M icroalgae are seen as a future source of biofuels, as they can yield between 10 and 100 times more fuel per unit area than other crops; can be grown in areas unsuitable for food production and can use saline rather than fresh water. Sandra Kentish and her team have developed a new way to transfer carbon dioxide directly into a microalgal culture, to accelerate the growth of this renewable source of biomass.
The process significantly increases the energy efficiency of delivering the carbon dioxide, by reducing the energy demand required to separate the CO2 from natural gas or power station fl ue gases. Further, losses of CO2 to the atmosphere are reduced. She says the algal growth rate is optimised by supplying the microalgae with carbon dioxide, usually by bubbling it through the bed.
However, as the algal beds are quite shallow (typically 30-50 cm deep), many of the CO2 bubbles are lost back to the atmosphere, meaning that the carbon footprint of the process is far from optimal. “In our novel approach, we pump the carbon capture solvent through the algal bed, rather than the gas,” she says. “Specifically, we contain the solvent, loaded with CO2, within commercial hollow fibre membranes.
The microalgae draw the carbon dioxide that they need through the walls of the membranes, while the solvent itself flows through otherwise unaltered.” She says the approach works with three diff erent solvents (potassium carbonate, potassium glycinate and monoethanolamine solutions) although the performance is compromised for monoethanolamine due to some migration of this molecule across the membrane. They have also proved it can work with several species of microalgae, both fresh water and saline species.
Dr Vishy Karri says his company Expert 365 was established to answer an agricultural question, “What is the precise amount of water quantity required, per square meter patch of the horticulture farm, for various crops, soil type and age of the plant for healthy yield?”.
Their solutions are built via sensors in soils, to monitor real-time soil moisture, electrical conductivity and temperature. This is relayed to Microsoft Azure cloud-based algorithms to provide irrigation recipes. His solution is being used in farms in NSW, QLD and WA and it is gaining international interest with orders from India and the USA. It has been shown to reduce water usage by up to 10 per cent while also achieving an increase of up to 15 per cent in crop yield.
“We believe this unprecedented technology represents a significant step towards implementing Internet of Things (IOT) in agriculture,” he says. “This revolution in soil sensor technology calculates the precise amount of water required for various horticulture plants based on a myriad of parameters, namely age, soil type, climate and rate of depletion of readily available underground water.”
In spite of the harsh climatic conditions and scarcity of irrigation water, Karri says water consumption by the agriculture industry increased up to 12,780 GL in 2012-14, and is still increasing, accounting for 65 per cent of total water consumption in Australia during that period. While imposing meters for restricted water usage and monitoring are some of the measures proposed, he feels there is an opportunity to save water by identifying precise amounts of water for eachcrop’s need.
“From a project management point of view, we have gone through an arduous journey of prototype development, proof of concept, building and testing reliability of the product and more recently mass production for larger scale commercialisation,” he says. “There are approximately 120,000 small to medium scale farmers in Australia addressing a large $6.7 billion market. Within that market, the Australian vegetable industry is one of Australia’s largest horticultural industries with an estimated annual gross value of production of $3.7 billion in 2014-15, with around 5300 agricultural businesses that produce vegetables.”
Aft er more than three decades of applied research, Edgar Johnson has defined the detailed technical, management and quality requirements for the in-situ calibration of large flow meters, with an assured traceability to a flow reference standard through an unbroken chain of calibrations.
Bulk water meter errors are a major contributor to ‘non-revenue water’ for utilities, costing approximately $15billion/year globally, and relatively small errors can result in substantial financial losses.
To provide both quality and psychological assurance in data generated by permanently installed large in-line water meters, Johnson defined the requirements for a practical calibration in the field. He facilitated the first use in Australia of a very accurate Laser Doppler Velocimetry (LDV) system, developed by a German organisation, Optolution, for the calibration of large flow meters in Queensland. Aft er a 2013 planning investigation identifi ed the operating regime errors of SE Queensland large meters, Johnson was brought in to assess the available technology and develop a suitable in-situ calibration method.
LDV involves splitting a primary laser beam into two parallel beams, that intersect at the focal point, which is directed into the flow of water along a transept of the pipeline diameter. Minute particulate matter or bubbles passing through this point of intersection reflect the laser light at a fixed frequency (the Doppler effect), which is used to calculate the point velocity with an accuracy of ±0.1 per cent.
The LDV apparatus is robotically advanced in small increments across the pipeline diameter to compile a complete velocity profile. Implemented in 2015, calibration test results indicated levels of bulk water metering error greater than commonly assumed and identified asymmetrical fl ow profiles in two meters, which significantly affected meter accuracy.