Now showing 1 - 4 of 4
  • Publication
    Combining Wind and Pumped Hydro Energy Storage for Renewable Energy Generation in Ireland
    (Hindawi Publishing Corporation, 2014-08-21) ; ; ;
    Ireland has one of the highest wind energy potentials in Europe. The intermittent nature of wind makes this renewable resource impractical as a sole source of energy. Combining wind energy with pumped hydro energy storage (PHES) can overcome this intermittency, consuming energy during low-demand periods and supplying energy for periods of high demand. Currently Ireland has a number of hydroelectric power plants and wind farms of various scales in operation. A feasibility study was conducted to investigate the potential of securing a reliable source of renewable energy by increasing the penetration of hydroelectric power by means of combined wind-PHES developments. The greatest wind potential is experienced along the western coast of Ireland and a number of sites were identified here which satisfied a minimum mean wind speed criterion of 10.5 ms−1. Each site was then further evaluated according to topographical requirements for PHES. All but two of the identified sites are immediately unsuitable due to the presence of areas protected under European legislation; this highlights the nonenergy related obstacles in the path of renewable energy generation in Ireland and suggests that a compromise should be researched which could facilitate both renewable energy generation and species and habitat protection in Europe.
  • Publication
    An investigation into the efficacy of ozone for inactivation of microalgae cells in photobioreactors
    (American Society of Agricultural and Biological Engineers (ASABE), 2013-07) ; ; ; ;
    The sterilisation of photobioreactors is paramount to successful cultivation of microalgae. Due to the adhesive nature of microalgae, fouling of the light transmitting surfaces can be problematic. Traditional methods of sterilising photobioreactors between batches involve ultrasound, autoclaving or as seen in recent times, the photobioreactor incorporates a cleaning system. The objective of this project was to look at an alternative method of sterilisation. A preliminary study was carried out to determine the efficacy of ozone as treatment for the algae strain Dunaliella tertiolecta. Algae cultures at 104 cells CFU mL-1 were exposed to 3-51 μg mL-1 of ozone at different time periods (0-80 sec) and constant gas flow rates of 0.125 and 0.25 L min -1. Inactivation rates for total reduction of D. tertiolecta were found to increase significantly with an increase in ozone concentration and treatment time. This study supports the proposed mechanism of cell inactivation by ozone that causes cell membrane destruction and finally cell death. Therefore, it was found that ozone can be used to effectively eradicate microalgae in photobioreactors.
  • Publication
    Production of medicated bedding straw: challenges and perspectives
    Previous bacteriological findings have reported that animal disease outbreaks are associated with the quality of the animal environment. Animal bedding straw is a good source of bacteria and fungi, typically contaminated with (mycelia) yeasts and filamentous fungi species such as Aspergillus, Fusarium, Alternaria, Cladosporium, Epicoccum, Penicillium, Verticillium and Enterobacteria. The objective of this work was to assess the efficacy of different technologies on the production of medicated bedding straw. Four critical control points of an industrial straw disinfection processing line were identified. The levels of fungi and bacteria present in the straw during an industrially applied mechanical – chemical process were quantified. The plate counting revealed that propionic acid and formaldehyde chemicals reduced the microbial levels from the raw material and that they were more efficient on moulds than on bacteria. The potential use of ozone gas as an alternative greener technology to the current liquid chemical treatments was also evaluated. Trials conducted on ozone treatments (flow rates: 0.031, 0.125, 0.5 L/min, concentrations: 36, 99, 150 μg/mL, treatment time: 0, 5, 15, 30 mins, and residual times of 0 to 18 hrs) indicated that ozone successfully reduces the microbial counts and the fungi levels by more than 1.5 logs (cfu/g).
  • Publication
    Evaluation of the odour reduction potential of alternative cover materials at a commercial landfill
    The availability of virgin soils and traditional landfill covers are not only costly and increasingly becoming scarce, but they also reduce the storage capacity of landfill. The problem can be overcome by the utilisation of certain suitable waste streams as alternative landfill covers. The objective of this study was to assess the suitability of Construction & Demolition fines (C&D), Commercial & Industrial fines (C&I) and woodchip (WC) as potential landfill cover materials in terms of odour control. Background odour analysis was conducted to determine if any residual odour was emitted from the cover types. It was deemed negligible for the three materials. The odour reduction performance of each of the materials was also examined on an area of an active landfill site. A range of intermediate cover compositions were also studied to assess their performance. Odour emissions were sampled using a Jiang hood and analysed. Results indicate that the 200 mm deep combination layer of C&D and wood chip used on-site is adequate for odour abatement. The application of daily cover was found to result in effective reduction allowing for the background odour of woodchip.
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