Overview and details of the sessions of this conference. Please select a date or location to show only sessions at that day or location. Please select a single session for detailed view (with abstracts and downloads if available).
Beat Ultra-Low Phosphorus and Metals Targets with Reactive Filtration: How Your WWTP Could Consistently Hit µg/L Targets
With phosphorus-fed algae blooms plaguing many North American bodies of water and the danger of metals rising in the public consciousness, regulators are putting pressure on wastewater treatment facilities to meet ever-lowering limits, down to mg/L. Acceptable phosphorus levels can vary significantly between regions, but states across the US are seeing limits <0.1 mg/L, with some between 0.01 and 0.07 mg/L. Meanwhile, the impact of metals has captured similar attention, leaving wastewater engineers searching for technologies that can hit µg/L metals targets. These limits seemed impossible even 10 years ago but are now able to be met cost effectively using reactive filtration, as evidenced by Citronelle, Alabama and Georgetown, Colorado.
The goal is always to provide the most reliable treatment system while minimizing capital and life-cycle costs of the technology. In this presentation, we will provide a broad overview of various other techniques proposed for phosphorus removal and will then introduce and explain reactive filtration and how it was chosen.
We will include data sets from other installations, but it’s at Citronelle and Georgetown where the impact of reactive filtration can be seen. In Citronelle, the installation consistently produces <20 μg/L P effluent since commissioning in 2015. At Georgetown, the system has reduced cadmium and lead levels down to 0.1 μg/L, copper averages 3.3 μg/L, and zinc averages 0.12 mg/L, well below the 0.2 mg/L target. We will break down what these numbers mean for Citronelle and Georgetown, and what reducing effluent phosphorus and metals levels μg/L could mean for North American ecosystems and other municipalities with impending ultra-low phosphorus and metals limits.
11:15am - 12:00pm
What Role Do Metals Play in Enhanced Biological Phosphorus Removal Process? Composition of Metal-Polyphosphate Complexes
Yueyun Tse1,2, Sheikh Mokhlesur Rahman2, Guangyu Li2, William Fowle2, Per Halkjær Nielsen3, April Gu2,4
1Black and Veatch, United States of America; 2Northeastern University, United States of America; 3Center for Microbial Communities,Department of Chemistry and Bioscience,Aalborg University, Aalborg, Denmark; 4Cornell University,United States of America;
Successful enhanced biological phosphorus removal (EBPR) systems rely on the function of polyphosphate (PolyP) accumulating organisms (PAOs), and the intracellular PolyP polymers play an essential role in EBPR activity. Monovalent and/or divalent metal elements (Mg2+, K+, Ca2+, Na+) serve as counterions in PolyP polymers, forming complexes with the negatively charged phosphate residues. In addition to serving as counterions, certain metals (e.g. Mg, K) also play roles in phosphate transport, PolyP synthesis/degradation metabolic pathways. However, the associations between PolyP-metal composition and EBPR performance/stability have been hardly studied.
In this study, we investigated the linkage between PolyP-metal composition and EBPR performance/stability using four lab-scale sequencing batch reactors (SBRs) operated under the same feeding conditions but different solids retention times (SRTs). We quantified the PolyP-metal compositions in intact individual PolyP granules using scanning electron microscopy combined with energy dispersive X-ray spectroscopy (SEM/EDX) method. The diverse and dynamic distributions of different metal ions in PolyP granules from different EBPR systems were revealed for the first time.
A significant and strong correlation (Pearson correlation, r= 0.92, p value=0.03) was found between the average Mg content (i.e. Mg/P molar ratio) of PolyP granules and P removal stability evaluated as the cumulative frequency of achieving effluent phosphate < 1 mg P/L. Furthermore, the PolyP-metal composition diversity was shown to be potentially linked with the phylogenetic diversity (i.e. using 16 S rRNA gene sequence) of PAOs. The results evidenced the critical role of metal ions, especially Mg2+ , in successful and stable EBPR performance, and suggested that PolyP-Mg content can possibly serve as one of the indicators for EBPR performance monitoring.