Proposed changes to some Trade Waste Acceptance Criteria
We are improving the way we manage trade waste. Our proposed changes involve replacing a total dissolved solids (TDS) limit with a sodium concentration and load limit.
We have been seeking trade waste customer feedback on the proposed changes, which are being considered to reduce salinity in our sewerage system.
Consultation with our trade waste customers is now closed.
We've advised all our business customers about the proposed changes and reasons for them. Most of our customers will not be impacted. Businesses that will be impacted are those that are discharging higher levels of sodium to the sewer.
We received feedback via telephone calls, emails and meetings. The feedback we have received has been positive overall with most customers saying they understood why the changes were being made.
Of the impacted businesses, some had questions about how disposal charges would be affected. We explained that there would be no change to the current billing parameters and charges, and that the driver for changing sodium levels in trade waste was for compliance reasons.
One business had concerns about the effect of the proposed reduced sodium limit on their manufacturing process. We are continuing to work with them on ways to reduce sodium levels.
Why the changes?
Total Dissolved Solids (TDS) is currently classified as a Priority Pollutant for Melbourne Water’s Western Treatment Plant (WTP). Investigation work identified that the key parameter to manage within the broad suite of substances that constitute TDS is sodium.
We want to place a greater focus on sodium limits, the highest risk contaminant to recycled water usage. Managing sodium will have the greatest impact on managing the risks to soils and plants irrigated with recycled water within the Werribee Irrigation District (WID) from WTP.
It makes sense that Trade Waste Acceptance Criteria should reflect this.
How was the review done?
In 2016, an industry working group comprising Yarra Valley Water, South East Water, City West Water and Melbourne Water engaged a recycled water consultant to assess options to achieve salinity reduction in recycled water from WTP.
It was identified that most of the required salinity reduction could be achieved through a combination of dilution, diversion or blending options (collectively referred to as treatment options).
A smaller portion of the reduction (less than 25%) was found to be possible by undertaking targeted source control where specific trade waste opportunities may provide comparable or lower cost salinity reduction on a dollar per kilogram basis.
The assessment also identified that trade waste customers discharge only a portion of the sodium entering WTP.
What are the proposed changes?
Introducing sodium concentration and load acceptance criteria will enable Yarra Valley Water to focus on the largest customers where a change could make a difference to the risk level whilst significantly reducing the administrative burden for other customers and water businesses.
The table below outlines all the changes proposed.
The changed Acceptance Criteria will alter the current limits detailed in Schedule 2 – “Acceptance Criteria for Trade Waste” – of your Trade Waste Agreement or Letter of Consent, in the following sections:
Removal Schedule 2 - Part 1.2(c)
Compound Current limit (kg/day) Total Dissolved Solids 200
Insert Schedule 2 - Part 1.2(c):
Compound New concentration limit (mg/L) New load limit (kg/day) Sodium 270 1000
What are the benefits of these changes?
Currently customers requiring a C-SAC pay for the time spent processing it, depending on the retailer. Whilst some customers will have additional C-SAC requirements for other parameters the cost will reduce in line with the reduced time spent by the retailer processing the application.
When will the changes take effect?
For these changes to take effect, the Essential Services Commission (ESC) requires a customer impact assessment to be completed, based on customer consultation and feedback as part of the submission to change the acceptance criteria. All water businesses are consulting with customers about the proposed changes and what they will mean for them.
It is anticipated that the new Acceptance Criteria will be applicable by October 2017, subject to the ESC’s approval.