contamination. No contamination by E. coli was detected for
outflow waters from other wetland filters. However, this result
contradicted findings reported by Cirelli et al. (2012), who
presented results of a reuse scenario where municipal wastewater
was treated by constructed wetlands (tertiary treatment step), and
reused for the supply of irrigation water for vegetables in Eastern
Sicily, Italy. They found increased numbers of E. coli in the irrigation
water, which were frequently above the Italian threshold of
50 colony forming units (CFU)/100 ml for secondary treated urban
wastewater effluents.
The highest contamination by Streptococcus spp. was associated
with Filter 1 outflow water followed by those for Filters 3 and 5
(Table 6). Filter 4 had a higher Streptococci contamination than
Filter 2. Furthermore, preliminary treated wastewater was
observed with higher contamination by Streptococci than wastewater
samples, which were diluted with up to 80% of tap water.
The highest Salmonellae counting was observed in the outflow
water from Filter 5 followed by preliminary treated wastewater
(Table 6). Filter 1 outflow water was associated with higher
Salmonellae contamination than the water from Filter 3. Furthermore,
Salmonella spp. contamination in Control A outflow water
was higher than that associated with Control B. Salmonellae were
removed well from the outflow water of the wetland systems. This
confirms good bacteria removal efficiency of vertical-flow bed
systems as reported by Cui et al. (2003).
Table 6 shows that the microbial contamination of outflow
water from wetland filters contaminated with hydrocarbons was
higher than those from standard filters (uncontaminated). This
confirms findings by Benedek et al. (2013), who studied the impact
of long-term TPH, volatile petroleum hydrocarbons, total alkyl
benzenes and polycyclic aromatic hydrocarbons on the structure of