Hydrolysis of triphosphate from detergents in a rural waste water system

The concentrations of detergent phosphates in raw sewage entering a small, predominantly domestic waste water treatment facility were determined using an ion chromatographic-flow injection analysis technique. Hourly loads of detergent phosphates were measured between 0600 and 2300 hrs (the major flow period in the plant) on days of both low and high phosphorus loads. The calculated loads of detergent phosphorus entering the plant on low and high load days were 260 g P/day and 350 g P/day, respectively. The half-life of detergent phosphates (triphosphate) in waste waters was measured to be 7.3 hours at 15 degrees C and 3.0 h at 20 degrees C. The major factor contributing to triphosphate degradation in waste water was shown to be biological in nature, with the most likely mechanism being enzymatic hydrolysis.