The following outlines examples of the purposes for uncontaminated biosolids re-use:

Documents demonstrating the appropriate treatment and re-use of biosolids.

An example may be a biosolids management plan.

The management plan may include a flow diagram that outlines key steps for the treatment of biosolids prior to re-use to ensure they are uncontaminated.

Documents, for example a biosolids management plan, have been presented which demonstrate only uncontaminated biosolids are re-used.

This requirement will mitigate impacts on water quality and the risk of salinisation, therefore supporting the implementation of Criterion 2.6 and 2.7 respectively.

Records which demonstrate:

Records have been presented which demonstrate biosolids are not disposed of and/or released into receiving waterbodies, natural wetlands or other ecosystems.

There is no evidence of the discharge and/or release of biosolids into receiving waterbodies, natural wetlands or other ecosystems during the audit.

The UoC should develop and implement a biosolids management plan, which includes procedures relating to the containment of biosolids.

The appropriate containment of biosolids should consider the risk of runoff during anticipated and/or recurring extreme weather events, such as tropical storms or flooding.

Documents demonstrating the appropriate containment of biosolids. An example may be a biosolids management plan.

The management plan may include a flow diagram that outlines key steps for the containment of biosolids.

Documents, for example a biosolids management plan, have been presented which demonstrate the appropriate containment of biosolids.

Conformance should be confirmed through a visual inspection of the site.

Freshwater wells with a conductivity or chloride concentration above the thresholds in Indicator 2.7.4 will demonstrate that salinisation has taken place.

Specific conductance or chloride concentration should be monitored at a frequency adapted to fluctuations due to natural factors, such as seasonal rains.

Records of specific conductance of freshwater wells on, or in proximity to the site (within 1km radius).

Regulatory records obtained where applicable, to demonstrate well-monitoring is not permitted by law.

Monitoring records are available for freshwater wells in proximity to the site, which demonstrate either conductivity or chloride concentration is below the relevant threshold specified in Indicator 2.7.4.

Monitoring has taken place at least every six months and considered natural factors, such as seasonal rains.

Regulatory records are available for instances where well-monitoring is not permitted by law.

The records demonstrate conductivity testing has taken place.

Hand-held refractometers can be used to measure salinity. These devices are appropriate for salinities of approximately 2 or 3 ppt, but they are not sensitive enough to determine if sites are causing the salinisation of freshwater bodies.

The quickest and easiest method to evaluate salinity of water is to measure specific conductance with a conductivity meter. An alternative method is a chloride test kit, which is typically cheaper.

Salinity levels are: Freshwater (limnetic; <0.5 ppt), slightly saline (oligohaline; 0.5-4.9 ppt), moderate saline (mesohaline; 5-17.9 ppt), highly saline (polyhaline; 18-29.9 ppt) and seawater (euhaline; 30-34.9 ppt).

River estuaries are an example of a waterbody that have periodic varying salinity levels. These can also be referred to as poikilohaline waterbodies.

Salinity testing of effluent water in the receiving waterbody or natural wetlands should be conducted.

Salinity levels in the receiving waterbody or natural wetlands may be obtained from credible sources, e.g. results of government monitoring.

To comply with the exception in the indicator, salinity testing in the waterbody or natural wetland should take place. Alternatively, test results can be obtained from credible sources, e.g. scientific or government body.

Results of salinity testing for effluent water and in the receiving waterbody or natural wetlands.

If applicable, reports or measurements determining whether waterbodies and natural wetlands have naturally varying salinity levels.

Salinity test results have been presented which determine one of the following:

The location and/or route of the discharge of brackish or saltwater effluent to demonstrate discharge does not take place over land.

Examples of evidence may include maps/plans of the discharge locations/routes.

Evidence has been presented, such as maps/plans, to demonstrate brackish or saltwater effluent is not discharged over land.

Brackish water has a salinity of 0.5-29.9 ppt, while seawater has a salinity of > 29.9 ppt.

Low permeable liners include liners made from:

Records demonstrating the installation and maintenance of low permeable liners in ponds.

Low permeable liners have been installed and maintained in ponds.

For UoCs located in tidal systems, timing of measurements should correspond with high and low tides, to reflect variations related to the tidal regime.

The UoC can conduct DO monitoring immediately downstream of the last site in a waterbody whilst still following the sampling method in Appendix 8 (8.11).

This may reduce sampling costs when there are multiple sites discharging point source effluent releases to a Type B waterbody near each other.

The methods outlined in Appendix (8.11.2 and 8.11.3) shall be used to record DO concentrations used to determine daily diurnal DO (DDDO).

Any missed samples or deviations in sampling time should be accompanied by a written justification.

Records that DO measurements correspond to high and low tides in tidal systems.

The location of the sampling point, demonstrating that measurements have taken place downstream from the outflow point.

Results of daily DO monitoring and DDDO fluctuation calculations.

DO measurements have taken place at high and low tides in tidal systems.

DO measurements have taken place downstream from the outflow point.

The UoC has presented results of the DDDO calculations based on DO measurements collected in accordance with the methods outlined in Appendix 8.11.1 and 8.11.2.

Confirm the fluctuation level based on the DDDO calculation is ≤65% saturation level.

Written justifications were provided if there were any missed samples or deviations in the sampling time.

Methods to measure Total Suspended Solids (TSS) can be found in Appendix 8 (8.12).

Concentration of settleable solids (ml/L) can be measured by calculating the volume of solids that settles to the bottom of a conical cone (Imhoff cone) in one hour.

More sophisticated methods such as spectrophotometer readings can also be used to measure settable solids.

Details and location of the system used to treat effluent prior to discharge.

Evidence regular testing of TSS and settleable solids has taken place. Quarterly testing would demonstrate best practice.

Results from the testing of point source releases which demonstrate ≥65% of TSS are captured and the concentration of settleable solids in effluent water is consistently <3.3ml/L.

A treatment is in place and located prior to the point of discharge.

Results of testing from the UoC which confirm the treatment system captures ≥65% of suspended solids and that the concentration of settleable solids in effluent water is <3.3ml/L.

Quarterly monitoring ensures the UoC can capture any seasonal or inter-annual variations in the data collected.

Measurements should be timed to coincide with, or immediately follow, annual turnover events when the waterbody is not permanently stratified (holomictic).

The UoC should calibrate equipment used to measure DO, TN, TP, SD and Chl-a according to the technical specifications of the equipment.

The UoC should conduct measurements of the parameters in-situ.

Samples may be sent for laboratory analysis, however variability with sample maintenance during transit can lead to inconsistent results. This is particularly evident with DO and Chl-a samples.

Documentation outlining the sampling plan to conduct quarterly monitoring and that is in accordance with Appendix 8 (8.8).

Quarterly monitoring data has been collected and submitted to the ASC Water Quality Calculator. Data should be submitted at least annually.

Evidence that quarterly monitoring data has been timed with annual turnover events (where applicable).

That equipment to measure DO, TN, TP, SD and Chl-a has been calibrated according to technical specifications.

The sampling methodology to conduct quarterly monitoring is in accordance with Appendix 8 (8.8).

The UoC has conducted quarterly monitoring of the water quality parameters and submitted data to the ASC Water Quality Calculator at least annually.

Evidence has been provided demonstrating the UoC has calibrated equipment to measure DO, TN, TP, SD and Chl-a in accordance with the technical specifications.

Paerl, H.W., Scott, J.T., McCarthy, M.J., Newell, S.E., Gardner, W.S., Havens, K.E., Hoffman, D.K., Wilhelm, S.W. and Wurtsbaugh, W.A., 2016. It takes two to tango: when and where dual nutrient (N & P) reductions are needed to protect lakes and downstream ecosystems. Environmental science & technology, 50(20), pp.10805-10813.

Information on the appropriate use of Secchi Disks can be found here: ‘What is a Secchi disk’, accessed November 22, 2023: <https://www.nalms.org/secchidipin/monitoring-methods/the-secchi-disk/what-is-a-secchi-disk/>

Example of a method for Chl-a measurements made using ethanol extraction followed by spectrophotometric measurement at wavelengths 665 and 750nm (using accredited methods: EPA method 445.0: Method 445.0 In Vitro Determination of Chlorophyll a and Pheophytin ain Marine and Freshwater Algae by Fluorescence, accessed November 22, 2023: https://cfpub.epa.gov/si/si_public_record_report.cfm?Lab=NERL&dirEntryId=309417

Cost effective example for measuring using in-situ Chl-a using a field spectroflurometer include the FluoroSense handheld fluorometer manufactured by Turner Designs and the YSI handheld meter with EXO1 (#599080) or EXO2 (#599201) sondes.

Hamdhani, H., Eppehimer, D.E., Walker, D. and Bogan, M.T. (2021) Performance of a Handheld Chlorophyll-a Fluorometer: Potential Use for Rapid Algae Monitoring. Water, 13, 1409: https://doi.org/10.3390/w13101409

Kuha, J., Järvinen, M., Salmi, P. and Karjalainen, J. (2020). Calibration of in situ chlorophyll fluorometers for organic matter. Restoration of Eutrophic Lakes, 847, 4377-4387: <https://doi.org/10.1007/s10750-019-04086-z>