Simulation Of Irrigation Runoff Sediment Removal With Vegetal Filters PDF Download

California is tremendously dependent on water for a highly productive agricultural industry, growing commercial and industrial sectors, and the human population. In the next 15 years, the population is expected to grow dramatically, which will only put more pressure on an already tight water supply. Effective, low cost, simple, and reliable water treatment methods need be developed to alleviate this pressure. Two experiments were conducted to determine the efficacy of slow sand filters (SSFs) to remove plant pathogens from water to be reused for irrigation. The first experiment evaluated three increasing loading rates to determine if SSFs maintain efficacy. The second experiment was a field study in which SSFs that were initially exposed to Phytophthora capsici were then used to treat stream water known to contain numerous Phytophthora spp. A third experiment examined the effect of chilling and agitation on the recovery rate of P. capsici. Very low numbers of colony forming units were recovered below the sand surface during the fall trial of the slow sand filtration optimization experiment. Chilling and agitation of P. capsici propagules reduced the recovery of colony forming units. Slow sand filters are very effective at removing more than 99% of plant pathogen propagules from water and there was little difference in the removal rate between the slowest loading rate (0.15 m/hr) and the fastest (0.50 m/hr). In colder temperatures, the medium (0.25 m/hr) and fast loading rates caused the filters to foul. Slow sand filters established in the presence of P. capsici can remove other Phytophthora spp., however frequent fouling occurred due to turbidity of the creek water. Slow sand filtration is a simple, low cost, low maintenance, effective and reliable technology that can be used by nurseries to reduce water consumption.