Wastewater Treatment with Plants in Nutrient Films

摘要

The nutrient film technique (NFT) is a unique modification of a hydroponic plant growth system which utilizes plants growing on an impermeable surface. A thin film of water flowing through the extensive root system provides nutrients for plants and associated microbial growth. Root masses up to 15 cm thick or more have been obtained. This self-generating plant system could be used as a filter to immobilize and use the gross and trace organics in wastewater. The goal of this study was to determine the economic, technical, and practical feasibility of using plants grown in the NFT system as pollution control systems. NFT systems appear capable of providing secondary quality treatment with some nutrient removal on a relatively small area compared to overland flow systems. At loading rates of 10 cm per day the effluent quality with primary settled sewage was often less than 10 mg/l for suspended solids and biochemical oxygen demand. Estimated area needs of an NFT system designed for BOD and SS removal appear to be approximately 3 hectares for a community of 10,000 people.