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Thermal treatment in Australia is gaining interest due to legislative changes, waste reduction goals, and the need to address contaminants risks in biosolids used for agriculture. The resulting biochar product has the potential to be beneficially recycled as a soil amendment. On-farm management practices were reviewed to identify barriers that need to be overcome to increase recycling and examine the role of pyrolysis and gasification in effectively improving the quality and safety of biochar. Key findings revealed: (1) thermal treatment can effectively eliminate persistent organic pollutants, microplastics and pathogens, and (2) more than 90% of the total heavy metals content in biosolids become immobilized when these are converted to biochar, thus reducing their bioavailability following land application. While reported research on the short-term effects of biosolids-derived biochar suggested promising agronomic results, there is dearth of information on long-term effects. Other knowledge gaps include optimisation of land application rates, understanding of rate of breakdown and fate of contaminants in soil and water, heavy metal mobility in soil and bioaccumulation or transfer to the food chain. Improved understanding of nutrients and contaminants dynamics in soils receiving biosolids-derived biochar is a pre-requisite for their safe use in Australian agriculture, and therefore it is highlighted as priority area for future research.

Mechanical solid-liquid separation is an emerging closed-loop technology to recover and recycle carbon, nutrients and water from dilute livestock manure. This closed-loop concept is tested using a modular separation technology (Z-Filter) applied at full-scale for the first time to treat effluent from a pasture-based dairy. Effluent flow rates were 200-400 L min

The Australian Red Meat Processing (RMP) industry is challenged with ever increasing environmental pressures to reduce their environmental footprint. Wastewater is high strength and requires qualit...

Ensiling of sugarcane trash (SCT) and sugarcane stalks (SCS) was studied to assess the effects of molasses (MOL) and lactic acid bacteria (LAB) inoculant on methane potential. The experiment was run for 70 days and monitoring parameters were analyzed at days 0, 5, 15 and 70. Biochemical methane potential (BMP) tests performed with fresh and ensiled material at day 70 showed an increase in methane potential by 24.0%, 23.4%, 1.7% and 71.1% for SCSctr, SCTctr, SCTmol and SCTmol + lab, respectively. Such improved performance is explained by the formation of organic acids (mostly acetate and lactate) which were able to decrease the pH of the silages from 5.7–5.9 to 3.8–4.2 for all SCT treatments and from 5.9 up to 3.4 for SCS treatment. Thus, the ensiling process provided similar effects to a pre-treatment at low acid concentrations, which in turn improved the digestibility of the cellulosic biomass for methane production.

This article explores the potential of producing domestic, home-scale biogas using anaerobic digestion in the suburbs of the developed world – an urban context where currently biogas production is almost non-existent. The current status of food waste management across the globe shows that internationally, cities are increasingly using anaerobic digestion as a central technology at commercial scale to treat food waste and decarbonise through the recovery of energy and nutrients. However, in order to achieve this, it is preferable to separate organic waste such as food waste from other waste streams. Australia currently does not offer any schemes that support source separation of household food waste. Notwithstanding this, there are upwards of five large-scale plants currently treating commercial food waste and substantial scope exists to increase this provided appropriate waste management strategies are put in place. Nevertheless, the absence of food waste management schemes in developed countries may provide an impetus for individuals in urban landscapes to explore the potential of home-style biogas systems to produce energy and biofertiliser using food waste derived from households. This article provides a novel case study of one operator's experience using a domestic system, the ‘HomeBiogas 1.0’ unit, in the suburbs of Melbourne, Australia. A critical analysis of the system was performed, including a cost benefit analysis of the recently released ‘HomeBiogas 2.0’ unit. The cost benefit analysis indicated that the system could pay for itself in 4.45 years if simply mitigating the cost of natural gas. This payback period is likely to be reduced if the value of fertiliser were included or if use of a HomeBiogas unit allows for disconnection from the gas grid (avoiding service fees), as it did in this case study. The paper concludes by identifying barriers from a technical, regulatory and education perspective.

A key environmental sustainability requirement for the treatment of organic waste via anaerobic digestion (AD) is the prevention of unwanted methane emissions in the production chain whenever possible. Identifying and quantifying these emissions has been frequently investigated, particularly in Europe. However, the challenges of climate change are also becoming vitally important in Australia. This novel study presents the results from emission measurement campaigns carried out at two biogas plants and one landfill site in Australia. An on-site approach consisting of leakage detection and emission quantification by a static chamber method was applied. Twenty-nine leakages were detected predominantly on the digesters (gastight covered anaerobic lagoons) of the biogas plants. Ten emission hot spots were found on the surface cover of a landfill site. Methane emission rates of 9.9 ± 2.3 kg h−1 (10.5 ± 2.4% CH4) for biogas plant A, 3.0 ± 1.9 kg h−1 (8.1 ± 5.2% CH4) for biogas plant B and 41–211 g h−1 for the two largest emission hot spots from the landfill were measured. Since not every single leakage or hot spot could be quantified separately, the stated overall emission rates had to be extrapolated. Importantly, the emission rates from the landfill should be interpreted carefully due to the limited overall area which could be practicably investigated. Leakages occurred at common components of the covered anaerobic lagoons such as the membrane fixation or concrete walls. Repairing these parts would increase the plant safety and mitigate negative environmental effects.

The work reported in this article was conducted to determine thin layer drying rates and equilibrium moisture contents of abattoir paunch waste. The equilibrium moisture content of paunch varied from 7.14% to 13.12% for drying in air between 35 and 55 °C, and at 40–80% relative humidity. A predictive equilibrium moisture content equation based on the Chung-Pfost model was developed with the constants A found to be 586.72, B (27.461), and C (28.913) with a standard error of ±0.0035. These values were comparable to the published values for wheat and barley. The thin layer drying constant, k, varied from 0.00023 to 0.0029 min -n with an average time exponent, n, value of 1.42 for air temperatures in the range of 35–55 °C. The variation in drying rates demonstrated a significant sensitivity to humidity.

Thermobaric pre-treatment of a combination of dissolved air flotation (DAF) sludge and slaughterhouse wastewater was evaluated for performance over 50 days of continuous anaerobic digestion. Continuous digestion was conducted over three phases represented by varying fat, oils and grease (FOG) concentrations and organic loading. In comparison with earlier biochemical methane potential (BMP) investigations using thermobaric treated substrate by Harris, Schmidt and McCabe (Harris et al., 2017) which yielded an 8.32% increase in specific methane production, pre-treated DAF sludge produced negative impacts on digestion under continuous conditions. Average pH was consistently lower by 0.04, and loss of volatile organics during pre-treatment reduced methane yield by 12.1%. H2S concentration was 56% higher on average with 795 ppm compared with 510 ppm in the controls owing to enhanced protein degradation. Alkalinity was low due to insufficient replacement from the substrate. Fresh substrate containing double the fat content (236 mg/L) and reduced organic loading rate (OLR) caused both control and treatment reactors to fail, highlighting the need for consistent substrate characteristics. Magnesium hydroxide addition effectively recovered both pH and biogas production within digesters rapidly, addressing the underlying complication of insufficient alkalinity contribution by the substrate.

This study presents results from lab-scale studies and highlights issues related to process monitoring equipment and analytical methods at the field scale. This includes the evaluation of data from on-site online sensors and sample analyses as well as results from discontinuous and continuous digestion tests in a biogas laboratory. The results demonstrate the influence of the organic loading and wastewater composition on process stability, sludge activity, and biogas production. Key recommendations for plant operation include the avoidance of strong fluctuations in input volume and concentration, to ensure good functioning of online sensors, and to adapt the management of the different wastewater streams according to their characteristics.

Bovine bile was assessed as a novel bio-surfactant pre-treatment to enhance anaerobic digestion of lipid-rich dissolved air flotation (DAF) sludge using biochemical methane potential (BMP) tests. Bile was dosed at arbitrary concentrations from 0.2–6 g/L. At 0.6 g bile/L, methane yield increased by 7.08%. Doses above 2 g bile/L produced negative impacts on SMP, kinetics and digestion profile. At 6 g/L bile produced a 6% decrease in specific methane production and up to 79% additional inhibitory duration, delayed time of peak methane production by up to 74%, and slowed total digestion time by up to 65%. Reaction kinetics declined linearly with respect to bile addition, reaching half the control value at 6 g/L bile concentration. Subsequent anaerobic toxicity assays between 1 and 6 g bile/L revealed that bile has an inhibitory effect under BMP testing at these higher doses. The economic viability of using bile as a bio-surfactant was assessed. In comparison to the current use of bile as a sale product to pharmaceutical companies, the addition of 0.2 g bile/L to existing slaughterhouse waste streams could increase the value of bile to 220% of its current sale value. The promising results of bile dosed at 0.6 g/L under BMP testing warrant further investigation into long-term impact of bile pre-treatments of high-fat slaughterhouse wastewater in semi-continuous digestion experiments.

In Australia, recycling of paunch waste to farmland has been suggested as a cost-effective and practicable environmental option, but little is known about its agronomic value. Experimental work was undertaken to assess potential risks due to weed seed contamination, determine the agronomic response of ryegrass ( L.) to soil incorporation of paunch, and investigate short-term greenhouse gas (GHG) emissions. Five types of paunch with compost ages between 2 and 16 weeks were compared with urea (46% N) and applied at field equivalent rates of 0 (control), 150, and 300 kg ha-1 N. The risk of weed contamination from paunch applied to soil appeared to be negligible; however, techniques that enable seed viability to be determined may be required to fully discard such risk. Average dry matter yield with paunch was ~30% higher than untreated grass, but ~35% lower than with urea. Dry matter yield in paunch-treated grass was between 2500 and 3250 kg ha-1 over five cuts conducted at 25-day intervals. Paunch N responses were between 1.12 and 3.25 kg DM kg-1 N depending on compost age, but lower than with urea N (~6.5 kg DM kg-1 N). Nitrogen use efficiency of paunch ranged between 3% and 20%, compared to about 35% with urea. Nitrogen fertilizer replacement value (NFRV) of paunch was highest in the 6-week-old compost (~60%) and ranged between 20% and 55% across all other organic materials. Short-term N2O emissions were similar (p > 0.05) with both mineral and organic amendments; however, CH4 emissions were higher (p < 0.05) from paunch compared with urea-treated soil. Overall, there appears to be potential for paunch-derived products to be used as a source of C and nutrients in crop production. Industry quality specifications for compost are available, but they need to be expanded to incorporate guidelines relevant to paunch. There is a requirement for the value proposition to industry to be determined, including reduced cost of paunch disposal via gate fees. Keywords: Byproducts, Composting, Fertilizer replacement value, Nutrient recovery, Nutrient use efficiency, Recycling of abattoir-derived waste.

Organomineral fertilizers (OMF) derived from treated sewage sludge (biosolids) were produced using a novel technique that enables addition of nitrogen (N) to biosolids (BS) to increase the N:P ratio of the sludge and improve its agronomic suitability. Two OMF products (OMF WWTP1 and OMF WWTP2) were formulated and tested in a glasshouse facility on pot-grown ryegrass (Lolium perenne L.). The agronomic performance of OMF was compared with urea and two types of biosolids (BS WWTP1 and BS WWTP2) sourced from different wastewater treatment plants located in southern Queensland, Australia. The fertilizer materials had the following N:P2O5 compositions: 5:12.5 (BS WWTP1), 5.5:6 (BS WWTP2), ≈15:10 (OMF WWTP1), ≈15:5 (OMF WWTP2), and urea (46:0), respectively. Cubical-shaped particles (median size: ≈5x5x5 mm) of BS and OMF, and granular urea were applied to soil (Red Ferrosol) in pots at field-equivalent rates ranging from 0 (control) to 750 kg N ha-1 at regular increments of 75 kg N ha-1, and six grass cuts performed at intervals of 30 days. Results showed that cumulative dry matter yield (DMY) was between 13% and 21% higher with OMF and BS compared with urea, depending on fertilizer type and rate (P

On-farm, intensive feeding and processing in Australian red meat, dairy and pork industries produce substantial quantities of organic waste (∼79 GL·annum−1 liquid waste plus ∼2 megatonnes·annum−1 solid waste) and waste management is a major cost (∼180 million Australian dollars. annum−1 for red meat plus dairy processing). Anaerobic digestion can instead extract value from organic waste as biogas energy and biofertiliser to reduce operational costs and environmental impacts, and to improve industry profitability. Understanding key information gaps is a fundamental step towards fully realizing profitable opportunities for anaerobic digestion. This is addressed here via a critical evaluation of available information on Australian agro-industries (specifically dairy, pork and red meat), their waste availability, biogas energy potential, and potential anaerobic digestion approaches. The analysis revealed varying extents of information, but good biogas energy potential (∼13.8 PJ·annum−1) to meet a significant energy demand (∼18 PJ·annum−1). Waste management within respective agro-industries influenced waste amounts and characteristics, which affected anaerobic digestion options. Anaerobic co-digestion, involving aggregated digestion of two or more waste types within or across industries, can provide further opportunities by boosting biogas production and harnessing spare digestion capacity. Overall, cross-industry collaboration, policy support and technology development could help harness the significant opportunities for aggregated biogas production in Australian agro-industries.

The livestock sector is a fundamental part of the modern global economy and provides food, clothing, furnishings, and various other products. So as to ensure its resilience to changes in consumer expectations, cost of production, and environmental sustainability, the sector must shift to a circular economy model. Current strategies to recover value from wastes and low-value co-products from livestock industries yield limited value; hence, new technologies are required to upgrade wastes and co-products, and generate high-value products that can feed into the livestock value chain. Anaerobic digestion can convert high organic-content waste to biogas for energy and a stable nutrient-rich digestate that can be used as fertiliser. Microbial technologies can transform wastes to produce nutritionally advanced feeds. New materials from waste can also be produced for livestock industry-specific applications. While aiming to add commercial value, the successful implementation of these technologies will also address the environmental and productivity issues that are increasingly valued by producers and consumers.

In this review, the use of MESe are evaluated in the monitoring of volatile fatty acids (VFAs) during the anaerobic digestion of high strength wastewater, with a focus on slaughterhouse wastewater. VFAs are identified as a key intermediary in anaerobic digestion, hence their accumulation could be used to infer possible process instability of anaerobic digesters. Current sample measurement for VFAs through off-line laboratory analysis can be costly, time consuming, and require specialist skills. Consequently, microbial electrochemical sensors (MESe) are currently being investigated as a low-cost alternative method for in-line VFA measurement. In this paper, the fundamental operation of MESe is summarised, including the exploration of several factors that would impact the operation of MESe in real wastewater applications. It is found that, in the context of wastewater sensing, MESe technology has been unable to bridge the gap between the laboratory and real-world anaerobic digesters effectively. Important issues surrounding biofouling, sensitivity, and detection range are explored and prioritised in this review, and an overview of potential research pathways is provided. These include the potential to further explore alternate electrode materials, use of ion exchange membranes, and development of other sensor components, as further described in the review.

On-farm, intensive feed and processing sectors from Australian red meat, dairy and pork industries produce significant quantities of waste. The management of these wastes is a significant cost for these industries exceeding AUD100-200 (≈USD75-150) million per year. In addition, primary production and processing costs are rising and there is an ongoing need to improve productivity to maintain future industry profitability and environmental performance. Understanding key information gaps on waste composition and quantities in these industries is a fundamental step to fully realizing the opportunities in unlocking new revenue streams to produce energy products, fertilizers, feeds and chemicals for use in agriculture. One of the key strategies for ensuring the development of viable commercial outcomes from this research program is to underpin the work with research into the waste resources available in Australia and opportunities to aggregate the waste resources that can lead to new business models for adoption. This paper will provide a literature review of the work undertaken in this area. The critical evaluation scoped out available information, and data was collated from these various sources and synthesized. This process has confirmed that beef, pork and dairy industries all have varying information available on waste resources and overall there is a lack of high-resolution data available. This activity presents an opportunity to assist industries in waste resource recovery by achieving higher resolution data, through collaborations with Australian Biomass for Bioenergy Assessment (ABBA), Rural Research and Development Corporations (RDCs), industry stakeholders and regulatory bodies to garner specific information on co-digestion opportunities and interest in high value add products.

In this study, anaerobic digestion of slaughterhouse wastewater with the addition of trace elements was monitored for biogas quantity, quality and process stability using CSTR digesters operated at mesophilic temperature. The determination of trace element concentrations was shown to be deficient in Fe, Ni, Co, Mn and Mo compared to recommendations given in the literature. Addition of these trace elements resulted in enhanced degradation efficiency, higher biogas production and improved process stability. Higher organic loading rates and lower hydraulic retention times were achieved in comparison to the control digesters. A critical accumulation of volatile fatty acids was observed at an organic loading rate of 1.82 g L–1 d–1 in the control compared to 2.36 g L–1 d–1 in the digesters with trace element addition. The improved process stability was evident in the final weeks of experimentation, in which control reactors produced 84% less biogas per day compared to the reactors containing trace elements.

This paper explores pre-treatment options for the anaerobic digestion (AD) of high-fat cattle slaughterhouse wastewater by assessing and attempting to compare pre-treatment methods used to treat various waste streams. The central focus on cattle slaughterhouse wastewater stems from the problematic nature of high fat, oil and grease (FOG) present in Australian red meat processing (RMP) waste water. Fully integrated abattoirs such as those operating in Australia typically produce wastewaters that carry high FOG loads of 100–4000+ mg/L. While excessive levels of fat can be inhibitory to the AD process, these fats contain a very high theoretical methane potential of 1014 L CH4/kg VS when compared with carbohydrates at 370 L CH4/kg VS and proteins at 740 L CH4/kg VS. However, due to the hydrophobic and inhibitory nature of fat, oil and grease, accessing this methane potential is difficult. This article serves as a review of the literature in the field of pre-treatment of wastewaters and subsequent anaerobic digestion with the goal of increasing biogas yield, with an emphasis on digestion of wastes high in fat, oil and grease. This review covers mechanical pre-treatments including high-pressure homogenisation, ultrasonication and electrokinetic disintegration, and other forms of pre-treatment including thermal, chemical, thermochemical, and enzymatic hydrolysis, and biochemical emulsification. Biological pre-treatments, also known as pre-hydrolysis and two stage digestion are briefly reviewed. The most significant considerations for selecting a pre-treatment technology are the energy balance and costs. Therefore, this review will also provide a commentary on the advantages and disadvantages of the pre-treatment methods reviewed and conclude by evaluating their relative worth in pre-treating FOG.

Operations at meat processing plants result in the production of a range of solid and liquid wastes. Traditional solid waste management practices in Australia include rendering of offal, bones and blood into saleable products (example bone meal), composting (on-site and off-site) and off-site disposal whereas wastewater is treated on-site using anaerobic lagoons. The last decade has seen considerable interest in alternative technologies for the treatment of solid and liquid waste driven by a range of factors including rapidly increasing energy and fertilizer costs, increasing costs of disposal, odor emission and urban encroachment onto traditional rural areas and the potential for improved regulatory compliance. This work provides an overview of closed-loop opportunities for the production of bioenergy and bioproducts using solid and liquid waste at Australian red meat processing facilities. Our investigations undertaken at one of Australia’s largest processing plants have centered on developing tools and practices that better manage waste streams. This work will present results on biogas process optimization of a covered high rate anaerobic lagoon including addition of trace elements and investigation of crust management strategies. The use of solid organic waste in co-digestion and investigations into the reuse of paunch as a fertilizer are also provided. In addition, a review of value added products in the form of blood products was carried out to identify new opportunities in this area.

This work aimed to enhance the anaerobic digestion of fat-rich dissolved air flotation (DAF) sludge through chemical, thermobaric, and thermochemical pre-treatment methods. Soluble chemical oxygen demand was enhanced from 16.3% in the control to 20.84% (thermobaric), 40.82% (chemical), and 50.7% (thermochemical). Pre-treatment altered volatile fatty acid concentration by −64% (thermobaric), 127% (chemical) and 228% (thermochemical). Early inhibition was reduced by 20% in the thermochemical group, and 100% in the thermobaric group. Specific methane production was enhanced by 3.28% (chemical), 8.32% (thermobaric), and 8.49% (thermochemical) as a result of pre-treatment. Under batch digestion, thermobaric pre-treatment demonstrated the greatest improvement in methane yield with respect to degree of pre-treatment applied. Thermobaric pre-treatment was also the most viable for implementation at slaughterhouses, with potential for heat-exchange to reduce pre-treatment cost. Further investigation into long-term impact of pre-treatments in semi-continuous digestion experiments will provide additional evaluation of appropriate pre-treatment options for high-fat slaughterhouse wastewater.

Low-rate anaerobic digestion technology can be influenced by environmental conditions, most notably temperature. The effect of temperature on lipid degradation and crust formation in lagoon digesters treating red meat processing (RMP) wastewater is especially pronounced, impacting on the anaerobic digestion process, resulting degradation and biogas generation. This study investigates the effect of temperature reduction from 38 °C to 25 °C to simulate the annual seasonal temperature range experienced in a covered anaerobic lagoon treating slaughterhouse wastewater located in South-East Queensland, Australia. A step-wise temperature reduction was carried out over a three-month period in continuous stirred tank reactors, and anaerobic digestion performance was compared to digesters operating at optimal mesophilic conditions. After reaching the minimum seasonal temperature, the organic loading rate was increased to identify the limits for organic loading at the different temperature levels. Lower temperatures had a negative impact on degradation efficiency, biogas production, and process stability. The translation of lab scale results to commercial scale operation indicated a 30% reduction in biogas production at a temperature of 31 °C, which corresponded to the highest annual temperatures in the covered anaerobic lagoon. A further decrease to 25.5 °C, which represents the lowest annual temperature in the lagoon, with an increase of the organic loading rate caused up to 80% difference in gas production and negatively influenced process stability. Economic assessment indicated that by operating lagoons under optimal mesophilic conditions, natural gas consumption could be offset with biogas to reduce yearly expenditure of natural gas by up to 25.4%.

Covered anaerobic ponds offer significant advantages to the red meat processing industry by capturing methane rich gas as a fuel source for bioenergy while reducing greenhouse gas emissions (GHG). This paper presents the results of a novel-designed anaerobic pond system at an Australian abattoir in relation to pond performance and potential biogas production. Key findings in assessing the effectiveness of the system revealed that the covered ponds are capable of efficient wastewater decomposition and biogas production. The primary issue with the covered ponds at the abattoir was the build-up of fat/crust that prevented the accurate measurement of biogas and effective use of the cover. In the absence of field biogas data the novel application of the computer modelling software BioWin® was carried out to simulate chemical oxygen demand(COD) removal rates and subsequent biogas yield. The unique parameter used to fit field data was the fraction of the inlet COD due to a superficial crust which did not follow anaerobic digestion. Field data effluent COD removal rates were matched to simulated rates predicted by BioWin when measured influent COD was reduced to 30%. Biogas modelling results suggest significant variation in the economic benefit of biogas energy, with the quantity of biogas potentially varying tenfold (from 328 m3/d to 3284 m3/d) depending on site factors such as pond efficiency, pond configuration and operational practices.

Due to the high strength nature of abattoir wastewater, the accumulation of crusts on anaerobic ponds is a systemic problem in the red meat processing industry in Australia and can limit the ability to accurately obtain biogas measurements. In this study, BioWin was used to simulate chemical oxygen demand (COD) removal rates and subsequent biogas production rate based on field data from two abattoirs where crust accumulation was an issue. BioWin is a Microsoft Windows-based simulator developed by EnviroSim Associates Ltd, which has seen use in the design and optimisation of wastewater treatment plants. In assessing overall anaerobic decomposition efficiency it was hypothesised that a large percentage of influent COD was present as a surface crust which remained largely unbiodegradable. Field data effluent COD removal rates were matched to simulated rates predicted by BioWin when measured influent COD was reduced to 30% (absolute relative error of 11–14%), thus supporting the notion that a significant portion of COD is not taking part in the anaerobic digestion process. The simulation provides a preliminary assessment of pond performance in terms of COD removal rates and also subsequent biogas production rates. BioWin was able to predict approximate biogas production rates ranging between 113 to 173 m3/d and 52 m3/d for the two abattoirs investigated. Further work to validate simulation using BioWin includes obtaining actual biogas measurements and performing COD measurement of crust.

Churchill Abattoir Pty Ltd (CA) is a beef abattoir and rendering facility that has operated for 43 years as a government entity, and for the past 11 years as a private enterprise. Since the changeover, there have been significant improvements in CA's environmental performance. In response to improving waste treatment and minimisation, CA has developed a novel covered anaerobic pond design for the treatment of abattoir wastewater. This design consists of five smaller ponds arranged in a cell configuration which has been driven by a number of factors including, manageability (for desludging ponds) and ease of removing and applying covers. Industry design and management standards are based on generalised metrics for anaerobic ponds rather than industry specific data. To inform pond design, an intensive study of pond behaviour was performed on the covered anaerobic ponds. This paper gives an overview of the literature reported on the use of anaerobic ponds in the treatment of high-strength wastewater and outlines the key findings in the preliminary assessment of the behaviour and performance of these novel anaerobic ponds. The use of five smaller ponds instead of one larger pond has proven successful in terms of crust and sludge removal. The primary issue with the covered ponds at Churchill, however, was the build-up of fat/ crust that prevented the capture of biogas and effective use of the cover. Despite the operational difficulties in relation to fat/crust accumulation, results indicate that satisfactory, stable operation has been achieved for the smaller five-pond system, notwithstanding the higher than desired organic loading rate of the two primary ponds.

In Australia, the red meat processing industry actively seeks approaches to improve the management of solid waste from processing operations and enhance the environmental performance. Recycling of paunch waste to farmland could be a cost-effective and practicable environmental option. However, little is known about the agronomic value of fresh and composted paunch, and the associated requirements for land application. Therefore, a short-term experimental work was undertaken to assess potential risks due to weed seed contamination and determine the agronomic response of ryegrass (Lolium perenne L.) to soil incorporation of paunch. The risk of weed contamination from soil application of paunch appeared to be low; however, methods that account for viability of seeds may be required to fully discard such a risk. Soil application of paunch at field equivalent rates of 150-300 kg ha-1 of N increased dry matter yield by ≈30% on average compared with untreated grass, but was approximately 35% lower than a mineral fertilizer treatment applied at the same rates. Dry matter yield of paunch-treated grass was between 2000 and 3000 kg per ha over four consecutive cuts at 25-day intervals. Nitrogen use-efficiency of paunch was approximately 10% (range: 3% to 20%, depending on paunch type), and total N in harvested plant material showed values, which were between 2% and 3%. Overall, there appears to be potential for paunch-derived products to be used as a source of carbon and nutrients in crop production. Areas that merit a research priority within this space are also outlined in this paper. Such work is required to inform soil-, climate- and crop-specific land application rates, optimize agronomic performance, and minimize environmental concerns. There is also a requirement for the value proposition to industry to be determined, including reduced cost of disposal of material via gate fees and fertilizer replacement value.

The ability to appreciate the inter-connectedness of complex biological relationships can be difficult for many students. Graphical knowledge in the form of concept maps and flow charts are learning tools which can assist students to recognise the inter-connectivity. This report focuses on a trial which incorporates these two related visual learning tools using a tablet PC to support their instruction in an undergraduate introductory microbiology class. The objectives of the trial were to introduce both concept maps and flow charts so as to assist students in linking theory with practical knowledge, to make connections within and outside their course of study, and to increase student preparedness and time management in laboratories. An integrated approach to teaching using a pen-based technology with live audio visual in both lectures and laboratories was used. This report details the implementation of the teaching approach focusing on the application of the concept maps and flow charts and how tablet PC ...

This article documents my personal experiences in entering research in tertiary teaching and learning. My role as a science academic has included teaching both undergraduate science and nursing students, as well as incorporating scientific research in the discipline of microbiology. Through teaching these two different cohorts of students I have come to realise that they demand different teaching styles and strategies. Previous studies concerning science courses in nursing programs suggested that nursing students have a negative attitude towards the relevance of science in nursing and lack the confidence to study this subject. In an attempt to improve this situation. I have taken the approach of investigating my teaching and learning practices in nurse education by undertaking a comprehensive evaluation of the course, and in doing so I have become more open to learning about new teaching and learning activities. This shift in research experience, from laboratory-based to educational, has produced an interesting parallel. The new experiences and anxieties that I faced in entering a new paradigm of educational research can be seen as analogous to those experienced by my nursing students when studying science in nursing for the first time. This paper provides a personal account of this shift in research and reflects on how my lived experience of entering a new field of research has facilitated the way that I understand how students learn.

A procedure for the immobilization of rhizomycelia of two strains of anaerobic fungi, namely Piromyces sp. KSX1 and Orpinomyces sp. 478P1 using Ca-alginate beads has been developed. Zoospores were found to be suitable propagules for the immobilization of the monocentric strain KSX1 giving rise to colonization in 100% of beads. For polycentric strain 478P1, which produced very few zoospores, partially homogenized rhizomycelia proved a suitable inoculum for the beads. The distribution of rhizomycelial growth inside the beads and on the surface depended on which fungal strain was immobilized. Strain 478P1 grew as a mycelial network inside the beads whereas strain KSX1 grew in microcolonies throughout the bead and on the surface, and was unable to evenly colonize the entire Ca-alginate matrix.

Two anaerobic fungi, one a monocentric strain ( Piromyces sp. KSX1) and the other a polycentric strain ( Orpinomyces sp. 478P1), were immobilised in calcium alginate beads and cultured in sequential batches where spent medium (containing 0.25% cellobiose) was repeatedly drained and replaced. beta-Glucosidase production with KSX1 was maintained for 45 days over six repeated batch cultures yielding a maximum level of 107 mIU/ml. For 478P1, beta-glucosidase production was maintained for 30 days over four repeated batches yielding a maximum level of 34 mIU/ml. Although repeat-batch cultures of KSX1 produced more beta-glucosidase than strain 478P1, the maximum specific beta-glucosidase produced from these immobilised cultures was similar. The immobilised polycentric strain proved to be operationally superior to strain KSX1, as strain 478P1 did not produce any growth in the culture liquor.