Use of wastewater as a nutrient solution in a closed gravel hydroponic culture of giant reed (Arundo donax)

The objective of this experimental work was to examine the efficiency of giant reed (Arundo donax L.), as a source of biomass production and as a biofiltering device for sewage effluents. Two giant reed populations were cultivated in a closed gravel hydroponic system, where pigʹs waste was used as a nutrient solution. The results showed that stem biomass production varied from 12 to 23 kgDMm−2 yr−1, more than the ordinary production in the soil. According to stem analysis, for the first two years, there was an average infiltration rate of 31 gm−2 yr−1 total N, 7.5 gm−2 yr−1 total P, 18.8 gm−2 yr−1 K, 2.1 gm−2 yr−1 Ca, 2.1 gm−2 yr−1 Mg, 0.27 gm−2 yr−1 Fe, 0.02 gm−2 yr−1 Mn, 0.14 gm−2 yr−1 Zn and 0.08 gm−2 yr−1 Cu. During the third year, when a nutrient solution with added P was used, the average infiltration rate for most elements increased by 46% and for P by 169%.