Spatial and temporal changes in estuarine water quality during a post-flood hypoxic event
- Authors: Wong, Vanessa , Johnston, Scott , Bush, Richard , Sullivan, Leigh , Clay, Christina , Burton, Edward , Slavich, Peter
- Date: 2010
- Type: Text , Journal article
- Relation: Estuarine, Coastal and Shelf Science Vol. 87, no. 1 (2010), p. 73-82
- Full Text: false
- Reviewed:
- Description: A major fish kill occurred in the Richmond River estuary in January 2008 due to oxygen depletion following extensive overbank flooding. This paper examines spatial and temporal changes in the chemistry of main channel waters, thereby identifying the primary sources of deoxygenating water. Over 40 km of the mid- to lower estuary main channel was deoxygenated within seven days of the flood peak. Hypoxia was confined to downstream of the confluences with mid-estuary backswamp basins and occurred during the later phase of the flood recession. Water chemistry at key locations in the estuary indicated elevated concentrations of redox sensitive species associated with acid sulfate soils (ASS) during the hypoxic period. Peak concentrations of Fe
A sequential extraction procedure for acid sulfate soils : Partitioning of iron
- Authors: Claff, Salirian , Sullivan, Leigh , Burton, Edward , Bush, Richard
- Date: 2010
- Type: Text , Journal article
- Relation: Geoderma Vol. 155, no. 3-4 (2010), p. 224-230
- Full Text: false
- Reviewed:
- Description: A new sequential extraction scheme for acid sulfate soil materials has been evaluated for iron partitioning in a range of synthetic iron-bearing minerals and natural acid sulfate soil materials. This sequential extraction procedure employs six steps to quantify (1) exchangeable (magnesium chloride extractable), (2) acid (hydrochloric acid) soluble, (3) reactive organic-bound (pyrophosphate extractable), (4) crystalline oxide (citrate buffered dithionite (CBD)) extractable, (5) pyrite-bound (nitric acid extractable) and (6) residual (acid/peroxide digestible) forms of iron. Given its intended use for acid sulfate soil materials that frequently contain pyrite, a primary aim of this new sequential extraction procedure was to differentiate iron bound in pyrite from iron contained in other minerals. The results demonstrated that dissolution of pyrite was effectively isolated in the pyrite-bound extraction step, with dissolution of other iron mineral phases (i.e. akaganeite, ferrihydrite, goethite, hematite, jarosite, magnetite, and schwertmannite) occurring within the other five extraction steps. Following a systematic examination of these synthetic iron mineral phases, the sequential extraction scheme was applied to an acid sulfate soil profile, with detailed data presented for two soil layers: one representative of the sulfidic (unoxidised) conditions, and the other sulfuric (oxidised) conditions. Partitioning data for pyrite-bound iron in the acid sulfate soil profile showed good agreement with that calculated via the independently measured pyrite-bound reduced sulfur. This study indicates that the new sequential extraction procedure is suitable for the assessment of iron partitioning in acid sulfate soil materials. © 2009 Elsevier B.V. All rights reserved.
Effect of sample pretreatment on the fractionation of Fe, Cr, Ni, Cu, Mn, and Zn in acid sulfate soil materials
- Authors: Claff, Salirian , Burton, Edward , Sullivan, Leigh , Bush, Richard
- Date: 2010
- Type: Text , Journal article
- Relation: Geoderma Vol. 159, no. 1-2 (2010), p. 156-164
- Full Text: false
- Reviewed:
- Description: A sequential extraction procedure was applied to acid sulfate soil materials from a soil profile to investigate the effect of sample pretreatment on the geochemical fractionation of selected metals. The samples were prepared for analysis by oven-drying, sieving and grinding the soil, or were examined as collected in field condition. The soil profile encompassed oxidising conditions near the surface, through to reducing conditions at depth. Six metals (Fe, Cr, Ni, Mn, Cu, and Zn) were measured during the sequential extraction procedure, and their fractionation determined in the oxidised and in the reduced zone. Although cumulative totals (the sum of all steps in the sequential extraction procedure) for the metals extracted from both the field condition and dried/ground samples were similar, some significant differences in fractionation within individual extraction steps were observed. Of particular interest was the redistribution of metals from the sulfide-bearing (pyrite-bound) fraction to the more readily available fractions (i.e. labile and acid-soluble), as a result of oven-drying and grinding. The results indicate that when assessing metal fractionation in acid sulfate soil materials, samples should be analysed in field condition in order to avoid the considerable metal fractionation artifacts that are induced by drying and grinding. © 2010 Elsevier B.V.
Comparison of sample preparation methods for the GC–MS analysis of monoethanolamine (MEA) degradation products generated during post-combustion capture of CO2
- Authors: Reynolds, Alicia , Verheyen, Vincent , Adeloju, Samuel , Chaffee, Alan , Meuleman, Erik
- Date: 2016
- Type: Text , Journal article
- Relation: International Journal of Greenhouse Gas Control Vol. 52, no. (2016), p. 201-214
- Full Text: false
- Reviewed:
- Description: As the development of chemical absorption technology for post-combustion capture (PCC) of CO2 from coal-fired power station flue gases proceeds towards commercial deployment, the focus on establishing a thorough understanding of the degradation of the aqueous amine absorbents is increasing. However, there is a need to develop and demonstrate robust analytical methods that are capable of measuring the concentrations of amine degradation products in aqueous monoethanolamine (MEA) matrix during pilot-scale PCC. In this study, sample cleanup and derivatisation methods that enable reliable and robust analysis of MEA degradation products by GC–MS are described. Two sample cleanup methods were evaluated: dehydration (by rotary evaporation and molecular sieves) and cation exchange. The cation exchange sample preparation method was preferred for the analysis of organic degradation products in these samples because it achieved higher recovery and repeatability of GC–MS measurements than those obtained with the dehydration method. Furthermore, the cation exchange method resulted in less continued amine degradation during subsequent analysis steps because of its ability to separate acidic analytes from basic analytes, as well as to remove some inorganic interferences. Further improvement of the sensitivity, repeatability and accuracy of this GC–MS analytical method can be accomplished by: (a) increasing the scale of the cation exchange and/or derivatisation procedures; (b) optimizing the derivatisation reaction conditions; and (c) using a narrower bore (e.g. 0.25 mm ID) GC–MS column. The proposed cation exchange and derivatisation procedures can be readily adopted for the quantification of organic degradation products in other aqueous amine absorbents to provide important insights into the degradation of amine absorbents during PCC of CO2. © 2016 Elsevier Ltd
Contemporary pedogenesis of severely degraded tropical acid sulfate soils after introduction of regular tidal inundation
- Authors: Johnston, Scott , Keene, Annabelle , Bush, Richard , Burton, Edward , Sullivan, Leigh , Smith, Douglas , McElnea, Angus , Martens, Michelle , Wilbraham, Steve
- Date: 2009
- Type: Text , Journal article
- Relation: Geoderma Vol. 149, no. 3-4 (2009), p. 335-346
- Full Text: false
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- Description: Marine tidal inundation was partially restored to a severely degraded tropical acid sulfate soil landscape after having been excluded for over 30 years. The effects on soil acidity and iron-sulfide mineral reformation were investigated by comparing the geochemistry of soils before and after five years of regular tidal inundation. The soil pH increased by 2-3 units and titratable actual acidity (TAA) decreased by ∼ 40-50 μmol H+ g- 1 within former sulfuric horizons. Relict acidity remained at depth (> 1 m) in the underlying sulfidic horizons. δ34S data indicate that tidal inundation caused exchange of marine solutes within former sulfuric horizons, but not within underlying sulfidic material. There was considerable reformation of pyrite within former sulfuric horizons after tidal inundation with reduced inorganic sulfur increasing by ∼ 60 μmol g- 1. Acid-volatile sulfide also accumulated, but mainly near the soil surface (up to 16 μmol g- 1). Reduction of Fe(III) minerals strongly influences the geochemistry of the tidally inundated soils. After tidal inundation the soil pH and Eh closely followed the iron redox couple and there was non-sulfidic solid-phase Fe(II) up to 600 μmol g- 1. There was also substantial diagenetic enrichment of poorly crystalline Fe-oxides near the soil surface following tidal inundation, with reactive Fe spanning 400-1800 μmol g- 1. While the decreases in soil acidity documented here are likely due to a combination of marine alkalinity inputs and reduction of both Fe and SO42-, the relative importance of each process remains to be determined. This study demonstrates that marine tidal inundation can be an effective landscape-scale strategy for ameliorating severe acidity associated with drained acid sulfate soils. © 2008 Elsevier B.V. All rights reserved.
Evaluation of methods for monitoring MEA degradation during pilot scale post-combustion capture of CO
- Authors: Reynolds, Alicia , Verheyen, Vincent , Adeloju, Samuel , Chaffee, Alan , Meuleman, Erik
- Date: 2015
- Type: Text , Journal article
- Relation: International Journal of Greenhouse Gas Control Vol. 39, no. (2015), p. 407-419
- Full Text: false
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- Description: Amine degradation is an important and current focus in the development of chemical absorption technology based on the use of aqueous amines for post-combustion capture (PCC) of CO
Changes in water quality following tidal inundation of coastal lowland acid sulfate soil landscapes
- Authors: Johnston, Scott , Bush, Richard , Sullivan, Leigh , Burton, Edward , Smith, Douglas , Martens, Michelle , McElnea, Angus , Ahern, Col , Powell, Bernard , Stephens, Luisa , Wilbraham, Steve , Van Heel, Simon
- Date: 2009
- Type: Text , Journal article
- Relation: Estuarine, Coastal and Shelf Science Vol. 81, no. 2 (2009), p. 257-266
- Full Text: false
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- Description: This study examines the remediation of surface water quality in a severely degraded coastal acid sulfate soil landscape. The remediation strategy consisted of partial restoration of marine tidal exchange within estuarine creeks and incremental tidal inundation of acidified soils, plus strategic liming of drainage waters. Time-series water quality and climatic data collected over 5 years were analysed to assess changes in water quality due to this remediation strategy. A time-weighted rainfall function (TWR) was generated from daily rainfall data to integrate the effects of antecedent rainfall on shallow groundwater levels in a way that was relevant to acid export dynamics. Significant increases in mean pH were evident over time at multiple monitoring sites. Regression analysis at multiple sites revealed a temporal progression of change in significant relationships between mean daily electrical conductivity (EC) vs. mean daily pH, and TWR vs. mean daily pH. These data demonstrate a substantial decrease over time in the magnitude of creek acidification per given quantity of antecedent rainfall. Data also show considerable increase in soil pH (2-3 units) in formerly acidified areas subject to tidal inundation. This coincides with a decrease in soil pe, indicating stronger reducing conditions. These observations suggest a fundamental shift has occurred in sediment geochemistry in favour of proton-consuming reductive processes. Combined, these data highlight the potential effectiveness of marine tidal inundation as a landscape-scale acid sulfate soil remediation strategy. © 2008 Elsevier Ltd. All rights reserved.
Flexible operation of CSIRO's post-combustion CO2 capture pilot plant at the AGL Loy Yang power station
- Authors: Bui, Mai , Gunawan, Indra , Verheyen, Vincent , Feron, Paul , Meuleman, Erik
- Date: 2016
- Type: Text , Journal article
- Relation: International Journal of Greenhouse Gas Control Vol. 48, no. (May 2016), p. 188-203
- Full Text:
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- Description: Flexible operation has the potehtial to significantly improve the economic viability of post-combustion CO2 capture (PCC). However, the impact of disturbances from flexible operation of the PCC process is unclear. The purpose of this study was to investigate the effects of flexible operation in a PCC pilot plant by implementing step-changes for improved dynamic data reliability. The flexible operation campaign was conducted at the CSIRO PCC pilot plant at AGL Loy Yang using monoethanolamine (MEA) absorbent. The pilot plant was operated under a broad range of transient conditions (changing flue gas flow, liquid absorbent flow and steam pressure) to capture the dynamics of a PCC process during flexible operation. The study demonstrated that the dynamics of flue gas flow rate was faster than absorbent flow rate. The greatest CO2 removal% was achieved at the lowest flue gas flow rate or at the highest absorbent flow rate; however, the latter provided improved energy efficiency. The steam pressure parameter could adjust the temperature of all columns simultaneously which can be used to compensate for effects from ambient conditions or heat losses. These results verify the technical feasibility of flexible PCC operation and provide a suitable dataset for dynamic model validation. (C) 2015 Elsevier Ltd. All rights reserved.
A technology review for regeneration of sulfur rich amine systems
- Authors: Garg, Bharti , Verheyen, Vincent , Pearson, Pauline , Feron, Paul , Cousins, Ashleigh
- Date: 2018
- Type: Text , Journal article , Review
- Relation: International Journal of Greenhouse Gas Control Vol. 75, no. (2018), p. 243-253
- Full Text: false
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- Description: Reducing the capital cost of post combustion CO2 capture by eliminating flue gas desulfurisation (FGD) pre-treatment, requires management of the amines preferential SO2 absorption. Novel technologies such as CS-Cap restrict the impact of SO2 to only a small fraction of the amine inventory resulting in high sulfate burden amines. Traditional thermal reclamation of these spent absorbents has advantages regarding simplicity, but ranks poorly for industrial ecology around PCC. These amines require low energy regeneration technologies compatible with their physico-chemical properties that also maximise the potential for valorising by-products. This review summarises the sulfur chemistry and outlines several amine reclamation processes. It assesses the status of established and novel regeneration technologies for their applicability to high sulfur loaded amines. Should deep sulfur removal be required, a hybrid approach with initial bulk removal (as product) followed by a polishing step to further reduce sulfur is prospective. A preliminary estimation of the relative cost of using standard reclamation methods for treating Sulfur loaded CS-Cap absorbent revealed the cost would increase due to its higher sulfate burden despite comparable treatment volumes. Research gaps are identified which would enable better comparison between the costs of traditional FGD versus higher reclamation costs for combined capture technologies.
Integrative conservation of riparian zones
- Authors: González, Eduardo , Felipe-Lucia, Maria , Bourgeois, Berenger , Boz, Bruno , Nilsson, Christer , Palmer, Grant , Sher, Anna
- Date: 2017
- Type: Text , Journal article
- Relation: Biological Conservation Vol. 211, no. (2017), p. 20-29
- Full Text: false
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- Description: Riparian zones are the interface between aquatic and terrestrial systems along inland watercourses. They have a disproportionate ecological role in the landscape considering their narrow extent, which makes them a good example of small natural features (sensu Hunter, 2017-inthisissue). Characteristically, riparian zones increase species richness in the landscape and provide key services to society, such as soil fertility, water purification, and recreation. Despite the recognized importance of riparian zones for ecological, economic and social reasons, and the vast amount of scientific literature exploring measures for their conservation, current management is still failing at enabling a proper ecological functioning of these areas. The best practices for conservation of riparian zones have mostly focused on manipulating biotic and physical components (e.g. renaturalizing flow regimes, improving channel mobility, and controlling invasions of exotic ecosystem engineer species). However, these strategies face important technical, socio-economic, and legal constraints that require a more integrative approach for effective conservation. In this paper we summarize the main problems affecting riparian zones and their current management challenges. Following Hunter et al. (2017-inthisissue), we review novel approaches to conservation of riparian zones, complementary to manipulating processes that reflect contemporary management and policy. These include (1) investing in environmental education for both local people and technical staff, (2) guaranteeing qualitative and long term inventories and monitoring, (3) establishing legislation and solutions to protect riparian zones, (4) framing economic activities in riparian zones under sustainable management, and (5) planning restoration of riparian zones at multiple and hierarchical spatio-temporal scales. © 2016 Elsevier Ltd
Integrating cultural ecosystem services valuation into coastal wetlands restoration : a case study from South Australia
- Authors: Clarke, Beverley , Thet, Aung , Sandhu, Harpinder , Dittmann, Sabine
- Date: 2021
- Type: Text , Journal article
- Relation: Environmental Science and Policy Vol. 116, no. (2021), p. 220-229
- Full Text:
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- Description: Elaborating the benefits humans receive from coastal wetlands using a Cultural Ecosystem Services assessment is an emergent and important field linking human wellbeing to ecosystem function. Translating these benefits into useable concepts for environmental policymakers, and managers is challenging yet important for supporting landscape restoration projects. This study responds to the call for Cultural Ecosystem Services case studies beyond the northern hemisphere. A household survey of residents adjacent to a peri-urban coastal wetland in South Australia and an online survey of interest groups were administered to identify co-benefits associated with a coastal restoration project in the region. A dynamic/relational cultural values framework guided the analysis. Findings reveal that visitation has a positive influence; people valued most the places with which they were familiar. The analysis confirms a mutual connection between: ‘doing’ (undertaking an activity), environmental awareness and appreciation, the formation of attachment to place, and having positive experiences. The analysis also points out that the naturalness of this coastline is highly valued. The findings here diverge from previous coastal landscape assessments based singularly on scenic value. The implication is that localised, place-based landscape assessments which include cultural values, offer a more deliberative approach to policy development and planning and will more likely incorporate what matters most to people. © 2020 The Author(s)
Techno-economic evaluation of amine-reclamation technologies and combined CO2/SO2 capture for Australian coal-fired plants
- Authors: Garg, Bharti , Haque, Nawshad , Cousins, Ashleigh , Pearson, Pauline , Verheyen, Vincent , Feron, Paul
- Date: 2020
- Type: Text , Journal article
- Relation: International Journal of Greenhouse Gas Control Vol. 98, no. (2020), p.
- Full Text:
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- Description: CSIRO's patented CS-Cap process aims at reducing the costs of amine-based post-combustion capture by combining SO2 and CO2 capture using one absorbent in a single absorber column. By avoiding the need for a separate flue gas desulfurization unit, the process offers potential savings for power plants requiring CO2 capture. High-level cost estimates based on lab and pilot data are presented for two amine reclamation techniques i.e. thermal reclamation and reactive crystallisation. Only regeneration via reactive crystallisation reduces CS-Cap costs below base case FGD/SCR-PCC. Cost estimations suggest a potential reduction of 38–44% in the total plant cost when using the CS-Cap process compared to base case. However, the amine reclaimer operating cost governs the overall cost of the CS-Cap process and is highly sensitive to sulfur content. A 50% reduction is observed when SO2 levels reduce from 700 to 200 ppm. Comparing levelised cost of electricity and CO2 avoided costs for CS-Cap against our base case, low sulfur brown coal has a slight (5–7%) cost advantage; however, confirmation requires pilot data on amine recovery. © 2020
Insights from long-term shorebird monitoring for tracking change in ecological character of Australasian Ramsar sites
- Authors: Hansen, Birgita , Szabo, Judit , Fuller, Richard , Clemens, Robert , Rogers, Danny , Milton, David
- Date: 2021
- Type: Text , Journal article
- Relation: Biological Conservation Vol. 260, no. (2021), p.
- Full Text:
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- Description: The Ramsar Convention is the centrepiece of international efforts for wetland conservation, aiming to maintain the ecological character of wetlands through holistic ecosystem management. Here, we review studies on shorebird populations at individual Australasian Ramsar sites and compare these against original listings under Criterion 6 to determine if there have been potential changes in ecological character. One to 12 migratory shorebird species have declined at four New Zealand and 18 Australian Ramsar sites over a 12 to 36-year period, resulting in 22 species (at 13 sites) no longer reaching Criterion 6 thresholds for Ramsar designation. In addition, 10 species at six Australian sites had exceeded the Limits of Acceptable Change. Despite these concerning results, there were remarkably few published site-based determinations of listed shorebird species' trends (and even fewer that were ≤5 years old). This is especially surprising since shorebird populations are regularly monitored at 27 out of 35 Australasian Ramsar sites (listed on the basis of one or more shorebird species). Thus, despite the volume of data available for analysis, long-term shorebird monitoring provides only limited insights about Ramsar ecological character. The value of these data would be greatly enhanced through complementary monitoring of other ecological characters at sites, particularly where shorebird populations provide early warning signs of potential deterioration. The main impediment to achieving a good understanding of how Ramsar sites are changing in Australasia appears to be a lack of analysis and centralised system for data and analytics, rather than a lack of monitoring data. © 2021 Elsevier Ltd