The Sustainable Treatment Effect of Constructed Wetland for the Aquaculture Effluents from Blunt Snout Bream (Megalobrama amblycephala) Farm

Abstract

In aquaculture, constructed wetland (CW) has recently attracted attention for use in effluent purification due to its low running costs, high efficiency and convenient operation,. However, less data are available regarding the long-term efficiency of farm-scale CW for cleaning effluents from inland freshwater fish farms. This study investigated the effectiveness of CW for the removal of nutrients, organic matter, phytoplankton, heavy metals and microbial contaminants in effluents from a blunt snout bream (Megalobrama amblycephala) farm during 2013–2018. In the study, we built a farm-scale vertical subsurface flow CW which connected with a fish pond, and its performance was evaluated during the later stage of fish farming. The results show that CW improved the water quality of the fish culture substantially. This system was effective in the removal of nutrients, with a removal rate of 21.43–47.19% for total phosphorus (TP), 17.66–53.54% for total nitrogen (TN), 32.85–53.36% for NH4+-N, 33.01–53.28% NH3-N, 30.32–56.01% for NO3−-N and 42.75–63.85% for NO2−-N. Meanwhile, the chlorophyll a (Chla) concentration was significantly reduced when the farming water flowed through the CW, with a 49.69–62.01% reduction during 2013–2018. However, the CW system only had a modest effect on the chemical oxygen demand (COD) in the aquaculture effluents. Furthermore, concentrations of copper (Cu) and lead (Pb) were reduced by 39.85% and 55.91%, respectively. A microbial contaminants test showed that the counts of total coliform (TC) and fecal coliform (FC) were reduced by 55.93% and 48.35%, respectively. In addition, the fish in the CW-connected pond showed better growth performance than those in the control pond. These results indicate that CW can effectively reduce the loads of nutrients, phytoplankton, metals, and microbial contaminants in effluents, and improve the water quality of fish ponds. Therefore, the application of CW in intensive fish culture systems may provide an advantageous alternative for achieving environmental sustainability.

Artificial Intelligence in Internet of Things System for Predicting Water Quality in Aquaculture Fishponds

“…Traditionally, most fishers have judged water quality through visual inspection. Now, some fishers have measured with a dissolved oxygen meter in person at different positions in the pond [6,7]. However, these are inefficient, inaccurate, and dangerous ways.…”

Purification of aquaculture effluent using Picralima nitida seeds

“…Aquaculture effluents have been managed using different treatment methods such as biodegradation 7 – 9 , coagulation 10 – 12 , oxidation 13 , 14 , filtration 15 – 17 , adsorption 18 – 20 , electrocoagulation 21 – 23 , or in constructed wetlands 24 , 25 or even a combination of these methods 26 prior either reuse or disposal. However, the majority of the above-mentioned treatment methods do produce sludge, require much higher energy, and depend on frequent maintenance 1 , which makes the development of effective and low-cost treatment imperative.…”

“…These components are considered fish aquaculture pollutants, resulting in major environmental issues 1 such as eutrophication and oxygen depletion 2 . The production of 1 tonne of channel catfish releases an average of 9.2 kg of nitrogen, 0.57 kg of phosphorus, 22.5 kg of BOD, and 530 kg of settleable solids into the environment 5,6 .Aquaculture effluents have been managed using different treatment methods such as biodegradation 7-9 , coagulation 10-12 , oxidation 13,14 , filtration [15][16][17] , adsorption [18][19][20] , electrocoagulation [21][22][23] , or in constructed wetlands 24,25 or even a combination of these methods 26 prior either reuse or disposal. However, the majority of the above-mentioned treatment methods do produce sludge, require much higher energy, and depend on frequent maintenance 1 , which makes the development of effective and low-cost treatment imperative.…”