At U.S. wastewater industrial plants, the Environmental Protection Agency enforces requirements to ensure that operators pretreat pollutants in their wastes to protect local sanitary sewers and wastewater treatment plants. They have strict parameters on which operators must conform, and operators need to ensure that they comply with these requirements if they want to be deemed suitable for U.S. market. Most U.S. wastewater treatment facilities are built prior to the early 1990s, and, as such, they are not equipped with upconversion devices to convert solid pollutants into less harmful waste.
These industrial plants often operate with very small wastewater volumes that are simply too small to meet EPA guidelines. However, these facilities are usually located far from any residences, so it isn't until the pollutants from these plants have been distributed into local creeks and rivers that operators need to be concerned with pretreatment.
There is a very limited amount of research and development in water purification methods, and, due to the expense of such processes, most U.S. wastewater plants only have the capacity to pretreat 10% of their inputs. As a result, most plants only pretreat 50% of their inputs, and, as a result, there is still a lot of pollutants in their treated water.
U.S. wastewater treatment facilities often use reverse osmosis, and, as a result, they are also forced to rely on chlorination to combat the remaining pollutants. As a result, there are pollutants such as trihalomethanes, or THMs, in U.S. treated water. While the amount may not be harmful to humans, the EPA has stated that they cannot be ignored any longer!
Reverse osmosis is costly, energy intensive, and has a tendency to become a source of soil erosion. The other treatment options that U.S. plants have are more efficient, but not necessarily safer. Ion exchange, for instance, is cheaper and more effective. However, ion exchange can reduce the amount of calcium and magnesium in the water, which can be detrimental to plants. The addition of chlorine may be the most cost-effective approach to providing U.S. plants with a safer water system.
