For the most part, none, unless you have a very low hurdle for “hazardous”. There are/were surface owners in E Texas who welcomed rigs because they knew their pasture land would benefit when the mud pit was pumped through sprinklers at the end of the well. There were no negative effects. read more
These needed oil changes periodically and that used oil was hauled offsite to a disposal plant. Washing the rig and equipment produced oily or greasy water but that was what the cellar was for. When it was pumped, again the material was rotated back to a location designed to deal with it. read more
The ratio of produced water to oil in conventional well was approximately 10 barrels of produced water per barrel of oil. According to the American Petroleum Institute (API) Exit, more than 18 billion barrels of waste fluids from oil and gas production are generated annually in the United States. read more