Treatment of flow-through trout aquaculture effluents in a constructed wetland

Performance of pilot-scale vertical flow constructed wetlands with and without the emergent macrophyte Spartina alterniflora treating mariculture effluent

“…Studies utilizing a natural mangrove wetland (Gautier et al, 2001) and a free water surface flow constructed wetland (Tilley et al, 2002) to treat the brackish effluent from shrimp culture recorded ammoniacal nitrogen increases likely due to dissolved oxygen limitations to effectively sustain sequential processes of mineralization and nitrification (Herbert, 1999;Chen et al, 2006). As confirmed in this study, the artificial wetlands with subsurface flow usually reached high ammoniacal nitrogen removal from aquaculture effluents (Schultz et al, 2003;Lin et al, 2005;Sindilariu et al, 2007). Heterotrophic bacteria have a competitive advantage over nitrifying bacteria, hence the available oxygen is preferentially utilized for organic mater mineralization instead of ammoniacal nitrogen oxidation (Herbert, 1999;Chen et al, 2006).…”

“…Sequential processes of nitrification and denitrification, which occurs by the passage of the wastewater through oxidative and reductive zones, resulting in nitrogen volatilization, are one of the main purification phenomena in wetlands (IWA, 2000). However, in wetlands applied for the aquaculture, these processes have not been easily predicted and optimized (Schulz et al, 2003;Lin et al, 2005;Sindilariu et al, 2007). For example, Lin et al (2005) related the storage of nitrate in a constructed wetland linked with a shrimp culture to a high hydraulic loading rate and scarcity of organic carbon, but it also could be due to high oxygen concentrations preventing denitrifying activities.…”

“…microbial processes, molecular diffusion) (IWA, 2000;Stottmeister et al, 2003). Owing to the complexity of factors governing the processes of wastewater purification, it has been challenging to understand and predict the effects of wetlands upon eutrophic effluents (Wiessner et al, 2005a(Wiessner et al, , 2005bLymbery et al, 2006;Sindilariu et al, 2007;Borges et al, 2008). The wide flexibility in constructed wetlands design and operation adds to the challenge (IWA, 2000;Stottmeister et al, 2003).…”

“…Based on both economic and environmental demands for more sustainable production practices (e.g., Baccarin and Camargo, 2005;Ramos et al, 2009), the aquaculture community has constructed wetlands as a promising option to deal with its wastewaters, which have eutrophic characteristics. However, there is still a lack of knowledge to allow complete understanding and optimization of key processes such as organic mineralization, nitrification, denitrification, and phosphorus removal (Lin et al, 2005;Lymbery et al, 2006;Sindilariu et al, 2007). Studies about the treatment of marine (Sansanayuth et al, 1996) or brackish (Tilley et al, 2002) aquaculture wastewater by constructed wetlands are scarce.…”

The potential of a salt-tolerant plant (Distichlis spicata cv. NyPa Forage) to treat effluent from inland saline aquaculture and provide livestock feed on salt-affected farmland

“…Cripps and Bergheim, 2000;Lin et al, 2002; Schultz et al,. 2003;Lymbery et al, 2006;Sindilariu et al, 2007Sindilariu et al, , 2009Zachritz et al, 2008;Webb et al, 2012), and they compare favourably with mechanical filters that typically remove 10 -43% of total nitrogen and 49 -63% of total phosphorus (Mäkinen et al, 1988;Lekang et al, 2000).The results from our study indicated that plants were a necessary component of wetland ecosystems for the removal of nitrogen and phosphorus. The role of plants in constructed wetlands is not fully understood.…”