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The purpose of this investigation was to explore the possibility of utilising post-sap residues for bio-oil production, that are produced after liquid fertiliser extraction from Kappaphucus alverizii, red macroalgae. The sap — a liquid fertiliser — was expelled by crushing the K. alverizii. The residual macroalgae were hydrothermally liquified at varying operating conditions (temperature, biomass to solvent ratio, residence time, catalyst dose), in order to understand its influence over the productdistribution and composition from thehydrothermal liquefaction (HTL) process. The maximal yield for crude bio-oil was 28.4 ± 0.6 wt.%, which was possible only when the HTL reactor was operated in presence of a ZSM-5 catalyst at 300 °C using 20 g of biomass for 30 min duration. Still, the bio-oil derived from the HTL process seems to possess higher oxygen content. Hence, the hydro-deoxygenation (HDO) process was carried out to upgrade the crude bio-oil into oxygenates less oil. The bio-char along with ZSM-5 derived from the previous HTL process was utilised as a catalyst in the HDO process. Catalysed HDO processes were able to improve the HHV of upgraded oil to 36.7 MJ/kg. Overall, this study implies that the crude bio-oil can be effectively produced from the post-sap residue, which can be further upgraded to calorific-rich fuel. [ABSTRACT FROM AUTHOR]

Ammonium is known to be one of the most significant pollutants in water bodies. The presence of ammonium in water is mainly originated from agricultural activities, domestic sewage and industrial effluent. This study evaluates the performance of two commercial thin film composite (TFC) membranes, i.e., NF270 and XLE from FilmTec™ for ammonium removal using synthetic wastewater and domestic sewage. The filtration experiment was conducted at different feed ammonium concentrations, humic acid concentrations, pHs and pressure. Results showed that the membrane rejection against ammonium increased dramatically with increasing ammonium concentration. However, the membrane flux was slightly compromised at higher ammonium concentration. With respect to pH, highest ammonium removal rate was able to be achieved at an optimum pH of 10. Besides, the permeation flux increased gradually with increasing feed pressure. From the results, the XLE membrane outperformed the NF270 membrane in terms of ammonium rejection. The retentate of XLE membrane filtration process was found to be useful as liquid fertiliser for plant growth. The results indicated that the TFC membrane process is not only able to produce permeate with an ammonium concentration below the acceptable limit of 10 mg/L but also able to produce retentate with enriched ammonium for plant growth.

• Feasibility of producing chicken feed and liquid fertiliser recycling food waste. • Production of chicken feed of same quality as the one available in the market. • Production of liquid fertiliser meet commercial feed solution for hydroponic system. Most of the food waste (FW) generated by commercial activities and the majority of household FW is collected as part of general waste, which is either incinerated or landfilled. There is an increasing interest in the collection of FW as a separate waste stream and use it for the production of compost or recovery of energy through anaerobic digestion (AD) or pyrolysis. This study focused on using FW to produce chicken feed and liquid fertiliser (CFLF). The food waste samples were collected from food related businesses such as service club, café, restaurant, bakery and supermarket. The CFLF process was used to produce chicken feed pellets containing 19% of protein content, which is within the range of 16 to 22% of most commercial chicken feed pellets and within the National Research Council (NRC) recommended range of 15 to 23%. The liquid extract derived from CFLF process had high nutrient concentrations similar to those present in the feed solution used in hydroponic systems. Hence, the liquid extract from CFLF can be used to replace the commercial liquid fertiliser used in hydroponic systems. Environmental impact analysis of CFLF process using GaBi life cycle analysis (LCA) software indicated that the CFLF process can yield environmental credits for 15 out of 19 categories of impacts considered in the analysis. The measured environmental credits were significantly higher than the other disposal options such as, anaerobic digestion (AD), incineration and landfill. [ABSTRACT FROM AUTHOR]

Leptospermum scoparium 'Kea', 'Kiwi' and 'Ruru' were evaluated for production as potted plants. Following environmental effects were investigated; (a) Temperatures regimes for 40 days each for two periods; (b) Photoperiods for 25 and 50 days; (c) Combined effects of temperature and duration; (d) Combined effects of temperature and irradiance and (e) Combined effects of day length, irradiance and fertilisers treatments. Floral initiation was completed following 25 days of a 9–12 h short-day (SD) photoperiod at 15/13°C (day/night). Floral development was accelerated at 20/18°C during the first period, and at 25/23°C during the second period. Flower buds were initiated at 14–15/11–14°C and SD. Although the irradiance and nutrition effects were less prominent than temperature and photoperiod, 25/22°C, high irradiance discharge (HID), and 100 ppm of nitrogen from a liquid fertiliser (LF) with 0.5 g of slow-release fertiliser (SRF) are suggested optimum for flowering. The following conditions are recommended for production of compact plants with maximum number of flowers year round starting from small propagules of three L. scoparium hybrids: 9–12 h SD under 15/13°C (day/night) for 25 days, at 20/17°C for 30 days, under 42 Wm−2 HID, and fertilisation of 100 ppm N in LF with 0.5 g of SRF. [ABSTRACT FROM AUTHOR]

A preliminary method for extraction of soluble nutrients from organic materials is presented that investigates important characteristics of design for efficient extraction. The study was conducted in Polyvinyl Chloride (PVC) columns (length: 50 and 100 mm, diameter: 87.5 mm) filled with fresh and composted chicken manures, packed to densities in the range of 0.2–0.6 g cm −3 . The columns were leached with distilled water. A total of 5 cm 3 of water per cm 3 of material was applied. Leachate collection was sequentially partitioned to enable determination of soluble nutrients throughout time, including: total dissolved nitrogen (TDN), water soluble phosphorus (P) and potassium (K). Waste material state, density of packing and lengths of column all significantly ( P < 0.05) affected the concentration of ions in the leachate. In general, longer contact time between the percolating water and the material resulted in higher ( P < 0.05) concentration of ions in the leachate. Cumulative TDN and water soluble-P were greater ( P < 0.05) in fresh manure leachates, compared with compost leachates. Although, compost leachates provided relatively greater ( P < 0.05) concentration of K. Salinity ionic concentration of leachates, determined as Na and Cl, was consistently greater from fresh manure as compared to that from mature compost. Fresh manure and mature compost were determined to provide different responses to nutrient leaching because of differences in physico-chemical characteristics. Saturated hydraulic conductivity in fresh manure columns reduced rapidly with application of water to the columns. The mechanisms involved in this process are discussed with the implication for nutrient extraction and use of leachate from chicken manure waste sources. [ABSTRACT FROM AUTHOR]

Runoff of nutrients and sediment from agricultural catchments can impair the health and resilience of aquatic ecosystems in receiving waterbodies. The sugarcane (Saccharum sp.) industry in Australia has adopted strategies to improve farm runoff water quality. Rainfall simulation trials were conducted to quantify the relative effectiveness of some sugarcane soil and fertiliser management practices on nutrient and sediment loss in runoff. The trials were conducted within the Herbert River catchment in the Wet Tropics of Queensland. Simulated rainfall (~76 mm h–1) was used to generate runoff from 1.70 m2 plots in first ratoon sugarcane on well-drained Ferralsols at Abergowrie and from 1.55 m2 plots in sugarcane planted into furrows and mound beds on an imperfectly drained Luvisol at Trebonne. At Abergowrie, the practices studied were; crop residue retention after harvest (green cane trash blanketing), applying a liquid rather than a granular fertiliser, and applying fertiliser to the sub-surface rather than to the surface on ratoon phase sugarcane. At Trebonne, sub-surface fertiliser placement was studied on plant cane and after varying amounts of time and repeated rainfall after fertiliser application. Comparisons were made with a similar study in plant cane at Macknade. Particulate nitrogen (N), particulate phosphorus (P), and suspended sediment losses in runoff were reduced by crop residue retention, which was expected. Dissolved inorganic N (DIN) loads (but not concentrations) were also reduced by residue retention. Dissolved inorganic N and filterable reactive P concentrations in runoff were reduced by sub-surface fertiliser placement, as expected, and by the liquid fertiliser that was studied. In contrast to expectations, DIN concentrations increased in mound beds (but not in furrows) with increasing time and rainfall after fertiliser application. The increase was attributed mainly to increases in soil mineral N and runoff volume. The practice that was most effective at reducing DIN loads in runoff (64–85% reduction) was sub-surface rather than surface placement of fertiliser. • Sugarcane crop residue retention reduced sediment and particulate nutrients in runoff. • Sub-surface application of N fertiliser reduced DIN concentrations in runoff. • A liquid fertiliser reduced DIN concentrations in runoff relative to a granular form. [ABSTRACT FROM AUTHOR]