3. Results and discussion
3.1. Climatic and operating conditions
Table 1 contains temperature and rainfall data. For the study
period, the average annual temperature value was 16.4 ◦C and the average annual rainfall depth 678 mm, with an average annual rain
frequency of 115 days/year. The heavier incidents of rain took place
during winter and early spring months. The maximum energy flux
value during the summer months was about 280 W/m2. These values
are typical of North Mediterranean climate.
The influent loading rates used in this study (Table 1) were
higher than most of those reported in the literature. Brix
and Arias [5] recommendations for HLR and OLR applied in
VFCWs in Denmark are 0.05–0.06 m/d and 10–40 g BOD5/m2 d.
Prochaska et al. [26] presented higher HLR (0.08–0.17 m/d) and
OLR (20–40 g BOD5/m2 d) in pilot-scale VFCWs in N. Greece.
Langergraber et al. [27] applied three OLRs (20–40 g COD/m2 d)
to three VFCWs in Austria. Zhao et al. [28] tested a HLR
and OLR of 0.43 m/d and 1055 g COD/m2 d, respectively. French
VFCWs, with no wastewater pre-treatment, are heavily loaded, i.e.,
167–250 g COD/m2 d with a HLR up to 19.2 m/d [15,29].