This placement makes efficient use of space, provides dry and wet environments to encourage a range of treatment processes, and provides seating for visitors.
Water then moves down through the sand layer which contains fine brick material.
Iron, which gives brick its red color, attracts and stores phosphorus. The constructed wetland under the soil filter mimics either a high or low marsh depending on the water level, which is externally controlled. Since wastewater is rich in microbes, organic materials, and therefore odor, a charcoal layer near the surface of the soil filter is designed to prevent the movement of objectionable odors into the surrounding courtyard. A tipper bucket at the exit drain of cell 1 provides useful information about the flow rate through the cell. The marsh supports wetland plants whose roots are crowded with microbes .