This process will be discussed further during the stabilization process. The water then enters the greensand pressure filters utilizing the water pressure provided by the supply wells. The filters are constructed as horizontal cylinders with layers of filtering material. The top layer is anthracite. It filters out the precipitated insoluble iron produced by the injection of the potassium permanganate.
Manganese greensand is the middle layer.
This layer absorbs any residual potassium permanganate left over in the water. It also filters out and converts any iron still left in the water at this point. The final layers are multi-sized gravel to support the upper layers and provides filtering for any particles which may have passed through the upper layers. All of the water entering the plant passes through this iron removal process. Any scaling on the membrane surface would prevent the passage of the water through the membrane.