Graywater Recycling Using a Biological Treatment System

The demand for and scarcity of clean water in some areas of the world has made water recycling an appealing solution. The reuse ofblackwater has been an unattractive venture in some municipalities; however, the reuse of graywater, which contains minimal contaminants, is a better solution. The main objective of this project was to determine whether a soil and plant system could be used to clean up household graywater containing laundry detergent as the main contaminant. Household gutters were set up so that the graywater would run through the soil containing grass, clover or ornamental peppers and be collected at the end of the gutter. Synthetic graywater was made using tap water and Tide Clean Breeze powder detergent which also contains some fluorescing compounds. Fluorescence spectroscopy and Chemical Oxygen Demand (COD) were used to analyze the removal of detergent from the waste water. The fluorescence levels in the graywater were a factor of three higher than the levels in the remediated water, indicating that some clean up had occurred. The COD qualitatively confirmed that lower levels of nutrients are present in those samples that were remediated through the biological system