|N. Gruyer, M. Dorais, V. Gravel, G.J. Zagury
|greenhouse effluent, pathogens, ponds, recycling drainage solution
Due to the lack of high quality water and potential pollution of groundwater by leached nutrients, recirculation of nutrient solutions for greenhouse cultures is now unavoidable.
Even though closed growing systems offer several advantages from an environmental point of view, risks associated with pathogen dissemination are a major concern for growers.
Artificial wetland is a low-cost alternative for treating agricultural wastewaters.
Therefore, the objective of this study was to evaluate the effectiveness of three types of artificial wetland to reduce the content of Pythium ultimum propagules in greenhouse effluents.
An experiment was conducted from January to April 2009 under greenhouse conditions, using horizontal subsurface flow artificial wetlands filled with pozzolana and implanted with common cattail (Typha latifolia). Wetland units contained either a simple (AWS), complex (AWC) or no (AW) carbon source.
Wetland units received a reconstituted greenhouse effluent and were inoculated with a suspension of P. ultimum (100 to 1800 CFU per ml). Daily samples of wetland effluent were collected and P. ultimum propagules concentration was evaluated using the selective media PDA-PARP. Populations of mesophilic bacteria, Pseudomonas spp., and Bacillus spp. were evaluated.
Results showed that artificial wetlands effectively eliminated P. ultimum propagules in greenhouse effluent when concentrations ranged from <100 to 1600 CFU per ml.
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