Hydraulic characterization and optimization of total nitrogen removal in an aerated vertical subsurface flow treatment wetland

Effect of hydraulic loading rate on pollutant removal efficiency in subsurface infiltration system under intermittent operation and micro-power aeration

“…Nevertheless, intermittent operation with a HLR of 0.12 m 3 /m 2 d could result in filter clogging while higher HLR could lead to system breakdown quickly (Leuerenz et al, 2009;Li et al, 2015). As an option, intermittent artificial aeration in wetlands matrix could achieve the alternation of aerobic and anaerobic environment, and create conditions for improved nutrient removal (Boog et al, 2014;Fan et al, 2013;Foladori et al, 2013;Li et al, 2014;Tang et al, 2009). A few studies also showed that intermittent artificial aeration enhanced pollutant removal efficiency in multi-soil-layering (MSL) system, and in soil infiltration bioreactor incorporated with pyrite-based (mixotrophic) denitrification with surface loading rate of 0.106 m 3 /m 2 d and SWIS with HLR of 0.06 m 3 /m 2 d (Kong et al, 2015;Luanmanee et al, 2002;Pan et al, 2015).…”

उपचार आर्द्रभूमियााँ

“…As can be seen in Table 6.4 (previous section), aerated HF and aerated VF wetlands are both extremely efficient in removal of carbon and ammonium nitrogen, and remove TN more effectively than either traditional HF or VF designs. Intermittent aeration (multiple on-off aeration cycles per day) has been shown to improve TN removal in VF aerated wetlands (Fan et al, 2013;Foladori et al, 2013;Boog et al, 2014).…”

Treatment Wetland Aeration without Electricity? Lessons Learned from the First Experiment Using a Wind-Driven Air Pump

“…The internal hydraulics of these two designs are different. Aerated vertical down-flow systems have been reported to be extremely well mixed along the vertical direction, as a result of the counter-movement of water and air, and exhibit hydraulics similar to that of one continuously stirred tank reactor [12]. Horizontal flow wetlands, on the other hand, exhibit hydraulics similar to that of three to five tanks-in-series, which is due to the different dimensions of the wetland and the fact that the direction of flow and the movement of air bubbles are perpendicular to one another [17].…”

“…In theory, small-scale wind power stations could be constructed with local materials and should be specifically adapted to wetland aeration, further improving the ecological and economical sustainability of the treatment system. Wind speed fluctuations are likely to result in intermittent aeration, which has been shown to improve total nitrogen removal [12][13][14], and thus perhaps not be a detriment to treatment.…”

“…The source of the electrical energy, which is often fossil fuels, affects the ecological footprint of the treatment system. Several attempts have been made to decrease the energy demand for air supply by using intermittent [12][13][14] and spatial [15] aeration patterns. Aerated wetlands require the existence of centralized electrical infrastructure in order to operate.…”