Production, the oil and gas industry, has a problem with an enormous volume of liquid waste, and 80% of the liquid waste produced is water, which is called produced water. This water differs from water because it contains dangerous chemicals and other elements in oil and gas. In this study, an adsorption process followed the electrocoagulation process using Iron electrodes with voltage variations of 3, 6, 9, and 12V using silica sand from bottom ash and active carbon from a coconut shell. It proposed the combination of these processes as an alternative method for treating produced water. It carries this combination method out in a continuous reactor series where sampling is done at the 30, 60, 90, 120, and 150 minutes. The results of the study show that the highest decrease in oil and grease (98.14%) from the initial content of 377 Mg/L becomes 7 Mg/L, COD (97.39%) from the initial content of 430.25 Mg/L to 11.24 Mg/L, TDS (91, 19%) from the initial content of 12670 Mg/L to 989 Mg/L, Ammonia (69.18%) from the initial content of 17.71 Mg/L to 5.46 Mg/L, Alkalinity (92.84%) of the initial content 317.86 Mg/L to 7 Mg/L, Total Hardness (93.74%) from the initial content of 201.84 Mg/L to 12.63. The best conditions are to get at 12V voltage for 150 minutes to reduce produced water to meet quality standards based on Minister of Environment Regulation no. 19 of 2010.