The effect of halophyte planting density on the efficiency of constructed wetlands for the treatment of wastewater from marine aquaculture

Unravelling the potential of halophytes for marine integrated multi-trophic aquaculture (IMTA)— a perspective on performance, opportunities and challenges

“…Previous observations have shown even higher removal rates (up to 100%) of TDIN , Webb et al 2012. Some studies stated that the majority of N removal results from microbial processes and, to a lesser degree, from plant uptake (Lin et al 2002a, Hadad et al 2006), but studies with certain species of halophytes advocate otherwise (Webb et al 2012(Webb et al , 2013. Recently, Quintã et al (2015b) concluded that hydroponically grown S. europaea and A. tripolium could assimilate dissolved organic nitrogen (DON, specifically alanine-N and trialanine-N), suggesting that DON removal should also be taken into consideration in phytoremediation of wastewater.…”

“…The variables that need to be studied concerning the selection of the best halophyte plants for IMTA inlclude salinity tolerance, macro-and micro-nutrient re quirements, light and hydraulic regimens, plant density and the potential for economic valorization (Verhoeven & Meuleman 1999, Vymazal 2010, Buhmann & Papenbrock 2013b. For example, in order to investigate the relevance of plant density, Salicornia europaea was grown at 10 000 and 200 plants m −2 in CWs, with no significant differences in nutrient removal; up to 85% of total dissolved inorganic nitrogen (TDIN) was removed, with a maximum removal rate of 1.5 g N m −2 d −1 (Webb et al 2013). Previous observations have shown even higher removal rates (up to 100%) of TDIN , Webb et al 2012.…”

Growth and potential purification ability of Nitzschia sp. benthic diatoms in sea cucumber aquaculture wastewater

“…Economic development has led to a rapid increase in the demand for sea cucumber in recent years because of its importance in the diet (Hatakeyama et al., ; ;Xia & Wang, ), resulting in expansion of commercial farming in the Asia‐Pacific region, including China, over the past decade (Kang & Sui, ; Purcell, Hair, & Mills, ; Zhang, Song, Hamel, & Mercier, ). However, sea cucumber breeding produces a large amount of aquaculture wastewater, which contains relatively high levels of nutrients such as nitrogen and phosphorus (Su, Xing, & Wang, ; Webb et al., ). Releasing wastewater directly into coastal sea waters without treatment generally results in eutrophication of sea water, promoting rapid algae propagation and potentially leading to the dangerous and destructive phenomena known as red tide or green tide, thus damaging the coastal environment (Chai, Shi, & Liu, ; Grigorakis & Rigos, ; Liu et al., ; Lyssenko & Wheaton, ; Tantanasarit, Englande, & Babel, ).…”

“…Treatment of aquaculture effluent has been a significant focus of attention in coastal areas around the world, including those of China (Quintã, Santos, Thomas, & Le, ; Su et al., ). Methods of treating aquaculture wastewater are generally classified as physical methods, chemical methods or biological methods (Chaitanawisuti, Santhaweesuk, & Kritsanapuntu, ; Oladoja, Adelagun, Ahmad, & Ololade, ; Webb et al., , ). Biological treatment methods are particularly suitable for wastewater treatment because of their high efficiency, low cost and lack of secondary pollution (Chaitanawisuti et al., ; Quintã et al., ; Webb et al., , ).…”

“…Methods of treating aquaculture wastewater are generally classified as physical methods, chemical methods or biological methods (Chaitanawisuti, Santhaweesuk, & Kritsanapuntu, ; Oladoja, Adelagun, Ahmad, & Ololade, ; Webb et al., , ). Biological treatment methods are particularly suitable for wastewater treatment because of their high efficiency, low cost and lack of secondary pollution (Chaitanawisuti et al., ; Quintã et al., ; Webb et al., , ). Algae that utilize nitrogen and phosphorus may be used to remove nutrients from eutrophic aquaculture wastewater (Chaitanawisuti et al., ; Deviller, Aliaume, Nava, Casellas, & Blancheton, ; Quintã et al., ; Vílchez, Garbayo, Lobato, & Vega, ).…”