Somersby, Australia
Somersby, Australia

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Sarmah A.K.,Landcare Research | Srinivasan P.,Landcare Research | Srinivasan P.,University of Waikato | Smernik R.J.,University of Adelaide | And 4 more authors.
Australian Journal of Soil Research | Year: 2010

We examined the retention ability of a New Zealand dairy farm soil amended with 3 types of biochar produced from a variety of feedstocks for a steroid hormone (oestradiol, E2) and its primary transformation product (estrone, E1). Biochars produced from corn cob (CC), pine sawdust (PSD) and green waste (GW) were characterised by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and solid-state 13C nuclear magnetic resonance spectroscopy. Batch sorption studies were performed on soil amended with each biochar (0.5% and 1% by weight) using a complex solvent extraction scheme, and isotherms were fitted to the Freundlich model. All isotherms were highly non-linear, with N values in the range 0.460.83 (E2) and 0.660.88 (E1) in soil amended with different percentages of biochars. Overall, addition of all 3 biochars was found to increase the soil sorption affinity for the hormones, with E2 sorption being the highest in the soil amended with 1% PSD biochar. There was no marked difference in hormone sorption ability in the other 2 treatments (soil treated with 1% CC biochar and 1% GW biochar). Overall, the effective distribution coefficient (Kd eff) values for E2 at the lowest equilibrium concentration (Cw 0.5mg/L) ranged from 35 to 311L/kg in soil amended with the 3 types of biochar. Addition of 0.5% of PSD biochar resulted in ∼560% increase in the Kd eff value for E2, while at 1% addition of PSD biochar, uptake of E2 was nearly 1400% higher than the control. For E1, the percentage increase in Kd eff was comparatively smaller than E2; however, it still ranged from 40 to 280%, and 60 to 320% at addition of 0.5% and 1% PSD biochar, respectively, compared with the control soil. Highest treatment temperature and associated greater surface area, low ash content, higher carbon content, and the abundance of polar functional groups (e.g. OH, C≤O) may explain why the soil amended with PSD biochar exhibited high sorptive capacity for the hormones. © CSIRO 2010.

Downie A.,University of New South Wales | Munroe P.,University of New South Wales | Cowie A.,University of New England of Australia | Van Zwieten L.,University of New England of Australia | And 2 more authors.
Critical Reviews in Environmental Science and Technology | Year: 2012

Biochar technology has been proposed as a geoengineering solution that has potential to actively reduce the atmospheric concentrations of greenhouse gases and enhance the sustainability of agriculture. The magnitude of the technologies net benefit must be considered in relation to the associated risks. Hazards posed by biochar technology need to be managed to a level that the resulting risks are deemed acceptable by society; identification of hazards is an essential first step. Effectively implemented risk management and sustainability guidelines, driven by informed policy directives, will result in biochar technology being an important tool for environmental and atmospheric greenhouse gas management. © 2012 Copyright Taylor & Francis Group, LLC.

van Zwieten L.,Australian Department of Primary Industries and Fisheries | Kimber S.,Australian Department of Primary Industries and Fisheries | Downie A.,Pacific Pyrolysis | Morris S.,Australian Department of Primary Industries and Fisheries | Rust J.,Australian Department of Primary Industries and Fisheries
Sugar Tech | Year: 2012

The sugarcane industry in many parts of the world produces food and energy (stationary and fuel). The industry is well positioned to offer greenhouse gas abatement and climate change mitigation. The thermal conversion, via a slow pyrolysis process, of cane residues such as green harvest trash and bagasse can produce thermal or electrical energy as well as biochar. Studies have shown that a commercial slow pyrolysis unit could generate over 1 MWhr of electricity from every two tonnes of trash (dry basis), with a biochar recover of between 31.3-33.6 %. Due to its highly stable nature, biochar has recently been suggested as a sequestration pathway to remove CO 2 from the atmosphere. One tonne of bagasse derived biochar would sequester in the order of 2.3 tonnes of CO 2 equivalents. In addition to C sequestration, biochar has other significant benefits (when used as a soil amendment) such as offering improved soil quality, higher CEC and nutrient availability, and improved soil physical characteristics. This work demonstrates that biochar application can reduce emissions of greenhouse gases from cane soils, such as nitrous oxide. Biochars derived from cane trash and bagasse were applied in incubation studies to soils from the Burdekin region in Australia. We found declines in emissions of the greenhouse gas nitrous oxide (N 2O), from urea-fertilised soil when bagasse biochar was applied at a rate of 10 t/ha. The agronomic performance of biochar is being assessed in a 15 plot trial conducted on a sugar cane property in the Tweed Valley, NSW. Biochars (from non-sugarcane sources) were tested using relevant controls. Each plot consists of 3 rows of cane and was 30 m in length to enable commercial-scale harvesting. Although no significant effects in yield have been recorded this trial is expected to continue for several more seasons allowing additional data on yield effects to be evaluated. Our work has demonstrated that implementing slow pyrolysis and biochar utilisation in the sugarcane industry has potential to provide (1) renewable energy (2) income from waste (3) climate mitigation through stabilisation of carbon and (4) climate mitigation through reduced emission of N 2O from soil. Further research is required to demonstrate agronomic benefits of sugarcane biochars and to develop an understanding of how they may address soil constraints in these systems. © 2012 Society for Sugar Research & Promotion.

Kaudal B.B.,University of Melbourne | Chen D.,University of Melbourne | Madhavan D.B.,University of Melbourne | Downie A.,Pacific Pyrolysis | Weatherley A.,University of Melbourne
Biomass and Bioenergy | Year: 2016

The purpose of this study was to evaluate the suitability and optimum rate of addition of Urban Biochar (UB) as an alternative to standard coir peat in plant growing media. UB was prepared through pyrolysis of 2:1 ratio of biosolids to greenwaste on a dry mass basis. Two incubation experiments are reported both with five different growing media mixtures which were subjected to periodic wetting and drying. Media mixtures consisted of different rates of UB (100%, 60%, 40%, 20%) mixed with composted pine bark on a volume basis and compared to an industry standard media with 0% UB. The physical and chemical properties of the mixtures were compared pre and post incubation. Substituting coir peat with UB increased media pH, C:N mass ratio, nutrient content, air filled porosity and bulk density. Furthermore, addition of UB to media also increased the proportion of particles in the desirable range for growing media (0.25-2 mm). UB amended mixes were found to be most stable in terms of both bulk density and resistance to particle breakdown. Fourier transform infrared spectroscopy analysis suggested that periodic wetting and drying enhanced surface oxidation. We found that UB amended substrates, up to 60% biochar on a volume basis, could deliver similar physical and chemical benefits to those of coir peat based industry standard media. © 2015 Elsevier Ltd.

Kaudal B.B.,University of Melbourne | Chen D.,University of Melbourne | Madhavan D.B.,University of Melbourne | Downie A.,Pacific Pyrolysis | Weatherley A.,University of Melbourne
Journal of Analytical and Applied Pyrolysis | Year: 2015

Biochar produced from mixture of biodegradable urban resources such as biosolids and greenwaste was slowly pyrolysed at 650 °C and characterised for its chemical and physical properties. The biochar was then compared to published values for growing media. It was found that this biochar has high surface area, inherent nutrient content, high porosity, high stability, desirable water holding capacity, air filled pore space and bulk density. Comparing the results of characterisation of this biochar with ideal potting substrate showed the highly porous and nutrient rich biochar were desirable however the high salt content was problematic. Fourier transform infrared analysis shows that carboxyl/carbonyl bands were very weak in biochar spectra due to loss of carboxyl groups in the decomposition of carbohydrates in high temperature pyrolysis which also contributed to low cation exchange capacity. The pyrolysis process has multiple advantages such as waste management, energy generation in the form of syngas and long term sequestration of carbon in biochar. © 2015 Elsevier B.V. All rights reserved.

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