Professor Univ of Texas-Arlington Arlington, Texas
A current challenge for landfills is removal of heavy metals and recalcitrant organics from leachate. Even if leachate is sent to a municipal wastewater treatment plant (WWTP), metals and organics (natural organic matter, including humic and fulvic acids), and per- and poly-fluoroalkyl substances, or PFAS must first be removed; else, they can inhibit WWTP biological processes or accumulate in sludge, preventing its reuse as compost or fertilizer. Adsorbents have been demonstrated to effectively remove heavy metals and organics, using fewer chemicals and energy than many competing techniques (e.g., advanced oxidation processes). Adsorbents made from wastes like Rice Husk (RH), Rice Husk Ash (RHA), Sewage Sludge (SS), and Sewage Sludge Char (SSC) are more sustainable than traditional activated carbon (AC), which is made from coal, a non-renewable resource. Reusing waste materials reduces waste disposal costs and is typically cheaper. A single type of adsorbent, however, is not effective in removing the variety of heavy metals and organics present in leachate. The principal goal of this project is to develop a multiple sorbent mixture “MultiSorb” from readily available waste materials, to cost-effectively remove different type of pollutants from leachate . Sorbent leaching characterization using LEAF Method 1314 showed release of heavy metals and organics from RHA and SSC to be within drinking, irrigation, aquatic standards/guidelines nationally and internationally, except for slightly elevated arsenic levels from RHA. RH and SS, however, released several metals above standards/guidelines. Additional results will be available at the time of the conference.
