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Water Utility Lime Sludge Reuse – An Environmental Sorbent for Power Utilities
Citation:
Patterson, C., S. Dastgheib, H. Salih, AND M. Elovitz. Water Utility Lime Sludge Reuse – An Environmental Sorbent for Power Utilities. In Proceedings, AWWA WQTC, Indianapolis, IN, November 13 - 17, 2016. American Water Works Association, Denver, CO, (2016).
Impact/Purpose:
Huge amounts of lime sludge waste, generated from hundreds of water treatment utilities across the U.S., is currently disposed in landfills. This project evaluated a sustainable and economically-attractive approach to the use of lime sludge waste as a valuable resource for power generation utilities.
Description:
Lime sludge can be used as an environmental sorbent to remove sulfur dioxide (SO2) and acid gases, by the ultra-fine CaCO3 particles, and to sequester mercury and other heavy metals, by the Natural Organic Matter and residual activated carbon. The laboratory experimental set up included a simulated flue gas preparation unit, a lab-scale wet scrubber, and a mercury analyzer system. The influent mercury concentration was based on a range from 22 surveyed power plants. The reactivity of the lime sludge sample for acid neutralization was determined using a method similar to method ASTM C1318-95. Similar experiments were conducted using reagent calcium carbonate and calcium sulfate to obtain baseline data for comparing with the lime sludge test results. The project also evaluated the techno-economic feasibility and sustainable benefits of reusing lime softening sludge. If implemented on a large scale, this transformative approach for recycling waste materials from water treatment utilities at power generation utilities for environmental cleanup can save both water and power utilities millions of dollars.