Ozwater is Australia's international water conference and trade exhibition, and is run annually by the Australian Water Association. We (Mike Martin and Koen Windey) presented our paper ‘Prospect Mini hydro: A case study of remediation through Stakeholder Engagement and root cause analysis’.
The theme for OzWater ’16 was ‘Water for liveable communities and sustainable industries’ – a theme that resonated with us, and positioned within our core specialisations in cogeneration and mini-hydro plants.
We were informed at the keynote address that while improvements had been made within the water recycling and energy efficiency areas (with a focus on cogeneration), that there was far greater room for improvement.
Of particular interest to us was David Hardy’s presentation ‘Melbourne Water’s low carbon future’ - Melbourne Water treat their sewage at two major plants; the Eastern Water treatment plant and the Western water treatment plant. At these sites there is a mix of Jenbacher and MWM engines; not dissimilar to Sydney Water’s portfolio.
We learnt that their next phases of renewable development are in the mini and micro hydro areas; bringing Melbourne Water’s renewable generation capacity to 125 GWh per year (Compared to 87 GWh pa for Sydney Water).
Phase 3 as it was referred to, involves development of mini and micro hydro turbine sites with installed capacities of <125 kW; which had previously been shown to be uneconomical in remote locations; prompting further discussion within our team on possible sites for development.
Of the poster presentations, the one that caught my eye was ‘Lysotherm: From wastewater plant to power plant’.
Lysotherm is a thermal pressure hydrolysis process; applied to treatment of Waste Activated Sludge (WAS). Sludge is fed into the system at 5-10 bar; and heated to 140-170 ᵒC. Heat is supplied by existing Combined Heat-Power (CHP) systems; with oil used as the heat transfer medium. A temperature-pressure reaction occurs; increasing biogas yield and resulting in lower viscosity by-product. The heat applied to the Lysotherm system is then recovered.
Figure 1: Biogas production at different hydrolysis temperatures
Lysotherm’s benefits include the use of waste heat only (no steam required)
Lysotherm and equivalent technologies reflect the direction that Waste Water treatment plants may take to improve digestion and biogas production.
The poster tied in well with a previous presentation on the feasibility of the refinement of biogas to biomethane by Mitch Laginestra, GHD.
Biomethane is a quality product of high calorific value; suitable to be injected into the existing gas grid in Canberra.
The option study performed by the author demonstrated that despite the lower cost to refine the biogas (compared to LNG); the opportunity cost of sending the gas offsite compared to use onsite with cogeneration engines (Combined Heating and Power plants); was not in the biomethane’s favour.
The golden circle concept was presented in the final address; urging participants to innovate using the guide words of ‘What, Why, How’.
We know our clients desire increased generation from their assets, to increase their return on investment.
So we’ve put together a do list of the ‘How’; how we can assist our clients meet their sustainability and generation goals.
Investigate, in partnership with Flexim flow services ways to accurately measure turbine inflow with the aim of tuning the Kaplan turbine at Prospect to improve efficiency
Continue to develop our Ignition Dashboard across multiple sites, to develop our predictive maintenance capability.
Keep abreast with AEMO (Australian Energy Market Operator) rule changes; especially with respect to ‘virtual tariff meters’ to maximise the return per MWh generated.
Recommend to our clients that they review time of day controls to maximise the return on investment
OzWater Was a great opportunity for us to think a little more laterally and discuss the challenges of the future.