Nitrogen removal in subsurface wastewater infiltration systems with and without intermittent aeration

Identification of Nitrous Oxide Generation in Subsurface Wastewater Infiltration System Filled With Mixed Matrix

“…For the SWIS process, nitrate nitrogen (NO 3 -) in influent will be discharged, used by microorganisms and converted into gaseous nitrogen (Pan et al, 2016a). In order to quantitatively analyze its fate,nitrate concentration in effluent and soil, N 2 O generation rate, 15 N abundance in soil, effluent and N 2 O were analyzed and calculated (Figure 2).…”

“…Moreover, using isotopic techniques, the contribution of nitrification and denitrification processes to N 2 O release was successfully revealed in the Eastern Tropical South Pacific (Ji et al, 2015). Thus, the aim of this paper is to explore our current understanding and knowledge gaps of the role of nitrification and denitrification in N 2 O generation in the SWIS process, and to provide a basis to effectively control the Introduction Subsurface wastewater infiltration systems (SWIS) offer a promising opportunity to transform municipal wastewater into renewable energy with significantly reduced energy consumption (Pan et al, 2016a;Jiang et al, 2017). Generally, the SWIS process is a soil-based sewage treatment technology.…”

The design and operation of subsurface wastewater infiltration systems for domestic wastewater

“…Under aerobic conditions, ammonia nitrogen (NH 4 + –N) is transformed to nitrite nitrogen (NO 2 − –N) by nitrite bacteria and is oxidized to nitrate nitrogen (NO 3 − –N) by nitrate bacteria. An oxygenated environment guarantees good nitrification (Kadlec et al., ; Pan, Yuan, Zhang, Huang, Cheng, et al., ; Yamaguchi et al., ). Denitrification is a process in which NO 2 − –N and NO 3 − –N are reduced to nitrogen (N 2 ) by denitrifying bacteria under anoxic conditions, implying the complete removal of nitrogen.…”

“…A lack of oxygen and the excessive accumulation of pollutants are the main reasons for the low HLR and clogging in an SWI system (Pan, Yuan, Zhang, Huang, Cheng, et al., ). With favorable oxygen conditions, the purification capacity of an SWI system can be maintained for long‐term operations under a higher HLR (Sato Kuniaki, ).…”

“…Pan, Yuan, Zhang, Huang, Cheng, et al. () studied the growth and reproduction of nitrifying and denitrifying bacteria in SWI systems both with and without intermittent aeration under different levels of organic loading rates. The number of nitrifying bacteria decreased with increasing organic loading rates without aeration, but the opposite occurred with intermittent aeration.…”