ROYAL MELBOURNE GOLF CLUB

Transcription

1 SLIDE 1 ROYAL MELBOURNE GOLF CLUB OVER 8 YEARS OF STORMWATER HARVESTING AND TREATMENT EXPERIENCE NATIONAL STORMWATER CONFERENCE 2018 PETER GORDON KURT DAHL

2 OVERVIEW SLIDE 2 Background - Initial solution - Need for more Upgraded Treatment Solution - Water Treatment Plant - Stormwater Victoria Award: Excellence in Infrastructure Knowledge and Experience Journey 8+ years of Operation - Process changes Conclusions and Recommendations

3 SLIDE 3 BACKGROUND

4 ROYAL MELBOURNE GOLF CLUB SLIDE 4 Ranked amongst the best golf courses in the world Continued drought during Criticism of using drinking water - Water restrictions - Negative impact of tankers (recycled water) - Playing surfaces deteriorated substantially - Including impact of saline bore water RMGC examined alternative solutions to diversify supply - Already using groundwater, although limited availability Stormwater identified as preferred solution to supplement groundwater

5 INITIAL SOLUTION SLIDE initial investment in stormwater harvesting scheme - Initial design intent: harvest 60 ML/year of stormwater Infrastructure Stormwater Harvesting Pipe Gross Pollutant Trap Pump Wet Well Accumulator Storage Lagoon Purpose Stormwater is harvested from a Melbourne Water stormwater pipe that runs under the East course. Stormwater flows under gravity via a diversion chamber into the Gross Pollutant Trap (GPT) to catch gross pollutants in the water greater than 3mm. From the GPT the water flows into pump wet well, from which a set of transfer pumps initially pumped the water to the new storage lagoon (see later change to this configuration). Excess water from the GPT is directed to an underground 1ML accumulator that is connected directly to the pump wet well. The 35ML storage lagoon is designed for storage of stormwater and groundwater and assists in buffering water supply and irrigation demand over the course of a year.

6 NEED FOR MORE SLIDE 6 20 ML stormwater harvested vs. 60 ML design Permeate Partners engaged in August Revised project objectives Increased water supply - Optimisation of stormwater/groundwater supplies - Maximising recovery of any additional treatment Stormwater treatment - Conform to National Guidelines - Unrestricted irrigation - Reduce / remove solids, nutrients, oil & grease - Reduce risk of algal blooms Groundwater treatment - Reduce salt levels - Sufficient for use on all surfaces (greens + fairways) Maximise reuse of existing infrastructure

7 SLIDE 7 UPGRADED TREATMENT SOLUTION

8 RMGC UPGRADED FLOWSHEET New Infrastructure Modified Infrastructure SLIDE 8 Existing Infrastructure Optimised to increase yield Maximise water recovery Groundwater system (extends across the course) Manage: TSS, O&G, Nutrients Tablet Chlorinator Disinfection and pre-treatment Surface Wetland UF Waste Disinfection + residual Bioretention Filter Storage Lagoon Modified to allow low flow capture Ultra Filtration Chlorination Salt load management Stormwater extraction Underground Maximise accumulator water recovery Stormwater Drain RO Permeate Practice fairway irrigation Reverse Osmosis RO Brine Irrigation storage

9 WATER TREATMENT PLANT SLIDE 9 Feed is a combination of stormwater and groundwater - Varies at different times of the year UF capacity = 1.6 MLD RO capacity = 0.4 MLD - Side stream treatment Overall plant achieves ~ 98% recovery across the year - UF backwash recovery - Brine irrigation

10 PROCESS PERFORMANCE SLIDE 10 Membranes commissioned in January 2010 Stormwater Victoria Award for Excellence in Infrastructure in Stopping here would not be the complete story - The journey continues First 10 months, stable operation - Dec/Jan increased level of fouling - Combination of reversible and irreversible fouling - Repeatable trend - ph fluctuations - Membrane integrity not compromised PERMEABILITY Summer Periods TIME

11 SLIDE 11 KNOWLEDGE & EXPERIENCE JOURNEY

12 SLIDE 12 EARLY CONCLUSIONS (BUT NOT THE END ) Feed source 38 ML dam: Key observations in summer - Noticeable algae formation - Increase in feed water ph - Increase in feed water turbidity - Regular strainer blockage (slime, NOM and living organisms) - RO biological fouling (confirmed with membrane replacement) Everything pointed towards UF membrane organic based fouling Changes implemented: - Coagulant dose (ACH based) - Shock biocide dosing - Cleaning trials with speciality cleaners

13 WHAT DO WE DO NOW. SLIDE 13 Year 8, time to replace the membranes - Overall deterioration in permeability, potentially impacting capacity Membrane selection process Need more Knowledge (field experience) - Otherwise more of the same Independent Membrane autopsy and cleaning study - Membrane360 - Initial focus was to identify best cleaning method to maintain permeability - Identify foulant to identify best cleaning approach BUT.THERE WAS A SURPRISE

14 AUTOPSY OUTCOME SLIDE 14 No obvious fouling, discolouration or solid build-up

15 AUTOPSY OUTCOME SLIDE 15 SEM Images identified extensive scaling (membrane surface)

16 MORE IMAGES SLIDE 16 Crystalline structure on membrane surface Crystalline structure inside membrane

17 MORE IMAGES SLIDE 17 Crystalline structure on membrane surface X-section

18 MORE IMAGES (CHROMATIC ELEMENTAL IMAGING) SLIDE 18 CEI Image of the inside of a fibre (permeate side) CEI Image of the x-section of a more fouled fibre

19 MORE IMAGES SLIDE 19 CEI Image of feed side of a more fouled fibre CEI Image of the x-section of a more fouled fibre

20 SLIDE 20 PROCESS CHANGES

21 AUTOPSY CONCLUSIONS SLIDE 21 Main cause of fouling - Calcium Carbonate (primary) - Aluminium (secondary, although more distributed) - Very little organic fouling Cleaning study indicated fouling is irreversible, however proved the following: - Low ph cleaning to be below 2.5 (above 2!) - Maximise high ph clean - Boost clean with a high ph speciality cleaner recommended - Provided best performance recovery - High cost / low frequency

22 PROCESS CHANGES (SUMMARY) SLIDE 22 Observation Cause Process Changes Calcium scaling Carbonate High feed ph decreasing solubility, especially during summer. Insufficient ph reduction during acid chemical clean to adequately remove the scale on the membrane surface. Feed water composition. Aluminium scaling High feed ph, higher Al solubility, reducing effectiveness of coagulation process. Inadequate coagulant dose control. Feed ph control introduced (sulphuric acid), with a PID acid dosing loop to control to a setpoint to increase calcium carbonate solubility at the lower ph. Optimised low ph membrane cleaning procedure with the inclusion of a ph control step to maximise removal of carbonate scale. Changed the source water for the chemical clean to rather use RO permeate (reduce risk of scale formation during high ph clean). Feed ph control (same as above) to ensure coagulant process operates within optimum ph range. Optimised high ph membrane cleaning procedure with the inclusion of a ph control step to maximise removal of Al scale. More regular jar testing to optimise coagulant dose control along with linking dose control to feed turbidity. Irreversible fouling Hardened scale. Introduction of planned membrane cleans using speciality membrane cleaners to target Al and Carbonate (Boost clean).

23 OTHER PROCESS CHANGES SLIDE 23 To maximise benefits additional storage was required - Additional storage added to the scheme - Allowed more flexibility in stormwater and groundwater harvesting - Stormwater needs storage.. ph correction - Treated water ph correction to reduce impact of alkalinity on soil and turf health - Control of feed ph to optimise coagulation process performance

24 CONCLUSIONS AND RECOMMENDATION SLIDE 24 System has operated successfully - Project objectives achieved - Treated water quality objectives exceeded - All available water used for irrigation +350 ML of stormwater treated Process optimisation and troubleshooting been fundamental in ensuring ongoing success (not just stopping at the award) Performance and sharing of results provides a good basis into the future as a template for future stormwater treatment facilities, providing design, operation and maintenance experience for stormwater harvesting. Indirect potable re-use testing???? What if.we had done the membrane autopsy earlier.

25 ACKNOWLEDGEMENTS SLIDE 25 Royal Melbourne Golf Club, in particular: - Alan Evans driving the project from the beginning - Richard Forsyth course Superintendent - Club support and operations staff (no formal WTP operations training/experience) For their continuing support of the project and the value they have placed on following industry best practices and reducing their reliance on potable water

26 SLIDE 26 QUESTIONS?