Water treatment residual (WTR), a waste sludge that is generated during the drinking water purification process, has shown promises to be used as a remediation technique for a variety of soil and water contaminants. Our previous studies showed that WTR collected from a local drinking water treatment plant, has a high affinity for a variety of environmental contaminants, including arsenic, total phosphorus (TP), and lead (Pb). The long term goal of our research group is to reuse WTR as a chemical amendment to i) remove TP from the point source discharge to decrease the eutrophication potential of local streams, rivers, and lake and ii) immobilize soil-Pb in the residential properties of Rochester city neighborhoods. Our data so far established the need of sustainable remediation processes to solve these problems: TP levels were found to be surpassing the advisory limit (20 µg/L) all streams/rivers/lake in the area; moreover, local Sewage Treatment Plants (STPs) contribute significantly (p&lt;0.001) to increase the trophic profile of the streams, in which they discharge their effluent. Currently we are designing a constructed wetland using native plants and WTR as this combined process effectively (&gt;90%) removed TP from the STP effluents and did not disorb any within the study period. Similarly, immobilizing soil-lead in the residential properties of the Rochester city neighborhoods is an utmost priority as more than 95% of homes were built prior to the ban of lead-based paint in 1978, meaning that current residents may be at risk. Indeed, we have found strikingly high levels of lead in a residential property, as high as 5000 mg/kg in bulk soil and up to 50,000 mg/kg in soils with buried paint chips. WTR’s effectiveness in immobilizing lead is evident from our initial sorption/desorption experiment, where &gt;90% lead was absorbed by 5% WTR upto 1000 mg/L initial Pb concentration and almost no lead was released in three sequential desorption cycles. Ongoing experiments aim to determine the physicochemical characteristics of WTR to understand the mechanism of its affinity towards TP and Pb. Additionally, environmental safety of WTR is being assessed using the Toxicity Characteristic Leaching Procedure (TCLP) and Synthetic Precipitation Leaching Procedure (SPLP). The results of these studies will determine whether WTR indeed represents a safe, cost-effective, and sustainable remediation strategy for the removal of environmental contaminants.

Potential of reusing WTR, A water treatment by-product, to design sustainable remediation techniques for Rochester, NY communities

2019 Spring National Meeting

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