Research focusing on plant performance in constructed wetlands and agronomic application of treated wastewater – A set of experimental studies in Sicily (Italy)

Abstract

Constructed wetlands are sustainable technologies for the treatment of wastewater. These biological systems have been widely studied throughout the world for more than 30 years; however, most studies have focused on the effects of design and engineering on pollutant removal from wastewater. Undoubtedly, agro-technical aspects have been given too little consideration by research. This paper reports the main results of a set of experiments carried out on two pilot horizontal subsurface flow systems in Sicily (Italy). Festuca , Lolium and Pennisetum spp. in combination and three emergent macrophytes– Arundo donax L., Cyperus alternifolius L. and Typha latifolia L.–alone, were assessed. The aim of the study was to demonstrate that, under predetermined hydraulic and design conditions, the choice of plant species and the management of the vegetation can significantly affect the pollutant removal performance of constructed wetlands. In addition, wastewater (after treatment) can also be used for agricultural purposes leading to increased sustainability in agricultural systems. Arundo and Typha -planted units performed better than Cyperus -planted units in terms of chemical, physical and microbiological contaminant removal. All the species adapted extremely well to wetland conditions. Polyculture systems were found to be more efficient than monocultures in the removal of dissolved organic compounds. The reuse of treated wastewater for the irrigation of open fields and horticultural crops led to significant savings in the use of freshwater and fertilizers. The results of physical-energy characterization of A . donax above-ground plant residues and pellets highlighted the fact that a constructed wetland could also be a potential source of bioenergy.

Effects of Irrigation with Different Sources of Water on Growth, Yield and Essential Oil Compounds in Oregano

“…In areas with prolonged water shortage, as is found in the Mediterranean region, the use of treated wastewater (TWW) for combined irrigation and fertilization represents a sustainable cultivation practice also for aromatic plants. Many studies have examined the effects of TWW on horticultural and open field crops, evaluating how TWW affects plant growth and soil characteristics both in the short and long-term period [ 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ]. Little attention has been paid to the use of TWW for the cultivation of aromatic species [ 48 , 49 , 50 , 51 ], probably due to cultural reasons related to public acceptance and bad perception of TWW reuse in agriculture [ 52 , 53 , 54 ].…”

“…plants led to an increment in EO concentration, but to a reduction in peppermint ( Mentha piperita L.) and sweet marjoram ( Origanum majorana L.) plants [ 51 ]. It is well-known that the major risk associated with the use of TWW is the possible contamination of edible plants due to pathogen accumulation [ 43 , 44 , 45 , 46 ]. Therefore, wastewater (WW) must be treated and purified with single or combined treatment systems.…”

Constructed wetland for improved wastewater management and increased water use efficiency in resource scarce SAT villages: a case study from Kothapally village, in India

“…Common flood irrigation method requires about 500 m 3 /ha water per irrigation event. Thus, the use of the treated wastewater for fertigation (Licata et al 2019) led to the addition of 7.5 kg/ha of nitrogen in the fields per irrigation. The treated wastewater was utilized by a local farmer to cultivate the 0.6 ha agricultural land adjacent to the treated wastewater storage tank.…”

Bacteriological Quality of a Forage Grass (<i>Pennisetum purpureum Schumach</i>) Used in Constructed Wetland Removing Domestic Wastewater Pathogenic Microorganism

“…Due to the advantages offered by CWs, namely the possible valuation of certain plant species, the scientific community should increasingly be confronted with the problem of the quality of plants of economic interest used in the process. However, this issue remains very little to be discussed and presented in fora and article publications, in contrast to those focusing on the sanitation efficiency of CWs [6] [7], the removal processes and the design [8] [9] and operational parameters that affect the removal processes in the systems [3] [10].…”