PHOSPHORUS SPECIATION PROVIDES DIRECTION TO PRODUCE 10 UG/L

Analytical methods are posing a significant technical challenge to meet low phosphorus limits. Research and testing showed that understanding the chemical species becomes a key to interpreting and improving technologies for phosphorus removal to very low limits. Phosphorus appears in wastewater in many forms such as orthophosphate, condensed phosphates, organic phosphorus, chemical phosphorus, and others. The phosphorus species change in wastewater treatment due to chemical and biological actions. Phosphorus species can be differentiated in terms of soluble and particulate forms as well as their reactivity under acid and heat. Phosphorus speciation was conducted to better understand the removal mechanisms and opportunities for process optimization.Reactive phosphorus measurements will delineate not only soluble orthophosphate but other reactive phosphorus species such as chemically precipitated phosphorus. This complicates the interpretation of analytical data. Separating the results into soluble and particulate fractions provide a simple and effective method to interpret results.Pilot studies have demonstrated that the removal efficiency of various phosphorus species is different for various treatment technologies. Characterization of phosphorus species including soluble and particulate phosphorus with different separation filter sizes, reactive and non-reactive species, provides insight into the treatment technology effectiveness and the application to achieve very low phosphorus concentrations. However, at this time it appears that practical removal of phosphorus to 10ug/L is beyond the ability of current technology.