ABSTRACT
Natural wetlands have been used to treat wastewater with varying efficiency. Wetland plants have evolved many structural and physiological adaptations for survival in water-dominated environments. This chapter discusses major categories of wetland vegetation and morphological and physiological adaptations to environmental gradients and examines the abilities of plants to affect their environment and transform wastewaters. Plants in wastewater systems have been viewed as storage compartments for nutrients where nutrient uptake is related to plant growth and production. Plants absorb nutrients and excrete or lose small amounts during the growing season but release a large percentage at senescence. Harvesting before senescence may permanently remove nutrients from the system. Alternatively, nutrients tied up in litter and, eventually, sediments represent semipermanent storage. Few generalizations can be made about mineral uptake by wetland plants. Emergent plants utilize their roots to obtain sufficient nutrients from the interstitial water. Free-floating species have roots with numerous root hairs and can successfully obtain nutrients from the water column.
