|Resource Efficiency and Production
|Technology and Treatment
|Guidelines and Validation
Wastewater goes through a number of treatment processes before it is suitable for use as recycled water. Producing the highest quality (potable) recycled water involves removing organics, salts, ionic contaminants, micro-organisms and viruses. This can be achieved using granulated activated carbon, ozonation, hydrogen peroxide and/or by filtration using a membrane. Traditionally, filtration has relied on the use of membranes made from polymers, but new ceramic membranes have greater chemical, thermal and structural stability than polymers.
This project operated a demonstration plant to evaluate whether a ceramic membrane system hybridised with ozonation is an economical and robust treatment technology with a low carbon footprint for Australia. Improvements to water quality (pathogen inactivation, colour removal, etc.), maintenance and cleaning chemical requirements were also assessed.
WORK UNDERTAKEN AND OUTCOMES
Activities prior to completing this project focussed on continued operation of the pilot plant based at Melbourne Water’s Eastern Treatment Plant. Major technical outcomes were:
- Maximum sustainable flux for membrane filtration without ozonisation or coagulation was 50 L/m2.h.
- Addition of inline coagulation enhanced sustainable flux between 100 L/m2.h and 150 L/m2.h.
- Ozonisation and coagulation applied together reached 182 L/m2.h flux; as this flux was limited by the ozone equipment on site, higher fluxes may have been achievable.
- Demonstrating the viability of ceramic membranes as a pathogen barrier: log removal value for bacteria and protozoa based on E.coli was greater than 3.2; virus removal potential using the virus surrogate MS2 measured a log removal value of 4.0.
|Annual OPEX assessment demonstrates that ceramic membrane plants are cheaper to operate than traditional polymer membrane treatment plants; this is principally due to the longer life and lower replacement cost of ceramic membranes.
ADOPTION AND IMPACT
Economic assessment of ceramic membranes based on a 22 megalitre per day plant showed that their high flux and long life are key features that reduce their capital and operating expense. Net present value analysis showed that the operating expense of ceramic membranes was cheaper than polymeric membranes over the life of the plant irrespective of replacement scenario (15, 20 or 25 years).
High flux operation for challenging waters such as secondary effluent, and enhanced total disinfection are features with significant benefits for waste water recycling—they could reduce chemical cleaning, and their robustness and longevity allows smaller plant size and greater operational freedom. The demonstration plant has been transferred to Water Corporation in Western Australia to conduct further trials.
|Victoria University Institute for Sustainability and Innovation
|South East Water
|Water Research Australia (formerly Water Quality Research Australia)
|Black & Veatch
|PWN Technologies (The Netherlands)
|About the AWRCoE
|List of Publications