Phosphorus Speciation Provides Direction to Produce 10 Ug/L

Abstract

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.

The Fate of Recalcitrant Nutrients Through an Anaerobic Digester and Anammox Sidestream Treatment Process

“…However, in order to mitigate the impacts of the return stream on a BNR process, additional treatment may be required to remove NRDP compounds. Various combinations of coagulation, filtration and absorption have been shown to successfully remove dissolved phosphorus in wastewater effluent (Neethling, 2007;Gu et al, 2009;Arnaldos & Pagilla, 2010). Further research is required to assess the suitability of this particular treatment approach for a sidestream flow that is composed of dewatering centrate and WAS thickener underflow.…”

“…However, during sludge digestion DON can be released into the treatment process through cell metabolism processes that excrete biomolecules, cell decay and cell lysis (ibid.). Non-reactive dissolved phosphorus (NRDP) is also difficult to remove with conventional treatment, requiring advanced treatment processes with multiple stages including filtration, coagulation and adsorption (Neethling et al, 2007). As with DON, NRDP can increase through biological production (Neethling & Stensel, 2013).…”

WEF/WERF Cooperative Study of BNR Plants Approaching the Limit of Technology: I. What Can We Learn About the Technologies?

“…For example, some plants may have greater amounts of refractory dissolved organic nitrogen (RDON) in their influent than others (Bratby et al, 2007, Pehlivanoglu-Mantas et al, 2008, meaning that the LOT for that plant will be higher than for plants with lower RDON levels. Similar issues arise relative to phosphorus speciation (Neethling et al, 2007, Scherrenberg et al, 2008. Also, these parameters can change with time, such as an increase in concentration because of public response to water conservation programs.…”

Effect of floated sludge recycling on phosphorus removal in dissolved air flotation

“…When considering tertiary treatment after the biological process in wastewater treatment plants, compact flotation is more favourable (Neethling et al, 2007) than sedimentation, which requires a large space. Flotation efficiency in removing phosphorus depends on j soluble orthophosphates being converted into solid flocs j bubbles attaching onto flocs to form bubble-floc agglomerates j phosphorus not being released during floated sludge handling.…”