ISHS Acta Horticulturae 691: International Conference on Sustainable Greenhouse Systems - Greensys2004
DISINFECTION OF DRAINAGE WATER IN GREENHOUSE CULTURES BY SOLAR ENERGY |
| Authors: | M.C. Rocamora Osorio, J.M. Cámara Zapata, H.M. Puerto Molina |
| Keywords: | soilless culture, water disinfection, solar collector, radiation, thermal time |
| Abstract:
Water scarcity in the Southeast of Spain drives greenhouse producers to recirculate the drainage water in hydroponic cultures to improve the overall water use efficiency and reduce the pollution of aquifers and surface waters. Drainage water can be used for irrigation and also for misting or fog systems in summer. But water recirculation requires a thorough control of the population of plant pathogens to avoid spreading of diseases through the irrigation or refrigeration system. In this work, a solar disinfection system is proposed, based on a solar collector that uses solar radiation to heat the water and profits of the naturally occurring UV radiation. In two field experiments, the reservoir of the collector was filled with drainage water obtained from a commercial greenhouse in Pilar de la Horadada (Alicante, Spain). Global and ultra-violet radiation and water temperature were measured along the experiments. Water samples were taken at different hours and analysed to determine total aerobic bacteria and coliform bacteria concentrations. Heating treatment was effective in bacteria elimination with a thermal time requirement of 240 ºC•h for total aerobic and 217ºC•h for coliform bacteria. The disinfection was effective irrespective of the initial bacterial load and the daily global radiation. | |
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