Melbourne Water

Biogenic taste and odour (T&O) events pose a series of challenges to drinking water treatment plants, increasing treatment costs and influencing consumer perception of water quality. Granular activated carbon (GAC) can be used to adsorb T&O compounds, such as geosmin and 2-methylisoborneol (2-MIB). The development of biofilms on the GAC granules convert the system into biological activated carbon (BAC), extending its lifetime; however, the evolution of biofilms in BAC systems and how it affects biofiltration performance of T&O compounds is not well understood. In this study, two sets of experiments designed to develop BACs under different conditions, such as carbon type, age, exposure to T&O and flow regimens, were conducted to investigate how the evolution of the biofilm affects the removability of geosmin and 2-MIB, and the effects of pre-exposure to T&O on removal efficiency to simulate the effects of seasonal T&O loading. The kinetics of T&O removability by BAC were statistically the same as the removability by GAC; approximately 90% removal of T&O compounds was observed and, of the total, 90% was removed within the first 72 hours as determined via the newly developed batch adsorption test. Pre-exposure to T&O had little to no effect on the BACs capacity to remove these compounds. These results indicate that adsorption still plays a major role in T&O removal even after the system has become BAC and attests to the resilience of BAC systems against intermittent periods of non-exposure to T&O. • Micropore volume had strong correlation with taste and odour adsorption. • Taste and odour removal remained high after perceived adsorption exhaustion. • Pre-exposure to taste and odour compounds had little effect on their removability. • Similar removal kinetics observed between aged and fresh granular activated carbon.

Seagrass restoration is a critical strategy for reversing habitat loss, yet the mechanistic drivers of early recruitment failure remain poorly understood. Seed-based approaches offer a scalable and cost-effective solution for large-scale restoration, but low germination and establishment success in situ continue to limit their effectiveness. This study investigates the effects of sulphide-rich sediments on the germination of the temperate seagrass Zostera muelleri (syn. Nanozostera muelleri) as a model species and explores whether the presence of native infaunal bivalves can mitigate sulphide stress. A multi-factorial mesocosm experiment reflecting observed ranges in temperate seagrass systems was conducted manipulating sediment sulphide levels and bivalve presence. Germination success, sediment sulphide accumulation, and subsequent plant growth were monitored to investigate biotic and abiotic interactions affecting seedling establishment. High sediment sulphide concentrations significantly reduced Z. muelleri germination and the presence of native bivalve S. trigonella did not reduce sediment sulphide accumulation. At low sulphide levels, bivalve presence improved germination; however, under high sediment sulphide conditions, bivalve presence further suppressed germination, likely due to synergistic effects of biodeposition and organic enrichment. These findings demonstrate that elevated sediment sulphide concentrations can act as a bottleneck to seed germination, with implications for both natural recruitment and seed-based restoration across seagrass systems. By evaluating generalizable mechanisms, this work positions Z. muelleri as a model species for understanding the impact of sediment geochemistry on restoration outcomes.

BackgroundThis study presents findings from a 15-year longitudinal surveillance program (2009–2024) monitoring Cryptosporidium and Giardia in protected drinking water catchments in Melbourne and environs in the State of Victoria, Australia. As one of the few major cities worldwide sourcing largely unfiltered water from forested catchments, Melbourne presents a unique opportunity to assess the occurrence and prevalence of protozoan parasites in a minimally disturbed ecosystem.MethodsA total of 14,960 animal faecal samples were analysed using polymerase chain reaction (PCR)-based sequencing, including 8695 samples collected over the past 9 years.ResultsCryptosporidium was detected in 3.15% of samples and Giardia in 0.16%. A total of 12 recognised Cryptosporidium species and genotypes were identified, nine of which have known zoonotic potential, as well as two sub-assemblages (AI and AIII) of Giardia duodenalis, including four novel assemblage AI variants. Parasite diversity was the highest in eastern grey kangaroos, which hosted at least 18 Cryptosporidium variants. Temporal analyses revealed significant inter-annual variation, with peak prevalence during the 2023 La Niña year and seasonal differences by host group. Notably, C. ubiquitum, C. muris and C. occultus were recorded for the first time in these catchments. In spite of the low prevalence of high-risk species such as C. parvum and the absence of C. hominis, the detection of emerging and previously uncharacterised genotypes emphasises the importance of sustained surveillance.ConclusionsThese findings have broad implications for managing zoonotic risk in unfiltered water systems worldwide. Advances in metagenomics and high-throughput sequencing platforms will be critical for enhancing future pathogen monitoring and catchment management strategies in the context of increasing climate and environmental pressures.Graphical Supplementary InformationThe online version contains supplementary material available at 10.1186/s13071-025-07048-8.

During a wildfire, parts of the vegetation such as twigs or bark can detach, ignite and become firebrands or embers. When they travel ahead from the main fire front, they can ignite secondary fires in a process known as spotting. We introduce pyBrands , an open-source python tool that uses coupled fire-atmosphere simulations to calculate firebrand trajectories. This module integrates aerodynamic and combustion models for firebrands. This study compares the existing drag and lift models, and combustion models for firebrands by simulating a realistic wildfire plume in a large numerical domain. Firebrands with different properties were injected into the plume and their landing densities were compared. Results indicate that travelled distances strongly depend on the aerodynamic and combustion model. This makes the choice of models difficult and impractical due to the required time step. pyBrands could be used to test and develop new models, improving firebrand behavior prediction in wildfires. • A python module is developed to compare different drag and mass-loss models for firebrands. • Drag and lift models affect the dispersion of firebrands. • Mass-loss models affect the final landing distance of firebrands. • Turbulence and firebrand characteristics can explain long-range transport of firebrand.

Abstract Environmental flows are commonly provided in regulated rivers to maintain and restore riverine environments, including riverbank vegetation. Given the expense and political sensitivity of providing water for the environment, greater certainty regarding the expected benefits of environmental flows is required. We assessed the role of managed flows (for both environmental and consumptive purposes) in delivering sediment and plant propagules to facilitate riverbank recovery. Using artificial turf mats, we determined sediment and seed deposition from 11 flow events over 3 years of varying magnitudes, durations and timing in a heavily regulated lowland river in south‐east Australia. At three sites on the Goulburn River, Victoria, mats were placed on different geomorphic features along an elevation gradient (bars, benches, banks and ledges) before a flow event, and the sediment deposited during the event was analysed and assessed for seedling emergence. A total of 401 kg of sediment and 110 980 seeds were sampled. Mats that were inundated via managed flow releases had an order of magnitude more sediment, and around twice the richness of seed taxa, than mats that were not inundated. More sediment and seed taxa were deposited on low‐lying bars than on more elevated features, while seed composition but not abundance varied across features. A longer duration of inundation was associated with the deposition of more sediment, but not seed taxa or abundance. Unexpectedly, there was no evidence that managed flows delivered less sediment and seeds compared with unregulated tributary inflows. Our findings suggest that in regulated rivers, environmental flows are likely to be critical for providing the sediment and seed necessary to restore geomorphic conditions and promote plant recruitment. Longer flow durations are likely to provide more sediment, while high‐flow events may be particularly important for promoting diverse native riparian plant communities across the full range of in‐channel geomorphic features.

ABSTRACT The dynamics of dissolved organic matter (DOM) in two river waters were investigated after their catchments had been severely burnt in the 2019/20 Australian wildfires. Shortly after these wildfires, dissolved organic carbon (DOC) concentrations were recorded at high levels (∼ 19 mg/L & 30 mg/L) and these became much lower (up to ∼80% less) in the following winter when river flows had increased. Satellite imagery-based data indicated up to 95% of catchment areas burnt and up to ∼50% subsequent vegetation recoveries after two years. Shifts in burn index values for the burnt areas coincided with DOC concentration variations. Specific colour of waters increased up to 40% as daily river flows increased, indicating higher input of humic content from the burnt catchments. Chlorophyll-a was detected at highest levels in waters soon after the fires when river flows were lowest. Enhanced alum doses were predicted using two feed-forward models; one based on DOC and turbidity data and the other based on UV@254nm, colour and turbidity. Doses predicted using the two models showed high correlations (r > 0.9) and were highest for waters directly after the fires. These models were developed for diverse source waters including those impacted by extreme climate events.

This paper presents an overview of integrating new research outcomes into the development of a structural health monitoring strategy for the floating cover at the Western Treatment Plant (WTP) in Melbourne, Australia. The size of this floating cover, which covers an area of approximately 470 m × 200 m, combined with the hazardous environment and its exposure to extreme weather conditions, only allows for monitoring techniques based on remote sensing. The floating cover is deformed by the accumulation of sewage matter beneath it. Our research has shown that the only reliable data for constructing a predictive model to support the structural health monitoring of this critical asset is obtained directly from the actual floating cover at the sewage treatment plant. Our recent research outcomes lead us towards conceptualising an advanced engineering analysis tool designed to support the future creation of a digital twin for the floating cover at the WTP. Foundational work demonstrates the effectiveness of an unmanned aerial vehicle (UAV)-based photogrammetry methodology in generating a digital elevation model of the large floating cover. A substantial set of data has been acquired through regular UAV flights, presenting opportunities to leverage this information for a deeper understanding of the interactions between operational conditions and the structural response of the floating cover. This paper discusses the current findings and their implications, clarifying how these outcomes contribute to the ongoing development of an advanced digital twin for the floating cover.