Joe Lane

Long-term trends and opportunities for managing regional water supply and wastewater greenhouse gas emissions

Greenhouse gas emissions are likely to rise faster than growth in population and more than double for water supply and wastewater services over the next 50 years in South East Queensland (SEQ), Australia. New sources of water supply such as rainwater tanks, recycled water, and desalination currently have greater energy intensity than traditional sources. In addition, direct greenhouse gas emissions from reservoirs and wastewater treatment and handling have potentially the same magnitude as emissions from the use of energy. Centralized and decentralized water supply and wastewater systems are considered for a scenario based upon a government water supply strategy for the next 50 years. Many sources of data have large uncertainties which are estimated following the IPCC Good Practice Guidelines. Important sources of emissions with large uncertainties such as rainwater tanks and direct emissions were identified for further research and potential mitigation of greenhouse gas emissions.

Environmental benefits and burdens of phosphorus recovery from municipal wastewater

The environmental benefits and burdens of phosphorus recovery in four centralized and two decentralized municipal wastewater systems were compared using life cycle assessment (LCA). In centralized systems, phosphorus recovered as struvite from the solids dewatering liquid resulted in an environmental benefit except for the terrestrial ecotoxicity and freshwater eutrophication impact categories, with power and chemical use offset by operational savings and avoided fertilizer production. Chemical-based phosphorus recovery, however, generally required more resources than were offset by avoided fertilizers, resulting in a net environmental burden. In decentralized systems, phosphorus recovery via urine source separation reduced the global warming and ozone depletion potentials but increased terrestrial ecotoxicity and salinization potentials due to application of untreated urine to land. Overall, mineral depletion and eutrophication are well-documented arguments for phosphorus recovery; however, phosphorus recovery does not necessarily present a net environmental benefit. While avoided fertilizer production does reduce potential impacts, phosphorus recovery does not necessarily offset the resources consumed in the process. LCA results indicate that selection of an appropriate phosphorus recovery method should consider both local conditions and other environmental impacts, including global warming, ozone depletion, toxicity, and salinization, in addition to eutrophication and mineral depletion impacts.

New multi-regional input–output databases for Australia – enabling timely and flexible regional analysis

ABSTRACT Decision-making at regional scales requires timely information. Within four months of the release of official national statistics, we have produced a time-series (2008–2015) of balanced sub-national, multi-regional supply-and-use tables (MR-SUT), integrated with a set of socio-economic and environmental accounts. This was achieved using the Australian IELab, where data used in this study are available (https://ielab.info/resources/91). Four multi-regional, environmentally extended supply-use tables regionalised in different ways were produced to demonstrate the flexibility of tailoring input–output models to specific research or policy questions. Results for satellite coefficients are sensitive to the chosen regional grouping and method for regionalisation. We demonstrate the relevance of such purpose-built information to government and corporate decision-makers by analysing the indirect economic and employment consequences of a slowdown of the mining boom in Western Australia. The demonstrated innovations in flexibility and timeliness will help move past some of the limitations that have historically hindered the uptake and utility of applied input–output analysis.

The diverse environmental burden of city-scale urban water systems

Recent years have seen an increase in the use of Life Cycle Assessment (LCA) to inform urban water systems research. The attraction of LCA is its capacity to identify trade-offs across a broad range of environmental issues and a broad range of technologies. However, without some additional perspective on the scale of the results, prioritisation of these concerns will remain difficult. LCA studies at the whole-of-system level are required to identify the diversity of life cycle environmental burdens associated with urban water systems, and the main contributors to these impacts. In this study, environmental impact profiles were generated for two city-scale urban water systems: one typical of many urban centres, with a high reliance on freshwater extraction and the majority of treated wastewater being discharged to the sea; and one that adopts a more diverse range of water supply and wastewater recycling technologies. The profiles were based on measured data for most system components, otherwise best available empirical data from the literature. Impact models were chosen considering the substantial methodological developments that have occurred in recent years. System operations, directly within the sphere of influence of water system managers, play the dominant role in all but one of the 14 life cycle impact categories considered. While energy use is the main cause of changes in the impact profiles when the alternative water supply technologies are included, it is not the only important driver of impacts associated with city-scale urban water systems. Also extremely important are process emissions related to wastewater treatment and dams (notably fugitive gases, wastewater discharges, and biosolids disposal). The results clearly indicate a diverse range of environmental impacts of relevance, extending beyond the traditional concerns of water use and nutrient discharge. Neither energy use, nor greenhouse gas footprints, are likely to be an adequate proxy for representing these additional concerns. However, methodological improvements will be required for certain LCA impact models to support future case study analysis, as will a comprehensive critique of the implications from selecting different impact models.

Including N2O in ozone depletion models for LCA

PurposeRecent literature has highlighted a renewed debate amongst the scientific community about the relevance of nitrous oxide (N2O) emissions to future ozone layer management. This raises the question as to whether the life cycle assessment (LCA) community should also consider incorporating N2O into its ozone depletion models. This discussion summarises a preliminary investigation into the justification for doing so.MethodsLiterature on the atmospheric science of ozone depletion and N2O was reviewed, in particular recent proposals for an ozone depletion potential (ODP) factor that can be applied to anthropogenic N2O emissions. To identify their potential significance to life cycle impact assessment (LCIA) results, these ODP values were applied to both a wastewater management case study and global emissions inventories. The literature review was also used to highlight certain issues that need further consideration if N2O is to be incorporated into LCIA models.ResultsAtmospheric modelling has shown that continued anthropogenic N2O emissions could substantially affect ozone layer recovery. Furthermore, N2O now represents one of the biggest remaining opportunities for emissions abatement. The two steady state ODP factors for N2O available in the literature are in close agreement, with one of the models used showing reasonable calibration to accepted ODP values for other substances. Analysis of the wastewater case study showed that the incorporation of these interim ODP values for N2O could have a substantial impact on LCIA results interpretation. This finding should be equally relevant for other case studies where N2O emissions play a prominent role.ConclusionsThe inclusion of N2O into marginal-impact LCIA ozone depletion models would seem justified, given the relevance of N2O emissions to a number of planning debates in which LCA currently has a prominent role. If this is not pursued, then the use of LCIA to support decision-making could mask, rather than reveal, an issue that may be environmentally relevant. Published ODP values for N2O could be used as an interim measure. However, they are dependent on assumptions that may not be the most relevant choice for application to LCA studies. Further investigation is therefore required on how best to specify a range of ODP values for N2O that can support robust sensitivity analysis in LCIA. Fortunately, the state of atmospheric modelling science would seem sufficiently mature to be able to inform this process. LCA-specific methodological challenges (e.g. choice of time frames, spatial implications) will also need to be addressed.

Source-to-exposure assessment with the Pangea multi-scale framework-case study in Australia

Effective planning of airshed pollution mitigation is often constrained by a lack of integrative analysis able to relate the relevant emitters to the receptor populations at risk. Both emitter and receptor perspectives are therefore needed to consistently inform emission and exposure reduction measures. This paper aims to extend the Pangea spatial multi-scale multimedia framework to evaluate source-to-receptor relationships of industrial sources of organic pollutants in Australia. Pangea solves a large compartmental system in parallel by block to determine arrays of masses at steady-state for 100 000+ compartments and 4000+ emission scenarios, and further computes population exposure by inhalation and ingestion. From an emitter perspective, radial spatial distributions of population intakes show high spatial variation in intake fractions from 0.68 to 33 ppm for benzene, and from 0.006 to 9.5 ppm for formaldehyde, contrasting urban, rural, desert, and sea source locations. Extending analyses to the receptor perspective, population exposures from the combined emissions of 4101 Australian point sources are more extended for benzene that travels over longer distances, versus formaldehyde that has a more local impact. Decomposing exposure per industrial sector shows petroleum and steel industry as the highest contributing industrial sectors for benzene, whereas the electricity sector and petroleum refining contribute most to formaldehyde exposures. The source apportionment identifies the main sources contributing to exposure at five locations. Overall, this paper demonstrates high interest in addressing exposures from both an emitter perspective well-suited to inform product oriented approaches such as LCA, and from a receptor perspective for health risk mitigation.

Stratospheric Ozone Depletion

The stratospheric ozone layer plays a critical role in regulating conditions on Earth, but has been substantially depleted by CFC (chlorofluorocarbon) and other halocarbon emissions. This has increased transmission of UVB radiation to the surface, and been implicated in a range of negative human and ecosystem health impacts.