Abstract:

The preliminary study showed that the integrated mode for water quality control, named as “5% water spinach (Ipomoea aquatica Forsk.) + 10% filler + algae splashing (Chlorella pyrenoidose)” is worth popularizing. To further verify the effect, the purification effect of different water spinach planting ratios on nitrogen and phosphorus in pond water was studied. Water quality indexes, such as TN (total nitrogen), NH₃-N (ammonia nitrogen), TP (total phosphorus), COD_Mn (permanganate), TSS (total suspended solid), pH and DO (dissolved oxygen), were determined by setting the planting proportion of 5%, 8% and 10% of water spinach, the environmental and economic benefits were also evaluated. The results showed that the TN, NH₃-N, TP, COD_Mn and TSS in tilapia pond were reduced to a certain extent by the cultivation of water spinach. The removal rates of TN and TP were 10%-15% and 20%-40% respectively. The 5% water spinach planting group also had the good removal effect on NH₃-N and COD_Mn, and the economic benefit of this mode was good, which was suitable for application.

Key words: pond water quality control, in-situ remediation integration, Chinese medical herb, fish-vegetable ratio, nutrient removal efficiency, cost accounting