Australian Wastewater Treatment Plants Research Articles

16S rRNA gene amplicon sequencing data from an Australian wastewater treatment plant.

Amplicon sequencing data of the 16S rRNA (V1-V3) gene from 56 effluent and sediment samples from an Australian wastewater treatment plant are reported. Proteobacteria (3.50%-90.09%), Actinobacteria (0.02%-45.71%), and Cyanobacteria (0.05%-63.73%) were dominant in the effluent. The sediment samples were dominated by Proteobacteria (13.14%-84.83%), Chloroflexi (0.84%-42.52%), and Firmicutes (1.54%-17.21%).

Mass quantification of nanoplastics at wastewater treatment plants by pyrolysis–gas chromatography–mass spectrometry

Municipal wastewater treatment plants (WWTPs) play a crucial role in the collection and redistribution of plastic particles from both households and industries, contributing to their presence in the environment. Previous studies investigating the levels of plastics in WWTPs, and their removal rates have primarily focused on polymer type, size, shape, colour, and particle count, while comprehensive understanding of the mass concentration of plastic particles, particularly those <1 µm (nanoplastics), remains unclear and lacking. In this study, pyrolysis gas chromatography–mass spectrometry was used to simultaneously determine the mass concentration of nine selected polymers (i.e., polyethylene (PE), polypropylene (PP), polystyrene (PS), poly(ethylene terephthalate) (PET), nylon 6, nylon 66, polyvinylchloride (PVC), poly(methyl methacrylate) (PMMA) and polycarbonate (PC)) below 1 µm in size across the treatment processes or stages of three WWTPs in Australia. All the targeted nanoplastics were detected at concentrations between 0.04 and 7.3 µg/L. Nylon 66 (0.2–7.3 µg/L), PE (0.1–6.6 µg/L), PP (0.1–4.5 µg/L), Nylon 6 (0.1–3.6 µg/L) and PET (0.1–2.2 µg/L), were the predominant polymers in the samples. The mass concentration of the total nanoplastics decreased from 27.7, 18 and 9.1 µg/L in the influent to 1, 1.4 and 0.8 µg/L in the effluent, with approximate removal rates of 96 %, 92 % and 91 % in plants A, B and C, respectively. Based on annual wastewater effluent discharge, it is estimated that approximately 24, 2 and 0.7 kg of nanoplastics are released into the environment per year for WWTPs A, B and C, respectively. This study investigated the mass concentrations and removal rates of nanoplastics with a size range of 0.01–1 µm in wastewater, providing important insight into the pollution levels and distribution patterns of nanoplastics in Australian WWTPs.

Direct injection liquid chromatography-tandem mass spectrometry as a sensitive and high-throughput method for the quantitative surveillance of antimicrobials in wastewater

Environmental antimicrobial pollution and antimicrobial resistance pose a threat to environmental and human health. Wastewater analysis has been identified as a promising tool for antimicrobial monitoring and the back-estimation of antimicrobial consumption, but current pretreatment methods are tedious and complicated, limiting their scope for high-throughput analysis. A sensitive direct injection method for the quantification of 109 antimicrobials and their metabolites in wastewater samples was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method was validated for both wastewater influent and effluent in terms of specificity, calibration range, matrix effect, filtration loss, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ). Most analytes achieved calibration of R2 > 0.99, and the calibration range was from 0.0002 to 150 μg L−1. Recoveries ranged consistently between ~50 % and ~100 % and losses were attributed to sample filtration. Method LOQs were determined as low as 0.0003 μg L−1, and acceptable accuracy (75 %–125 %) and precision (within 25 %) were achieved for >90 % of the analytes. The method was subsequently further assessed using wastewater of raw influent and treated effluent collected from 6 Australian wastewater treatment plants in 2021. In total, 37 analytes were detected in influent and 22 in effluent. Most of them could be quantified at concentrations ranging from 0.0053 to 160 μg L−1, with benzalkonium chloride-C12, amoxicilloic acid, and cephalexin detected at the highest concentrations. The current study provides a straightforward analytical method for antimicrobial monitoring in wastewater with a fast and simple pretreatment procedure.

Mass quantification of microplastic at wastewater treatment plants by pyrolysis-gas chromatography–mass spectrometry

Municipal wastewater treatment plants (WWTPs) are a central point of collection of plastic particles from households and industry and for their re-distribution into the environment. Existing studies evaluating levels of plastics in WWTPs, and their removal rates have reported and used data on polymer type, size, shape, colour, and number of plastic particles, while the total mass concentration of plastic particles (especially >1 μm) remains unclear and unknown. To address this knowledge gap, raw influent, effluent, and reference water samples from three WWTPs in Australia were collected to analyse the mass concentrations and removal rates of seven common plastics (>1 μm in size) across the treatment schemes. Quantitative analysis was performed by pressurized liquid extraction followed by pyrolysis coupled to gas chromatography mass spectrometry. Results showed that the total plastic content in the WWTPs raw influent samples was between 840 and 3116 μg/L, resulting in an inflow of between about 2.1 and 196.4 kg/day of the total measured plastics. Overall, >99 % by mass of the plastics entering the three WWTPs from the raw influent was removed during the pre-treatment stages, presumably ending up in the sewage sludge, which means emissions (via treated effluent) from the treatment plants are low. Compared with the raw influent, the plastic mass concentrations in the treated effluents (i.e., Class C, A, and final effluent) from the three WWTPs, as well as the reference water samples within their catchments were below the limits of reporting. Of the five quantified plastic types, polyethylene (PE, 76.4 %), and polyvinylchloride (PVC, 21 %) dominated by mass, while polyethylene terephthalate (PET, 1.9 %), polypropylene (PP, 0.4 %) and polymethyl methacrylate (PMMA, 0.3 %) accounted for a small proportion of the total. Overall, this study investigated the mass concentrations of plastic particles above 1 μm in wastewater and their removal, which provided valuable information regarding the pollution level and distribution characteristics of plastic polymers in Australian WWTPs.

Prevalence and emergence of steroidal and non-steroidal anabolic agents in the Australian community measured through wastewater analysis

Develop and validate a method for the detection of performance- and image-enhancing drugs (PIEDs) in wastewater. Investigate prevalence of steroidal and non-steroidal anabolic agents in around 45% of the Australian population during Census week in August 2021. Explore changes and patterns in use over a 13-year period (2009–2021) and emergence of non-steroidal anabolic agents, e.g., selective androgen receptor modulators (SARMs), within one Australian wastewater treatment plant (WWTP) catchment. Performance- and image-enhancing drugs include, inter alia, steroidal (anabolic-androgenic steroids) and non-steroidal anabolic agents [e.g., SARMs, peroxisome proliferator-activated receptor delta (PPAR-δ) agonists, growth hormone secretagogues]. Despite known serious negative health side effects, these substances are misused by athletes and non-athletes to boost physical performance as well as appearance. Due to their misuse, often at concentrations significantly higher than for medical purposes, easy access through the internet, and lack of quality controls, PIED use has become a public health problem. The extent of this issue is difficult to quantify and is currently monitored through the combination of multiple data sources such as surveys, seizures, and anti-doping. To fully understand the prevalence of these substances, especially among the general population, a broader monitoring tool is needed to complement current sources of data. In the past two decades, wastewater-based epidemiology has been developed to investigate exposure to, use, and prevalence of chemicals within entire populations and has potential to be a useful additional tool for PIED monitoring. A solid-phase extraction (SPE) liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed and validated for the detection and quantification of around 50 anabolic agents and metabolites in wastewater. This method was applied to wastewater samples collected in August 2021 from 51 WWTPs across Australia, covering roughly 11.6 million people. This method was also used for temporal analysis of anabolic agents in wastewater from one catchment collected from 2009 to 2021. Limits of quantification (LOQs) were, with few exceptions, in the low ng/L with steroids and their metabolites generally having higher LOQs than the non-steroidal anabolic agents. Spatial wastewater analysis showed the use of multiple types of PIEDs within the Australian population in August 2021. Results of temporal samples indicated no clear trends for detected steroidal anabolic agents. However, they showed that the first non-steroidal anabolic agent was detected as early as 2011, with others following in later years. After their first detection, all non-steroidal anabolic agent concentrations increased almost linearly until 2021, often with a peak in concentration in 2018. LOQs are suitable for the detection of trace amounts of PIEDs in wastewater, especially for SARMs and other non-steroidal anabolic agents. As the method is semi-quantitative, concentrations only give an indication of anabolic agent levels, however, these estimates are likely conservative. The analysis of wastewater across 51 Australian WWTPs revealed widespread use of multiple types of steroidal and non-steroidal anabolic agents. The steady increase of concentrations of non-steroidal anabolic agents in the temporal wastewater samples demonstrates the growing popularity of these substances within the general community. A suitable SPE LC-MS/MS method was developed for the analysis of steroidal and non-steroidal anabolic agents in wastewater influent and was successfully applied to spatial and temporal wastewater samples. Many non-steroidal anabolic agents were detected in wastewater for the first time. Spatial analysis showed the prevalence of anabolic agents and temporal analysis revealed the first detections and subsequent emergence of non-steroidal anabolic agents within an Australian WWTP catchment. Results demonstrated that wastewater analysis is a useful complementary tool to further our understanding of PIED use within the general population and that wastewater data may be useful to public health and PIED researchers.

Direct injection analysis of oxypurinol and metformin in wastewater by hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry.

The increasing global prevalence of gout and diabetes has led to a rise in the use of their respective medications, allopurinol and metformin. These are excreted via urine as oxypurinol and metformin and are discharged into wastewater and the environment. Current environmental monitoring of those two polar chemicals requires labour intensive and potentially inefficient sample pre‐treatments, such as using solid‐phase extraction or freeze‐drying. This study validated a sensitive and simple method using direct‐injection LC–MS/MS for the simultaneous measurement of oxypurinol and metformin in wastewater. The final method utilised a hydrophilic interaction liquid chromatography together with simple filtration through 0.2 μm regenerated cellulose filter followed by dilution in acetonitrile with a dilution factor of 10. The developed method was validated with the limit of quantifications (LOQ) of 0.11 and 0.34 μg/L for metformin and oxypurinol, respectively. The new method was applied to 42 influent wastewater samples and 6 effluent samples collected from 6 Australian wastewater treatment plants. Both compounds were detected well above the LOQ at concentrations 29–214 μg/L in influent and 2–53 μg/L in effluent for metformin, and 24–248 μg/L in influent and 4–81 μg/L in effluent for oxypurinol, demonstrating its high applicability.

Temporal trends of perfluoroalkyl substances in an Australian wastewater treatment plant: A ten-year retrospective investigation

Per- and poly-fluoroalkyl substances (PFAS) are a problematic group of chemicals used in various industrial and household products. They have been extensively detected in wastewater as a result of day-to-day product usage. Due to concerns about their safety, voluntary and regulatory action to limit the manufacture and use of some individual PFAS has occurred since the year 2000. The impact that this intervention has had on the use and potential exposure of Australians has not been measured. Wastewater serves as a powerful tool to assess the chemical use or consumption patterns of a population over time. We accessed a ten-year wastewater archiving program to conduct a temporal analysis of PFAS trends in an urban Australian population between the years 2010 and 2020. Results showed a decline in the concentrations for most PFAS, and a change in the PFAS profile from perfluorosulfonic acids and long-chain perfluorocarboxylic acids, to the short-chain perfluorocarboxylic acids and PFOS-replacement degradation products such as 5:3 FTCA. Intermittent pulses of PFAS that were significantly higher than ‘background’ levels (i.e., representing the PFAS input from primarily households) were observed, suggesting continuing industrial PFAS input within the wastewater catchment. This study highlights the long-term consequences of the diffuse use of persistent chemicals in products, and their ability to continue to enter the wastewater stream for decades.

Wastewater treatment efficacy evaluated with in vitro bioassays

Bioassays show promise as a complementary approach to chemical analysis to assess the efficacy of wastewater treatment processes as they can detect the mixture effects of all bioactive chemicals in a sample. We investigated the treatment efficacy of ten Australian wastewater treatment plants (WWTPs) covering 42% of the national population over seven consecutive days. Solid-phase extracts of influent and effluent were subjected to an in vitro test battery with six bioassays covering nine endpoints that captured the major modes of action detected in receiving surface waters. WWTP influents and effluents were compared on the basis of population- and flow-normalised effect loads, which provided insights into the biological effects exhibited by the mixture of chemicals before and after treatment. Effect removal efficacy varied between effect endpoints and depended on the treatment process. An ozonation treatment step had the best treatment efficacy, while WWTPs with only primary treatment resulted in poor removal of effects. Effect removal was generally better for estrogenic effects and the peroxisome proliferator-activated receptor than for inhibition of photosynthesis, which is consistent with the persistence of herbicides causing this effect. Cytotoxicity and oxidative stress response provided a sum parameter of all bioactive chemicals including transformation products and removal was poorer than for specific endpoints except for photosynthesis inhibition. Although more than 500 chemicals were analysed, the detected chemicals explained typically less than 10% of the measured biological effect, apart from algal toxicity, where the majority of the effect could be explained by one dominant herbicide, diuron. Overall, the current study demonstrated the utility of applying bioassays alongside chemical analysis to evaluate loads of chemical pollution reaching WWTPs and treatment efficacy.

An audit of microplastic abundance throughout three Australian wastewater treatment plants

Wastewater treatment plants (WWTPs) have been identified as an important pathway of microplastics to the environment. Most studies have focused on wastewater effluent, but generally only a small fraction of microplastics entering WWTPs are present in treated effluent. Instead, the majority of microplastics are expected to be retained in the sludge. To our knowledge, there is limited information on microplastics in sludge/biosolids from Australian WWTPs, despite 75% of biosolids produced in Australia being used for agriculture. This study evaluated the abundance of microplastics throughout the treatment trains of three WWTPs in Australia. The fate of microplastics >25 μm during treatment and their release to the environment was evaluated using an audit approach. The highest microplastic concentrations were detected in the influent, with fibres the dominant form of microplastic found. The screening and grit removal process preceding primary treatment removed 69–79% of microplastics, with these microplastics transported to landfill. Only 0.2–1.8% of the total microplastics in the influent were present in the final effluent, while 8–16% were retained in biosolids. This equates to between 22.1 × 106 to 133 × 106 microplastic particles per day released in effluent, between 864 × 106 to 1020 × 106 microplastic particles per day in biosolids, and between 4100 × 106 to 9100 × 106 microplastic particles per day transported to landfill. This study shows for the first time that most microplastics are retained during the initial screening and grit removal process with the load of microplastics going to landfill an order of magnitude greater than that in biosolids. Landfills may thus be an important sink (and potential future source) of microplastics from wastewater.

Long-term trends in tobacco use assessed by wastewater-based epidemiology and its relationship with consumption of nicotine containing products

Measurement of population tobacco use via wastewater-based epidemiology (WBE) provides objective data to evaluate the efficacy of tobacco control strategies. However, current WBE tobacco-use estimates based on nicotine metabolites (cotinine and hydroxycotinine) can be masked by use of non-tobacco nicotine-containing products. To better understand nicotine and tobacco use, we analysed tobacco-specific biomarkers, anabasine and anatabine, as well as nicotine metabolites, cotinine and hydroxycotinine, in wastewater samples collected for 6 weeks per year over 6 years (2012–2017) from an Australian wastewater treatment plant serving approximately 100,000 people. Population-normalised mass loads were used to estimate tobacco and nicotine use trends and were compared with surveys and taxation statistics. Significant annual declines were observed for anabasine, anatabine, cotinine and hydroxycotinine of −3.0%, −2.7%, −2.4%, and −2.1%, respectively. The results corresponded with the annual declining trends reported from surveys (−5%) and taxation statistics (−4%). Significant annual decreases in the ratios of anabasine to cotinine (−1.2%) and anatabine to cotinine (−1.0%) suggested a relative increase in the use of non-tobacco nicotine products at the same time that tobacco use was declining. Monitoring tobacco use with anabasine and anatabine removed influence from nicotine-containing products, showing larger reductions in this Australian city than via nicotine biomarkers, whilst also demonstrating their suitability for monitoring long-term trends.

Determination of anabasine, anatabine, and nicotine biomarkers in wastewater by enhanced direct injection LC-MS/MS and evaluation of their in-sewer stability

Wastewater-based epidemiology (WBE) has been used to estimate tobacco use in the population. However, the increased use of nicotine replacement therapies and e-cigarettes contributes to the load of nicotine metabolites in wastewater, causing over-estimation of tobacco use if nicotine metabolites were used in WBE back-estimation. This study aims to develop a rapid method for determining the tobacco-specific biomarkers, anabasine and anatabine, in wastewater and to evaluate their in-sewer stability for better estimation of tobacco use by WBE. An enhanced direct injection LC-MS/MS was developed to quantify anabasine and anatabine as well as nicotine biomarkers (nicotine, cotinine and hydroxycotinine). The method was optimal when wastewater was filtered through 0.2 μm RC syringe filters and a pre-conditioned SPE cartridge (Oasis HLB 1 cc, 30 mg) before 50 μL was injected into the LC-MS/MS system. Limits of quantification varied between 2.7 and 54.9 ng/L with recoveries from 76% to 103% for all five compounds. In sewer reactors, anabasine and anatabine were less stable than cotinine and hydroxycotinine. They were more stable in the gravity sewer reactor with <20% loss in 12 h than in the rising main sewer reactor with ~30% loss in the same period. We then applied the new method to 42 daily wastewater influent samples collected from an Australian wastewater treatment plant. The five biomarkers were detected in all samples with concentrations ranging from 9.2 to 7430 ng/L. All five compounds were positively correlated with one another. Our results suggested a high throughput analytical method for feasible application in anabasine and anatabine as biomarkers of tobacco use in routine wastewater monitoring.

Combining environmental isotopes with Contaminants of Emerging Concern (CECs) to characterise wastewater derived impacts on groundwater quality

The potential for Wastewater Treatment Plants (WWTPs) to cause adverse impacts to groundwater quality is a major global environmental challenge. Robust and sensitive techniques are required to characterise these impacts, particularly in settings with multiple potential contaminant sources (e.g. agricultural vs. site-derived). Stable (δ2HH2O, δ18OH2O, δ15NNO3, δ18ONO3 and δ13CDIC) and radioactive (3H and 14C) isotopes were used in conjunction with three Contaminants of Emerging Concern (CECs) - carbamazepine, simazine and sulfamethoxazole - to discriminate between multiple potential contamination sources at an Australian WWTP. The radioactive isotope tritium provided a sensitive indicator of recent (post-1990s) leakage, with groundwater activities between 0.68 and 1.83 TU, suggesting WWTP infrastructure (activities between 1.65 and 2.41) acted as a recharge ‘window’, inputting treated or partially treated effluent to the underlying groundwater system. This was corroborated by water stable isotopes, which showed clear demarcation between δ18OH2O and δ2HH2O in background groundwater (δ18OH2O and δ2HH2O values of approximately −5 and −28‰, respectively) and those associated with on-site wastewater (median δ18OH2O and δ2HH2O values of −1.2 and −7.6‰, respectively), with groundwater down-gradient of the plant plotting on a mixing line between these values. The CECs, particularly the carbamazepine:simazine ratio, provided a means to further distinguish wastewater impacts from other sources, with groundwater down-gradient of the plant reporting elevated ratios (median of 0.98) compared to those up-gradient (median of 0.11). Distinctive CEC ratios in impacted groundwater close to the WWTP (∼3.0) and further down-gradient (2.7–9.3) are interpreted to represent a change in composition over time (i.e., recent vs. legacy contamination), consistent with the site development timeline and possible changes in effluent composition resulting from infrastructure upgrades over time. The data indicate a complex set of co-mingled plumes, reflecting different inputs (in terms of both quantity and concentration) over time. Our approach provides a means to better characterise the nature and timing of wastewater derived impacts on groundwater systems, with significant global implications for site management, potentially allowing more targeted monitoring, management and remedial actions to be undertaken.

Complete Genome Sequence of Moraxella osloensis Strain YV1, Isolated from an Australian Wastewater Treatment Plant.

We report the complete genome sequence of Moraxella osloensis strain YV1, which was isolated from a wastewater treatment plant in Australia. The YV1 genome comprises a 2,615,801-bp chromosome and four plasmids. Moraxella osloensis strain YV1 displays the distinctive morphology of Eikelboom morphotype 1863.

An investigation into per- and polyfluoroalkyl substances (PFAS) in nineteen Australian wastewater treatment plants (WWTPs)

Quantifying the emissions of per- and polyfluoroalkyl substances (PFAS) from Australian wastewater treatment plants (WWTP) is of high importance due to potential impacts on receiving aquatic ecosystems. The new Australian PFAS National Environmental Management Plan recommends 0.23 ng L−1 of PFOS as the guideline value for 99% species protection for aquatic systems. In this study, 21 PFAS from four classes were measured in WWTP solid and aqueous samples from 19 Australian WWTPs. The mean ∑21PFAS was 110 ng L−1 (median: 80 ng L−1; range: 9.3–520 ng L−1) in aqueous samples and 34 ng g−1 dw (median: 12 ng g−1 dw; range: 2.0–130 ng g−1 dw) in WWTP solids. Similar to WWTPs worldwide, perfluorocarboxylic acids were generally higher in effluent, compared to influent. Partitioning to solids within WWTPs increased with increasing fluoroalkyl chain length from 0.05 to 1.22 log units. Many PFAS were highly correlated, and PCA analysis showed strong associations between two groups: odd chained PFCAs, PFHxA and PFSAs; and 6:2 FTS with daily inflow volume and the proportion of trade waste accepted by WWTPs (as % of typical dry inflow). The compounds PFPeA, PFHxA, PFHpA, PFOA, PFNA, and PFDA increased significantly between influent and final effluent. The compounds 6:2 FTS and 8:2 FTS were quantified and F–53B detected and reported in Australian WWTP matrices. The compound 6:2 FTS was an important contributor to PFAS emissions in the studied Australian WWTPs, supporting the need for future research on its sources (including precursor degradation), environmental fate and impact in Australian aquatic environments receiving WWTP effluent.

Profiling the diversity of Cryptosporidium species and genotypes in wastewater treatment plants in Australia using next generation sequencing

Wastewater recycling is an increasingly popular option in worldwide to reduce pressure on water supplies due to population growth and climate change. Cryptosporidium spp. are among the most common parasites found in wastewater and understanding the prevalence of human-infectious species is essential for accurate quantitative microbial risk assessment (QMRA) and cost-effective management of wastewater. The present study conducted next generation sequencing (NGS) to determine the prevalence and diversity of Cryptosporidium species in 730 raw influent samples from 25 Australian wastewater treatment plants (WWTPs) across three states: New South Wales (NSW), Queensland (QLD) and Western Australia (WA), between 2014 and 2015. All samples were screened for the presence of Cryptosporidium at the 18S rRNA (18S) locus using quantitative PCR (qPCR), oocyst numbers were determined directly from the qPCR data using DNA standards calibrated by droplet digital PCR, and positives were characterized using NGS of 18S amplicons. Positives were also screened using C. parvum and C. hominis specific qPCRs. The overall Cryptosporidium prevalence was 11.4% (83/730): 14.3% (3/21) in NSW; 10.8% (51/470) in QLD; and 12.1% (29/239) in WA. A total of 17 Cryptosporidium species and six genotypes were detected by NGS. In NSW, C. hominis and Cryptosporidium rat genotype III were the most prevalent species (9.5% each). In QLD, C. galli, C. muris and C. parvum were the three most prevalent species (7.7%, 5.7%, and 4.5%, respectively), while in WA, C. meleagridis was the most prevalent species (6.3%). The oocyst load/Litre ranged from 70 to 18,055 oocysts/L (overall mean of 3426 oocysts/L: 4746 oocysts/L in NSW; 3578 oocysts/L in QLD; and 3292 oocysts/L in WA). NGS-based profiling demonstrated that Cryptosporidium is prevalent in the raw influent across Australia and revealed a large diversity of Cryptosporidium species and genotypes, which indicates the potential contribution of livestock, wildlife and birds to wastewater contamination.

A mass estimate of perfluoroalkyl substance (PFAS) release from Australian wastewater treatment plants

Perfluoroalkyl substances (PFASs) have been used in large quantities for a variety of applications in Australian industry and household products. Through the course of their everyday use, PFASs enter the wastewater stream however current treatment processes provide only partial removal of these chemicals from wastewater. The release of treated effluent and re-use of biosolids represents an important point source of PFASs into the Australian environment yet the scale of PFAS release from Australian WWTPs is unknown. For the first time, influent, effluent and biosolids samples from 14 WWTPs across Australia were assessed for 9 PFASs and the national loads of these PFASs released from WWTPs estimated. Ʃ9PFASs ranged from 0.98 to 440 ng/L (influent), 21-560 ng/L (effluent) and 5.2-150 ng/g (biosolids). National loads of PFOA and PFOS in effluent were estimated at 65 kg and 26 kg per annum respectively. In biosolids, annual loads were estimated at 2 kg and 8 kg respectively. The continued detection of PFOS over a decade after its phase out, the increasing use of PFOS alternatives together with their resistance to degradation processes suggests that PFASs will be a priority for regulators and waste management to prevent further contamination of Australia's water resources.

Innovative graphene microbial platforms for domestic wastewater treatment

Supplying clean water to fulfill human requirements is one of this century’s priorities. Global water resources are barely aligned with the rising demand, which is further aggravated by rising population, climate change and water quality problems. Consequently, there is a persistent need for innovative technologies to valorize unconventional water resources such as domestic wastewater. Graphene holds promising prospects in developing domestic wastewater treatment to qualitatively enhance treatment efficiency and quantitatively increase water supply. This review highlights the existing wastewater treatment processes along with their challenges according to South Australian wastewater treatment plants (WWTPs) which are representative of many modern WWTPs. The discussion will also cover the current and potential applications of graphene for domestic wastewater treatment, as well as obstacles and research priorities required for commercialization.

Dissolved methane in the influent of three Australian wastewater treatment plants fed by gravity sewers

Methane (CH4) is an important anthropogenic greenhouse gas and a by-product of urban sewage management. In recent years and contrary to international (IPCC) consensus, pressurised (anaerobic) sewers were identified as important CH4 sources, yet relatively little remains known regarding the role of gravity sewers in CH4 production and conveyance. Here we provide the results of a nine month study assessing dissolved CH4 levels in the raw influent of three large Australian wastewater treatment plants (WWTPs) fed by gravity sewers. Similar to recent international research and contrary to IPCC guidance, results show that gravity sewered wastewater contains moderate levels of CH4 (≈1mgL−1). Dissolved CH4 concentration correlated negatively with daily sewage flow rate (i.e. inversely proportional to sewer hydraulic residence time), with daily CH4 mass loads on average some two-fold greater under low flow (dry weather) conditions. Along with sewage hydraulic residence time, sewer sediments are thought to interact with sewage flow rate and are considered to play a key role in gravity sewer CH4 production. A per capita load of 78gCH4person−1y−1 is offered for gravity sewered wastewater entering WWTPs, with a corresponding emission estimate of up to 62gCH4person−1y−1, assuming 80% water-to-air transfer of inflowing CH4 in WWTPs with combined preliminary–primary plus secondary treatment. Results here support the emerging consensus view that hydraulic operation (i.e. gravity versus pressurised, sewage flow rate) is a key factor in determining sewer CH4 production, with gravity sewer segments likely to play a dominant role in total CH4 production potential for large metropolitan sewer networks. Further work is warranted to assess the scale and temporal dynamics of CH4 production in gravity sewers elsewhere, with more work needed to adequately capture and assess the scale of diffuse sewer network CH4 emissions from sprawling urban settlements globally.

Cryptosporidium Attenuation across the Wastewater Treatment Train: Recycled Water Fit for Purpose.

Compliance with guideline removal targets for Cryptosporidium which do not provide any credit for the inactivation of oocysts through wastewater treatment processes can considerably increase the cost of providing recycled water. Here we present the application of an integrated assay to quantify both oocyst numbers and infectivity levels after various treatment stages at three Victorian and two South Australian (SA) wastewater treatment plants (WWTPs). Oocyst density in the raw sewage was commensurate with community disease burden, with early rounds of sampling capturing a widespread cryptosporidiosis outbreak in Victoria. The level of infectivity of oocysts in sewage was stable throughout the year but was significantly lower at the SA WWTPs. Removals across secondary treatment processes were seasonal, with poorer removals associated with inflow variability; however, no decrease in the oocyst infectivity was identified. For SA WWTPs, those oocysts remaining within the secondary treatment-clarified effluent were proportionally more infectious than those in raw sewage. Lagoon systems demonstrated significant inactivation or removal of oocysts, with attenuation being seasonal. Examination of a UV system emphasized its efficacy as a disinfectant barrier but conversely confirmed the importance of a multibarrier approach with the detection of infectious oocysts postdisinfection. The ability to characterize risk from infectious oocysts revealed that the risk from Cryptosporidium is significantly lower than previously thought and that its inclusion in quantitative risk assessments of reuse systems will more accurately direct the selection of treatment strategies and capital expenditure, influencing the sustainability of such schemes.IMPORTANCE Here we present the application of a recently developed integrated assay not only to quantify the removal of Cryptosporidium oocysts but also to quantify their infectivity across various treatment stages at five wastewater treatment plants (WWTPs), thereby better measuring the "true effect" of the treatment train on oocyst risk reduction. For a number of the WWTPs analyzed in this study the risk, is significantly lower than previously thought. Therefore, the inclusion of oocyst infectivity in guideline values and in quantitative microbial risk assessment (QMRA) has the potential to affect future treatment directions and capital expenditure.

Treatment challenge of a cyanobacterium Romeria elegans bloom in a South Australian wastewater treatment plant – a case study

ABSTRACTA bloom of the non-toxic cyanobacterium Romeria elegans in waste stabilisation ponds (WSPs) within Angaston waste water treatment plant (WWTP) has posed an unprecedented treatment challenge for the local water utility. The water from the WSPs is chlorinated for safety prior to reuse on nearby farmland. Cyanobacteria concentrations of approximately 1.2 × 106 cells mL−1 increased the chlorine demand dramatically. Operators continuously increased the disinfectant dose up to 50 mg L−1 to achieve operational guideline values for combined chlorine (0.5-1.0 mg L−1) prior to reuse. Despite this, attempts to achieve targeted combined chlorine residual (CCR) failed. In this study, samples from the waste stabilisation pond at Angaston WWTP were chlorinated over a range of doses. Combined chlorine, disinfection by-product formation, cyanobacteria cell concentration, Escherichia coli inactivation, as well as dissolved organic carbon and free ammonia were monitored. This study shows that, in the occurrence of cyanobacterial blooms, CCR does not directly suggest pathogen removal efficiency and is therefore not an ideal parameter to evaluate the effectiveness of disinfection process in WWTP. Instead, E. coli removal is a more direct and practical parameter for the determination of the efficiency of the disinfection process.