Comparing subsurface flow constructed wetlands with mangrove plants and freshwater wetland plants for removing nutrients and toxic pollutants

Leung, Jonathan Y.S.; Cai, Qinhong; Tam, N.F.Y.

doi:10.1016/j.ecoleng.2016.06.016

Cited by 40 publications

(9 citation statements)

References 50 publications

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“…Ideally, artificially constructed mangrove forests for waste treatment require tidal regimes (low and high tide) in order to generate aerobic and anaerobic conditions in the sediments which promotes nitrification and denitrification processes and facilitation of ammonia removal [34]. Ammonia is oxidized to NO 2 and then to NO 3 if oxic conditions prevail.…”

Section: Discussionmentioning

confidence: 99%

Nutrient Removal Efficiency of Rhizophora mangle (L.) Seedlings Exposed to Experimental Dumping of Municipal Waters

et al. 2018

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Mangrove forests are conspicuous components of tropical wetlands that sustain continuous exposure to wastewater discharges commonly of municipal origins. Mangroves can remove nutrients from these waters to fulfill their nutrients demand, although the effects of continuous exposure are unknown. An experimental greenhouse imitating tidal regimes was built to measure the efficiency of mangrove seedlings to incorporate nutrients, growth and above biomass production when exposed to three periodic wastewater discharges. The experiment totaled 112 d. Nutrient removal by the exposed group, such as phosphates, ammonia, nitrites, nitrates and dissolved inorganic nitrogen (97%, 98.35%, 71.05%, 56.57% and 64.36%, respectively) was evident up to the second dumping. By the third dumping, all nutrient concentrations increased in the interstitial water, although significant evidence of removal by the plants was not obtained (p > 0.05). Nutrient concentrations in the control group did not change significantly throughout the experiment (p > 0.05). Treated plants increased twofold in stem girth when compared to the control (p < 0.05), although control plants averaged higher heights (p < 0.05). Biomass of treated group increased up to 45% against 37% of the control during the duration of the experiment (p < 0.05). We suggest that nutrient removal efficiency of mangroves is linked to the maintenance of oxic conditions in the pore-water because of oxygen transference from their aerial to their subterranean radicular system that facilitates the oxidation of reduced nitrogen compounds and plants uptake. Nevertheless, continuous inflows of wastewater would lead to eutrophication, establishment of anoxic conditions in water and soil, and lessening of nutrient absorption of mangroves.

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Section: Discussionmentioning

confidence: 99%

Nutrient Removal Efficiency of Rhizophora mangle (L.) Seedlings Exposed to Experimental Dumping of Municipal Waters

et al. 2018

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“…Whether natural or constructed mangrove wetlands (mesocosm), they are used for treating WW from aquaculture, sewage or others sources (Leung et al, 2016;Ouyang and Guo, 2016). WW is often a complex mixture of many pollutants, the most notable of which are the excess of organic matter and nutrients (mainly ammonium and phosphorus) but may also contain pharmaceutical residues, pesticides, heavy metals, etc.…”

Section: Introductionmentioning

confidence: 99%

Wastewater bioremediation by mangrove ecosystems impacts crab ecophysiology: In-situ caging experiment

Theuerkauff

Rivera‐Ingraham

Lambert³

et al. 2020

Aquatic Toxicology

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Mangroves are tidal wetlands that are often under strong anthropogenic pressures, despite the numerous ecosystem services they provide. Pollution from urban runoffs is one such threats, yet some mangroves are used as a bioremediation tool for wastewater (WW) treatment. This practice can impact mangrove crabs, which are key engineer species of the ecosystem. Using an experimental area with controlled WW releases, this study aimed to determine from an ecological and ecotoxicological perspective, the effects of WW on the red mangrove crab Neosarmatium africanum. Burrow density and salinity levels (used as a proxy of WW dispersion) were recorded, and a 3-week caging experiment was performed. Hemolymph osmolality, gill Na+/K+-ATPase (NKA) activity and gill redox balance were assessed in anterior and posterior gills of N. africanum. Burrow density decreased according to salinity decreases around the discharged area. Crabs from the impacted area had a lower osmoregulatory capacity despite gill NKA activity remaining undisturbed. The decrease of the superoxide dismutase activity indicates changes in redox metabolism. However, both catalase activity and oxidative damage remained unchanged in both areas but were higher in posterior gills. These results indicate that WW release may induce osmoregulatory and redox imbalances, potentially explaining the decrease in crab density. Based on these results we conclude that WW release should be carefully monitored as crabs are key players involved in the bioremediation process. Highlights ► Mangroves are suggested as biofiltering systems of domestic effluent. ► Mangrove crabs are involved through their bioturbation activities. ► Wastewater release impacts crab burrow density. ► Mangrove crabs are physiologically impacted by wastewaters.

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“…CWs are a reliable wastewater treatment technology with low investment and low energy consumption, in which the wetland vegetation and the domesticated microbial communities have the potential to remove a wide variety of pollutants from wastewater. Many studies indicated that CWs could remove dissolved organic matter (DOM) efficiently [11], and also showed a high-performance for the removal of toxic organic pollutants [12]. However, research on HCHO removal using CWs was still scarcely reported.…”

Section: Introductionmentioning

confidence: 99%

Assessment and Optimization of Formaldehyde Removal Using Tidal Flow Constructed Wetlands

Si¹,

Song²,

Wang³

et al. 2020

Pol. J. Environ. Stud.

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Assessment of formaldehyde (HCHO) removal using constructed wetlands (CWs) was scarcely ever reported. Here, the feasibility of HCHO removal was studied in tidal flow CWs (TFCWs) with/without wetland vegetation (Canna indica L.). The HCHO removal efficiencies of TFCWs with various initial loads (25, 50, 75, and 100 mg L-1) were investigated, then the impact of influent pH and DO values on HCHO removal was evaluated. Results showed that microbiological degradation was the main HCHO removal pathway. The aerobic condition (DO concentration >4 mg L-1) and neutral/weak alkaline pH (approximately 7-8) was favorable for the HCHO removal. In order to upgrade the HCHO removal potential, a two-stage cyclic CW (t-TFCW) was designed. For an influent HCHO concentration around 100 mg L-1 , t-TFCW showed a stable and efficient HCHO removal performance, where the average HCHO removal rate was found to be 98.1% after a 6-hour treatment.

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Comparing subsurface flow constructed wetlands with mangrove plants and freshwater wetland plants for removing nutrients and toxic pollutants

Cited by 40 publications

References 50 publications

Nutrient Removal Efficiency of Rhizophora mangle (L.) Seedlings Exposed to Experimental Dumping of Municipal Waters

Nutrient Removal Efficiency of Rhizophora mangle (L.) Seedlings Exposed to Experimental Dumping of Municipal Waters

Wastewater bioremediation by mangrove ecosystems impacts crab ecophysiology: In-situ caging experiment

Assessment and Optimization of Formaldehyde Removal Using Tidal Flow Constructed Wetlands

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