Compounded Ecological Ditch used for Improving Fishpond Water

Jian-qiang Zhu；Gu Li；Yuan Zhou；Xiu-juan Wang

Aquiculture water ； compounded ecological ditch ； freshwater pond ； water environment ； water quality

Advance Journal of Food Science and Technology

4卷5期（2012 / 10 / 20）

322 - 326

英文

In order to guarantee a good water quality for freshwater aquiculture in fishpond, compounded ecological was constructed around the fishpond and an experimental study was made that it improves fishpond water quality. A compounded ecological ditch based on the simple transformation of general ditch, has a regular cross-section of isosceles trapezoid, with a lining of permeable brick where ceramsite stroma etc were filled in the grids of the permeable bricks and some hydrophytes were grown in the ditch, including spatterdock, Myriophyllum verticillatum, Vallisneria natans (Lour.) Hara etc. According to the study, after aquiculture wastewater treated by the compounded ecological ditch, the water quality will be improved obviously; the important sign is an increase for DO and apparent decrease for TN, TP, NO_3^(-)-N, NH_4^(+)-N and COD_Mn. The removal rate (R_m) of the main substances is significantly relative to their initial Concentration (C_0) and the distance of them carried by flowing water (D_f). When compounded ecological ditch is used to purify fishpond water, besides slow velocity of the flow (6-9 m/h), the ditch must have a certain length which is suggested to be more than 100 m. On the other hand, a good effect will be procured in fishpond water purification only if an initial concentration exceeds 2.0 mg /L for TN, 0.6 mg/L for NO_3^(-)-N and 8.0mg/L for COD_Mn.