AWWA ACE68824

This powerpoint presentation begins by presenting management options for residual solids, including the following: dispose of wet residuals (liquid and solid) to a wastewater treatment plant through a sewer connection; dewater wet residuals to reduce water content and dispose of solids in a landfill; and, increasing regulations regarding residual disposal. The growing trend in research for possible reuse and recycle options, especially in water and wastewater treatment residual solids (WTRS) is presented. WTRSs as a water treatment material includes: Alum Recovery; Wet residual solids - used as a coagulant, sewage treatment (Galarneau and Gehr, 1997), hydrophobic dye removal (Chu, 2001), and lead removal (Chu, 1999); dry residual solids - used as an adsorbent, phosphorus adsorption (Kim et al, 2003, Mortula et al, 2007), and suitable for wastewater treatment. Batch adsorption experiments are presented, along with partial analysis of dried WTRSs, Langmuir Isotherm Modelling, and practical implications. Presentation summary includes the following: ferric and lime residual solids appeared to be a stronger adsorbent than the alum residual solids for phosphate adsorption from spiked DI water and wastewater effluent; nearly 100% of phosphate was removed from wastewater during adsorption onto all residuals; competing species in wastewater (i.e., TOC) appeared to impact adsorption on lime and alum solids; competing species in wastewater did not appear to impact adsorption on ferric solids; similarities in arsenate and phosphate chemistry provide another application for the reuse of WTRSs; and, despite differences in Qmax, alum, ferric, and lime residuals adsorbed phosphate from DI water and MWW effluent, reaching > 90% removal, potential for application in wastewater industry, provided integrity is verified. Includes tables, figures.