Treatment efficiency of wastewater from catfish farming by an artificial system: Combining constructed wetland with adsorption materials and biological tanks planted hydroponic vegetables

The treatment system combines constructed wetland (CW) tanks with adsorption materials and biological tanks planted with hydroponic vegetables to treat wastewater from catfish (Pangasianodon hypophthalmus) pond in a production cycle. The CW tanks were completely randomized with two treatments using sand and adsorbent materials as bed media. Adsorbent materials derived from peat soil and combusted beehive charcoal residues, with a ratio of 70:30 by weight. Wastewater flows continuously in CW tanks at a rate of 0.3 m3/h and then flows through hydroponic vegetable tanks. Treated wastewater was evaluated in accordance with Vietnamese standards, as outlined in Circular 44/2010/TT-BNNPTNT and QCVN 02-20:2014/BNNPTNT, and was found to be suitable for reuse in catfish ponds. The pollutant reduction capacity for BOD₅, COD, total phosphorus (TP), and total Kjeldahl nitrogen (TKN) of the CW with adsorbent was higher than that of the CW with sand. Treatment efficiency for BOD5, COD, TP, and TKN reached an average rank of 76.97% - 92.57%. The system’s advantages are stable processing of large wastewater from fishponds, low cost and simple operation. This is an effective solution for mitigating pollutant loads from fishponds' effluents in the Mekong Delta, Viet Nam.