 Treatment efficiency Constructed wetlands with horizontal subsurface flow usually provide high treatment effect in terms of removal of organics (BOD5, COD) and suspended solids (SS). The removal of nitrogen and phosphorus is lower but comparable with conventional treatment technologies which do not include special nutrient removal step. Treatment efficiency of constructed wetlands with horizontal subsurface flow in terms of concentrations are summarized in tables 1-5. (Vymazal J.: The use of sub-surface constructed wetlands for wastewater treatment in the Czech Republic: 10 years experience. Ecological Engineering 18/2002, pp. 633-646) Table 1. Average influent and effluent concentration (mg/l) and removal efficiencies (%) of organics (BOD5) in horizontal, subsurface flow vegetated beds in different countries
Table 2. Average influent and effluent concentration (mg/l) and removal efficiencies (%) of organics (COD) in horizontal, subsurface flow vegetated beds in different countries
Table 3. Average influent and effluent concentration (mg/l) and removal efficiencies (%) of suspended solids in horizontal, subsurface flow vegetated beds in different countries
Table 4. Average influent and effluent concentration (mg/l) and removal efficiencies (%) of total phosphorus in horizontal, subsurface flow vegetated beds in different countries
Table 5. Average influent and effluent concentration (mg/l) and removal efficiencies (%) of total nitrogen in horizontal, subsurface flow vegetated beds in different countries
The well designed and constructed Wastewater Gardens® system complies with Polish environmental regulations, European standards, United States Environmental Protection Agency (EPA), and German ATV. It is confirmed by recent results from the pilot Wastewater Garden in Krempna. The measurements are made for the purposes of master thesis research done by students of the Faculty of Surveying and Environmental Engineering of the Mining and Metallurgy University in Krakow. The average results from first three months of the system's operation are presented in Table 6. It shows that effluent quality limits are met, even though the plants were still young and not full developed. Higher efficiency rates are expected in the course of time as the plants' roots get more established. Table 6. Results from the pilot Wastewater Gardens® system in Krempna
Figure 1 presents comparison of removal efficiency of Wastewater Garden subsurface flow systems with average North American surface and subsurface flow wetlands.  Figure 2 presents results from the pilot program Wastewater Gardens at Birdwood Downs homestead, Derby, West Australia, September 2000 - December 2001.
|
