A composite radial filter was developed and evaluated for filtration of NO₃-N, P, and K₂O from paddy field runoff for recharging aquifers. For zeolite (Z), granular activated charcoal (C), coarse sand (CS), and gravel (G) filter medias were placed in the annular concentric rings of the developed filter in various combinations of different thickness, viz. 1:2:4:4, 1:3:4:4, 1:2:2:4, 1:3:2:4 and 0:2:1:2 individually for five treatments, viz. T₁, T₂, T₃, T₄, and T_5, respectively. At the radial filter output, a chlorination unit was used to inject sodium hypochlorite solution, commonly known in a dilute solution as bleach solution at a rate of 0.1 ml per unit discharge (lps) in order to purge bacterial contamination from the filtered water. Analysing water samples for four different inflow/outflow rates−0.42, 0.82, 1.24, and 1.66 lps before and after filtration allowed investigators to assess the efficacy of the composite radial filter. At all flow rates, the filtered water's NO₃-N, P, and K₂O values were determined to be within allowable limits. Based on removal efficiency of NO₃-N, P, and K₂O and reduced cost, the T₅ treatment, which consists of filter materials C, CS, and G with thicknesses of 20, 10, and 20 cm (2:1:2), respectively, was found to be superior to the other four treatments (T₁, T₂, T₃, and T₄). After five hours of filter operation, the filter materials were cleaned and reused. Reused filter media were found to have NO₃-N, P, and K₂O values of 5.3, 5.8, and 10.9 ppm, respectively. These values were found to be slightly higher than those obtained from initially original filter materials for the same duration of operation.

开发并评估了一种复合径向过滤器，用于过滤稻田径流中的 NO ₃ -N、P 和 K _{2 O，以补给含水层。}对于沸石（Z）、颗粒活性炭（C）、粗砂（CS）和砾石（G）过滤介质，以不同厚度的各种组合放置在所开发的过滤器的环形同心环中，即：1:2:4:4、1:3:4:4、1:2:2:4、1:3:2:4 和 0:2:1:2 分别用于五个处理，即 T ₁、T ₂、T ₃、T ₄和T _{5 ，}分别。在径向过滤器输出处，使用氯化装置以每单位排放量 (lps) 0.1 毫升的速率注入次氯酸钠溶液（通常在稀释溶液中称为漂白剂溶液），以清除过滤水中的细菌污染物。通过分析过滤前后四种不同流入/流出速率（0.42、0.82、1.24 和 1.66 lps）的水样，研究人员可以评估复合径向过滤器的功效。在所有流量下，过滤水的NO ₃ -N、P 和K ₂ O 值均确定在允许的限度内。基于NO ₃ -N、P和K ₂ O的去除效率和降低的成本，T ₅由厚度分别为 20、10 和 20 cm (2:1:2) 的过滤材料 C、CS 和 G 组成的处理被发现优于其他四种处理（T 1 _、 T ₂、 T ₃和T ₄ )。过滤器运行五个小时后，将过滤材料清洗干净并重复使用。发现重复使用的过滤介质的 NO ₃ -N、P 和 K ₂ O 值分别为 5.3、5.8 和 10.9 ppm。发现这些值略高于在相同运行时间内从最初的原始过滤材料获得的值。