potential End Uses Ongoing Monitoring Parameter Compliance Value Monitoring Frequency Notes Control Measures B E. coli2 < 100 MPN or cfu/100 mL Monthlya
Incident reporting In the event of incident or non-conformance an incident report must be prepared, including detailed information regarding the incident, any corrective actions, results of any monitoring, correspondence and any preventive actions. Where critical limits for water quality or recycled water system operation are exceeded, each event shall be logged as an incident and reported (see Section 8.2). Emergency reporting Emergency events shall be recorded and reported (see Section 8.2) as soon as practicable including the incident, date, time, immediate corrective actions, any monitoring and proposed further actions. An emergency incident report detailing the monitoring results and the preventive actions should also be added following a review of the incident. 11.2 Audit Reporting DoH may request the recycled water system proponent to engage an auditor to audit and prepare compliance reports on a regular basis; as set by the conditions of the Wastewater Works Design Approval. The audits are to confirm that the recycled water system is operating within the Management Procedures and will ensure that: the ongoing operation and maintenance requirements are being undertaken the system is performing to produce recycled water that conforms to the appropriate water quality compliance values the operational procedures are up-to-date and reflect the actual operational activities the record and reporting requirements are maintained. More information on ‘Evaluation and and ‘Review and continuous improvement’ is contained respectively in AGWR Sections 2.11. & 2.12. All auditing is to be performed by an independent, accredited party auditor. The auditor shall be responsible for conducting the audit and providing DoH with a compliance report. The provision of these audit services shall be at the expense of the recycled water system proponent. All data, whether required to be recorded under this guideline or recorded as part of the treatment plant operation and maintenance by any responsible person shall be made available to auditors in electronic or other suitable format as required by the auditor. The auditor report shall be provided to DoH on their request.
Appendix 2: Standards for Microbiological Quality of Recycled Water for Irrigating Commercial Food Crops This Appendix details the standards for the microbiological quality of recycled water supplied for irrigating commercial food crops. These standards provide clarification to the ‘potential end uses’ detailed in Tables 5 & 6 of these Guidelines and are only permitted to be used for wastewater systems with a Wastewater Works Design Approval. These standards are based on Queensland Regulations/Standards for recycled water and also the Australian Guidelines for Water Recycling: Managing Health and Environmental Health Risks (Phase 1), in particular Table 3.8. Type of Commercial Food Crop Method of Irrigation & On-site preventative measures Class Type E. coli Crops consumed raw or unprocessed e.g. carrots, broccoli, onions, cabbage Includes rockmelons Spray, drip, flood, furrow or subsurface No preventative measures required although pathogen reduction will happen between harvesting and sale A+ <1 cfu/100 mL Crops for produce grown in hydroponic conditions e.g. lettuce Hydroponic A+ <1 cfu/100 mL Crops with limited or no ground contact and eaten raw e.g. tomatoes, capsicums Drip irrigation No harvest of wet or dropped produce B <100 cfu/100 mL Crops with ground contact with skins removed (other than rock melons) before consumption e.g. watermelons Spray, drip, flood, furrow or subsurface If spray irrigation, minimum 2 days between final irrigation and harvest Pathogen reduction between harvesting and sale B <100 cfu/100 mL Type of Commercial Food Crop Method of Irrigation & On-site preventative measures Type E. coli