The production wastewater contains phenol from the Non-Destructive Testing (NDT) unit because it uses solvents; meanwhile, the manganese originates from the metal material washing process. On the basis of laboratory test results, the wastewater originating from the NDT unit of Y Industry, resulted in a phenol level of 2.33 mg/L, exceeding the quality standard of 0.5 mg/L and manganese level of 14.13 mg/L that exceeded the quality standard of 2 mg/L, based on the Regulation of the Minister of the Environment Number 5 of 2014 concerning Wastewater Quality Standards. This research used the pretest-posttest experimental research design without control. The sample in this study was wastewater from the NDT unit of the Y Industry. The average phenol level after passing through the adsorbent media at a thickness of 40 cm, 60 cm, and 80 cm resulted in 0.99 mg/L with 63% reduction, 0.60 mg/L with 77% reduction, and 0,28 mg/L with 89% reduction, respectively. The average manganese level after passing through the adsorbent media at a thickness of 40 cm, 60 cm, and 80 cm resulted in 0.10 mg/L with 61% reduction, 0.06 mg/L with 76% reduction, and 0,05 mg/L with 80% reduction, respectively. The most effective thickness variation in reducing the phenol and manganese levels of NDT wastewater is 80 cm thickness.