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The Potential of Floating Treatment Wetlands for Pollutant Removal in the Recirculating Aquaculture System of Catfish

Oktaviyani Dian, Pratiwi Niken Tunjung Murti, Krisanti Majariana, Chrismada Tjandra, Susanti Evi

Journal of Ecological Engineering

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2024

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Vol. 25, nr 4

111--118

EN

Floating treatment wetland (FTW) as a wastewater processing technology in recirculating aquaculture systems (RAS) of catfish is considered to be effective in eliminating the pollutant load of nitrogen, phosphorous, and organic matter. This research aims to reduce the concentration of pollutant loads and obtain an effective ratio between the volume of the FTW and the total water volume of the catfish RAS. The FTW system uses Vetiveria zizanoides grown on floating media and equipped with an aerator in the bottom layer of the pond. Several FTW volume ratios were used to determine an FTW system that is effective in reducing pollutant loads according to the mass balance concept. This approach was conducted to maintain acceptable water quality in catfish cultivation ponds. The study results showed that most pollutant load concentrations decreased in all ponds. The largest removal percentage included the parameters TAN, COD, TSS, TP, nitrate, phosphate, and TN, namely 88.54%, 66.17%, 85.68%, 91.30%, 83.85%, 61.46%, and 44.68%, respectively. The effective ratio between the volume of the FTW processing system and the total water volume of 0.543 with an age group of fish of 9–12 weeks was able to eliminate the pollutant loads from catfish pond wastewater.

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Evaluation of Evapotranspiration and Performance of Emerging Plants: Case of Cyperus papyrus and Typha latifolia

Benrahmane Loubna, Mouhir Latifa, Laaouan Mohamed, El Hafidi Mustapha, Saafadi Laila

Journal of Ecological Engineering

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2023

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Vol. 24, nr 11

257--267

EN

The treatment of wastewater in small rural settlements requires special attention in the choice of the purification technique to be used, insofar as experience has shown that the technologies initially developed for the urban environment do not prove to be as effective for the rural environment. The current trend tends towards autonomous systems. Among these systems are Floating treatment wetlands. The objective of this study was to evaluate the evapotranspiration and the performances of two emerging plants; Cyperus papyrus and Typha latifolia. The experimental device was composed of three test tanks whose dimensions were: length = 1 m, width = 1 m and water height = 0.85 m – two tanks with emerging plants (Cyperus papyrus and Typha latifolia) and a control tank without vegetation. The monitoring of the evolution of plant evapotranspiration and the evaporation of the control tank for different periods and temperatures showed that the volumes of water lost were respectively for Cyperus papyrus, Typha latifolia and control tank: (1) 130 liters, 230 liters and 5 liters for two days at an average temperature of 26.3 °C; (2) 125 liters, 150 liters and 0 liters for two days at an average temperature of 26.7 °C; (3) 240 liters, 280 liters and 5 liters for three days at an average temperature of 27.3 °C; (4) 140 liters, 260 liters and 10 liters for two days at an average temperature of 26 °C; (5) 140 liters, 240 liters and 5 liters for two days at an average temperature of 27.3 °C; (6) 260 liters, 550 liters and 10 liters for four days at an average temperature of 28.6 °C. It turned out that the presence of plants as well as the temperature and the retention time in the tanks have a impact on the loss of water and more precisely those with emerging macrophytes. The present study has shown that the floating treatment wetlands planted with Cyperus papyrus and Typha latifolia can be used for wastewater treatment. Indeed, the removal efficiency in terms of COD, BOD5 and SS were respectively: 76%, 75.3% and 95.90% for Cyperus papyrus and 70.45%, 66.5% and 93.70% for Typha latifolia.

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Effectiveness of Floating Treatment Wetlands with Cyperus papyrus Used in Sub-Humid Climate to Treat Urban Wastewater: A Case Study

Benrahmane Loubna, Mouhir Latifa, Kabbour Amal, Laaouan Mohamed, El Hafidi Mustapha

Journal of Ecological Engineering

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2022

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Vol. 23, nr 7

157--168

EN

The wastewater from small communities and rural areas, usually discharged in an unsuitable manner, requires an appropriate treatment. The floating treatment wetland has revealed a great potential due to good performance, low cost and low maintenance means of improving water quality over a broad range of applications. The aim of this article was to present the results of the adaptation period (57 days) of a macrophyte plant “Cyperus papyrus” and its potential for treating wastewater generated by the campus of the National Office of Electricity and Drinking Water (ONEE) of Rabat. Two hydraulic retention times were applied: 2 and 4 days. Pilot experimental setups (two tanks) were installed: one tank where the macrophyte, being the subject of the study, was installed and the other served as a control. The macrophyte plants were suspended in floating mat, keeping the plant roots permanently in contact with the water and removing pollutants via several processes. During the adaptation of the plant which concerned four parameters: the evolution of the density, the height of the stems, the number of shoots as well as the state of health of the plants, a period of adaptation to the medium of implantation of fifty-seven days was observed. Along this adaptation phase, the results showed that: plant density increased from 9 to 29 units; the heights of the four identified stems of Cyperus papyrus increased from 15, 6, 11 and 8 cm to 73, 43, 30 and 24 cm, respectively; the appearance of 72 shoots and the plant has completed the adaptation phase in good health (absence of disease Symptoms). The treated water obtained from outlet and wastewaters were analyzed for various water quality parameters, such as Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), and Suspended Solids (SS). The floating treatment wetlands system is able to remove 37.8% of COD; 47.6% of BOD5and 74.4% of SS for HRT of 2 days and 63.7% of COD; 78.4% of BOD5 and 89.1% of SS for HRT of 4 days. Moreover, it was found that the purification efficiency in terms of these three pollution parameters is all the more important as the hydraulic retention time is high.