Development of the Nutrient Film Technique for Renovation of Wastewater for Nonpotable Reuse

摘要

The specific goals of the project were: to construct a Nutrient film technique (NFT) pilot plant, screen and select crop plants for use with an outdoor NFT in Florida, test the selected crops with both secondary effluent and raw wastewater, and to determine how to maximize the NFT's performance in terms of wastewater removals and crop production. Of the crops tested, only para grass (Brachiaria mutica) was suitable. Monitoring of the system removals revealed: (1) that grab sampling is an inadequate means of describing system performance; (2) that a gravel matrix was needed in the NFT channels; (3) that the crops were very sensitive in their responses to small daily weather changes; (4) that para grass uses ammonium-N better than nitrate-N; and (5) a possible need to acidify the wastewater. Neither secondary effluent nor raw wastewater was totally suitable for use with para grass; primary effluent is recommended.