ABSTRACT
Hybrid treatment wetlands are a combination of the basic types of constructed wetlands that are being increasingly applied to particularly difficult wastewater treatment problems. Industrial and agricultural wastewater is often high strength or contains an array of contaminants not present in domestic wastewater. Tertiary treatment of domestic sewage is increasingly necessary due to emerging organic contaminants from pharmaceutical and personal care products pesticides and antiseptics. In addition to the indirect measures provided by the removal of biological oxygen demand and total suspended solids, wastewater treatment and stormwater discharge permits now often require discharge maximums for ammonium, nitrates, phosphorus, heavy metals and pathogenic bacteria into sensitive water bodies and recreation areas. Hybrid wetlands are designed to treat agricultural wastewaters and the effluent from a wide range of industries, landfill leachate and contaminated groundwater and river water. Treatment wetlands are increasingly designed as multistage facilities where more than one type of constructed wetland is employed to achieve tertiary effluent quality.
