However,as shown by Abidi et al. (2009), a hybrid system could optimize the contribution of the plants and improve the hydraulics, especially regarding retention times in the planted and unplanted units. The different retention times in the planted and unplanted unit.The differant retention times of the wastewaterlogger in a H-SSF system than in a V-SSF one-would determine a change in the general aerobic/anaerobic conditions and affect the chemical oxidation mechanisms regarding pathogens.
An interesting aspect of this study regarded waterloss in the planted subunits of the pilot system.The main reason for studying water balance in the CW was to establish if the choice of plant hydraulic and design conditions, and to determine water savings. In dry ares of the Mediterranean, where treated wastewater is often used in irrigation, it makes sense to look for macrophytes with non-excessive water loss in a CW planted with emergent macrophytes can be 7 or 8 times higher than that of normal evaporation without plants. There is very little in literature, especially concerning Mediterranean regions, on choosing macrophytes based purely on ET water consumption.
In morocco found ET values to be around 40 mm in a CW planted with Arundo donax and 60 mm in a CW planted with Phragmites australis, in two sites which were climatically highly different, stated that the role of plants in dispersing water is similar even under different, stated that the role of plants in dispersing water is similar even under different environmental conditions but that ET differs depending on the site and throunghout the growing season of both the same year and also different years. In our research, data showed greater water losses in the reedmace-based treatment than the umbrella-sedge, probanly due to different average leaf surface and foliar density, as sustained by Sanchez-Carillo et.al.(2001)However, differences in ET water loss for the two macrophytes were not excessively hight using average values and, therefore, we cannot determine, based only on water consumption, which species is better than another under identical field conditions. It is clear that further researh is needed regarding various aspects in this area in order to provide a more complete picture.
5. conclusions
The comparison of two emergent mscrophytes grown under indentical conditions snd subjected to the same hydraulic load highlighted the fact, in a monospecies system and in the absence of interspecific competition, there was a significant difference in plant ability to treat the main pollutants and to influence the purification efficiency of the chosen wastewater treatment system. The role of the plant species must not, therefore, be condidered of secondary importance insofar as, under constant conditions(daily hydraulic load, gravel size and substrate depth), as was the case in this study, it is clear that the treatment efficacy of a system can vary significantly with the species and based on interactions between the plants. Our results showed that T. latifolia outperformed C. alternifolius. Our results showed that T. latifolia outperformed C. alternifolius, both in terms of biomass production and nitrogen uptake and storage, and this is due not only to its competitive and aggressive nature in colonizing the inert substrates but also to ability to adapt to diverse and not always optimal climate conditions. These findings highlight that, regarding selection criteria of plant species, knowledge on the adaptability of a species to climatic conditions is fundamental in order to ensure maximum results from the plants in wastewater treatments. It is clear that a series of from the plants in wastewater treatments. It is clear that a series of longterm experiments to compare other species which are typical of the Mediterranean environment but which have been studied little to date should be carried out in order to increase knowledge on plant ability to treat wastewater in both mono-and poly-species systems(also an aspect which has enjoyed little attention to date).
Acknoledgements
the authors would like to the thank the Sicilian Regional Ministry of Food and Agricultural Resources, Research Centre Corissia and the University of Palermo for having provided the funds for the funds for the study. A special thanks also goes to Branwen Hornsby for her continuing support to the research and linguistic contribution. We would also like to thank the reviewers for their constructive comments.
However,as shown by Abidi et al. (2009), a hybrid system could optimize the contribution of the plants and improve the hydraulics, especially regarding retention times in the planted and unplanted units. The different retention times in the planted and unplanted unit.The differant retention times of the wastewaterlogger in a H-SSF system than in a V-SSF one-would determine a change in the general aerobic/anaerobic conditions and affect the chemical oxidation mechanisms regarding pathogens.
An interesting aspect of this study regarded waterloss in the planted subunits of the pilot system.The main reason for studying water balance in the CW was to establish if the choice of plant hydraulic and design conditions, and to determine water savings. In dry ares of the Mediterranean, where treated wastewater is often used in irrigation, it makes sense to look for macrophytes with non-excessive water loss in a CW planted with emergent macrophytes can be 7 or 8 times higher than that of normal evaporation without plants. There is very little in literature, especially concerning Mediterranean regions, on choosing macrophytes based purely on ET water consumption.
In morocco found ET values to be around 40 mm in a CW planted with Arundo donax and 60 mm in a CW planted with Phragmites australis, in two sites which were climatically highly different, stated that the role of plants in dispersing water is similar even under different, stated that the role of plants in dispersing water is similar even under different environmental conditions but that ET differs depending on the site and throunghout the growing season of both the same year and also different years. In our research, data showed greater water losses in the reedmace-based treatment than the umbrella-sedge, probanly due to different average leaf surface and foliar density, as sustained by Sanchez-Carillo et.al.(2001)However, differences in ET water loss for the two macrophytes were not excessively hight using average values and, therefore, we cannot determine, based only on water consumption, which species is better than another under identical field conditions. It is clear that further researh is needed regarding various aspects in this area in order to provide a more complete picture.
5. conclusions
The comparison of two emergent mscrophytes grown under indentical conditions snd subjected to the same hydraulic load highlighted the fact, in a monospecies system and in the absence of interspecific competition, there was a significant difference in plant ability to treat the main pollutants and to influence the purification efficiency of the chosen wastewater treatment system. The role of the plant species must not, therefore, be condidered of secondary importance insofar as, under constant conditions(daily hydraulic load, gravel size and substrate depth), as was the case in this study, it is clear that the treatment efficacy of a system can vary significantly with the species and based on interactions between the plants. Our results showed that T. latifolia outperformed C. alternifolius. Our results showed that T. latifolia outperformed C. alternifolius, both in terms of biomass production and nitrogen uptake and storage, and this is due not only to its competitive and aggressive nature in colonizing the inert substrates but also to ability to adapt to diverse and not always optimal climate conditions. These findings highlight that, regarding selection criteria of plant species, knowledge on the adaptability of a species to climatic conditions is fundamental in order to ensure maximum results from the plants in wastewater treatments. It is clear that a series of from the plants in wastewater treatments. It is clear that a series of longterm experiments to compare other species which are typical of the Mediterranean environment but which have been studied little to date should be carried out in order to increase knowledge on plant ability to treat wastewater in both mono-and poly-species systems(also an aspect which has enjoyed little attention to date).
Acknoledgements
the authors would like to the thank the Sicilian Regional Ministry of Food and Agricultural Resources, Research Centre Corissia and the University of Palermo for having provided the funds for the funds for the study. A special thanks also goes to Branwen Hornsby for her continuing support to the research and linguistic contribution. We would also like to thank the reviewers for their constructive comments.
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