fulfill nitrogen concentration limits (Tunçsiper 2009). HF CWs are anaerobic and
provide the necessary conditions to attain denitrification, while the intermittently fed
VF CWs are aerobic, thus enabling nitrification (Vymazal and Kröpfelová 2015).
The removal of total nitrogen in hybrid CWs may amount to 85% (Kantawanichkul
et al. 2001). The hybrid CW Kotenčice, Czech Republic, was built in 2011 in Central
Bohemia and consists of various HF beds with the total area of 911 m
2 and VF beds
with the total area of 300 m
2 being alternately connected (Hudcová et al. 2013). This
hybrid CW has been designed to test the optimum combination of the HF and VF
beds. The results from this CW shows that nitrogen was reduced up to 79% in the
summer period and up to 62% in the winter period.
18.1.2 CWs for Treatment of Agro-Industrial Wastewaters
Constructed wetlands are used, among others, for treating agricultural wastewaters,
especially wastewaters from animal feedlots (Knight et al. 2000) or drainage waters
(Xue et al. 1999; Poe et al. 2003). The problem of feedlot wastewater is that the
organics content characterized by biochemical oxygen demand (BOD 5 ) is usually
one order of magnitude higher in domestic waters (Cronk 1996). Healy et al. (2007)
reported BOD 5 concentrations reaching up to 7130 mg L
À1 (the average of seven
observed CWs treating concentrated animal waste). Dairy, swine, and cattle wastewater respectively are also rich in total suspended solids (TSS). Knight et al. (2000)
reports the TSS concentrations reaching up to 1111 mg L
À1 , 128 mg L
À1 , and
291 mg L
À1 , respectively. Total nitrogen concentrations from pig farms, poultry
farms, and dairies averaged 407 mg L
À1 , 89 mg L
À1 , and 103 mg L
À1 , respectively.
Agricultural wastewater also includes food processing. Such wastewaters can be
characterized by high loads of organics. Especially chemical oxygen demand (COD)
loads can reach up to 7406 mg L
À1 during the wine making season; however, even
during the rest of the year it can be as high as 1721 mg L
À1 (Grismer et al. 2003).
Some authors report even higher concentrations—up to 15,400 mg L
À1 (Grismer
et al. 2003) or 25,400 mg L
À1 (Šereš et al. 2017)—in winemaking facilities. The
results of the review done by Sultana et al. (2015) show that the use of hybrid
systems is desirable for treating such waters because VF CWs are able to treat
extremely high loads of pollution.
18.1.3 Emerging Pollutants and CWs
Due to the increased consumption of pharmaceutical products, there is a rising
concern regarding the harmful effects of such substances on the environment (Reif
et al. 2008). The concerns are also connected with the overuse of veterinary
pharmaceuticals and other active substances belonging to the so-called pharmaceutical and personal care products (PPCPs). The persistence of pharmaceutical residues
18 Field Study VI: The Effect of Loading Strategies on Removal. . .
397
provide the necessary conditions to attain denitrification, while the intermittently fed
VF CWs are aerobic, thus enabling nitrification (Vymazal and Kröpfelová 2015).
The removal of total nitrogen in hybrid CWs may amount to 85% (Kantawanichkul
et al. 2001). The hybrid CW Kotenčice, Czech Republic, was built in 2011 in Central
Bohemia and consists of various HF beds with the total area of 911 m
2 and VF beds
with the total area of 300 m
2 being alternately connected (Hudcová et al. 2013). This
hybrid CW has been designed to test the optimum combination of the HF and VF
beds. The results from this CW shows that nitrogen was reduced up to 79% in the
summer period and up to 62% in the winter period.
18.1.2 CWs for Treatment of Agro-Industrial Wastewaters
Constructed wetlands are used, among others, for treating agricultural wastewaters,
especially wastewaters from animal feedlots (Knight et al. 2000) or drainage waters
(Xue et al. 1999; Poe et al. 2003). The problem of feedlot wastewater is that the
organics content characterized by biochemical oxygen demand (BOD 5 ) is usually
one order of magnitude higher in domestic waters (Cronk 1996). Healy et al. (2007)
reported BOD 5 concentrations reaching up to 7130 mg L
À1 (the average of seven
observed CWs treating concentrated animal waste). Dairy, swine, and cattle wastewater respectively are also rich in total suspended solids (TSS). Knight et al. (2000)
reports the TSS concentrations reaching up to 1111 mg L
À1 , 128 mg L
À1 , and
291 mg L
À1 , respectively. Total nitrogen concentrations from pig farms, poultry
farms, and dairies averaged 407 mg L
À1 , 89 mg L
À1 , and 103 mg L
À1 , respectively.
Agricultural wastewater also includes food processing. Such wastewaters can be
characterized by high loads of organics. Especially chemical oxygen demand (COD)
loads can reach up to 7406 mg L
À1 during the wine making season; however, even
during the rest of the year it can be as high as 1721 mg L
À1 (Grismer et al. 2003).
Some authors report even higher concentrations—up to 15,400 mg L
À1 (Grismer
et al. 2003) or 25,400 mg L
À1 (Šereš et al. 2017)—in winemaking facilities. The
results of the review done by Sultana et al. (2015) show that the use of hybrid
systems is desirable for treating such waters because VF CWs are able to treat
extremely high loads of pollution.
18.1.3 Emerging Pollutants and CWs
Due to the increased consumption of pharmaceutical products, there is a rising
concern regarding the harmful effects of such substances on the environment (Reif
et al. 2008). The concerns are also connected with the overuse of veterinary
pharmaceuticals and other active substances belonging to the so-called pharmaceutical and personal care products (PPCPs). The persistence of pharmaceutical residues
18 Field Study VI: The Effect of Loading Strategies on Removal. . .
397